The woolly fleece of the Awassi
seems to be a very early achievement of sheep breeders in southwest Asia, being
traceable to the urban revolution in Mesopotamia. In Sumer sheep breeding, wool
spinning and weaving were organized by the temple authorities of the various
cities. In the territory of Lagash, more than 15 000 people were employed in
the wool industry. In the Baba (Baü, Ba'u) temple in Lagash, the several
operations of textile manufacturing were allotted to three distinct groups of
craftswomen, made up of 127 slave girls and 30 of their children. Forty female
slaves cleaned and prepared the wool from the goddess's flocks, eighteen others
did the spinning, and a third group the weaving.
Sorting was done by the weavers. The wool was plucked from the sheep in a
special compound outside the temple precincts. The average yield was 666 g — or
715 g according to another account — for each animal. Part of it was
distributed as rations to members of the community and another part was
exported. The best quality in Lagash, Drēhim and Ur came from 'fat-tailed sheep
from the mountains'; black wool was of the lowest quality. The goddess also
possessed breeding stock to ensure the production of good raw material. The
flocks were tided over periods of drought with barley (Childe, 1942; Frankfort,
1951; Waetzoldt, 1972).
Nuzi documents of
about 1500 BC mention Canaanite wool and discuss the wool of the sheep of
ancient Palestine (Breasted, 1935). The histological examination of parchment
samples from early scrolls from Palestine indicates that 2 000 years ago local
wool was finer than that of the recent Awassi breed (Ryder, 1962). The sheep
skin has two kinds of follicles: primaries and secondaries. Primary follicles
are large and are basically arranged in groups of three known as trios. In wild
and hairy domestic sheep, these produce the long, coarse, hairy fibres of the
outer coat. The secondaries are smaller and more numerous than the primaries
and in wild sheep they produce the fine woolly fibres of the undercoat. Being
shorter than the hairs, they are obscured by them. The fundamental difference
between the primary and secondary follicles that distinguishes them in the skin
is the association of the primary follicle with a sweat gland and erector
muscle, and the absence of these in the secondaries. Both types of follicle do,
however, have sebaceous glands. In the evolution of woolled sheep, a gradual
movement of the secondaries from between the primaries seems to have taken
place, accompanied by a decrease in size of the primaries, their closing
together, and a tendency to grow less hairy fibres. On this basis Ryder found
that among 20 samples of parchment from the Dead Sea (Qumran) Scrolls (about
100 BC-AD 69) and five from the nearby site of Murabba'at (about AD 130-135),
there were some that had nearly as large groups of fine fibres as are
characteristic of recent Merino sheep, fibres as fine as in the Merino, and a
surface scale pattern of the fibres also suggestive of the Merino.
While the evidence
provided by the parchments demonstrates that a certain number of true
fine-wooled sheep did exist in Palestine before the Christian era, more recent
evidence from wool cloth from caves near the Dead Sea, dated about AD 130,
shows that although the wool appeared fine to the naked eye, thus supporting
the ancient records of fine wool, microscopic examination revealed a certain
proportion (15-20 percent) of medium fibres within a majority of fine fibres,
indicating a fleece type more primitive than the true fine-wooled (Ryder,
personal communication, 1963).
The cloth referred
to was part of the material from the 'Cave of Letters' near the Dead
Sea, which comprised
six pieces of leather, one specimen of unspun wool, one of yarn, and two of
cloth, that had belonged to Jewish rebels against Roman rule. The scale pattern
of the surface cuticle of the wool fibres was clear, particularly in the medium
fibres, in which an irregular-waved mosaic pattern could be discerned. Some of
the medium fibres from the leather had an irregular mosaic pattern lacking a
wave. Wool from the two pieces of cloth was non-medullated, but a few of the
medium fibres from the unspun wool had a fragmental medulla.
Some fibres from the yarn had an interrupted medulla, while others had an
unbroken medulla for an appreciable length and could therefore be regarded as
fine hairs. One of these fibres, 44 μ in
diameter, had a medulla 12 μ wide, while
a fibre from a parchment of the Dead Sea Scrolls was only 16 μ in diameter, yet had a medulla 12 μ wide and was apparently from a hairy
sheep. The mean fibre diameter of the unspun wool from the Cave of the Letters
was 24 μ, of the yarn 30 μ, and of the two pieces of cloth 24 μ and 25 μ,
respectively. The fibre diameter of the unspun wool and the cloth ranged
from 10 to 48 μ, and of the yarn
sample up to 54 μ. The diameter
frequency had a skewed distribution with the greatest number of fibres in the
fine diameter range (see Fig. 6-1). This explains why the specimens appeared
fine to the naked eye, whereas in fact most of them came from sheep of a
medium-wooled type. Only one was from a fine-wooled sheep with a fibre diameter
ranging from 16 to 24 μ, similar
to the fibres from the Dead Sea Scrolls (10-28 μ)
(Ryder, 1964).
In the patriarchal
household of barbarism, sheep breeders probably did not pay particular
attention to the colour of their flocks, which comprised white, tan, grey,
black, and variegated animals. Laban's flocks, which were herded by Jacob with
such profitable results to himself, included brown, variegated and speckled
sheep. The unpigmented wool of the Awassi and other breeds of sheep is traceable to the purple-dyeing industry, first developed
on a large scale on the coast of Phoenicia, which provided the impetus for the
gradual elimination of coloured sheep from improved flocks, for none but a
black dye can be used on wool that is black, tan or grey. As
the extension of murex fishery
started the Phoenicians on their maritime career, purple dyeing spread
throughout the Mediterranean region, and with the dyeing industry, extended the
demand for white wool (Epstein, 1955).
The pigmentation
of the head of the Awassi is probably a result of artificial and natural
selection. It is of value in subtropical regions characterized by intense solar
radiation as it provides immunity to affections associated with the extreme
photosensitivity of unpigmented and exposed areas of the head and ears.
Pigmentation of the hoofs and lower part of the legs serves to strengthen them.
Yield.
For the wool of improved Awassi sheep in Israel, Becker (1958) gives a
clean scoured yield of only 40-50 percent, but the fleeces of 45 improved
Awassi ewes of different ages, examined by Goot (1972), yielded 74.6 ±7.0
percent scoured wool.
In Lebanese Awassi
flocks, the normal yield of scoured wool averages 50-60 percent. In a flock
kept at the experimental farm of the American University of Beirut, the annual
average yield in two successive years was 66.3 percent (McLeroy & Kurdian,
1958).
In 147 samples of
wool of six months' growth from 9-, 15-, 21-, 27- and 33-month-old Awassi ewes
of Syrian derivation in Egypt, shrinkage varied between 20.2 and 31.3 percent,
with an average of 25.4 percent. The greasy fleece weight of sheep of all ages
averaged 1.308 kg, and the clean scoured fleece weight 0.976 kg, that is, a
yield of 74.6 percent. Age had no significant effect on yield (Ghoneim, Ashmawy
& El-Mekkawi, 1967).
At the Hofūf Agricultural Research Centre, Saudi Arabia,
patch samples of wool of six months growth were taken from the right mid-side
of 20 ewes and 15 nearly four-month-old lambs of an improved Awassi flock
originally imported from Syria. After washing with a non-ionic detergent and
drying in the controlled atmosphere of a wool laboratory in Bangor, Wales, the
mean percentage yield of clean wool from the ewes was 77.9 and from the lambs
77.5, the shrinkage being attributed to the loss of some grease and a larger quantity
of dust, for the sheep were kept in dusty yards (Pritchard, Pennell &
Williams, 1975).
At the Ereğli Animal Breeding Research Station in central
Anatolia, a flock of İvesi sheep had
an average clean wool yield of 61.2 percent during two years of examination (Yalçin & Aktaş, 1969). Imeryüz, Müftüoğlu and Öznacar (1970) recorded a slightly
higher mean yield of scoured wool of 12 months' growth in adult İvesi sheep in
Turkey, namely 66.8 percent. In wool samples taken from the hip region, the
clean fibre yield was 77.0 percent for rams, 71.7 percent for ewes, and 78.2
percent for yearlings.
Figure 6-1. Distribution of fibre diameters in unspun wool from a cave near the Dead Sea, AD 130. (Source: Ryder, 1964)
In Iraqi Awassi
ewes, stationed in Abu-Ghraib near Baghdad, the mean yield of wool of 12
months' growth from 18-, 24-, 36- and 48-month-old animals ranged from 84.0 to
85.6 percent, with an overall average of 84.85 percent. As in the case of the
Syrian Awassi sheep in Egypt, the age of the ewes had no significant effect on
the scoured wool yield. The low shrinkage is attributed by Sharafeldin (1965)
to the comparatively small number of sudoriferous and sebaceous glands in the
wool-follicle structure of the Awassi.
Fibre types.
The Awassi is a long-wool sheep with an open, lofty and moderately lustrous
fleece of carpet wool with distinct wide crimps (Nichols, 1932). The fleece
consists of an outer coat, undercoat and kemp. It has the principal requisites
of carpet wool, namely, coarseness and resilience, qualities that make carpet
wool resistant to matting and wear. An ideal carpet
wool should have a fibre diameter of 30 μ,
a fibre length of 10 cm with a 20 percent variation in length and 4 percent by
weight of kempy fibres. Awassi wool complies with these requirements as regards
fibre thickness and length, but the fibre length variation and kemp contents
are somewhat larger.
The scales on the
surface of the fine fibres of the undercoat are arranged tile-like, not in
rows. The stronger fibres of the fleece are lustrous and more or less uniform,
save for their greater fineness toward the tips. The scales covering their
surface are broader and relatively shorter than those of the fine fibres
(Apler, quoted by Becker, 1958).
In fleeces of
Syrian Awassi sheep, Erokhin (1973) recorded the percentages of fibre types by
weight (Table 6-1). Table 6-2 gives the mean percentages of coarse, fine and
kemp fibres for clean wool samples of six months' growth taken from 20 ewes and
from 15 nearly four-month-old lambs of an Awassi flock of Syrian derivation at
the Hofūf Agricultural Research Centre
(Pritchard, Pennell & Williams, 1975).
Considerable
variability existed between individuals. Kemp fibres, shed in the fleece, were
present in most samples from the ewes and one sample consisted of 40 percent
kemp. No recognizable kemp fibres were found in any of the samples taken from
the lambs that were too young for the first
growth of
kemp fibres to have already occurred, but variability between samples in the
proportions of coarse and fine fibres was similar to that found in the ewes.
At the Ereğli Animal Breeding Research Station, wool of
12 months' growth taken from the hip region of İvesi sheep had the fibre-type
ratios given in Table 6-3 (Imeryüz, Müftüoğlu
& Öznacar, 1970).
In 264 samples of
wool of six months' growth from 9-, 15-, 21-, 27- and 33-month-old Awassi ewes
of Syrian origin in Egypt, Ghoneim, Ashmawy and El-Mekkawi (1967) recorded the
mean fibre-type ratios (Table 6-4).
The total average
ratio of undercoat, outer coat and kemp fibres was 69.7:24.4:5.9 by count, and
41.4:54.2:4.4 by weight, the estimate of the percentages of fibre type by count
being considered to be more accurate than by weight. The relatively high
percentage of kemp fibres by count as well as by weight clearly shows that the
Awassi has a kempy fleece.
There is no appreciable
difference in the ratio of outer coat, undercoat and kemp fibres among the
different ages of the sheep, but the location of the wool on the body has a
significant influence on the percentages by weight of the fibres. For the outer
coat and kemp the percentages are higher in the hip than in the shoulder region
at all ages (54.9:53.2 and 5.3:3.6, respectively), while the reverse obtains
with regard to the fibres of the undercoat (39.8:43.2) (Ghoneim, Ashmawy &
El-Mekkawi, 1967).
In an examination of
7 500 wool samples of 12 months' growth from the forequarters, sides and
hindquarters of Awassi sheep in three different parts of Israel, Lewin, Horowitz and Zacks (1957) found that
the average percentage of non-elastic, hard and brittle kemp fibres was 11.72
by weight, a figure very close to the mean percentage of coarse hair (11.4
percent) recorded in 800 samples of Israeli Awassi wool of ten months' growth
by Apler (see following section). The wool from flocks in the south of Israel
(Negev) contained the smallest percentage of kemp, namely 6.3 percent, the
samples from the two other parts of the country being 13.3 and 12.3 percent,
respectively. In all instances the wool from the forequarters included a
smaller percentage of kemp fibres than that from the sides and rump (Lewin, Horowitz & Zacks,
1957).
Goot (1972)
recorded the following percentages of hairiness (permanent medullated hair and
kemp) in 260 fleeces of dry yearlings and 25 fleeces of lactating yearlings,
and 134 fleeces of dry ewes and 1 082 fleeces of ewes in milk from improved
Awassi flocks in Israel (Table 6-5). The data indicate that the amount of
hairiness in the carpet wool fleeces of Awassi yearling and adult
ewes is not palpably influenced by lactation.
Nor was the
incidence of cotted fleeces in improved Awassi sheep in Israel affected by
lactation. As the cotting of wool, that is, the matting or entangling of fibres
broken at the base with the contiguous fibres, is influenced by nutrition, Goot
(1972) suggests that the high plane of nutrition prevalent in Awassi dairy
flocks in Israel prevents an increase in the percentage of cots in lactating
ewes (Table 6-6).
|
Fibre type |
Rams |
Ewes |
Yearlings |
|
True wool fibre |
75.8 |
78.2 |
80.8 |
|
Heterotype |
8.1 |
11.8 |
8.1 |
|
Medullated |
8.4 |
3.9 |
6.0 |
|
Kemp |
7.7 |
6.1 |
5.1 |
TABLE 6-4. Fibre-type
ratios in wool of Awassi
ewes at different ages (%) | ||||||
|
Age of ewes (months) |
Fibre-type ratio by weight |
Fibre-type ratio by count |
||||
|
Outer coat |
Undercoat |
Kemp |
Outer coat |
Undercoat |
Kemp |
|
|
9 |
53.8 |
41.3 |
4.9 |
25.4 |
65.1 |
9.5 |
|
15 |
53.8 |
42.0 |
4.2 |
24.9 |
71.6 |
3.5 |
|
21 |
53.0 |
42.5 |
4.5 |
23.6 |
72.8 |
3.6 |
|
27 |
55.9 |
40.1 |
4.0 |
25.4 |
67.7 |
6.9 |
|
33 |
54.6 |
41.0 |
4.4 |
22.7 |
71.3 |
6.0 |
| |||||||||||||||||||||||||||||||||||||||||||||
Staple and
fibre lengths. In fleeces of 12 months' growth from 729
Awassi ewes of various ages in Israel, Goot (1972) recorded a mean staple
length of 13.75 ±3.76 cm.
At the
experimental farm of the American University of Beirut, a flock of Awassi ewes
derived from the stock of nomadic shepherds from the Syrian desert
had fleeces of 12 months' growth with an average staple length of 10.05 cm in
two consecutive years (McLeroy & Kurdian, 1958).
In Turkey the
staple length of İvesi fleeces varies between 12 and 15 cm (Yalçin, 1979). At the Ereğli Animal
Breeding Research Station, wool samples taken from the hip region of İvesi
sheep in three consecutive years just before the annual shearing had the
following average staple lengths: rams, 15.9 cm; ewes, 14.5 cm; yearlings, 15.1
cm (Imeryüz, Müftüoğlu & Öznacar, 1970). In fleeces
of 12 months' growth from 225 Turkish İvesi sheep of varying coat types
belonging to three village flocks, Sidal (1973) measured an average staple
length of 16.4 cm. Staple length was found to decline with increasing age of
the sheep.
In Iraq, the
fleeces of 12 months' growth from 26 one-year-old Awassi rams, improved for
superior wool production, had an average staple length of 9.82 cm, and those of
seven two-year-old and older improved rams 9.68 cm, while the fleeces of 12
unimproved two-year-old and older rams had a staple length of 11.14 cm
(Kaminkova, Al-Azzawi & Rahman, 1967). At Abu-Ghraib, the mean staple
length of the fleeces of 12 months' growth from 268 Awassi ewes was 16.47 cm,
with a variation of less than 0.2 cm for the different age groups (18, 24, 36,
and 48 months). The mean fibre length ranged from 16.94 to 17.68 cm, with an
overall average of 17.37 cm. The small difference between fibre lengths and
corresponding staple lengths is attributed to weak crimp development in the
wool. A significant positive correlation was found between fibre length and
greasy fleece weight, and a highly significant negative correlation between
fibre length and yield, probably owing to the larger amount of impurities in
the long outer coat of the sheep. The age of the ewes had no significant effect
on the staple or fibre lengths. This may be due to the fact that the first
samples were taken at the age of 18 months, while most age differences in wool
characteristics are observed between the first and subsequent years. The lack
of an age effect on staple and fibre lengths may be taken as an indication that
the follicle structure of Awassi wool reaches its full development at an early
age and does not change afterwards (Sharafeldin, 1965).
The average fibre
length of 7 500 samples of Awassi wool of 12 months' growth taken from the
forequarters, sides and hindquarters of 2 500 fleeces from three different
regions of Israel measured 12.57 ±0.71 cm (Lewin, Horowitz & Zacks, 1957). The shortest wool — 10.97 ±0.71
cm — came from the forequarters, and the longest —
13.54 ±0.71 cm — from the side samples, the difference being statistically
significant. The fairly uniform length of the fibres in animals from different
flocks and different parts of the country is attributed to the fact that
shearing is completed in the whole of Israel within two weeks (see Fig. 6-2).
The fibre length of Awassi wool of approximately ten months' growth from 800
sheep of different flocks in Israel ranged from 8 to 23 cm (Apler in Becker,
1958). Table 6-7 gives the fibre lengths recorded by Erokhin (1973) for fleeces
of 12 months' growth from Syrian Awassi sheep.
In a study of 405
wool samples of six months' growth, taken from the shoulder and hip regions of
9-, 15-, 21-, 27- and 33-month-old Awassi ewes of Syrian derivation born in
Egypt, the average fibre length for the different ages ranged from 70.1 to
101.3 mm, with a total average of 85.2 mm. The longest fibres, averaging 122.2
mm in length, were from the outer coat. Those of the undercoat measured 77.6 mm
in average length, while the kemp fibres were shortest, namely 29.2 mm.
The average fibre
length increased from the age of nine to 15 months, and from 21 to 27 months,
Figure 6-2. Frequency distribution histogram of fibre lengths. (Source:
Lewin, Horowitz & Zacks, 1957)
|
Fibre type |
Rams |
Ewes |
|
Heterotype |
16.4 |
13.2 |
|
Undercoat |
11.3 |
9.6 |
|
Kemp |
20.6 |
15.8 |
Figure 6-3a and
b. Distribution of fibre lengths for various fibre
types. (Source: Ghoneim & Ashmawy, 1968)
and
decreased from 15 to 21 and 27 to 33 months. This is attributed to the
different seasons in which the sheep were shorn. The wool samples taken at the
ages of 9, 21 and 33 months were shorn in October of different years, while
those taken from 15- and 27-month-old animals were shorn in April. Wool grown
in summer was generally shorter than that grown in winter. The hip region
produced longer wool than the shoulder region (Fig. 6-3) (Ghoneim and Ashmawy,
1968).
Different types of
fibre in wool samples taken from the mid-side of 20 ewes and 15 lambs of an
Awassi flock of Syrian origin at the Hofūf
Agricultural Research Centre had the mean lengths given in Table 6-8
(Pritchard, Pennell & Williams, 1975).
Fineness.
The average fibre diameter of wool of 12 months' growth from forequarters,
sides and hindquarters, collected in southern Israel (Negev) and two other
areas, was 36.1 μ, equal to a 44s count (Lewin, Horowitz & Zacks,
1957). In all three regions of the country the side wool was finer
TABLE 6-8. Mean fibre length of
different fibre types in wool samples from Awassi ewes and lambs in Saudi Arabia
(cm) | ||
|
Fibre type |
Ewes |
Lambs
|
|
Coarse |
12.0 |
6.8 |
|
Fine |
8.6 |
4.2 |
|
Kemp |
5.3 |
— |
than that
from either the shoulder or rump. Wool fibres from forequarters averaged
approximately
37.0 μ, from the sides 34.3 μ, and the hindquarters 37.0 μ. in diameter. Table 6-9 gives the average
distribution of fibres according to fineness in the wool from the three parts
of the body (see also Fig. 6-4).
In 800 samples of
Awassi wool of approximately ten months' growth taken from different flocks
in Israel, Apler recorded the data in Table 6-10 on fibre fineness (Becker,
1958).
TABLE 6-9. Frequency
distribution of fibre fineness in Awassi wool in Israel (%) | ||||
|
Fineness of fibres (μ) |
Below 30 |
30-40 |
40-50 |
Above 50 |
|
Forequarters |
33.4 |
31.7 |
15.8 |
19.1 |
|
Sides |
42.3 |
29.7 |
11.5 |
16.5 |
|
Hindquarters |
32.5 |
32.4 |
13.9 |
21.2 |
Figure 6-4. Frequency
distribution histogram of fibre fineness in Awassi wool. (Source: Lewin, Horowitz & Zacks, 1957)
TABLE 6-10. Mean percentages of fibres of different
fineness in Awassi wool | ||||
|
Diameter (μ) |
Fibre length (cm) |
Count |
Uniformity |
% |
|
31 |
8-10 |
B II (58/60s) |
good |
13.3 |
|
54 |
13 |
D I (50/52s) |
good |
35.8 |
|
62 |
19 |
E (44/46s) |
medium |
37.0 |
|
90 |
20 |
F (40s) |
medium |
2.5 |
|
120 |
23 |
F (32/36s) |
poor |
11.4 |
Samples of Awassi
wool of 12 months' growth taken from the mid-side of an adult stud ram and
adult ewe of a highly improved dairy flock in Israel, and wool samples from a 4½-month-old male and a five-month-old female
lamb of the same flock were examined by Ryder (personal communication, 1979),
who noted that these were typical of a hairy carpet-type fleece (Table 6-11).
The wool of the
ram was particularly coarse, while that of the male lamb contained some
unusually coarse kemp fibres (Fig. 6-5). Becker (1958) claims that Awassi wool
of brown colour is generally finer than white wool.
In fellahin and
especially in bedouin flocks of Awassi sheep, the wool fibres are uneven in
thickness. The period of malnutrition during the year finds expression in the
growth of finer sections
of the fibres (Kamal, 1981). In fleeces of Syrian Awassi sheep, Erokhin (1973)
recorded the average diameters of the different fibre types (Table 6-12).
TABLE 6-11. Diameter range,
mode, mean and coefficient of variation (CV) of wool samples from an improved Awassi dairy flock in Israel | ||||
|
Sample |
Diameter range (μ) |
Mode |
Mean |
CV
(%) |
|
Ram |
28-132 |
40 |
56.5
±25.1 |
56.5 |
|
Ewe |
16-56,88,98 |
30 |
35.2
±15.9 |
45.3 |
|
Male lamb |
22-56, 140, 146, 150(2), 164,184 |
26 |
43.9
±31.4 |
71.4 |
|
Female lamb |
16-68, 76, 104, 110 |
28 |
35.3
±12.0 |
33.8 |
| Figure 6-5. Awassi wool samples: 1. adult ram, 12 months' growth; 2. adult ewe, 12 months' growth; 3. male lamb, 4½ months old; 4. female lamb, 5 months old |
|
Fibre type |
Rams |
Ewes |
|
Heterotype |
33.7 |
31.9 |
|
Undercoat |
26.4 |
24.0 |
|
Kemp |
56.9 |
49.0 |
At the Ereğli Animal Breeding Research Station, wool of
12 months' growth taken from the hip region of İvesi sheep had the fibre
diameters given in Table 6-13 (Imeryüz, Müftüoğlu
& Öznacar, 1970).
In wool samples
from 26 one-year-old Awassi rams, improved with a view to superior wool
production in Iraq, the average fibre diameter was 22.73 μ, and in seven two-year-old and older rams,
27.27 μ; the wool from 12 unimproved
two-year-old and older Awassi rams had an average fibre diameter of 32.02 μ. (Kaminkova, Al-Azzawi & Rahman, 1967).
In 268 Awassi ewes
in Abu-Ghraib in Iraq, the average fibre diameter of the wool of 12 months'
growth was 33.3 μ, with a range
from 32.8 to 34.0 μ between the
age groups of 18, 24, 36 and 48 months. The age of the ewes had no significant
effect on fibre diameter (Sharafeldin, 1965).
In wool samples of
six months' growth, taken from the shoulder and hip regions of Awassi ewes of Syrian
derivation born in Egypt, Ghoneim and Ashmawy (1968) found that kemp had the
thickest fibres, ranging from 51.4 to 75.8 μ
in diameter. These were followed by the fibres of the outer coat with a range
from 46.5 to 54.5 μ, while those of the
undercoat, measuring 23.9-29.8 μ in
diameter, were the finest. The total average fibre diameter of the samples from
9-, 15-, 21-, 27- and 33-month-old ewes varied between 32.3 and 38.2 μ. With advancing age, the fibre
diameter increased. In ewes of all ages, the wool grown on the hip region was
coarser than that of the shoulder (Fig. 6-6).
Different types of
fibre — coarse, fine and kemp—in wool samples from the mid-side of Awassi ewes
and lambs of a flock of Syrian origin stationed at the Hofūf Agricultural Research Centre had the
diameters given in Table 6-14 (Pritchard, Pennell & Williams, 1975).
|
| ||||||||||||||||||||||||||||||
Figure 6.6 a and b. Distribution of fibre diameters for different fibre types. (Source: Ghoneim & Ashmawy, 1968)
Figure 6-7. Different types of medullae in the outer coat fibres of the Awassi. (Source: Ghoneim, Ashmawy &
Al-Mekkawi, 1968)
Figure 6-8. Different
types of medullae in the kemp fibres of the Awassi. (Source: Ghoneim, Ashmawy & Al-Mekkawi, 1968)
The lambs were
similar to the ewes in the mean diameters of the coarse and fine fibres,
although the coarse fibres in the lambs' wool had a slightly higher mean value
than that of the ewes. The fine fibre diameters were comparable to Merino
wools. The diameters of the kemp in the wool samples from the Awassi ewes were
similar to those typical of the kemp fibres of sheep.
Medullation.
Awassi fleece is highly medullated. The difference in the percentage of
medullated fibres between the outer and undercoats is very large. Scattered, fragmental, discontinuous and
continuous types of medullae occur in the outer coat and kemp (Ghoneim, Ashmawy
& Al-Mekkawi, 1968). Kemp contains the highest percentage of medullated
fibres. (See Figs 6-7 and 6-8.)
The examination of
a large number of samples of wool of ten months' growth from Awassi sheep in
different parts of Israel showed that the fine and moderately fine fibres were
not medullated. The stronger fibres had either a very thin medullary canal or a
discontinuous medulla, present in some sections of the fibre and absent in
others. The coarse wool fibres, permanent hair and kemp had fully developed
medullae from root to tip. Table 6-15 gives the percentages of non-medulalted,
heterotype and medullated fibres (Apler, quoted by Becker, 1958).
In a sample of
wool of 12 months' growth taken from an adult Awassi stud ram of a highly
improved dairy flock in Israel, 23 percent of the fibres were medullated. The
same percentage of medullated fibres was found in wool from a 4½-month-old male lamb of the same flock. Nine
percent of the fibres of the wool of 12 months' growth from an adult ewe and 5
percent of the fibres in a sample from a five-month-old ewe lamb were
medullated (Ryder, personal communication, 1979).
In wool samples of
six months' growth taken from Awassi ewes of Syrian ancestry in Egypt, Ghoneim
and Ashmawy (1968) found 88.0-95.5 percent of the kemp fibres to be medullated.
In the outer coat the percentage of medullated fibres ranged from 61.8 to 71.0,
and in the undercoat from
|
Fineness of fibres |
Medullation |
% |
|
Fine |
Non-medullated |
13.3 |
|
Moderately fine |
Non-medullated or heterotype |
35.8 |
|
Strong |
Heterotype |
37.0 |
|
Very strong |
Medullated |
2.5 |
|
Hair and kemp |
Medullated |
11.4 |
TABLE 6-16. Medullation in wool
from improved and unimproved Awassi rams in Iraq | ||||
|
Type of rams |
Age (years) |
Number |
Discontinuous
medulla (%) |
Continuous medulla (%) |
|
Improved |
1 |
26 |
2.60 |
0.22 |
|
|
2 and older |
7 |
4.19 |
0.79 |
|
Unimproved |
2 and older |
12 |
4.63 |
7.12 |
11.6 to 14.1. The total average
percentage of medullated fibres in all samples was 54.8. The age of the ewes
had no significant influence on the medullation percentage; there was only a
slight decrease of the latter from 57.2 in wool from nine-month-old lambs to
52.7 in 33-month-old ewes. However, a significantly higher medullation
percentage was found in ewes of all ages in the wool samples from the hip than
from the shoulder region.
In Iraq,
Kaminkova, Al-Azzawi and Rahman (1967) compared the percentages of fibres with
continuous and discontinuous medullae between Awassi rams improved for superior
wool production and unimproved rams. The results of their study show that wool
from the improved type contains a considerably smaller percentage of medullated
fibres than that from the unimproved Awassi (Table 6-16).
Crimp.
In wool of 12 months' growth from different age groups (18, 24, 36 and 48
months) of Awassi ewes in Iraq, the mean number of crimps for every 2 cm ranged
from 3.8 to 4.4, with an overall average of 4.18. There was a significant
positive correlation between crimps and fibre diameter, but the age of the ewes
had no significant effect on crimp number (Sharafeldin, 1965). In Awassi
fleeces of ten months' growth in Israel, the fine, non-medullated fibres had
four to six crimps over a length of 1 cm (Apler, quoted by Becker, 1958).
In wool samples of
six months' growth taken from 9-, 15-, 21-, 27- and 33-month-old Awassi ewes of
Syrian derivation in Egypt, the average number of crimps over a length of 2 cm
varied between 4.61 and 5.05 for the ages studied. The wool of the undercoat
had more crimps than that of the outer coat, namely 6.10 on average versus
2.11. With the advancing age of the sheep, the number of crimps was found to
decrease. Wool from the shoulder region was more crimpy
than that from the hip region (Ghoneim & Ashmawy, 1968). (See Fig. 6-9.)
Figure 6-9 a and b. Distribution of crimps in different fibre types. (Source: Ghoneim & Ashmawy, 1968)
Tensile
strength and elasticity. At the Ereğli Animal Breeding Research Station, wool fibres of 12 months'
growth taken from the hip region of İvesi sheep had the absolute tensile
strength and elasticity given in Table 6-17 (Imeryüz, Müftüoğlu
& Öznacar, 1970).
A total of 270
tests of wool from the forequarters, sides and hindquarters of Awassi sheep in
three regions of Israel were carried out by Lewin, Horowitz and Zacks (1957) to
determine fibre strength. The average tensile strength for all samples was 1.24 ±0.01 g/denier (d). There were three significantly
different groups of fibres according to strength: the Negev (southern Israel)
wool from all three parts of the body, the rump wool from sheep in another area
of the country, and the forequarter and side wool from yet another region,
which gave 1.29 ±0.01 g/d. The hindquarter wool from
the third region gave 1.24 ±0.02 g/d, and the side
wool from the second one 1.18 ±0.02 g/d. The authors emphasize the high
strength of the Negev wools compared with the tensile strength of the wool
samples from the two other parts of the country. In all samples tested, a
positive correlation of 0.876 was found between fibre strength and thickness.
This is illustrated by the fact that wool from the sides of the body is
superior in fineness to that of the fore- and hindquarters, though 'rather
weaker'. Fig. 6-10 summarizes fibre strength distribution in the range of
samples investigated, the areas of the rectangle in the histogram being
proportional to the observed frequency (percent) over intervals.
|
|
Tensile strength (g) |
Elasticity (%) |
|
Rams |
19.9 |
32.0 |
|
Ewes |
17.5 |
31.7 |
|
Yearlings |
28.2 |
32.3 |
Figure 6.10. Frequency distribution histogram of fibre strength. (Source: Lewin, Horowitz & Zacks, 1967)
Yolk.
Unscoured Awassi fleeces have a very low yolk
content, a condition largely responsible for fibre and yarn harshness and poor
spinning quality. The quantity of wool fat secreted by the sebaceous glands
varies with season, level of nutrition, and individuality of the animals.
In Iraq, Eliya et al. (1969)
recorded the quantity of grease in the fleeces of four non-lambing and six
lambing three- to four-year-old Awassi ewes at monthly intervals for a year
(Table 6-18). While there was no difference in average body weight between
lambing and non-lambing ewes at lambing time in October and November, the
difference in weight between the two groups in February, toward the end of
winter, was very large (see p. 11). The differences in wool grease between
individual and between lambing and non-lambing ewes, either by unit surface
area of the skin (mg/cm2) or expressed as a percentage of the weight
of the wool taken after washing in cold tap water followed by thorough drying,
were statistically highly significant. This is attributed to the low level of
nutrition and the large
TABLE 6-18. Variation of wool
grease in lambing and non-lambing ewes (% and mg/cm2) | |||
|
|
February |
September |
Annual average |
|
Wool grease (as % of dried wool) |
|
|
|
|
Non-lambing ewes |
1.11 |
0.14 |
0.51 |
|
Lambing ewes |
0.92 |
0.06 |
0.38 |
|
Average |
0.99 |
0.09 |
0.43 |
|
Wool grease (mg/cm2 skin surface area) |
|
|
|
|
Non-lambing ewes |
0.216 |
0.013 |
0.071 |
|
Lambing ewes |
0.117 |
0.007 |
0.042 |
|
Average |
0.156 |
0.010 |
0:054 |
difference
in condition after the winter season between the ewes that had lambed in autumn
and those that had not lambed. Also significant were the monthly differences in
the percentage and quantity of wool grease. These were highest from January to
March and lowest from August to October.
Goot (1972) found
that lactation had no effect on the incidence of canary or yolk stains in
Awassi wool, although in dry yearlings a tendency to a higher percentage (71
percent) of slightly yellow fleeces was observed than in lactating yearling
ewes (58 percent) (Table 6-19).
|
| |||||||||||||||||||||||||||||||||||||||||||||||
Colour. Awassi wool,
delivered to a central collecting station in Israel over a period of several
years, consisted of 90 percent white to yellowish-white wool, 7 percent light
to dark beige, and 3 percent grey, red or black wool (Becker, 1958).
The average colour
distribution of 7 500 samples of Awassi wool from three different regions of
Israel, determined by visual inspection, is given in Table 6-20 (Lewin,
Horowitz & Zacks, 1957).
Wool from the
sides of the sheep was generally superior in colour to that from the fore- and
hindquarters. Negev wool contained a higher percentage of white and a lower
percentage of pigmented fibres than that from the two other regions. Together
with the side wool from one of the other regions of the country, it comprised
41.0 ±1.14 percent white fibres. The side wool from another area contained 33.7
± 2.05 percent white fibres, while the wool from the hindquarters of the two
regions north of the Negev contained only 23.0 ± 0.92 percent of these. The
greatest percentage of dark fibres was found in the hindquarter wool from one of
the two latter areas, namely 5.5 ±0.45 percent.
In Iraq, Asker and
El-Khalisi (1966) counted 5.5 percent coloured ewes among several thousand
sheep of commercial Awassi flocks. Previously, Williamson (1949) had claimed
that 20 percent of the Awassi wool in Iraq was coloured.
