The Awassi is the most numerous and
widespread type of sheep in southwest Asia. It is the dominant breed in Iraq,
the most important sheep in the Syrian Arab Republic, and the only indigenous
breed of sheep in Lebanon, Jordan and Israel. In the north of Saudi Arabia it
is bred under desert conditions (Pritchard, Pennell
& Williams, 1975). The Awassi is not mentioned by Spöttel (1938, 1939) among the breeds of
Anatolian sheep, but Past (1965) writes that the Awassi makes up 1 percent of
the ovine population of Turkey, and Mason (1967), following Yarkin
(1959) and Düzgüneş
(1963), gives a similar figure (0.9 percent). There is a small increase in
their number from year to year, so that in 1976 the Awassi accounted for 1.8
percent of the total number of sheep in Turkey (Yalçin, 1979). The breeding area in
southern Anatolia is situated in a border strip, Antakya
(Hatay) and south of the Gaziantep
and Urfa vilayets along the
main range of the breed in Syria. In Iraq the true Awassi is found north of the
Al-Amarah liwa (administrative
district) and in the centre of the country from Al-Kūt and
the lower Tigris marshes, up between the rivers through Al-Hayy,
Ad-Daghgharah, As- Samāwah,
Al-Hillah and Al-Jazirah,
west of the Tigris to the region of Mosul. The breed
is also widespread east of the Tigris, north of the lower Diyālá
and Baghdad, in the pastoral region stretching intermittently into the Mosul and Arbīl liwas and that
lying between the middle Diyālá and extending north to
the Little Zab (Williamson, 1949).
The name of the
Awassi is attributed to the El-Awas tribe between the
Tigris and Euphrates rivers. In literary Arabic, awas
is the term for red and white camel garb or for a white sheep (Hirsch,
1933). In the Islamic Republic of Iran it has been referred to as Ahvāz (or Ahwāz), a town in
Khuzestan, Iran, near the border with Iraq (Hinrichsen
& Lukanc, 1978). The name of the sheep is also
sometimes spelled Aouasse, Awasi,
El Awas, Iwessi, Oussi or Ussy. In Turkey the
breed is called İvesi or Arab and in some parts of
Syria Nu'amieh (also spelled Na'ami,
Naimi, Nami, Neahami, N'eimi, or Nuamiyat) or Shami, the latter
being the Arabic name for Damascus.
In addition to the
typical Awassi, several nearly allied varieties exist (Mason, 1967). In Syria,
the Deiri variety (from Deir
ez Zor) in the east has
been distinguished by Schuler (1936) from the Baladi
of the west, which is the typical Awassi, the term baladi
meaning 'local'. Among Awassi flocks in the semi-desert and maritime plain
of Syria, Mukhamed (1973) recognized three different
types of sheep, namely, Shagra (Chacra,
Chagra, Chakra) with a
reddish-brown face, Absa with a black face and Porsha with a grey face, associating these colour markings with different physiological and anatomical
properties. But the name Shagra has also been applied
to other breeds such as Red Karaman and Parasi (Mason, 1967).
In Iraq, the Gezirieh
(Jazirieh) or Gezrawieh
variety from the region between the Tigris and Euphrates has been reported as
being superior to the ordinary Awassi in mutton production, but inferior in
milk yield. Two other Awassi varieties in Iraq are called N'eimi
and Shafali, respectively. The N'eimi,
which is bred in particular by the Jabal Shammar to the north of the area of the Dulaim
(or Delaim) tribe in northwest Iraq, is a more
compact sheep than the ordinary Awassi, with shorter and more muscular limbs, a
finer and denser fleece and a higher milk yield. The face is generally black
but may also be reddish, and this colour sometimes
extends to the fleece. The N'eimi variety is named
after a tribe. The name does not refer, as has been suggested, to its being
superior.
In the region of
Al-Hayy and Al-Kūt in
south-central Iraq, Awassi sheep are kept on irrigation farms, to which the
name 'Shafali' (meaning a low-lying plain) refers.
This is rendered in English as Shevali, Shaffal or Ashfal, and into
French as Chevali, Chaffal
or Choufalié.
The Shafali is distinguished by the high carriage of
the head, a reddish-brown fleece with nearly black head and legs, and early
maturity. Since the Shafali is also bred by the Dulaim tribe in northern Iraq, it is also known as Delimi, Dilem, Dillène or Douleimi. In Syria, Shafali sheep
are found along the Euphrates, between Meyadin and
Abu-Kemal on the Iraqi frontier. Apparently the name
is applied to several types of sheep (Mason, 1967, 1974).
A somewhat more
remotely related variety of the Awassi is kept in Iraqi Kurdistan, southwest of
Mosul, by the Herki or Hargi tribe of Kurds. It is called Herki
(Harrick, Herrik, Hirrick, Hurluck), Mosuli (Mossul, Moussouli) or Dazdawi and is
distinguished from the true Awassi sheep of the same region by its larger size,
longer caudal appendix, rudimentary horns, the frequent presence of a topknot
and of brown spots on the fleece. The Herrik or Hirik of Turkish Kurdistan is of a similar type but has
shorter ears and no horns. Because of its resemblance to the Awassi of Israel,
the Herrik was chosen to overcome a shortage of
Awassi sheep in Israel during the years 1953-57 when 17 shipments totalling 14 632 Herrik ewes were
imported from the vicinity of Cizre on the Tigris in
Turkish Kurdistan near the borders of Syria and Iraq. While resembling the
Awassi sheep of Israel in general conformation and the shape of the fat tail,
the imported sheep were smaller than the improved type of Awassi, the live
weight of adult ewes varying between 40 and 45 kg, and their fleece being
somewhat heavier than that of the Awassi. The body and legs were white, while
the head was usually grey, occasionally brown or white. The milk yield,
including the milk sucked by the lamb, was only 100-120 kg per lactation and
the twinning percentage 5-6. No male Herrik sheep
were imported and the ewes were bred to improved Awassi rams so that their
descendants were absorbed by the Awassi flocks (Epstein & Herz, 1964).
The Cyprus
fat-tailed sheep (see appendix Figs A-l and A-2) present a special problem with
regard to their relation to the Awassi group. They are undoubtedly allied to
the Awassi of the mainland, which they resemble in many physical and
physiological respects. Maule (1937) writes that the 'Palestinian breed… is probably the one nearly akin to
the Cyprus sheep', while Mason (1967), grouping the Cyprus with the Awassi,
notes that the Cyprus breed 'is similar to the breeds of the neighbouring mainland and resembles the Awassi of Syria
more than the White Karaman of Turkey'. Yet there are
also significant differences between the two breeds, which may be due to the
long isolation of the Cyprus sheep on their island or the influence of Turkish
sheep. Thus, unlike the head of the Awassi with its typical brown coloration,
that of the Cyprus sheep is commonly white with black on the nose and around
the eyes, more rarely white, black, brown or mottled. The greatest difference
is the size, weight and shape of the fat tail. In the Cyprus the tail is much
longer, broader and heavier than in the Awassi, its twisted end often reaching
to the ground. It is widest in the middle third and then tapers gradually to
the tip, making a half-turn to the right or left at the junction of the middle
and lower thirds (Mason, 1967). Mason (personal communication, 1979) also notes
that 'it would be confusing to include the Cyprus as a variety of the Awassi
since the name Awassi has never been used for them'.
In physical and functional
properties, the Awassi seems to be very close to the prototype from which the
fat-tailed sheep of Asia, Africa and Europe are derived. Many of these still
show a close likeness to the Awassi. This holds true not only for the sheep of
Cyprus and North Africa and several Turkish and Iranian breeds, but animals
similar to the Awassi are also encountered among the Ronderib
Afrikander sheep of South Africa and the Mongolian
sheep of east Asia (Epstein, 1969,1970,1971). Fat-tailed breeds deviating from
the Awassi in some physical or functional properties may owe their
peculiarities either to evolution in a different environment, specialized
breeding aims or to crossbreeding.
Fat-tailed sheep have been bred in
the breeding area of the Awassi for at least 5 000 years. A fat-tailed ram
below a thoracic-humped zebu is represented in a floor mosaic of the synagogue
of Beyt Alfa, Israel (Fig. 1-1). A similar motif is
depicted in a wall panel in the synagogue of Dura Europus (El-Salihiyeh) on the
Euphrates, 48 km upstream of ancient Mari, which was built in the middle of the
third century AD. In Assyria, fat-tailed sheep were bred at the time of Tiglath Pileser III (Fig. 1-2).
They seem to have differed from the recent Awassi sheep of Iraq mainly in their
concave facial profile and the lesser development of the fat tail. In Sumer a woolless ram with a
clearly marked fat tail is depicted on the mosaic standard of Ur, dated c.2400 BC (Fig. 1-3). The earliest
representation of a fat-tailed sheep with an upturned tail tip is found on a
fragment of a stone bowl from the Uruk III period of
Ur (Fig. 1-4), indicating that the fat-tailed type is a very ancient product of
domestication in this area.
Figure
1-2. Assyrian fat-tailed
sheep from the time of Tiglath Pileser
III (745-727 BC)
Figure 1-3. Fat-tailed ram on mosaic standard from Ur
(c. 2400 BC). (Source: The
British Museum)
Figure 1-4. Fat-tailed sheep on a stone bowl from the Uruk
III period of Ur (c. 3000 BC). (Source: The
Metropolitan Museum of Art)
In the quest for
the cradleland of the fat-tailed sheep, the peculiar
character of the tail permits certain conclusions as the fat deposits on the
tail represent an accumulation of reserve material similar to the humps of
camels. Such deposits evolved under steppe and desert conditions which are
noted for long periods of drought and feed scarcity. The fat tail points,
therefore, to a steppe country as the place of evolution of these sheep.
The development of
store reserves on which the animal draws during periods of nutritional scarcity
can be explained by the mechanism of directed selection. This implies that fat
deposits on the tails of sheep may sporadically occur among any breed, but that
it is only in steppe and desert countries and among peoples lacking other
fat-producing animals that this feature is of such economic importance that
sheep with adipose deposits on the tail have been specially selected for
breeding purposes.
The belief in the
advantage of the fat tail to sheep in a semi-arid environment is, perhaps,
fictitious and not founded on a factual usefulness, for the fat tail appears to
constitute a concentration of reserve material which is not additional to the
normal accumulation of fat in the body, but is merely away from the body. This
assumption is based on an experiment in which the development and body
composition of docked Awassi lambs were compared with those of an undocked
control group (see also Table 5-13) (Epstein, 1961). In the docked lambs nearly
all the fat that would normally have been stored in the tail was distributed
over the body in the form of fat and muscle tissue. In other words, the body of
the fat-tailed lambs was leaner by nearly the whole amount of their tail fat than
the body of the docked lambs. Nel, Mostert and Steyn (I960), working
with Karakul sheep, arrived at a similar conclusion: 'Once the tail has been
removed the animal is capable of storing in other parts of the body the fat
which is usually deposited in the tail.'
It is uncertain if
the relatively lean body of fat-tailed sheep is advantageous to their heat
economy in a subtropical environment. Sir John Hammond (quoted by Mason, 1963)
argued that a store of fat was useful as a reserve of food and metabolic water
and a means of avoiding the insulating layer of subcutaneous fat, and gave
fat-tailed sheep as an example. Wright (1954) conceded that the localization of
a large fat reserve may incidentally give some small advantage to animals in
hot climates since in consequence they do not need a generalized subcutaneous
layer to prevent the dissipation of body heat. Mason (1963), however, denied
this on the grounds that cases of local fat deposits are an exception and not
the rule in wild desert animals. The absence of a thick layer of subcutaneous
fat could only be effective in the comparatively narrow range when the air
temperature is below body temperature but high enough for the animal to feel
uncomfortable, that is, about 27-38°C. Since the blood supply passes through
the subcutaneous fat, this channel of heat loss would not be affected, nor
would sweating or pulmonary evaporation, nor, it may be added, the conduction
of body heat to drinking water and its elimination with the urine, which are
the most important mechanisms of heat loss in sheep. Indeed, in a trial with five 15-month-old docked rams and five undocked control
sheep of the fat-tailed Ausimi and Rahmani breeds of Egypt, Hafez, Badreldin
and Sharafeldin (1956) found that docked sheep
exhibited greater efficiency in heat regulation than fat-tailed sheep. The
docked rams had a significantly lower respiration rate and lower skin
temperature, a phenomenon particularly pronounced during the hottest months of
the year as well as at the hottest time of the day. From May to October the
mean respiration rate of the docked rams was in every month lower than that of
the undocked animals, with a mean of 44.7 in the docked rams versus 46.4 in the
undocked rams for the whole period. At the same time, the average skin
temperature in all body regions studied was 35.9°C in the docked rams and
36.3°C in the fat-tailed control group. The authors suggest that the more
efficient heat regulation of the rams without fat tails may be due to the
better air circulation around their hindquarters since the middle and upper
regions of the fat tail, which are in contact with the hindquarters, have a
high skin temperature.
The concept of the
fat tail as a store of metabolic water has been virtually abandoned. The
oxidation of fat would lose more water in the pulmonary evaporation necessary
to supply oxygen than would be gained by combustion.
The fact that
localized fat reserves are not commonly found in domestic animals other than
those that normally inhabit desert and semi-desert areas suggests that the fat
reserves are primarily associated with the provision of stored energy. Even
though the animal may not actually gain from the accumulation of fat in its
tail and the breeder's belief in his own gain be
fallacious, the concentration of fat in a lump instead of its intermuscular and subcutaneous distribution throughout the
body may be an attraction to breeders under certain environmental and economic
conditions. Whatever the value of the fat tail, real or assumed, the very fact
that it has been regarded as desirable explains its evolution under
domestication.
Among ordinary sheep the sporadic
occurrence of both fat-tailed and fat-rumped sheep
has been recorded.
In the White-faced Woodland sheep of the United Kingdom 'the tail is inclined
to be fatty' (CBABG News-Letter, 1969), and Ryder (personal
communication, 1969) has 'seen reports that the Scottish Blackface has a
tendency towards a fat tail'. The Cotswold and Romney Marsh breeds, as Lydekker (1912) points out, 'exhibit a marked tendency to
accumulate fat on the rump almost to the degree of producing a deformity'; and
further: 'In confirmation of the view that the accumulation of fat in the
caudal region is merely a result of domestication, it may be recalled that two
of the ordinary British breeds display a tendency to this feature.' Ewart (1913-14) was even more explicit on this point when
he wrote that in 'some Border-Leicester and Cotswold rams there is a
considerable amount of fat at the root of the tail or in the buttocks' and further,
that 'in many lambs fat tends to accumulate in the root of the tail, while in
not a few breeds, when food is abundant, fat accumulates to the extent of
several inches over the rump. In this tendency to store fat, improved breeds
... approach the fat-tailed and fat-rumped breeds of
Central Asia'. Again, 'in lambs of improved modern breeds, the tip of the long
tail is sometimes turned upwards'.
Adametz (1927) has drawn attention to the tendency to fat
tail formation observable in Merino, Rambouillet, Tsigai
and Zackel sheep. New-born lambs of these breeds have
moderate, but clearly discernible, lateral skin folds at the tail root, which
correspond qualitatively to the marked development of folds (which subsequently
fill up with fat) on both sides of the upper section of the tail displayed by
the lambs of fat-tailed breeds. Since there exists no
economic necessity in any of the countries where these breeds occur to produce
a fat-tailed type of sheep, such animals are not selected for breeding
purposes. On the contrary, in mutton breeds of the United Kingdom they are
culled, as the fat deposits on the rump and tail are considered to be
undesirable. But there can be little doubt that fat-tailed breeds could still
be evolved from among ordinary sheep, were this desirable.
While the
fat-tailed type could have been evolved in any climatic and floral environment
where sheep can exist, it may be assumed that it was actually evolved in a
steppe and desert region by a people who lacked the fat-producing pig for sacral
or other reasons. The fat tail, then, may have been acquired long after the
domestication of the thin-tailed parent stock, in a region far distant from the
original home of the latter. Antonius (1922)
suggested that the fat-tailed type was evolved in the steppes of Syria and
Arabia where climatic conditions favoured the
development of fat reserves. In support of this he pointed out that no records
indicated the evolution of the fat-tailed variety in any other than those
regions.
In view of the occurrence in
central Arabia of several rock engravings of fat-tailed sheep with spears
pointing to their bodies (Fig. 1-5), Anati (1968)
claims that this environment 'may well have stimulated the development of the
fat-tail without necessarily implying domestication'. He further claims that
the fat-tailed type of sheep 'became domesticated in Arabia at a time when its
physical characteristics, including the enormous fat-tail, were already
formed', and that 'a general date in the second millennium BC may be suggested for
the domestication of this animal in Arabia. Thereafter, a few depictions
continue to show this animal wounded by the hunter's spears, and it is possible
that wild specimens continued to exist side by side with those bred in
captivity'.
Figure 1-5. Fat-tailed sheep.
Rock engravings from central Arabia, second or early first
millennium BC. (Source: Anati, 1968)
This theory is
unacceptable. Domesticated fat-tailed sheep were bred in Mesopotamia at least
one millennium (and probably much more) before the date suggested by Anati for their domestication in Arabia. Further, none of
the various races of wild sheep that have survived, including some living in
deserts or semi- deserts, has developed a fat tail. Indeed, none of them has
even a thin tail as long as that of the fat-tailed sheep depicted in the early
rock art of Arabia. Again, it is unlikely that in a country like Arabia,
teeming with wolves and jackals and other beasts of prey, wild sheep with the
enormous fat tails attributed to them could have outrun their pursuers. Such
heavy fat tails severely impede locomotion and can only be developed in sheep
protected by man.
While Antonius' suggestion regarding the possible evolution of
the fat-tailed type of sheep of the Syrian steppe may be correct, the evidence
available is insufficient to prove it. From the viewpoint of environment, the
fat tail could also have been evolved in another steppe region of western or
central Asia, as were the fat rump in sheep and the hump in zebu cattle.
Accordingly, Adametz (1927) suggested Mesopotamia,
Armenia and Iran in addition to Syria as possible areas of evolution of the
fat-tailed type. On the other hand, the fact that the Syrian steppe has since
prehistoric times been the habitat of Semitic peoples, most of whom did not
possess pigs, and that fat-tailed sheep could thence be readily diffused as far
as China in the east and the Cape of Good Hope in the south, and further, that
the fat-tailed sheep was known in ancient Mesopotamia but not in the Indus
valley, favour Antonius'
view.
The parent stock
of the fat-tailed sheep has doubtless to be sought among the
long-and-thin-tailed domesticated breeds of Asia. Although Duerst
(1908) believed that the fat tail in sheep was developed at Anau
after the climate of Turkestan changed and became
more arid, sufficient grounds do not exist for this assumption. The fat-tailed
type, like every other basic type of sheep, is the product of its total
history. This includes descent from a particular wild race, and may include the
outcrossing of domesticated stock to another or several other related wild
races; the interbreeding of various domesticated types evolved from the
originally domesticated stock in different environments; and artificial and
natural selection under different circumstances. It is probable that the
long-and-thin-tailed parent stock of the fat-tailed sheep was ultimately
derived from one of the local races of wild sheep in western Asia.
Sheep breeding is an ancient occupation in Palestine and its neighbouring countries where it has been practised for thousands of years. As early as 1500 BC, Nuzi documents mention Canaanite wool (Breasted, 1935) (see
also Chap. 6) and the early books of the Bible continually refer to sheep
breeding in Palestine and Mesopotamia. Sheep were bred by peasants and nomads
alike. The system of shepherding, as established in early times (probably soon
after the domestication of sheep) remained in vogue in southwest Asia virtually
unchanged until the early 1920s. Indeed, in many parts of southwest Asia, which
include the lands of the bedouin tribes of Israel, it
has remained unchanged to this day. The flocks are usually composed of sheep
and goats. In Israel those of the bedouin commonly
include more sheep than goats, and the flocks of the Arab villagers contain
more goats.
The indigenous
breed of sheep in Palestine is the fat-tailed Awassi. Its recent history in
this country began in 1884/85 when two young agricultural workers — immigrants
from tsarist Russia — bought a flock of Awassi sheep and local goats from bedouin and, dressed in the manner of bedouin
shepherds, pastured them in the fields of Rishon le
Zion and the swamps of Nabi Rubin and learned to milk
them. One night their flock was carried off by marauders and, while they
succeeded in recovering it, they could not overcome the severe losses caused by
disease and parasites. In despair they left the country, one for Australia and
the other for lands beyond the Atlantic.
It took a quarter
of a century for this sporadic attempt at sheep breeding in Palestine to be
repeated by Jewish immigrants. In 1908 a villager at Yavneel,
southwest of Lake Tiberias, acquired a flock of
Awassi sheep from bedouin of the Daleiqa
tribe and kept it in partnership with one of his bedouin
neighbours. Following his example, other farmers at Yavneel also purchased sheep and goats, leaving them either
in the care of hired bedouin shepherds or in
partnership with them. In a few years the number of Awassi sheep and Syrian
mountain goats at Yavneel rose to a thousand head.
The animals were kept in the open day and night, summer and winter, and
received no feed other than grazing. In these conditions mortality from disease
and parasites was very high and many animals were stolen or killed by jackals.
Sheep breeding at Yavneel was therefore given up
after a few years.
In 1910 a flock of Awassi sheep was
established at Ben Shemen. In 1912 the manager of the communal
farming village of Merhavia bought a flock of Awassi
sheep from bedouin. However, this was soon abandoned.
A more lasting effort was made in 1914 when several members of the Jewish
Guards' (Shomer) organization in Galilee in northern
Palestine attached themselves to the Turkeman tribe
of bedouin in the northern part of the Plain of
Sharon in order to learn the art of shepherding. After a year of nomadic life
with the tribal flocks, they returned to Galilee to work as shepherds in the
villages of Kinneret and Beyt
Gan. About the same time an organization called The
Shepherd was founded for the purpose of establishing flocks of Awassi sheep in
Jewish settlements (Mizpa, Sharona,
Hamara and Sheikh Abriq).
In 1915 an Awassi
flock was purchased for the Miqve Israel School of
Agriculture (Fái,
1979). In 1920 a shepherds' settlement was set up at Sharona
in eastern Galilee with a flock of Awassi sheep acquired from Arab breeders in
Palestine. In 1922 the Sharona flock was transferred
to Kefar Gil'adi in upper
Galilee. Stud rams for this flock were purchased in Transjordan
and the Jaulan (Jebel ed Druz). In 1923 an Awassi flock,
obtained from bedouin, was established at 'Eyn Harod and in 1924 another
flock of Awassi sheep at Tel Yosef under the care of
shepherds who had learned to work with sheep from the Sakher
tribe of bedouin near Beyt Shean. In Aiyelet Hashahar sheep farming was taken up in 1927 and in the same
year in Beyt Alfa. Until 1931 these four flocks were
the only ones kept at communal settlements (kibbutzim).
During the last
years preceding the First World War and the first years following it, Awassi
sheep were also introduced in several Jewish villages. In addition to Yavneel, they were brought to Kefar
Tavor, Ssejera (Ilaniya), Beyt Gan, Menahemiya, Kinneret, Matspeh, Rosh Pinna, Metulla, Yesud Hama'ala, Mishmar Hayarden, Zikron Ya'aqov, Hadera and 'Atlit. In 1927 these
village flocks numbered 1 500 animals and in 1931 over 2 100. The sheep were
kept mainly for their manure which was needed for orange groves and vineyards.
The majority of them were cared for by Arab shepherds. The sheep were kept in
the open during summer and winter, day and night, without any feed other than
pasture. Losses from exposure, disease, parasites, beasts of prey, and theft
were heavy. This level of feeding and maintenance and the absence of an
economic breeding aim rendered sheep farming in the Jewish villages unremunerative, with the result that most flocks were
disbanded.
The flocks of the
communal settlements, being maintained at a level of feeding, breeding and
management similar to the customary system among Arab villagers and bedouin, were at the beginning not in a condition much
better than the flocks of the Jewish villagers. Indeed, in some instances Arab
shepherds were training their Jewish colleagues in the ancient ways of shepherding.
However, the poor economic results did not cause the settlements to give up
their flocks, but induced them to improve their methods of sheep farming. Thus,
at the first annual meeting of sheep breeders at 'Eyn
Harod in 1924, the discussion centred
on the importance of sheep breeding to the economy of the communal settlements
and the necessity of improving Awassi flocks. In 1927 an article published in
the agricultural journal Hassadeh advised
sheep breeders to study the modern methods of other countries. At the second
meeting of sheep breeders, convened in Beyt Alfa, the
importance of increasing milk yields by means of selective breeding was
stressed. These events foreshadowed the beginning of development of the Awassi
breed of sheep in compliance with modern economic requirements.
The establishment of the Sheep
Breeders' Association at the annual meeting of breeders at Tel Yosef in 1929 marked an important step forward in the
improvement of Awassi sheep. At the association's annual assembly at Kefar Gil'adi in 1932, the
breeding aim of developing the Awassi into a milk-and-mutton breed was
formulated and a plan for uniform milk recording and bookkeeping adopted. In
1937 the annual assembly at Kefar Hahoresh
rejected a proposal to introduce the crossbreeding of Awassi with imported milch sheep in order to raise production more speedily than
by selection alone. At the same time the breeding aim was modified by
concentration on'… the increase of milk production, along with taking pains to
preserve the robust and healthy constitution of the Awassi breed of sheep'. A
detailed working plan was adopted, including fortnightly milk control by weight
instead of measure, standardization of lactation records by including an
estimated quantity of milk consumed by the lamb, and introduction of a common
card system for the keeping of records. In 1940 the Sheep Breeders' Association
began to publish the journal Hanoked ('the
sheep breeder'). Progeny testing of rams was introduced in the stud flock of 'Eyn Harod in 1941, and in 1943
the Flock Book of the Improved Awassi was opened for the registration of flocks
and individual ewes with minimum lactation records (see also Chap. 7). The
first exhibition of Awassi sheep took place at Kefar Yeladim in 1944. In 1950 the flock book administration
introduced ram certificates for every stud and flock ram, with particulars on
pedigree, breeding and score, and in 1951 the publication of annual flock files
began, providing information on the performance and breeding standards of all
registered flocks (Finci, 1957).
These steps and
events led to the speedy extension of sheep breeding to communal settlements.
In 1931 two additional flocks (in Merhavia and Mishmar Ha'emeq), and in 1932
another three (in Mizra, Sarid
and Ginegar), were established. This brought the
number of Awassi sheep in Jewish settlements to 4 000 in 1931 and 4 500 in
1932. But these numbers represented only a small fraction of the total Awassi
population of Palestine, which at that time counted approximately 250 000 head.
In addition, import figures recorded at quarantine stations showed that in
1931,152 000 slaughter sheep reached Palestine from neighbouring
countries. Actually the number of imported animals was considerably higher,
since many flocks were driven into Palestine passing the borders without any
veterinary observation (Hirsch, 1933). The sheep imported from Syria and Transjordan were all of the Awassi breed; only a relatively
small number of Najd sheep were trekked to Palestine
each year from Arabia.
During the period
1933-38, an average of six new Awassi flocks were
established in Jewish settlements annually. In 1939 a further 18 flocks were
added to the previous ones in communal settlements.
The establishment
of the State of Israel in 1948 gave a great impetus to the breeding of Awassi
sheep, so that by 1955, a quarter of a century after the formation of the Sheep
Breeders' Association, the number of Awassi flocks in communal settlements,
cooperative villages and on private farms had increased to 400 (Becker, 1958).
In cooperative villages and on
private farms the size of flocks has not undergone major changes during the
last four decades. But in the flocks of the communal settlements the average
number of breeding ewes and rams has increased continuously. In 1937/38 it
amounted to 89, in 1949/50 to 194, in 1959/60 to 440, and in 1969/70 to 723 (Fái,
1972).
Conformation. The unimproved Awassi is a robust and vigorous, medium-sized sheep of
milk and mutton type. The improved Awassi of Israel is larger and more refined
than the unimproved type and the characteristics of the respiratory type of milch sheep are more pronounced than are the mutton
features (Fig. 1-6). The bodily proportions are affected by the size and weight
of the fat tail which gives the impression of a want of balance between hind-
and forequarters. In ewes this impression is enhanced by the large udder (see
Fig. 1-7).
Size.
The height at withers of İvesi ewes in Turkey ranges
from 65 to 70 cm (Yalçin, 1979). Sönmez
(1955) and Yarkin, Sönmez
and Özcan
(1963) recorded the measurements of İvesi rams and
ewes of different ages given in Table 1-1.
The body measurements of Awassi ewes in Iraq
are higher. Eliya and Juma
(1970a) recorded a heart girth of 81.8 cm in 157 yearling ewes and 92.5 cm in
adult females, while Kazzal (1973) gives 86.3 cm for
yearlings at the Hammām Al'Alil
Agricultural Experiment Station. Further measurements of Iraqi Awassi rams and ewes
of different ages have been taken by Eliya (1969) and
Juma and Eliya (1973) (see
Table 1-2).
For unimproved Awassi sheep in Palestine, Hirsch (1933) has set down
the average measurements given in Table 1-3.
TABLE
1-1. Body
measurements of İvesi sheep in Turkey (cm) | |||||||
|
|
Age (years): |
1 |
2 |
3 or more |
|||
|
Sex: |
♂ |
♀ |
♂ |
♀ |
♂ |
♀ |
|
|
Height at withers |
|
59.5 |
57.7 |
— |
62.9 |
68.3 |
65.0 |
|
Length of body |
|
60.0 |
58.0 |
— |
59.7 |
62.1 |
61.8 |
|
Heart girth |
|
86.0 |
78.3 |
— |
82.5 |
93.0 |
86.5 |
TABLE 1 -2. Average body measurements of Awassi
sheep in Iraq at different ages (cm) | ||||||||||
|
Age (years) |
Number |
Height at withers |
Length
of body |
Depth of chest |
Heart girth |
|||||
|
♂ |
♀ |
♂ |
♀ |
♂ |
♀ |
♂ |
♀ |
♂ |
♀ |
|
|
1 |
105 |
109 |
69.3 |
66.8 |
59.5 |
52.9 |
32.3 |
30.3 |
93.3 |
83.6 |
|
2 |
11 |
62 |
74.8 |
69.2 |
63.9 |
55.8 |
36.9 |
32.8 |
110.3 |
90.4 |
|
3 |
3 |
87 |
80.4 |
70.1 |
70.3 |
57.1 |
39.3 |
33.5 |
115.8 |
93.0 |
|
4 |
— |
113 |
— |
69.3 |
— |
58.3 |
— |
33.7 |
— |
93.5 |
|
5 |
— |
67 |
— |
69.6 |
— |
58.2 |
— |
34.4 |
— |
95.2 |
|
6 and above |
— |
65 |
— |
70.5 |
— |
58.0 |
— |
34.5 |
— |
94.3 |
TABLE 1 -3. Average body measurements of unimproved
Awassi sheep in Palestine (cm) | |||||||
|
Sex |
Height at shoulder |
Height at back |
Height at rump |
Length of body |
Depth of chest |
Width of chest |
Heart girth |
|
Rams |
75 |
74 |
73 |
72 |
33 |
22 |
91 |
|
Ewes |
68 |
67 |
67.5 |
67 |
27 |
18 |
80 |
Table 1-4 gives respective measurements for 421 improved Awassi rams
and 2 039 ewes as recorded by Finci (1957) in Israel.
In addition, Finci recorded width of pelvis and shank
girth. For rams these are 23.8 (18-30) and 9.4 (8-11) cm, and for ewes 21.4
(15-28) and 8.0 (6.5-9.5) cm, respectively. In 1977/78, the author recorded the
measurements given in Table 1-5 for nine adult rams and 17 ewes of highly
improved Awassi dairy flocks in Israel (see also Tables 3-119 and 3-120). Of
particular interest are the great changes in chest dimensions of ewes between
1931 and the present, namely, an addition of 8.2 cm to the width of the chest
and 20.2 cm to its circumference, illustrating the increase in the size of
heart and lungs necessitated by the large increase in milk production and
metabolic rate.
| TABLE
1 -4. Average body measurements of improved
Awassi sheep in Israel (cm) | |||||||
|
Sex |
Height at shoulder |
Height at back |
Height at rump |
Length of body |
Depth of chest |
Width of chest |
Heart girth |
|
Rams |
77.7 |
77.0 |
77.3 |
74.8 |
35.9 |
20.7 |
100.7 |
|
(range) |
(66-87) |
(68-86) |
(67-86) |
(62-87) |
(28-42) |
(16-28) |
(80-124) |
|
Ewes |
69.3 |
69.3 |
69.4 |
68.5 |
32.7 |
19.5 |
94.0 |
|
(range) |
(58-78) |
(59-79) |
(58-79) |
(56-80) |
(28-39) |
(13-28) |
(76-116) |
TABLE
1 -5. Average body measurements of improved
Awassi rams and ewes in Israel (cm) | |||||
|
Sex |
Height at |
Height at hook
bones |
Length of |
Width of |
Heart |
|
Rams |
85.4 |
86.8 |
87.3 |
29.4 |
113.0 |
|
Ewes |
73.7 |
76.7 |
75.8 |
26.2 |
100.2 |
Weight. In Palestine in 1930,
Hirsch (1933) recorded a mean live weight of 74.6 kg for 13 Awassi rams kept in
three communal settlements and 41.7 kg for 116 ewes. The exceptionally large
mean weight for that time of 74.6 kg for unimproved rams must be attributed to
the small number weighed, very strict selection and a high plane of feeding.
Actually, the average live weight of unimproved rams bred by the bedouin and fellahin in Israel does not exceed 60 kg, while
in Syria and Iraq, because of superior grazing, it is somewhat higher. Thus, in
a flock of Awassi sheep established at the American University farm in Lebanon
on the basis of 47 ewes of about five years old purchased from Syrian nomads
summering in El Baq'a valley, Rottensten
and Ampy (1971a) recorded an average live weight of
45 kg in two-year-olds and 57 kg in four-year-old ewes in three weighings, four months apart, and approximately 90 kg in
three-year-old rams.
The recorded live weight of Awassi sheep
slaughtered in Syrian town slaughterhouses was about 42-45 kg (Gadzhiev, 1968). The weight of adult Syrian Awassi rams,
recorded by Erokhin (1973), ranged from 68 to 80 kg
and of adult ewes from 40 to 45 kg. In 1942-45 Epstein (1977) established an
average weight of 42 kg for several thousand Awassi ewes that had been
purchased in Transjordan, Syria and Iraq for
slaughter. In Turkey, Sönmez
(1955) reported an average live weight of 38.1 kg in İvesi
ewes. Yarkin and Eliçin (1966) recorded a weight of 52.9 kg in
mature İvesi ewes, while Sidal
(1973) found that 225 adult ewes from three village flocks weighed only 44.4 kg
on average. Mason (1967) gives a weight of 60-90 kg for unimproved Awassi rams
and 30-50 kg for unimproved ewes throughout the range of the breed in Syria,
Lebanon, Israel, Jordan, Iraq and Turkey.
For 391 improved Awassi rams in Israel, Finci (1957) established a mean live weight of 74.4 kg, and for 1211 improved ewes a mean live weight of 50.3
kg. In 1978 the author recorded an average weight of 126 kg in 20 adult rams
and 68 kg in 60 ewes of improved Awassi dairy flocks in Israel. The live weight
of adult stud rams, bred and employed by the highly developed ram-breeding
flock of the country, now varies between 130 and 160 kg. Three culled stud rams
sold for slaughter in 1978 had an average weight of 138 kg and four others
culled in 1979 averaged 141 kg. The mean live weight of 25 rams of improved
dairy type culled from four flocks in 1978 was 116 kg and of 1 799 ewes culled
from 15 flocks 65 kg. During the same period the weight of 460 culled ewes from
the stud flock was 75 kg on average.
The average weight of 56 yearlings, recorded
in Palestine in 1930, was 34.6 kg (Hirsch, 1933). Between 1963 and 1965 it had
risen to 40 kg (Table 1-11). In well-managed flocks in Israel in 1977 it was
not less than 50 kg, an increase of 50 percent over 35 years. In Iran, 48
Israeli Awassi yearlings, which did not lamb until the end of May, weighed 65.5
kg on average (Wallach & Eyal,
1974).
The live weights of
Awassi sheep vary with age, year and month. In ewes these differences are
particularly pronounced. (See Fig. 1-8.)
Figure 1-8. Average live weights of
Awassi ewes in Lebanon at different ages. (Source: Rottensten & Ampy, 1971a)
In Iraq, Asker and Juma (1966) found that the average body weight of Awassi ewes increased from 40.1 kg at the first shearing to 47.9 kg at the fourth, and then declined to 45.9 kg at the fifth shearing. After the lambing season, 157 Awassi yearling ewes in Iraq had a mean weight of 43.3 kg and adult ewes 51.3 kg (Eliya & Juma, 1970a). In an experimental flock Eliya (1969) recorded the weights of Awassi rams and ewes at different ages (Table 1-6).
In improved Awassi dairy ewes in Israel, the weights of animals given in Table 1-7 were recorded at different ages three days after lambing during the years 1958/59-1962/63 (Goot, 1966).
In Iran the weights, according to age, of pure-bred Awassi ewes imported from Israel in 1965 and 1966, or the progeny of the latter born in Iran, were recorded in 1970 (Wallach & Eyal, 1974). (See Table 1-8.)
TABLE 1-8. Weights
of Israeli Awassi ewes of different ages in Iran | |||||
|
Age (years) |
Three days after
lambing |
End of lambing season (25/5/1970) |
|||
|
Number of ewes |
Mean weight (kg) |
Number of ewes |
Mean number of days after lambing |
Mean weight (kg) |
|
|
1 |
54 |
66.8 |
71 |
67 |
62.2 |
|
2 |
19 |
78.2 |
33 |
82 |
68.3 |
|
3 and above |
21 |
82.0 |
53 |
94 |
74.6 |
In Iraq a
comparison between the mean body weights of four adult Awassi ewes that were
barren and six others that had lambed in October or November showed a decrease
from 60.1 kg in October to 40.9 kg in February for the ewes with lambs and from
60.2 to 55.9 kg for the barren ewes during the same period. The ewes with lambs
therefore lost 19.2 kg or 31.9 percent of their initial weight owing to milk
production and a poor level of nutrition during the winter, while the barren
ewes lost only 4.3 kg or 7.1 percent (Eliya et al.,
1969).
Goot (1966) also compared the mean live weights of two-tooth and adult ewes in two consecutive years, in June, shortly before the onset of the breeding season, and three days after lambing (Table 1-9).
TABLE 1-9. Mean weights of improved Awassi ewes in two successive years (kg) | |||
|
Year |
Age |
Mean weight |
Mean weight |
|
1961/62 |
2-tooth |
47 |
55 |
|
1962/63 |
|
50 |
62 |
|
1961/62 |
Adult |
58 |
68 |
|
1962/63 |
|
72 |
74 |
Large annual
differences in the body weight of Awassi ewes have also been recorded in
Turkey. At the Ereğli Animal Breeding Research
Station, mature ewes averaged 51.6 kg in 1966/67, but only 45.0 kg in 1967/68 (Yalçin
& Aktaş,
1969).
In 1962/63 Goot (1966) recorded the mean weights of improved Awassi
ewes of different ages in different months of the year, beginning with June
(Table 1-10).
In a test carried out between 1963 and 1965, 22 yearlings and 70 two- to ten-year-old ewes were separated at random from an improved Awassi flock of 60 yearlings and 400 ewes. The new units were divided into two groups, each according to similar average initial body weights. One group of yearlings and one group of ewes were pastured and the other two groups were stall-fed. The pastured ewes had a mean annual milk record of 300 kg and the stall-fed ones 281 kg. The weighing of the pastured yearlings and ewes was done in the morning before feeding and watering and of the stall-fed animals twice a day, before and after being driven out for exercise. The mean, maximum and minimum weights of the four groups were recorded in five successive months (Klein, 1974) and are given in Table 1-11.
|
Age |
Month |
|||||||||||
|
6 |
7 |
8 |
9 |
10 |
11 |
12 |
1 |
2 |
3 |
4 |
5 |
|
|
2-tooth |
50 |
50 |
51 |
52 |
53 |
55 |
59 |
63 |
63 |
64 |
65 |
62 |
|
4-tooth |
57 |
58 |
61 |
61 |
59 |
62 |
66 |
66 |
66 |
68 |
70 |
65 |
|
6-tooth |
61 |
63 |
65 |
67 |
68 |
70 |
73 |
74 |
73 |
72 |
72 |
69 |
|
Adult |
72 |
72 |
72 |
73 |
74 |
78 |
78 |
75 |
76 |
78 |
79 |
76 |
TABLE 1-11. Live
weights of yearlings and adult ewes in five consecutive months (kg) | ||||||
|
Weight |
|
January |
February |
March |
April |
May |
|
|
Pastured — 12 yearlings |
|
|
|
|
|
|
Mean |
|
41.8 |
40.3 |
45.9 |
51.3 |
53.0 |
|
Maximum |
|
48.0 |
47.0 |
51.0 |
61.0 |
62.0 |
|
Minimum |
|
36.0 |
36.0 |
40.0 |
45.0 |
47.0 |
|
|
Stall-fed —10 yearlings |
|
|
|
|
|
|
Mean |
|
42.2 |
42.0 |
45.5 |
48.6 |
54.7 |
|
Maximum |
|
44.0 |
45.0 |
49.0 |
53.0 |
59.0 |
|
Minimum |
|
41.0 |
38.0 |
42.0 |
46.0 |
51.0 |
|
|
Pastured — 50 ewes |
|
|
|
|
|
|
Mean |
|
57.0 |
54.3 |
56.5 |
59.8 |
61.5 |
|
Maximum |
|
69.0 |
68.0 |
76.0 |
78.0 |
78.0 |
|
Minimum |
|
46.0 |
43.0 |
45.0 |
48.0 |
55.0 |
|
|
Stall-fed —20 ewes |
|
|
|
|
|
|
Mean |
|
57.6 |
54.0 |
60.3 |
61.2 |
63.5 |
|
Maximum |
|
59.0 |
61.0 |
66.0 |
68.0 |
70.0 |
|
Minimum |
|
57.0 |
50.0 |
50.0 |
53.0 |
56.0 |
The live weight of Awassi ewes is influenced not only by nutrition but also by the physiological state of the animal. This is illustrated by two trials conducted in Cyprus with improved Awassi ewes derived from Israeli stock. In Trial I, two groups of 28 ewes each were kept on an unlimited ration of straw for six weeks before lambing, one group with an addition of 0.5 kg and the other with 1.0 kg of concentrates per day (Cyprus ARI, 1973). In Trial II, two groups of 17 ewes each were fed 0.9 and 1.3 kg of concentrates, respectively, in addition to a basic ration of 0.3 kg of lucerne straw per day during the last six weeks of pregnancy (Cyprus ARI, 1975). The average live weights of the ewes varied under different physiological conditions, as shown in Table 1-12.
TABLE 1-12. Effects
of nutritional and physiological conditions on live weight of improved Awassi
ewes in Cyprus (kg) | |||
|
Physiological state |
Plane of nutrition |
||
|
Trial I |
Low |
High |
|
|
6 weeks before lambing |
56.0 |
55.9 |
|
|
Shortly before lambing |
62.8 |
69.2 |
|
|
After lambing |
54.3 |
59.3 |
|
|
Trial II |
Medium |
High |
|
|
At mating |
62.1 |
61.6 |
|
|
43 days before lambing |
64.5 |
66.2 |
|
|
1½ days before lambing |
70.1 |
73.7 |
|
|
Immediately after lambing |
62.0 |
66.0 |
|
Head and horns. The
head is long and narrow with a convex profile. In adult, strongly horned rams,
the convex line of the profile may be broken by a slight indentation between
the forehead and the markedly curved nasal part of the head. The ears are
pendulous, about 15 cm long and 9 cm broad (see Fig. 1-9). Occasionally the auricula is rudimentary or entirely absent, and small,
fleshy ears also sometimes occur. In improved Awassi flocks the male lambs from
such ewes are not used for breeding, even though they themselves may have
normal ears.
Rams are nearly always horned. The horns, which are 40-60 cm
long and strongly wrinkled, curve backwards and downwards with the tips
directed outwards; in adult animals 1½
turns are usually described (see Fig. 10). In Syria and Iraq Awassi rams with
up to six horns are often encountered in bedouin
flocks. Horns of polycerate rams show a high degree
of variability and want of symmetry in shape and direction (Fig. 1-11). The
ewes have been described by Hirsch (1933) as 'very rarely' horned and Finci (1957) similarly writes that 'the females are mostly
hornless'. In Turkey 90 percent of İvesi (Awassi)
ewes are polled, the remaining 10 percent having poorly developed rudimentary
horns (Yarkin & Eliçin, 1966). According to Mason (1967),
Awassi ewes have 'occasionally (up to 25%) short horns (up to 10 cm)'. But the
present author has found that in Awassi dairy flocks in Israel the large
majority (perhaps 80 percent) of the ewes have thin, weak and shapeless
rudimentary horns or scurs, about 3-8 cm long, which
are partly covered by curls of hair. Fully developed, 10- to 15-cm-long crescentic horns are rare indeed in Awassi ewes, although
not as rare as are polled rams (see Figs 1-12 and 1-13).
Figure 1-11. Four- five-and six-horned Awassi rams
Figure 1-12. Skull of a polled Awassi ewe. Frontal and lateral views
Figure 1-13. Horned Awassi ewe
Body and legs.
The neck is fairly long, fine in the ewe, stronger in the ram. Lappets (Appendices
colli), consisting of skin, connective tissue,
nerves and blood vessels (differing from goat lappets in the absence of muscle
tissue) and constituting a dominant single-factor characteristic, are frequent.
The chest is long but of only moderate depth and width, with a small, thin
dewlap and prominent brisket. In unimproved flocks narrowness at heart is a
common weakness, but in improved sheep this is rare. The barrel is deep and
wide, the back long and straight, not more than 1 cm lower than the shoulder
and usually of equal height. The anterior part of the rump is relatively broad
and nearly on a level with the back, but aborally the
rump of the Awassi strongly slopes to the fat tail. The drooping rump is caused
by the anatomical structure of the ossa
pelvis. The angle between the os ilium and os ischii is nearly 180°. Taking the
head of the femur as the rotary centre, the entire pelvic girdle slopes
backwards and downwards. In addition, the os
sacrum is strongly bent down (Hinrichsen & Lukanc, 1978).
The legs are of
medium length and thickness, not as short and sturdy as those of some of the
early maturing mutton breeds of the United Kingdom such as the Romney Marsh,
Hampshire Down, Shropshire Down or Dorset Horn, nor
as long and thin as the legs of the hairy thin-tailed sheep of the savannah
region of West Africa. They are usually well placed, with strong pasterns and
their hoofs are of a strong material that wears well.
Fat tail. The fat
tail is broad and relatively short, usually ending above the hocks, more rarely
extending below them. In improved flocks long fat tails are considered
undesirable (see Figs 1-14 and 1-15), mainly because they are an obstacle in
the process of milking. The fat tail of the ewe is largest before lambing and
loses weight during the early months of lactation, more especially in deep milkers which have difficulty in consuming enough
concentrates to make up for the loss. In rams the fat tail is larger than in
ewes, not only absolutely but also in relation to body size and weight. In
adult rams the weight of the fat tail may amount to as much as 12 kg and in
ewes up to 6 kg; in heavy male lambs it may reach 8 kg (see Table 5-7). Without
the fat cushions the tail weighs about 70 g. The length and width of the fat
tail of Awassi rams and ewes of different ages have been recorded by Eliya (1969) in Iraq (Table 1-13).
Figure 1-14. Awassi ewe with an excessively long fat tail
Figure 1-15. Awassi ewes with fat tails of moderate
length
TABLE 1-13. Average length and width of fat tail of Awassi sheep in
Iraq (cm) | ||||||
|
Age (years) |
Number |
Length of tail |
Width Of tail |
|||
|
♂ |
♀ |
♂ |
♀ |
♂ |
♀ |
|
|
1 |
105 |
109 |
21.7 |
14.3 |
18.5 |
12.2 |
|
2 |
11 |
62 |
24.2 |
17.0 |
22.0 |
14.8 |
|
3 |
3 |
87 |
27.8 |
17.3 |
25.5 |
15.1 |
|
4 |
— |
113 |
— |
17.8 |
— |
15.5 |
|
5 |
— |
67 |
— |
18.7 |
— |
16.0 |
|
6 and above |
— |
65 |
— |
17.6 |
— |
15.3 |
In the improved
dairy type of Awassi in Israel the width of the fat tail is greater than the
width recorded in Iraq. Goot (1966) has measured the
breadth of the tail at its widest part in male lambs, yearlings and adult ewes
(Table 1-14). At the same time he remarks on the difficulty of taking exact
measurements of the width of the fat tail and on the possibility that the tail
may actually be broader than the figures indicate.
The main portion of the tail emerges from the lower part of the rump with the same width as the thurls and hangs down in two lobes which are separated by the caudal skeleton and are bare of hair or wool on the under-surface. In animals in good condition the lobes broaden out toward their lower portion which ends somewhat abruptly. In the middle of the lower portion the lobes are not connected but are divided by a deep notch which gives the under-side of the tail a heart-shaped appearance (Fig. 1-16). Slightly above this notch the tail skeleton turns upwards (Figs 1-17 and 1-18) to emerge from the fat moieties, producing a hairy tassel of variable length, which is usually devoid of fat but in some instances may contain some fat in the upper portion. This tassel hangs down from the apex of the upturned tail skeleton and is called a 'thorn' by breeders.
TABLE 1-14. Width
of fat tail in improved Awassi dairy sheep in Israel (cm) | |||
|
Type of sheep |
Number |
Width of fat tail |
|
|
Mean |
Range |
||
|
Male lambs |
13 |
18.4 |
13-21 |
|
Yearling ewes |
20 |
20.1 |
13-25 |
|
Adult ewes |
91 |
23.5 |
15-34 |
Figure 1-16. Hairless
under-side of an Awassi ram's fat tail
Figure 1-17. Tail of a 3-month-old Awassi lamb after
removal of fat cushion
Figure 1-18. Fat tail of a 3-month-old male Awassi lamb
with pelt removed
The scrotum. The
scrotum is well developed, extending to the level of the hocks, with large
testes of which the left one is usually a little larger than the one to the
right. In aged rams the scrotum is often elongated to below the hocks. On each
side of its attachment there is an opening of a large sebaceous gland and close to these openings are two or more
rudimentary teats. Rams in which only one testicle has descended into the
scrotum are not used for breeding. Other than in local goats, hermaphroditism is extremely rare in the Awassi.
The udder. In
unimproved Awassi ewes the udder and teats are extremely variable in shape and
with numerous faults. In some animals the udder is pendulous, occasionally
extending down as low as the heels. It may have the shape of two bottles or
sausages, with a deep indentation between the two halves. Frequently the teats
are very small, with either a downward, lateral or upward direction, or they
project, not from the bottom of the udder, but from its outer sides, rendering
milking difficult. (See Figs 1-19 to 1-25.)
|
|
|
Figure 1-19. Pendulous udders of old Awassi ewes. Caudal and lateral views. (Measure in cm) |
|
Figure 1-20. Well-shaped udder of an Awassi ewe, but
teats too high-set and projecting laterally. Caudal view.
(Measure in cm)
Figure 1-21. Large, well-shaped udder of an Awassi ewe, but teats too large for easy
suckling. Lateral view.
(Measure in cm)
Figure 1-22. Well-shaped udder of an Awassi ewe (with
additional rudimentary teats), but functional teats too high-set and nearly
horizontal. Frontal view
Figure 1-23. Awassi
ewe with a baggy udder and high-set, laterally projecting teats
Figure 1-24. Large, faulty udder of an Awassi ewe:
pendulous, baggy with teats very high and horizontal. Caudal view
Figure 1-25. Large udder of an Awassi ewe, baggy with teats very high and horizontal. Lateral view
In ewes of improved Awassi dairy
flocks the udder is generally well attached, of moderate depth, not pendulous
but of globular shape, wide between the legs, elongated anteriorly
and extending well to the rear. The teats are of fair length and moderate
thickness, with a downward direction. (See Figs 1-26 and 1-27.)
Prior to the
introduction of mechanical milking in the majority of improved Awassi flocks in
Israel, breeders paid little attention to the shape of the udder in the
selection of breeding stock. Even at the present time there still exists
considerable variability in this respect in many flocks, although a suitable
conformation of udder and teats is a precondition for successful machine
milking.
In 1957, Eyal, Volcani and Sharav (1958) and Sharav, Volcani and Eyal (1962) examined the udders of 200 ewes in an improved Awassi flock. The age of the ewes ranged from 2 to 11 years. At the time of the investigation their mean daily milk production was 1.28 kg, with a range of 0.25-2.50 kg.
The measurements shown
in Figure 1-28 and Table 1-15 were taken before and after milking.
The authors noted
that practically all udders differ in shape or in the size, placement and
direction of the teats, with many udders also having dissimilar halves.
However, with regard to general conformation, three main types can be
recognized: 1) cylindrical udders, of similar circumference throughout their
length; 2) pear-shaped udders, which are narrower near the attachment to the
body than at the level of the teats; and 3) spherical udders, generally small
and firmly attached to the body.
TABLE 1-15. Measurements of Awassi udders before and after milking (cm) | ||||
|
Measurement |
Condition |
Mean |
Minimum |
Maximum |
|
Depth of udder (from hip bone to lowest point of udder) |
full |
45.00 |
37.5 |
56.0 |
|
|
empty |
44.00 |
33.5 |
51.0 |
|
Superior udder girth |
full |
43.20 |
30.0 |
55.5 |
|
|
empty |
39.30 |
26.5 |
49.0 |
|
Udder girth at level of teats |
full |
49.70 |
39.0 |
58.5 |
|
|
empty |
44.00 |
34.0 |
53.0 |
|
Anterior udder length |
full |
15.60 |
9.0 |
23.0 |
|
|
empty |
15.10 |
7.5 |
23.0 |
|
Posterior udder length |
full |
23.20 |
18.5 |
30.0 |
|
|
empty |
21.60 |
14.0 |
28.0 |
|
Basal width of right teat |
full |
2.68 |
1.5 |
4.2 |
|
|
empty |
2.53 |
1.6 |
3.9 |
|
Basal width of left teat |
full |
2.60 |
1.4 |
4.4 |
|
|
empty |
2.58 |
1.7 |
4.2 |
|
Length of right teat |
full |
4.12 |
2.4 |
6.4 |
|
|
empty |
3.54 |
2.3 |
5.5 |
|
Length of left teat |
full |
3.95 |
2.3 |
6.6 |
|
|
empty |
3.64 |
2.4 |
5.8 |
As for the teats themselves, four main types can be distinguished on the basis of either their high or low setting-on, combined with a horizontal or oblique direction (Sharav, 1959; Sharav, Volcani & Eyal, 1962). Eyal, Volcani and Sharav (1958) subdivided the percentage of low-set and obliquely directed teats according to an oblique and a nearly vertical downward direction (Table 1-16).
| |||||||||||||||||||||
There appears to
be a connection between the placement of the teats and their
direction, for most of the highly placed teats have a horizontal
direction, whereas the majority of the low-set ones are oblique or vertical
(see Fig. 1-29). A connection also exists between the position of the teats and
their length and thickness; as indicated by the measurements given in Table
1-17, low set-on teats, more especially low-set oblique ones, are commonly
longer and thicker than teats set on higher on the udder (Sharav,
Volcani & Eyal, 1962).
The location of the teats affects the quantity of milk remaining in the udder
on completion of the first stage of the milking process (primary milking) (see
Fig. 4-3 and Table 1-15) (Eyal, Volcani
& Sharav, 1958).
|
|
|
Figure 1-29. Sketch of different Awassi udders and teats with percentage of occurrence |
Sharav (1973a) recorded the changes in the length and
thickness of the teats of 24 Awassi ewes in the course of the milking process.
The length of the teats was measured with a caliper from the base to the tip
and the diameter at the base before and after machine milking. In addition, the
length of the teats was measured in a transparent liner and the teat cup under
a pulsation vacuum at the beginning and end of milking. Table 1-18 gives the
mean data recorded.
|
Measurement |
Before milking |
On
entering cup |
In
cup at end of milking |
After
milking |
|
Length |
35.0 |
66.3 |
72.3 |
38.1 |
|
Diameter |
25.5 |
— |
— |
22.1 |
Additional
teats, up to a total of eight, are quite common in the Awassi (see Fig. 1-22).
Usually their canals are separated from those of the main teats. Supernumerary
teats have been considered by Wassin (1929) to be a
dominant hereditary characteristic. However, they provide no indication of
increased milk production in Awassi ewes, although some breeders regard them as
such. Rather, they are an obstacle to milking and may contribute to the uncleanliness of the milk.
On each side of the attachment of the udder there is an opening of a
large sebaceous gland, analogous to those near the attachment of the scrotum.
These glands serve to keep the skin of the udder oily and pliant.
In an examination
of the anatomy of the circulatory system of the Awassi ewe's udder, Perk and Epstein (1959) found the udder
halves separated by a well-defined, longitudinal groove which extends upwards
as the median connective tissue septum. Each half has an arterial system,
derived from a single source, the Arteria
pudenda externa, which emerges from the inguinal
canal to the base of the udder, entering it nearer to its posterior than to its
anterior attachment and descending in a solid stem down to the centre of the
udder with several smaller branches projecting forwards and backwards. Half-way
between its entrance into the udder and the milk cistern, the mammary artery
divides into a major branch which continues the medial descent downwards with a
moderate forward inclination and into a weaker offshoot. The latter turns
backwards and downwards, and then curves forwards at an angle of approximately
90°, continuing its way above the milk cistern to the lower anterior margin of
the udder, where it runs at a short distance from, and parallel to, the
terminal section of the Arteria mammaria medialis before the
latter enters the subcutis in the central part of the
abdomen. Fine lateral, upward and downward ramifications of the principal
arteries, which with constant branching diminish in size, supply the mammary
parenchyma, milk sinus, teat and derma. A dissection of Awassi ewes' udders did
not reveal any arterial anastomoses between the
halves such as are found in the udders of goats and cows.
The venous
branches of the Awassi ewe's udder merge into a major medial vein which
accompanies the main medial artery and its cranial branch and is deeply
embedded in the udder parenchyma. Cranially the mammary vein drains into the
large Vena subcutanea abdominalis,
and dorsally into the Vena pudenda externa. A perineal vein, such as is characteristic of the udders of
goats and of the rear quarters of those of cows, is absent in the Awassi ewe so
that there is no drainage from the internal pudic
vein through the udder. Similarly, no anastomotic
branches are found between the mammary veins in the basal portion of the udder.
While venous blood can thus flow from every part of the Awassi ewe's udder
forwards or upwards through the most suitable vein, it cannot flow across to
the opposite half (as in goats and cows).
Skin and coat. The skin of the Awassi is moderately
thin and elastic, unpigmented and very senstive (Eyal, 1963c). In aged
animals it loses its fineness and softness and becomes thicker and coarser.
There are no folds on the neck or body, but a thin dewlap extends from the
throat down to the brisket.
The head and ears
of the adult Awassi are covered with short, stiff hair and the back and sides
of the body and posterior part of the fat tail with wool. Until the age of
12-15 months, Awassi sheep also have the entire neck, including the throat,
covered with wool. In the large majority the wool disappears from the throat at
a later stage, and in many of them the neck also becomes short-haired, save for
its top ridge on which a thin cover of wool occasionally remains. In the ram a
fringe of longer and coarser wool extends from the throat along the dewlap to
the lower part of the brisket, a remnant of the mane characteristic of wild
male sheep and unimproved hairy, domesticated sheep. In Awassi lambs, wool
grows on the belly, although this is shorter and less dense than on the upper
part of the body. As the animals grow older, the wool on the belly is replaced
by fairly long, coarse hair, sparser even than the wool on the belly of the
lamb. The forelegs are usually short-haired and devoid of all wool, while the hindlegs may also be woolless or,
more rarely, be thinly covered with short wool down to the hocks, in some
animals as far down as the fetlocks. A coarse-haired tassel of variable length
emerges from the thin upturned end of the tail. As in all fat-tailed and fat-rumped breeds of sheep, the inner surface of the fat tail
of the Awassi is naked.
Generally, Awassi
sheep have a light fleece owing to the low density of wool follicles and the
limited surface area covered with wool fibres (Sharafeldin, 1965). For Awassi rams and ewes from Israel,
Lebanon, Syria, southern Turkey, Jordan and Iraq, Mason (1967) gives an average
annual fleece weight of 0.2-2.5 kg and 1.75 kg, respectively.
In Israel the
fleece weight of unimproved Awassi rams ranges from 2.0 to 3.0 kg, with an
average of 2.25 kg, and of ewes from 1.0 to 2.5 kg, with an average of 1.75 kg.
The fleece weight of four- to five-month-old lambs varies between 0.4 and 0.7
kg, with an average of 0.5 kg, and that of yearling lambs between 1.0 and 2.0
kg, with an average of 1.4 kg.
In 1931 the
following mean fleece weights were recorded in three Jewish communal
settlements in Palestine: 13 rams, 2.45 kg; 116 ewes, 1.73 kg; 21 four- to
five-month-old lambs, 0.6 kg; and 56 yearlings, 1.46 kg (Hirsch, 1933). Thirty
years later (1960-63), Goot (1966) recorded a mean
fleece weight of 2.5 kg in 100 improved Awassi yearling ewes, an increase of
more than 70 percent. In 1966-68 the average weight of 259 fleeces from adult
Awassi ewes, imported from Israel into Iran or descended from imported stock,
was 2.66 kg (Wallach & Eyal,
1974). Four hundred and three Israeli Awassi lambs born in Yugoslavia yielded
2.63 kg of greasy wool per head, while 1 561 ewes imported into Yugoslavia from
Israel had an average fleece weight of 2.85 kg at the first shearing and 2.71
kg at the second shearing, as compared with 2.96 kg in the pedigree flock in
Israel whence the ewes had
come (Todorovski, Ristevski & Popovski,
1973b,c,d). Hence, improved feeding, increased milk yields and increased body
size in the course of 35 years of improvement have led to an increase of over
50 percent in the average fleece weight of Awassi ewes in Israel.
Throughout the
period of improvement of the Awassi, first in Palestine and subsequently in
Israel, wool prices have been low, more especially in relation to milk and
mutton (lamb). For this reason breeders have not cared to introduce fleece
weight and quality into their selection programme. However, when this is done,
achievement is fairly rapid. Thus an improved flock with high milk yields
belonging to a communal settlement (Sarid) was
selected for heavier fleeces—in addition to milk and conformation — from 1938
on, with the result that 434 fleece weights, recorded in the years 1948, 1949,1950 and 1952 from ewes of all ages registered in the flock
book, showed a mean of 2.97 kg, or 70 percent above the breed average of 1.75
kg (Finci, 1957). The maximum fleece weight in a ram
of this flock was 6.8 kg and in a ewe 6.5 kg (Becker, 1958). In comparison, in
Syria, one ram of the improved Awassi flock at Wad-al-Azib
produced 9.96 kg of wool in a year (Gadzhiev, 1968).
In Lebanon, 391
yearling ewes from six different regions yielded 1.89 kg of wool of one year's
growth per head after lambing (Fox et al., 1971). At the experimental
farm of the American University of Beirut, Awassi ewes derived from stock of
Syrian nomads produced 1.67 kg of greasy wool on average annually during four
years (McLeroy & Kurdian,
1958). Later, 407 ewes of the same flock averaged 2.2 kg of machine-sheared
wool per year (Rottensten & Ampy,
1971a).
The average fleece
weight of Syrian Awassi sheep amounts to 1.8-2.0 kg, and under superior
conditions of management to 2.5-3.0 kg (Gadzhiev,
1968). According to Erokhin (1973), the annual wool
yield of adult Syrian Awassi rams averages 4.35 kg, of adult ewes 2.58 kg and
of 15- to 16-month-old Syrian yearling ewes, 3.49 kg. At the Hofūf Agricultural Research Centre in Saudi Arabia, the
average annual fleece weight of Awassi ewes of Syrian derivation was 2.03 kg. Pritchard, Pennell and Williams (1975)
note that the fleeces of these sheep are heavier than those of the desert-bred
Awassi in the north of Saudi Arabia. At the Ras
El-Hekma Desert Research Station in Egypt, Awassi
yearling ewes of Syrian origin, first shorn at the age of 16 months, had an
average fleece weight of 2.37 kg (Fahmy et al., 1968). At the Bahtim Experiment Station in Egypt, the weights of 165
greasy fleeces of six months' growth from fifty 9-, 15-, 21-, 27- and
33-month-old Awassi ewes, derived from stock imported from Syria in 1960,
ranged from 0.84 to 1.56 kg according to age, with a total average of 1.285 kg
(Ghoneim et al., 1968).
High variability
in the annual fleece weight of Awassi sheep is also encountered in Turkey. Sönmez (1955) recorded an average fleece weight of 1.35 kg,
ranging from 0.59 to 2.63 kg annually, while Yarkin
and Eliçin (1966) reported an annual yield of 2.19 kg, varying
between 1.0 and 3.7 kg, in Turkish Awassi sheep. Two hundred and twenty-five
Awassi ewes of different coat types, belonging to three Turkish village flocks, yielded 1.9 kg of greasy wool per head;
fleece weights declined with increasing age (Sidal,
1973). Imeryüz, Müftüoğlu
and Öznacar (1970) recorded an average greasy fleece
weight of 2.5 kg and a clean fleece weight of 1.67 kg in adult Awassi sheep in
Turkey. At the Ereǧli Animal Breeding Research Station in central
Anatolia, the greasy fleece weight of Awassi sheep averaged 2.9 kg in 1967 and
2.1 kg in 1968 (Yalçin
& Aktaş,
1969).
In Iraq, as Williamson (1949) has noted, Awassi rams and ewes produce not more than 1.0-1.5 kg of wool annually. In 1963, Sharafeldin (1965) recorded an average greasy fleece weight of 1.71 kg in 268 Awassi ewes in Iraq. Of 626 ewes that were weighed at the first five shearings carried out at yearly intervals beginning at 16.9 months of age, 1 456 fleeces averaged 1.37,1.55, 1.53, 1.51 and 1.46 kg, respectively, with a total average of 1.46 kg (Asker & Juma, 1966). At the Hammām Al'Alil Experiment Station in northern Iraq, the greasy fleece weight of adult Awassi rams averaged 2.46 kg, and of ewes 2.00 kg during the period 1965-71 (Ghoneim et al., 1973). The relatively high fleece weights obtained at Hammām Al'Alil are attributed to selection practised in the experimental flock for increased wool production for a period of six years. The heaviest fleeces were obtained at the first and second shearings. The average fleece weights of rams and ewes at different ages were as shown in Table 1-19.
Several factors
influencing the fleece weight of Awassi sheep have been studied. The fleece
weight of one year's growth differs considerably between lactating and dry,
yearling and adult ewes (see Table 1-20). Goot (1972)
weighed unskirted and uncrutched
fleeces from yearling and adult ewes often Awassi flocks in Israel immediately
after machine shearing in May, 12 months after the previous shearing. The
average lactation yield of the ewes was 311 kg, varying between 91 and 645 kg.
The statistically
highly significant data (P < 0.001) show that dry females grow heavier
fleeces than lactating ones and that dry yearlings have heavier fleeces than
dry adult ewes.
In their
investigation over a period of five years into the effects of non-genetic factors
on the weight of 756 fleeces from 336 Awassi sheep at the College of
Agriculture, University of Mosul, Iraq, Ghoneim et al. (1974) observed that rams grow
heavier fleeces than ewes at all ages (see Table 1-19). The mean difference was
0.46 kg and the largest 1.07 kg (3.15 vs. 2.08) at the age of 2½ years. Yearly
variations in fleece weight, ranging from 1.68 to 2.35 kg, mainly reflected
differences in feeding, management and health of the flock. In the two years of
the investigation, singles exceeded twins in fleece weight, while the reverse
obtained in the three other years. There were significant correlations between
fleece weights at the first shearing and those of the second and third shearings. Estimates of heritability and repeatability
showed that sires had a highly significant effect on the fleece weight of their
offspring at the first shearing and less so on the second and third shearings when the ewes were either pregnant or lactating
and hence influenced by non-genetic factors.
TABLE 1-19. Average fleece
weights of Awassi | ||||
|
Age (months) |
Male |
Female |
||
|
Number |
Weight
(kg) |
Number |
Weight (kg) |
|
|
18 |
69 |
2.33 |
187 |
2.10 |
|
30 |
13 |
3.15 |
135 |
2.08 |
|
42 |
8 |
2.47 |
127 |
1.93 |
|
54 |
3 |
2.57 |
89 |
1.92 |
|
66 |
1 |
2.36 |
55 |
1.81 |
|
78 |
— |
— |
41 |
1.91 |
|
90 |
— |
— |
28 |
1.87 |
|
Total |
94 |
2.46 |
662 |
2.00 |
TABLE
1 -20. Fleece weights of yearling and adult, dry and lactating Awassi
ewes | ||||
|
|
Yearlings |
Adult ewes |
||
|
Dry |
Lactating |
Dry |
Lactating |
|
|
Number of fleeces |
276 |
26 |
134 |
1
220 |
|
Fleece weight (kg) |
2.35 ± 0.57 |
1.85 ± 0.52 |
2.12
± 0.66 |
1.90+
0.69 |
Asker and Juma (1966) found a highly significant correlation between
the fleece and live weights of Awassi ewes in Iraq. With an increase in the
average body weight from 40.1 kg at the first shearing to 47.9 kg at the
fourth, the average fleece weight increased from 1.38 to 1.52 kg. With a fall
in the average body weight of ewes to 45.8 kg at the fifth shearing, the fleece
weight decreased to 1.47 kg. When the ewes were divided according to their body
weights into eight groups with class intervals of 4.54 kg, the maximum average
weight of fleeces (1.67 kg) was obtained from ewes weighing 57.2-61.2 kg.
Yearly fluctuations in average fleece weight owing to environmental factors
ranged from 1.08 to 1.65 kg during the five years of observation
(1959/60-1963/64).
Two shearings per year increase the total annual wool yield of
Awassi sheep as compared with one shearing. Al-Aubaidi
et al. (1968) examined the influence of autumn and spring shearings on the weight of fleeces washed before shearing
of 19 male and 19 female Awassi lambs in Iraq, with equal numbers of lambs,
shorn only in spring, as the control group. The male lambs, which suffered from
lice and scabies, yielded 1.73 kg of wool annually in two shearings
vs. 1.30 kg in one shearing, and the female lambs, which were healthy and free
of lice, 2.30 kg in two shearings vs. 1.78 kg in one.
Twice-a-year shearings therefore increased the yield
of wool by 0.43 kg (or 33.1 percent) in the male lambs,
and by 0.52 kg (or 29.2 percent) in the females.
Colour. Typically, the wool of the Awassi is
white with a yellowish hue. The head, ears and anterior part of the neck are
brown, while the legs may be wholly or partly brown. Some animals have a white
blaze on the head. Lambs born with a light brown, same-coloured
or spotted coat frequently grow white fleeces after the first shearing. In
unimproved flocks a fair number of animals deviate from the typical pattern
.Often brown spots or patches occur in the fleece, and some animals are wholly
light or dark brown or red. In Iraq about 10 percent of Awassi sheep have coloured fleeces (Ghoneim et
al., 1973). Ewes with black heads are also encountered. Among the İvesi sheep of Turkey two colour varieties
are distinguished, one black-headed and the other yellow-headed; there is no
significant difference between them in body measurements or milking performance
(Yarkin & Eliçin, 1967). Sheep with a black head are
called Karabaş
(black head) (Yalçjn,
1979). In improved Awassi dairy flocks black-headed animals are usually culled
and rams with black heads are never used for breeding. Black-fleeced sheep are
rare; in such instances the black pigment does not usually extend to the tassel
of the tail which remains white. While white sheep in which the head and ears
are also white occur, they are not favoured by
breeders since in a subtropical climate with intense solar radiation a
pigmented mucosa of the eyes, mouth, nostrils and ears is essential as
protection against injury and the diseases connected with these areas, such as
bighead which is related to the photosensitivity of an unpigmented
mucosa. The hoofs of the Awassi are dark in colour.
Hardiness.
In the course of several thousand years the Awassi has become fully adapted
to the subtropical environment of its extensive breeding area in the semi-arid
or arid regions of southwest Asia. The flocks of the bedouin
and of the majority of fellahin are kept in the open throughout the year, day
and night, and depend entirely on natural pasturage. They are not protected by
their masters against torrential rains in winter nor
the blazing heat of the summer. Their natural protection against the strong
solar radiation during the hot months of the year is their fleeces, the pigment
of their heads and their habit of keeping their heads in the shade below the
bellies of their flock mates. It is only from the cold storms of winter that
they may be sheltered behind stone walls or hedges of cactus or thorns.
However, the
hardiness of the Awassi may break down during a succession of rainy days during
the cold season when they remain without feed and have used up the fat reserves
accumulated in their tails and bodies in the previous spring and early summer
and have become completely emaciated. At such times the death rate from
exposure and starvation may be extremely high.
Body temperature. The adaptation of Awassi
sheep to their subtropical environment is to a considerable degree a result of
their physiological ability to regulate the heat balance of their bodies at
different seasons of the year, different diurnal temperatures and humidity
conditions, in both the shade and under direct solar radiation. Epstein and Herz (1964) reported that the average body temperature of
Awassi sheep in Israel was 0.9°C lower than that of imported Romney Marsh,
Dorset Horn and Suffolk sheep of the United Kingdom kept in the same place and
conditions.
In a study of the nychthemeral changes in the body temperature of Awassi
sheep made by Degen (1976, 1977c), six male and two
horned female six-month-old, unshorn lambs were exposed to the summer heat in
the semi-arid Negev region of Israel under nearly natural conditions, albeit
deprived of their behavioural cooling mechanism at
pasture. During the trial the lambs were kept in small individual pens with
slatted floors in an open yard with no shade or shelter. The feed consisted of
a pelleted concentrate-roughage mixture and water was
freely available. The trial began after a preparatory period of two weeks in
the pens and lasted for 21 days in August, the hottest month of the year. In
this period the site of the test has a mean minimum temperature of 20.2°C, a
daily mean of 26.8°C, and a mean maximum temperature of 33.5°C. During the
experimental period the mean relative humidity at 8.00 h was 63 percent, at
14.00 h 38 percent, and at 20.00 h 71 percent. At the beginning of the trial
the average body weight of the eight lambs was 31.4 kg and at its conclusion
36.8 kg.
The changes in
thermoregulatory responses during a 24-hour cycle were established every third
day. On these seven days of the test period, the rectal, external auditory meatus and skin temperatures were measured every four
hours, starting at 4.00 h (see Fig. 1-30).
Maximum readings
were obtained at the hottest time of the day (12.00 h) and minimum readings at
the coolest time (4.00 h). The lambs had a fairly stable rectal temperature
with a range of 1.1°C. The external auditory meatus
temperature was lower than the rectal temperature, the range of nychthemeral fluctuation being 2.1°C. Hence, the
hypothalamic temperature was maintained cooler than that of the body. The skin
temperature showed the highest fluctuation, namely 6.4°C, but on average was
only 0.2°C lower than the rectal temperature.
The Awassi does not use thermolability as a physiological adaptation to heat stress
(Degen & Morag, 1974). This applies to normal
conditions throughout the range of the breed. But in an investigation of the
responses of Awassi sheep to dehydration (see pp. 33, 37-38), Degen (1976, 1977d) found
that with a reduction in the quantity of drinking water offered to the animals,
the maximum daily rectal temperature did increase (Table 1-21).
Figure 1-30. Mean rectal,
external auditory meatus and skin temperatures of
eight penned Awassi lambs at different hours of the day. (Source: Degen,
1977c)
The ability to
regulate the heat balance, as expressed by body, skin and fleece temperatures
and pulse and respiration rates, has been investigated by Eyal
(1963a,b,c,d) in shorn and unshorn three-to
five-year-old improved Awassi ewes with an average lactation yield of 240 kg
and a live weight ranging from 55 to 65 kg, and in parallel groups of
unimproved ewes.
A group of five
ewes were shorn every month for a year and then left unshorn. The ewes of
another group were left in fleece for one year, after which the two groups were
switched. Two parallel investigations were conducted in this manner, one in the
coastal region in the centre of Israel with improved ewes, and the other with
unimproved ewes in the southern desert where the differences in temperature
between day and night and between summer and winter are far greater than in the
coastal area. The feeding and management of the sheep were similar in both
trials. The rectal temperatures of the animals were taken five times a day.
An increase in
ambient temperature is accompanied by an increase in body temperature in shorn
and unshorn sheep. In sheep kept in the shade the increase in rectal
temperature is steeper in shorn than in unshorn animals.
At temperatures above 30°C, shorn sheep have rectal temperatures higher than,
or equal to, those of unshorn sheep (see Fig. 1-31). As ambient temperatures
decrease, the differences in mean body temperature between shorn and unshorn
sheep become larger. At ambient temperatures below 30°C the body temperature of
shorn sheep is lower than that of unshorn sheep by an average of 0.16°C.
In spite of great
differences in ambient temperatures, there is no significant difference in body
temperature between winter and summer. At equal environmental temperatures the
mean rectal temperature is higher in winter than in summer. This seems to be
because of the fact that Awassi sheep commonly produce milk during the winter,
but are dry in the summer. Their thermoregulatory system at equal ambient
temperatures is therefore under a greater thermal stress in winter than in
summer, and their rectal temperatures correspond to the increased winter
stress.
On exposure to
direct sunlight, save for the winter months, shorn sheep reach a higher body
temperature than unshorn animals (Fig. 1-32). However, when
the sheep are transferred from the sun to the shade, or after sunset, the
rectal temperature of the shorn animals drops at a faster rate than that of the
unshorn ones. This is most conspicuous in sheep returning from pasture
(Fig. 1-33). Again, during the cool hours of the day shorn sheep have a lower
body temperature than sheep in fleece.
The smallest differences in body
temperature between shorn and unshorn Awassi sheep are found when the humidity
is at its lowest. A rise in relative humidity at ambient temperatures above 25°C causes a rise in body
temperature, particularly in sheep in fleece. In a hot, dry environment the
body temperature of shorn sheep exceeds that of unshorn ones. It therefore
appears that a rise in ambient temperature brings about a higher rate of increase
in the body temperature of shorn sheep, whereas a rise in relative humidity
produces a higher rate of increase of body temperature in unshorn sheep. Wind
velocity, both in the shade and in the sun, has a greater effect on the body
temperature of shorn than of unshorn sheep, reducing the impact of direct solar
radiation on shorn animals (Eyal, 1963a).
TABLE 1-21. Mean
rectal temperature of 6-month-old Awassi lambs at different rations of drinking
water | |||
|
Water
ration (litres) |
Bodytemperature (°C) |
||
|
6.00
h |
13.00h |
Variation |
|
|
Free |
38.6 |
38.8 |
0.23 |
|
4.5 |
38.7 |
39.0 |
0.30 |
|
3.0 |
38.7 |
39.1 |
0.36 |
|
2.5 |
38.9 |
39.7 |
0.80 |
|
2.0 |
39.7 |
40.4 |
0.73 |
|
1.5 |
39.7 |
40.5 |
0.80 |
|
1.0 |
40.0 |
40.8 |
0.83 |
Source: Degen, 1977d | |||
Figure 1-31. Average diurnal trends of body
temperature of Awassi sheep kept in the shade. (Source: Eyal, 1963a)
Figure 1-32. Diurnal trends of rectal temperature of Awassi sheep kept in the sun.
(Source: Eyal, 1963a)
Figure 1-33. Fall in body
temperature of Awassi sheep after return from pasture at noon. (Source: Eyal,
1963a)
The effect of docking on body
temperature has been investigated by Juma, Gharib and Eliya (1971) in five
docked and five undocked Awassi rams, approximately 19 months old, that were kept in open sheds at Abu-Ghraib
in Iraq during the four hottest months of the year. The data were recorded at
10.00, 14.00 and 18.00 h. In both groups the monthly variation in rectal
temperature displayed a similar trend to that of ambient temperature
(Fig.
1-34). In the undocked rams the rectal temperature averaged 39.10°C and in the
docked rams 39.03°C, the effect of docking on body temperature being
statistically significant.
Figure 1-34. Monthly
variation in rectal temperature in docked and undocked Awassi rams. (Source: Juma,
Gharib & Eliya, 1971)
There was a highly
significant diurnal variation in the rectal temperature of both groups; the
lowest temperatures were recorded at 10.00 h (undocked rams 39.02°C and docked 38.91°C)
and the highest readings at 18.00 h (undocked rams 39.28°C and docked rams
39.21°C).
The positive
correlation between rectal and ambient temperatures indicates that the heat
produced and accumulated in the body exceeded the heat lost. Docking resulted
in a greater efficiency of heat regulation, as shown by the lower rectal
temperatures in the docked animals. The authors suggest that this may be
because of the thicker layer of subcutaneous fat, greater air circulation
around the hindquarters and the improved heat-regulating capacity of the
scrotum.
Skin and fleece temperatures. Fleece provides shade for the sensitive unpigmented skin of the Awassi and encloses a layer of still air which forms a thermal barrier between the epidermis and the environment. Eyal (1963d) has estimated that the Awassi sheep traps approximately 80 1 of air in its 8-cm-long winter fleece and 501 in the 5-cm-deep summer fleece. This layer of air has a microclimate of temperature and humidity that is governed by the physiological activity of the skin and by changes in the ambient macroclimate. The changes occurring in the microclimate always lag behind environmental changes. Shorn sheep are entirely affected by the macroclimate and respond to changes in ambient temperature more quickly than unshorn sheep. The skin temperature, as well as the humidity and temperature within and on the surface of the fleece during various seasons of the year, at different ambient temperatures, in the shade and under direct sunlight, has been studied by Eyal (1963d) in shorn and unshorn Awassi ewes.
A rise in ambient temperature in the shade from 10 to 43°C is accompanied by an increase in skin temperature from approximately 34 to 40°C in unshorn sheep, and from 28 to 40°C in shorn ones. At the same rise of ambient temperature the surface temperature of the fleece increases from 13 to 42°C in unshorn sheep and from 16.5 to 39.5°C in shorn animals. (See Table 1-22.)
TABLE 1 -22.
Skin and fleece surface temperatures of unshorn and shorn Awassi ewes in the
shade (°C) | ||||
|
Air temperature |
Skin temperature |
Fleece surface temperature |
||
|
Unshorn |
Shorn |
Unshorn |
Shorn |
|
|
10 |
33.9 |
28.1 |
12.9 |
16.6 |
|
15 |
35.0 |
30.5 |
17.9 |
17.8 |
|
20 |
36.7 |
34.1 |
23.1 |
23.6 |
|
25 |
37.6 |
35.3 |
26.7 |
28.3 |
|
30 |
37.4 |
34.9 |
31.8 |
31.7 |
|
35 |
37.9 |
36.1 |
36.4 |
34.9 |
|
40 |
39.0 |
39.5 |
40.1 |
37.9 |
|
43 |
39.7 |
39.9 |
42.4 |
39.5 |
Source: Eyal, 1963d | ||||
TABLE 1 -24. Skin
temperatures of Awassi sheep standing in the sun at various air temperatures (°C) | ||||
|
Air
temperature |
Exposed
part |
Shaded part |
||
|
Unshorn |
Shorn |
Unshorn |
Shorn |
|
|
19-22 |
39.4 |
38.3 |
38.9 |
33.3 |
|
31-34 |
41.0 |
40.7 |
39.0 |
39.3 |
|
39-42 |
45.5 |
45.7 |
43.4 |
43.3 |
Source: Eyal, 1963d | ||||
TABLE 1 -23. Skin and fleece
surface temperatures of shorn and unshorn Awassi sheep at various winter and
summer temperatures in the southern desert (°C) | |||||
|
Season |
Air temperature |
Skin
temperature |
Fleece surface
temperature |
||
|
Shorn |
Unshorn |
Shorn |
Unshorn |
||
|
Winter |
12 |
32.5 |
27.8 |
13.3 |
15.9 |
|
|
18 |
35.5 |
32.2 |
19.3 |
21.2 |
|
|
25 |
38.9 |
35.6 |
28.5 |
27.9 |
|
Summer |
30 |
37.0 |
35.1 |
32.0 |
31.9 |
|
|
36 |
38.1 |
36.5 |
37.0 |
35.5 |
|
|
42 |
39.2 |
39.6 |
41.8 |
39.0 |
Note. Height of fleece in unshorn sheep, 7 cm in winter and 5 cm in
summer; in shorn sheep, 0.5 cm in all seasons. | |||||
The changes in the
skin temperature of shorn sheep in the course of the day are similar to the
changes of the ambient temperature, while the decrease in the skin temperature
of sheep in fleece sometimes lags behind a fall in environmental temperature.
Skin temperatures rarely exceed rectal temperatures, even at ambient
temperatures above the latter. The relation between the rise in skin and
ambient temperatures shows a step-wise pattern with breaks at similar
environmental temperatures for shorn and unshorn sheep, namely at 15 and 33°C,
although shorn sheep have a lower skin temperature than unshorn ones. Eyal (1963d) suggests that the breaks in the rise of skin
temperature may be due to a rise in the thermal conductivity of the fleece at
these points.
At very high
environmental temperatures, the fleece surface temperature may be lower than
the air temperature, more especially in shorn sheep in which it may sometimes
fall below the skin temperature, suggesting moisture evaporation at the surface
of the coat (Table 1-23).
Although only part
of an animal's body is exposed to direct solar radiation at one time, an
additional heat load is imposed from direct radiation as well as from that of
the sky and ground on sheep standing in the sun. In such conditions the skin
temperature of shorn and unshorn sheep rises markedly and may reach 47°C (see
Table 1-24).
The fleece temperature of unshorn Awassi sheep also increases greatly upon exposure to the sun, with a maximum of 55°C and occasionally of over 60°C midway between the skin and the fleece surface. Eyal attributes the lower temperature at the loose wool surface rather than within the fleece of unshorn Awassi sheep exposed to direct sunlight to convective cooling at the surface (Table 1-25).
TABLE 1-25. Skin and fleece temperatures of Awassi sheep standing in the midday sun at an airtemperature of 41 °C in the southern desert | |||||
|
Group |
Side
of body |
Temperature
(°C) |
|||
|
Skin |
Middle of fleece |
Fleece surface |
|||
|
Unshorn |
Exposed |
45.0 |
55.4 |
49.4 |
|
|
|
Shaded |
42.3 |
48.2 |
46.9 |
|
|
Shorn |
Exposed |
46.0 |
— |
46.3 |
|
|
|
Shaded |
45.3 |
— |
45.5 |
|
Source: Eyal, 1963d | |||||
The vapour pressure close to the skin of unshorn Awassi sheep
in the shade at ambient temperatures of 30-35°C varies between 35 and 40 mm Hg,
while in shorn animals in the sun or shade it is similar to that of the
environment. In Awassi sheep exposed to direct sunlight, the vapour pressure in the fleece and near the skin may
increase up to 80 mm Hg. Sometimes small drops of secretion appear on the skin.
In the southern desert a rise in vapour pressure
close to the skin is observed when the ambient temperature increases to
40-43°C. This rise in humidity is paralleled by a rise of vapour
pressure throughout the fleece. In unshorn Awassi sheep subjected to direct
solar radiation in the southern desert at an ambient temperature of 40°C, the
skin may become profusely covered with fluid, apparently sweat (Eyal, 1963d).
Pulse rate. Changes in the
muscular or metabolic activity of an animal are reflected in the cardiac output
and pulse rate. Eyal compared the pulse rates in
shorn and unshorn Awassi sheep kept in the shade or in direct sunlight during
different seasons of the year (Figs 1-35 and 1-36). Generally, the variability
of the pulse rate during the day corresponds to the daily changes in body
temperature and metabolic level. In unshorn sheep the fluctuations are greater
than in shorn ones.
Figure 1-35. Average
diurnal trends in pulse rate of Awassi sheep at all seasons in the shade. (Source: Eyal,
1963b)
Figure 1-36. Average
diurnal trends in pulse rate of Awassi sheep at all seasons in the sun. (Source: Eyal,
1963b)
During the summer
the pulse rate is lower than during the winter, namely 60-100 per minute for
unshorn and 63-100 for shorn sheep as against 90-130 for unshorn and 90-115 for
shorn animals. This phenomenon is attributed to lactation during the winter
months. With a rise in ambient temperature, especially during winter and
spring, the pulse rate tends to increase. In summer, on the other hand, a rise
in environmental temperature is accompanied by a lower pulse rate, with the
lowest of 42 per minute on hot dry summer days in the southern desert.
With a rise in rectal
temperature, particularly at low ambient temperatures (10-14°C), the pulse rate
increases in shorn and unshorn sheep. At the same rectal temperatures shorn
sheep have a higher pulse rate than unshorn animals during winter and spring
and on cool summer days. At high ambient summer temperatures equal rectal
temperatures in shorn and unshorn sheep are paralleled by equal pulse rates.
Since the rectal
temperatures of shorn sheep at high air temperatures or in the sun exceed those
of sheep in fleece, the pulse rate of the shorn sheep is correspondingly
higher. Eyal (1963b) suggests that the differences in
pulse rate between shorn and unshorn Awassi sheep reflect the combined effects
of metabolic rate, body temperature and vaso-motor
activity, all of which vary with season and environmental temperatures.
Respiration
rate. Sheep generally increase their respiration rate as
ambient temperatures rise. Panting on hot days suggests an insufficiency of
other cooling mechanisms. Although the respiration rate cannot be used as the
sole criterion in estimating heat resistance in sheep, a breed with a slower
respiration rate upon exposure to heat is generally better adapted to a hot
climate than sheep prone to panting on hot days. This is illustrated by a
comparison of the Awassi sheep of Israel with imported mutton breeds from the
United Kingdom. During the hot hours of summer days the average number of
breaths per minute recorded in Romney Marsh sheep was 170, in Dorset Horn 150
and in Suffolk sheep 128, as against 64 in Awassi sheep kept in the same place
and conditions. The high rate of breathing in the foreign breeds continued even
during the night and before the break of day when ambient temperatures were
generally lower. In consequence their lungs gave in and mortality from lung
troubles was exceedingly high in the imported animals and their offspring
(Epstein & Herz, 1964).
In a trial to examine the responses
of Awassi sheep to heat stress, six male and two female six-month-old unshorn
Awassi lambs were exposed to summer heat without shade (Fig. 1-37). The minimum
and maximum ambient open air temperatures during the trial were 16 and 45°C,
respectively. The mean panting rate of the lambs increased fourfold from the
coolest to the hottest part of the day, namely from 35 to 135 per minute.
German Mutton Merino lambs kept in identical conditions increased their panting
rate from 41 to 199 at the same hours, while their pantings
were shallower than those of the Awassi lambs (Degen
& Morag, 1974; Degen, 1976, 1977c).
Figure 1-37. Panting rate per minute of eight penned Awassi lambs at different
hours of the day. (Source: Degen, 1977c)
In a study of the
respiration rate of shorn and unshorn Awassi sheep in the shade and in direct
sunlight during various seasons of the year and at different hours of the day, Eyal recorded a mean respiration rate throughout the year
of 55 per minute in sheep in fleece and 32 in shorn sheep (Figs 1-38 and 1-39).
The diurnal trends of respiration
rate follow the ambient temperature more closely than the body temperature, the
maximum of which is reached in the evening. However, shorn sheep respond to the
cooler air toward evening more quickly than unshorn sheep, returning to their
basal respiration rate of 20-30 per minute within a short time. Shorn sheep,
therefore, are more efficient in dissipating heat than
unshorn ones in which the reduction of the respiration rate during the cooler
evening hours is delayed. At ambient winter temperatures of 8-25°C the increase
in respiration rate is steeper in sheep in fleece; at ambient temperatures of
22-42°C the increase is steeper in shorn animals. (See Figs 1-40 and 1-41.)
Figure 1-39. Diurnal trends
of respiration rate in Awassi sheep in the sun. (Source: Eyal, 1963c)
Figure 1-40. Rise in
respiration rate with increasing air temperature in Awassi sheep standing in
the sun.
(Source: Eyal, 1963c)
Figure 1-41. Respiration rate of Awassi
sheep at different ambient temperatures in the evening after standing in the
sun during the day. (Source: Eyal,
1963c)
In the shade the
critical temperature for the increased respiration of Awassi sheep is 22°C for
unshorn and 26-30°C for shorn animals. Under direct sunlight the critical
ambient temperature for an increase of the respiration rate is 15-18°C for
unshorn and 18-22°C for shorn sheep. During the hours of greatest heat the
respiration rate of shorn sheep exceeds that of unshorn ones, owing (as Eyal, 1963c, suggests) to the reflection of part of the
direct solar radiation by the fleece and the loss of heat by long-wave
radiation. Yet the overall average respiration rate of the shorn sheep is 74.1
as against 83.5 per minute for those in fleece, for the respiration rate of
shorn sheep decreases very rapidly on the return of the animals from the sun to
the shade.
With similar
rectal temperatures on cold winter or very hot summer days, the respiration
rates of shorn and unshorn Awassi sheep are similar. But at moderate ambient
temperatures unshorn sheep have a higher respiration rate than shorn sheep with
identical rectal temperatures.
There is hardly
any difference in the humidity effect on the respiration rate of shorn and
unshorn Awassi sheep at ambient temperatures below 26°C. However, at air
temperatures of between 27 and 34°C, increasing relative humidity is
accompanied by the higher respiration rate of unshorn sheep in the shade and a
lower one for shorn animals. The opposite obtains in sheep exposed to direct
sunlight. With rising relative humidity the respiration rate of shorn sheep
here not only increases but does so at a steeper rate than in animals in
fleece.
The differences in
respiration rate between shorn and unshorn sheep increase on a windy day. At
ambient temperatures above 18°C the respiration rate of shorn sheep is reduced
by wind, but at lower air temperatures the effect of wind on the respiration
rate of shorn sheep is negligible.
Eyal (1963c) concludes that the differences between the respiration
responses of unshorn and shorn Awassi sheep stem from the differences in their
thermal balance, which again are the result of differences in the insulating
characteristics of the body surface and between the macroclimate and the
microclimate in the fleece.
In a trial on the effect of dehydration on the physiological responses of Awassi sheep (see pp. 37-38), it was found that with a reduction in the daily water ration offered to six-month-old lambs, the panting rate decreased. Degen suggests that this may indicate a reduced amount of respiratory water loss, such as is observed in the Australian Merino and also in Sinai and Syrian mountain goats and in Grant's and Thompson's gazelles (Table 1-26).
In an investigation of the effect
of docking on the respiratory rate of Awassi rams carried out by Juma, Gharib and Eliya (1971) in five docked and five undocked,
approximately 19-month-old rams at Abu-Ghraib in Iraq
during the hottest months of the year, it was found that the monthly variation
in respiratory rate was significantly related to variations in atmospheric
temperature (Fig. 1-42). The docked rams maintained
lower respiratory rates than the control sheep; the average rate of respiration in the undocked rams
was 86.2 per minute and in the docked animals 78.4. The maintenance of lower
respiratory rates by the docked rams, along with lower rectal temperatures (see
Fig. 1-34), indicates that docking in Awassi sheep results in greater
heat-regulatory efficiency.
TABLE 1-26.
Average panting rate of 6-month-old Awassi lambs at different rations of
drinking water | |
|
Water ration (litres) |
Panting rate per minute at 13.00 h |
|
Free |
147 |
|
4.5 |
141 |
|
3.0 |
150 |
|
2.5 |
151 |
|
2.0 |
110 |
|
1.5 |
108 |
|
1.0 |
112 |
Source: Degen, 1976 | |
Figure 1-42. Monthly variation in respiratory rate in
docked and undocked Awassi rams. (Source:
Juma, Gharib
& Eliya, 1971)
TABLE 1 -27. Total body water in Awassi sheep grazing on dry summer and lush winter pastures | ||
|
|
Summer |
Winter |
|
Body weight (kg) |
34.8 |
36.6 |
|
|
25.7 |
25.3 |
|
Total body water (% of body weight) |
73.9 |
69.1 |
|
Source: Degen, 1976 | ||
Water economy and feed intake
under different conditions. Sheep adapted to arid and semi-arid conditions
are characterized by a low water turnover which enables them to exploit scanty
pasture growth in seasons of drought over a relatively wide distance from the
source of water.
In the range of
the Awassi the grazing is generally scarce and poor during summer and autumn so
that sheep maintained solely on natural pastures have to mobilize their fat
reserves during the dry season. During and shortly after the rainy season the
animals increase their body solids and gain weight. These differences affect
total body water and its distribution (see Table 1-27).
The seasonal changes in these respects have been examined by Degen (1976) in four female Awassi yearlings grazing on the dry pasture of abandoned cropland vegetation with a water content of less than 10 percent during October and November, and on shrub (mainly the saltbush species) during December and January, and in four other yearlings grazing on lush native pasture with a water content of 70-85 percent in February and March (see Table 1-28). In December and January the sheep received an additional ration of 500 g of concentrates and 250 g of groundnut straw a day, and in January also an unlimited quantity of onions. The animals had free access to water and shade at the grazing grounds. At night they were penned up. Again, in August nine Awassi sheep were pastured in a paddock with a uniform stand of the legume Medicago polymorpha with a relatively constant water content of less than 10 percent.
TABLE 1-28. Mean water turnover of Awassi sheep grazing on native pasture, shrub and legumes in different months of the year | ||||
|
Type of pasture |
Number
of |
Body weight (kg) |
Water turnover in 24 hours |
|
|
(i) |
(ml/kg body weight) |
|||
|
Native pasture |
|
|
|
|
|
October |
4 |
37.4 |
3.86 |
103.2 |
|
November |
4 |
36.4 |
3.07 |
84.3 |
|
February |
4 |
45.5 |
5.80 |
127.5 |
|
March |
4 |
48.6 |
6.60 |
135.8 |
|
Shrub |
|
|
|
|
|
December |
4 |
35.0 |
6.47 |
184.9 |
|
January |
4 |
35.4 |
4.26 |
120.3 |
|
Legumes |
|
|
|
|
|
August |
9 |
40.5 |
5.61 |
138.5 |
Source: Degen, 1976 | ||||
The animals turned
over more water when grazing on lush plants than on dry plants. However, they
more than doubled their water turnover when moved to saltbush characterized by
a high mineral content. When onions were offered, the water turnover decreased
at a similar rate as the saltbrush intake.
In a study carried
out for the purpose of estimating the water turnover and dry matter intake of
Awassi sheep under winter grazing conditions, Degen
examined five yearling ewes which were kept in fenced paddocks of sown barley
pasture for 24 hours a day (Table 1-29). The animals did not have access to
free water, which in any case is rarely taken by Awassi sheep pastured on
luscious grazing in winter. The trial lasted for five days in February and was
repeated for six days in March when the barley had a higher dry matter content,
namely 32.8 percent as against 18.5 percent in the previous month.
Estimated from the
water turnover, the sheep on average consumed 0.82 kg of dry matter per day in
February, and 1.51 kg in March (see Table 1-30). Based on a field estimate, the
mean dry matter intake per animal was 0.74 kg a day in February and 1.28 kg in
March. The total water intake per sheep in 24 hours was 3.61 in February and
3.11 in March.
In a trial carried out for the purpose of determining the water and feed intake of Awassi sheep under summer grazing conditions, Degen (1976) kept seven eight-month-old ewes and two rams with a mean body weight of 40.5 kg on a dry pasture of Medicago polymorpha during two periods of ten days each from 6.00 to 19.00 h a day. Weighed water was offered to the animals every morning and the remaining water was weighed at 19.00 h. The evaporation loss was determined separately.
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Another Awassi
ram, of similar age and body weight, was placed outdoors in a metabolic cage
near the grazing paddocks and was offered weighed herbage collected from the
field and weighed water at 6.00 h each day. The remains of the herbage and
water were weighed at 19.00 h. The animal was provided with shade at the same
times at which the grazing sheep were observed to be in the shade.
The water turnover
was estimated for the pastured sheep and the caged ram and the difference
between the daily mean of the total water turnover and water drunk was used to
estimate the mean daily herbage intake (Table 1-31).
In three tests with Awassi sheep in
the Negev desert of Israel during the hot month of August, Chen (1976) found
that differences in age, ambient temperature and feed did not appreciably alter
the water-to-feed ratio of 3:1 in total feed and water consumption, although
actual intakes of water and feed were changed by temperature, age and feed to a
greater or lesser extent (Table 1-32). Seven six-month-old lambs were tested in
each of two trials and in the third trial seven 2- to 2 ½-year-old ewes. The animals were kept in separate boxes during the
tests. In the first test the boxes were placed under the roof in a
well-ventilated shed. In the second test the boxes were exposed to direct
sunlight. In the third test with adult ewes, which were kept in the shade of a
screen cover for part of the day, the effect of differences in age and feeding
ration from those of the lambs on feed and water intake was tested. The lambs
were fed ad libitum a balanced ration of
concentrates and cotton-seed hulls containing 15.9 percent protein, while the
adult sheep received, also ad libitum, dry
natural pasture herbage, finely chopped, with a protein content of 4.8 percent.
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||
The water and dry
matter intake of the adult sheep was approximately 60 percent lower than that
of the lambs, while the ratio of water to feed was similar. The water intake of
the lambs kept in the sun was slightly greater than that of those kept in the
shade, but the difference was not statistically significant.
The mean water
intake of the adult ewes markedly differed between six four-hour periods of the
day. Thirty-five percent of the day's total water consumption was drunk during
the early hours of the day, from 7.00 to 11.00 h. The feed intake, on the other
hand, showed only slight differences in the six four-hour periods (Chen, 1976).
(See Fig. 1-43.)
Figure 1-43. Water
and feed (dry matter) intake of adult Awassi ewes at different hours of the
day. (Source: Chen, 1976)
In eight Awassi
lambs individually penned in the Negev desert of Israel in the hot summer sun
without shade, the mean ratio of feed (dry matter) to water intake, which with
normal feeding and watering was 1:2.9, changed after a 24-hour starvation
period to 1:3.7 (Benjamin, Degen & Vachnich, 1974).
In a study of the
physiological responses of Awassi sheep to a restricted water supply under
semi-arid summer conditions, Degen (1976,1977d) kept
three six-month-old male lambs in individual pens in a shadeless
place during the hot dry summer months of May and August. Before the beginning
of the trial the animals were adjusted to these conditions for a fortnight.
During the first ten days of the test they were allowed to eat and drink ad libitum in order to determine their normal feed and
water intake, the latter being 4.67 1 a day. The daily feeding ration during
the trial consisted of 1.8 kg of concentrates and 0.2 kg of straw, while the
water was rationed to 4.5, 3.0, 2.5, 2.0, 1.5 and 1.01a day for 9-12 days at
each level. The feed and water remains were weighed daily and the sheep were
weighed every two days. At the end of the experiment the animals again had free
access to water.
With free or 4.51
of water a day offered in the morning, the lambs took most of it in one
drinking. When offered 3.01 or less, they drank all the water at once. With a
reduction in the water ration the feed intake decreased, but the ratio of water
to feed remained constant at approximately 3:1 until the water ration came down
to 2.01 a day. At this point the lambs ceased eating almost completely and the
ratio of water to feed widened.
The lambs gained
weight as long as water was freely available or a 4.5-1 daily ration was
offered. They began to lose weight when the water ration was reduced to 2.51.
Most of the loss in body weight consisted of water. The total loss was 7.8 kg,
or 19.3 percent (Table 1-33).
Following
dehydration and a loss of 19.3 percent in body weight, the lambs, upon again
having free access to water, drank 7.11, or 21.8 percent of their last weight,
which represented 91 percent of their weight loss of 7.8 kg.
At the commencement of the trial the water content of the faeces was 65 percent. This gradually decreased to 45 percent with a reduction of the water ration to 1.01 a day (Table 1-34).
The faeces, which normally formed small smooth pellets, became
increasingly irregular in shape during the course of dehydration.
With a reduction in the water ration the concentration of the urine increased to an osmolality of 3 230 mosm per litre of H2O, and the ratio of urine to plasma from 2:5 to 8:3 (Table 1-35).
In a study of the changes of total body water and water turnover of Awassi ewes during the third, fourth and fifth months of pregnancy and the first month of lactation, Degen (1976,1977b) observed six pregnant and four unbred animals, maintained on natural pasture (Tables 1-36 and 1-37). During the fifth month of pregnancy the ewes received an additional ration of 500 g of concentrates and 250 g of groundnut straw, and during lactation a further addition of unlimited quantities of onions. At pasture, water and shade were within easy reach. At night the ewes were penned up. In the course of the test period the mean daily air temperature decreased from 22.7 to 11.1°C, while the mean relative humidity rose from 61.3 to 69.4 percent.
|
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TABLE 1 -36.
Mean weights and total body water (kg) of Awassi ewes in last 3 months of pregnancy and 1st month of
lactation, and of unbred ewes during same months | |||||
|
Month of pregnancy or lactation |
Pregnant or lactating ewes |
Unbred
ewes |
|||
|
Weight |
Total
body water |
Weight |
Total body water |
||
|
3rd pregnancy month |
56.3 |
41.9 |
37.4 |
26.7 |
|
|
4th pregnancy month |
56.9 |
43.1 |
36.4 |
26.8 |
|
|
5th pregnancy month |
54.9 |
41.6 |
35.0 |
25.5 |
|
|
1st lactation month |
44.8 |
32.2 |
35.4 |
25.8 |
|
|
Source: Degen,
1977b | |||||
TABLE 1 -37.
Mean water turnover (I and %
of body weight) of Awassi ewes in last 3 months of pregnancy and 1st month of
lactation, and of unbred ewes during same months | ||||
|
Month
of pregnancy or lactation |
Mean water turnover per ewe in 24
hours |
|||
|
Pregnant |
Unbred |
Pregnant |
Unbred |
|
|
(I) |
(I) |
(% of body weight) |
||
|
3rd
pregnancy month |
5.36 |
3.86 |
9.6 |
10.3 |
|
4th
pregnancy month |
4.88 |
3.07 |
8.5 |
8.4 |
|
5th
pregnancy month |
10.37 |
6.47 |
19.2 |
18.6 |
|
1st
lactation month |
6.91 |
4.26 |
15.3 |
12.4 |
Source: Degen,
1977b | ||||
The ewes of both groups, pregnant and unbred, lost weight during those months in which Awassi ewes are generally in lamb because at this time of year pastures are dry and of low nutritive value. At parturition the loss of weight (fluids, lamb and foetal membranes) amounted to 18.2 percent of the mean body weight; most of this consisted of water. The percentage of total body water increased during the test period in both groups, save for the fifth month during which it remained constant in the non-pregnant ewes. During the fourth month, when grazing on saltbush, all ewes more than doubled their water intake. During the lactation period the suckling ewes increased their water turnover by 29 percent.
Seasonal changes in the thyroid
gland and trachea. The seasonal changes in the thyroid gland of
one-year-old unimproved Awassi rams have been studied in central Iraq where the
climate is characterized by a long, very hot and dry summer season and cold,
humid winters. In summer, temperatures in the shade may rise to 50°C, and in
July and August the mean maximum temperature exceeds the body temperature of
sheep each day. During the coldest months the mean minimum temperature is
approximately 4°C. In summer the relative humidity is usually below 20 percent,
but in winter it may reach 100 percent.
A hundred thyroid
glands were examined in summer and the same number in winter (Injidi, Kassab & Rollinson, 1968). The mean weight of the glands was 1.78 g
(0.95-3.61 g) in winter and 2.28 g (1.05-3.10 g) in summer, the seasonal
difference being statistically highly significant. The mean diameter of 20
follicles from five glands each, examined in winter, was 152.1 μ (80.0-201.4 μ), and from the same number in summer 87.6 μ. (52.8-140.7 μ), the
seasonal difference being statistically significant.
Microphotographs
of sections of the thyroid gland show marked differences in the colloid within
the follicles. In the hot season the colloid is of a uniform
consistency (Fig.
1-44), whereas a marked tendency to cross-striation artefacts
is observed in colloids from glands in winter (Fig. 1-45). Further, in the hot
season there is a widespread and pronounced tendency to vacuole formation in
the periphery of the colloid, while in winter such vacuole formation is
negligible.
Figure 1-44. Section of thyroid gland of male Awassi sheep in summer. (Source: Injidi,
Kassab & Rollinson,
1968)
Figure 1-45. Section of thyroid gland of male Awassi sheep in winter. (Source: Injidi,
Kassab & Rollinson,
1968)
The authors suggest that in Awassi rams (which have lower thyroid activity than females), the larger size of the thyroid gland in summer may indicate increased thyroid activity. Again, the greater size of the glandular follicles in winter may be a result of an increased use of the products of the gland in summer and increased storage from reduced activity in winter.
This is confirmed
by a study of the thyroid of unimproved Awassi rams in Israel during different
seasons of the year. Volcani (1957) found that the
lumen of the thyroid greatly expands from June to September and the colloid
increases in quantity and changes from numerous drops to a smooth condition.
The height of the epithelium lessens from 6-7 to 2-4 μ, and its cuboidal columniform
condition gradually levels down, indicating the absence of activity and the end
of accumulation. The nucleus completely fills the cellular space. In June the
thyroid still produces a considerable quantity of secretion for partial
storage; during July-September accumulation reaches its peak and the thyroid
ceases to secrete.
Thyroidal activity
coincides with the main breeding season of the Awassi. In June and July the
highly active gland utilizes the accumulated colloid. In August and September
colloid accumulation increases again and the activity of the epithelium shows
signs of slowing down.
In Awassi rams in
Iraq the mean internal diameter of the trachea was 16.8 mm in winter and 19.8
mm in summer. Injidi, Kassab
and Rollinson assume that the larger tracheal
diameter in summer is caused by panting.
Haemoglobin
types in Awassi sheep. In adult sheep of different breeds three haemoglobin types occur, namely Hb-A,
Hb-B, and Hb-AB, which are
distinguishable by paper electrophoresis. The Awassi breed of sheep is
overwhelmingly of the haemoglobin type B. In sheep
from bedouin flocks in the Beersheba area of Israel,
a frequency of 0.06 of Hb-AB was recorded, and in
fellahin flocks in the Nazareth area a frequency of 0.08. In an improved Awassi
dairy flock of a Jewish communal settlement there were no animals of the Hb-A or AB types (Reshef, 1965),
but in another similar flock, Perk, Frei and Herz (1964) found one adult animal of Hb-AB
type among 61 lambs and ewes. Evans, Harris and Warren (1958) noted the
complete absence of Hb-AB-A in 39 Awassi sheep from
Israel and a frequency of 0.05 in 47 animals of the same breed from Iraq. It
would appear that sheep with Hb-B are better adapted
to the environment of Israel than are animals with Hb-A
or AB, and that selection for high milk yields has led to the disappearance of Hb-A from improved dairy flocks (Eyal,
1968). Reshef recorded the particulars given in Table
1-38 of Hb-B in samples from ten improved Awassi
dairy ewes.
| |||||||||||||||||
The paper electrophoretic haemoglobin
pattern in sheep shows the existence of two distinct erythrocyte populations,
one containing foetal and the other adult haemoglobin, which differ in several chemical,
physiological and physical properties. In the blood of new-born Awassi lambs an
average amount of 74.8 percent of foetal haemoglobin has been recorded, indicating that the synthesis
of adult haemoglobin (Hb-B)
commences before birth. With advancing age, foetal haemoglobin diminishes until its complete disappearance
after six to eight weeks (Perk, Frei & Herz, 1964).
Blood serum
proteins and lipoproteins. The electrophoretic
analysis of the blood serum of Awassi yearling ewes reveals the existence of
seasonal variation in the composition of serum proteins in this breed. During
the hot season of the year the concentration of proteins in the serum is
considerably higher than in winter (Table 1-39) (Peeri,
1963).
The higher protein concentration in summer results from an increase in the quantity of albumin in the serum, accompanied by a reduction in the ratio of the other protein fractions. Peeri holds that the larger albumin concentration facilitates the incorporation of fluids with the blood plasma and prevents excessive dehydration, hence increasing resistance to high ambient temperatures. Thus, Awassi sheep bred in the hot Beyt Shean valley, 244 m below sea level, have a higher percentage of albumin in the blood plasma than Awassi sheep of the same sex and similar age and conditions at a place 138 m above sea level (Table 1-40).
TABLE 1 -40. Mean percentages of electrophoretic
protein fractions in the blood plasma of Awassi sheep in two different climatic
regions | |||||||||
|
Climate |
Albumin |
Globulins |
Total |
||||||
|
α1 |
α2 |
α3 |
β1 |
β3 |
γ i |
γ 2 |
|||
|
Hot |
51.5 |
2.9 |
3.8 |
10.1 |
5.9 |
5.4 |
13.9 |
6.5 |
100.0 |
|
Warm |
44.9 |
3.8 |
6.0 |
10.7 |
4.5 |
5.5 |
16.3 |
8.3 |
100.0 |
Awassi sheep
possess a higher albumin concentration in their blood serum (44.9 ±3.8 percent)
than do German Mutton Merino (42.3 ±4.7 percent) and Corriedale
sheep (42.1 ±3.9 percent) in the same environment. This is believed to be one
of the factors responsible for the superior adaptation of the Awassi to a warm
climate. Yet total protein contents in the blood plasma of the Awassi are lower
than those of the imported Corriedale and Mutton
Merino breeds, namely 6.18 ±0.75 g% against 6.79 ±0.82 g% and 6.70 ±0.68 g%,
respectively.
In an
investigation of proteins and lipoproteins in the blood serum of 42 improved
Awassi sheep of different age groups and of both sexes, Perk and Lobl (1960) found that total serum proteins increased with
age in both males and females. In three-month-old male lambs 100 ml of serum
contained 5.65 g of protein, in yearling rams 6.95 g, and in three-year-old
rams 7.02 g. In female Awassi sheep the total protein contents in 100 ml of
serum rose from 5.78 g in three-month-old lambs to 7.12 g in yearlings and 7.36
g in adult lactating ewes. The increased total protein values result from a
rise in the globulins, especially pronounced in lactating ewes. Thus, in males
of the above three age groups, the albumin-globulin ratio dropped from 1:85 to
0:91-0:90, and in females from 1:75 to 0:99-0:77, respectively.
The same trend was
observed in the paper electrophoretic serum pattern,
which consists of seven fractions. A comparison between three-month-old and
adult males showed a reduction in the relative value for albumin from about 60
percent of the total to 46 percent. The α3 globulin value also dropped, albeit
to a lesser extent. The α2 and β1 globulins snowed no significant differences
between the age groups of the males, but β3 was absent in the older rams. In
the latter, αl globulin showed a slight
rise from 2.3 to 3.1, while the γ-globulin value rose from about 11 percent of
the total in the three-month-old male lambs to 23 percent in the older rams.
The γ2 fraction was absent in young
lambs; in the older rams it represented 6.8 percent of the total value. The female
Awassi sheep showed the same trend, but in lactating ewes the changes were more
marked. Thus the albumin value dropped from 61 percent in the three-month-old
female lambs to 41 percent of the total proteins in the ewes in milk, while the
combined γ-globulins rose from 11 to 36
percent. There are, therefore, no significant differences in the values for the
protein fractions of both sexes in the three-month-old lambs or the yearlings,
but the lactating adult Awassi ewes have lower albumin and higher γ-globulin values than rams of the same age.
Perk and Lobl (1960) suggest that these differences
are related to the endogenous female hormone secretion.
The authors found
no marked differences in the paper electrophoretic
protein patterns between adult Awassi and adult Rambouillet, Corriedale, Somali, East Friesian and Romney Marsh rams. In
lambs the high albumin-globulin ratio characteristic of the Awassi was also
found in Rambouillet and Karakul lambs.
The paper electrophoretic lipoprotein pattern of sheep serum shows
four distinct bands, referred to as albumin and α, β, and γ-lipoproteins. With increasing age the
lipoproteins from the albumin region decrease, a phenomenon most distinct in
lactating ewes, namely from 49.5 percent in three-month-old lambs to 33.4
percent in ewes in milk. In rams there is practically no change with age in the
α-lipoprotein, but in lactating ewes a
slight increase has been recorded. The most striking differences occur in the β-lipoprotein, where an increase of about 40
percent was found in yearlings and of 100 percent in adult ewes above its value
in three-month-old lambs. At the same time, the lipoprotein bound to the γ-globulin decreases in lactating ewes by about
15 percent (Perk and Lobl, 1960).
The analysis by Perk and Lobl of the blood serum of four 91-day-old, male, fat-tailed Awassi lambs and six lambs of the same breed and age that had been docked on the third day after birth showed only very slight and statistically insignificant differences in the protein and cholesterol contents of the blood serum and in the paper electrophoretic distribution of the protein and lipoprotein pattern between the two groups (Epstein, 1961) (see Tables 1-41 and 1-42).
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
This indicates that the synthesis of the blood serum proteins and lipoproteins was not affected by the docking of the fat tail and conforms with the almost equal liver weights of both groups as well as with the high rate of body fat accumulation in the docked lambs, which nearly counterbalanced the inhibited fat tail (see also p. 200, paras. 2 and 3, and Table 5-13).
