In view of the pronounced dairy
conformation and the large accumulation of fat in the tail, the Awassi is far
from being a mutton sheep. Yet male Awassi lambs and culled ewes and rams now
provide approximately one-half of the income of dairy flocks in Israel, and
nearly the entire income of mutton flocks.
Awassi fat lamb
production has passed several stages since the beginning of improvement of the
breed. Until the founding of the State of Israel in 1948, the male lambs in
improved flocks had to be done away with as soon as possible after birth as the
price relation between milk and lamb rendered it utterly uneconomical to give
the lamb any milk after the colostral stage. This situation, which was also
true for dairy cattle, continued for several years at the end of the 1940s and
the early 1950s in Israel, when meat prices were Government-controlled at a
very low level, while the price of milk was relatively high. The lambs were
slaughtered at the age of two or three days.
Toward the middle
of the 1950s, the Government policy with regard to meat prices underwent a
fundamental change. Prices for locally produced lamb and veal were raised to a
level that made the feeding of male lambs and calves profitable. Awassi lambs
from improved flocks began to reach the market at a live weight of about 12 kg,
a weight at which unimproved lambs used to be marketed by the bedouin and
fellahin at Eastertime. Lambs of greater weight were rejected by butchers who
regarded these as 'mutton'. However, as time went on and consumers did not
object to heavier cuts, the marketing weight of male Awassi lambs was raised
first to 20 kg and later to 30 kg. The greater weight remained in vogue until
the late 1960s when it was again increased to the present level of 45-55 kg.
The large fat tail
of heavy lambs has a negative effect on their sales price, especially during
the hot summer months when a large part of the accruing animal fat has to be
disposed of to soap and candle factories at very low prices. It is only in
recent years that the money value of the fat tail has somewhat increased, owing
to the replacement (introduced by many restaurant keepers in Israel) of the
expensive lamb in the popular oriental dish shashlik by the much cheaper
breast meat of chicken and .turkey. The addition of a piece of tail fat to
every two or three pieces of poultry meat on the spit imparts the flavour of
lamb to the roasted meat. Nevertheless, Awassi lambs still fetch a lower market
price than German Mutton Merino lambs.
In the course of the last three
decades, several slaughter tests with male Awassi lambs have been conducted.
Examples of some of these are given in Tables 5-1 to 5-12, not in the
chronological order of the tests, but in accordance with the increasing weights
at which lambs were sold during the period.
In 1951 the author
recorded the body composition of ten male two-month-old Awassi lambs (Table
5-1). In a slaughter test with five three-month-old male lambs, slaughtered
after a starvation period of 20 hours, Eyal and Goot (1960) recorded the data
given in Table 5-2.
In a trial with pure-bred Awassi and Finnish Landrace-Awassi cross-bred lambs, Goot et al. (1978) examined the carcass weight and composition of two male Awassi lambs born as singles and fed, without roughage, on unlimited quantities of concentrates until the age of five months when they were slaughtered. The average data for the two lambs are as shown in Table 5-3. On conclusion of a
TABLE 5-3.
Carcass weight and composition of two male Awassi lambs | ||||||||||
Carcass weight (kg)
and dressing percentage |
Carcass composition (%) |
|||||||||
Slaughter weight |
47.75 |
Muscle |
49.75 |
|||||||
Hot carcass weight |
22.40 |
Carcass fat |
32.95 |
|||||||
Cold carcass weight |
21.95 |
Subcutaneous fat |
20.50 |
|||||||
Dressing percentage |
46.90 |
Intermuscular fat |
12.45 |
|||||||
|
|
Bone |
14.95 |
|||||||
|
|
Waste |
1.70 |
|||||||
|
|
Dissection loss |
0.65 |
|||||||
|
Weight of different body parts (g) |
|
||||||||
Fat tail |
5 250 |
Liver |
765 |
|||||||
Head with horns |
2 608 |
Lungs with trachea |
689 |
|||||||
Unshorn skin |
6 350 |
Spleen |
70 |
|||||||
Blood |
2 400 |
Heart |
170 |
|||||||
Full stomach |
3 167 |
Pericardium |
71 |
|||||||
Empty stomach |
1 048 |
Kidneys |
120 |
|||||||
Kidney fat |
208 |
|
|
|||||||
Caul fat |
555 |
|
|
|||||||
Gut fat |
263 |
|
|
|||||||
|
|
Weight and composition of
different carcass joints |
|
|
||||||
Joint |
Weight (kg) |
Bone (%) |
Muscle (%) |
Subcutaneous fat (%) |
Intermuscular fat (%) |
Total fat (%) |
Waste
and dissection loss (%) |
|||
Neck |
2.263 |
18.15 |
50.10 |
12.00 |
14.15 |
26.15 |
5.60 |
|||
Thorax |
5.293 |
19.20 |
40.20 |
20.85 |
17.85 |
38.70 |
1.90 |
|||
Shoulder |
2.181 |
15.45 |
57.75 |
14.80 |
11.30 |
26.10 |
0.70 |
|||
Loin |
2.061 |
13.20 |
44.05 |
29.90 |
12.40 |
42.30 |
0.45 |
|||
Psoas muscles |
0.240 |
0 |
79.40 |
0 |
11.05 |
11.05 |
9.55 |
|||
Pelvis |
3.044 |
10.00 |
37.55 |
36.20 |
13.25 |
49.45 |
3.00 |
|||
Leg |
2.463 |
13.65 |
62.05 |
16.95 |
6.85 |
23.80 |
0.50 |
|||
feeding trial with male Awassi lambs (see Table 3-59),
Atzmon and Doron (1951) selected the heaviest 5½ -month-old lamb for an additional slaughter test (Table 5-4).
In 1977, Epstein
(unpublished) examined the body composition of male and female Awassi, Awassi-East
Friesian cross-bred (see Appendix B, 'Meat (lamb)'), and German Mutton Merino
lambs at marketing weights then common in Israel. Before despatch to the
slaughterhouse, three male Awassi lambs included in the investigation weighed
54 kg, and two female Awassi lambs 50.5 kg on average.
Table 5-5 gives the data recorded.
An extensive
investigation into the various factors involved in the slaughter of pure-bred
Awassi and cross-bred Awassi-East Friesian and German Mutton Merino-Awassi
lambs was conducted by Goot, Folman and Eyal (1967). The results of the test
with the Awassi lambs are given in Tables 5-6 and 5-7 and Fig. 5-1. (For those
of the cross-breds, see Appendix A, Tables A-40 to
A-46 and Fig. A-4; Appendix B, Tables B-28 to B-32 and
Fig. B-1.)
The test was
conducted in two stages. In the first stage the weight loss of the lambs in
transit from farm to slaughterhouse over a distance of 20 km, as well as the
carcass weight and the weights of different parts and organs, was recorded, and
at the second stage the weight loss of the carcass in transit from
slaughterhouse to butcher-shop and the composition of the carcass were
recorded.
The lambs used in
the test comprised three groups, each raised on a different plane of nutrition
from the age of four months. The lambs of group I received 500 g of hay a day
in addition to a concentrate mixture sufficient for maintenance and normal
growth; group II received 500 g of hay and a 20 percent larger concentrate
ration than the lambs of group I; group III received 500 g of hay and free
access to concentrates in a self-feeder (see Tables 3-65 and 3-66).
The mean weight
loss in transit from farm to slaughterhouse and during 21 hours without water
and 35 hours without feed amounted to 4 kg for each lamb, or 5.8 percent. Days
of sharab (hot desert wind), on which the ambient temperature rose to a
maximum of 30°C and the relative humidity fell from 78 to 35 or 24 percent, had
no effect on shrinkage during transit and fasting. Goot, Folman and Eyal (1967)
commented that the mean shrink of 5.8 percent was considerably lower than the
9.0 and 10.7 percent, respectively, recorded by Epstein (1961) for 12 docked
and 12 undocked male Awassi lambs from which feed and water had been withheld
for 18 hours prior to slaughter. Obviously, the difference in the percentage of
shrink is due to the different weights and ages of the lambs used in the two
trials. The lambs tested by Goot, Folman and Eyal (1967) were 306 days old and
weighed 69.1 kg on average before shipment, whereas those tested by Epstein
were 91 days old and weighed 29.9 (docked) and 30.8 kg (undocked). Indeed, in
three male Awassi lambs of an average live weight of 54 kg before dispatch, the
author recorded a loss of only 5.2 percent in transit and 24 hours without feed
and water (see Table 5-5). As Snapp and Neumann (1960) remarked on the
shrinkage in cattle, 'calves may shrink up to 10 percent and more while heavy
cattle may not shrink over 4 or 5 percent'.
TABLE 5-4.
Live and slaughter weights of different parts of a male Awassi lamb (kg) | |
|
Weight |
Live weight at 51/2 months |
50.00 |
Weight after slaughter and bleeding |
48.90 |
Forequarters |
10.20 |
Hindquarters |
11.65 |
Fat tail |
4.25 |
Head |
2.30 |
Liver |
0.80 |
Heart, spleen, lungs and trachea |
1.30 |
Kidneys and kidney fat |
0.25 |
Testicles |
0.30 |
Caul fat |
0.60 |
Viscera |
9.80 |
Pelt and feet |
5.90 |
Total |
47.35 |
Weight loss |
1.55 |
TABLE 5-5.
Mean body composition of three male and two female Awassi lambs (kg) | ||||||
|
|
Male |
Female |
|||
Age (months) |
|
6½ |
8 |
|||
Live weight on farm |
|
54.0 |
50.5 |
|||
Live weight after 24 hours'
starvation at slaughterhouse |
|
48.8 |
45.0 |
|||
Weight loss during shipment and 24
hours withholding feed and water |
|
5.2 |
5.5 |
|||
|
(%) |
9.6 |
10.9 |
|||
Total carcasses at slaughterhouse |
|
28.400 |
25.600 |
|||
|
(warm dressed weight) |
|
|
|
||
at butcher-shop |
|
27.677 |
25.200 |
|||
Weight difference between warm and
cold dressed weight |
|
0.723 |
0.400 |
|||
|
(%) |
2.5 |
1.56 |
|||
Forequarters |
|
12.270 |
11.350 |
|||
Hindquarters |
|
11.377 |
10.670 |
|||
Fat tail |
|
4.030 |
3.180 |
|||
Carcass, total |
|
27.677 |
25.200 |
|||
Killing-out percentage |
|
56.7 |
56.0 |
|||
Forequarters |
Neck |
|
2.197 |
1.700 |
||
|
Leg and shoulder |
|
4.317 |
3.275 |
||
|
Chest |
|
5.713 |
6.365 |
||
|
Weight loss |
|
0.043 |
0.010 |
||
|
Total |
|
12.270 |
11.350 |
||
Hindquarters |
Loin and rump |
|
3.850 |
3.645 |
||
|
Leg and thigh |
|
7.450 |
7.010 |
||
|
Weight loss |
|
0.077 |
0.015 |
||
|
Total |
|
11.377 |
10.670 |
||
Fat tail |
Tail fat |
|
3.890 |
3.060 |
||
|
Tail |
|
0.140 |
0.120 |
||
|
Total |
|
4.030 |
3.180 |
||
|
Male |
Female |
||||||||||
Forequarters |
Neck |
Leg and shoulder |
Chest |
Neck |
Leg
and shoulder |
Chest |
||||||
Bone |
0.510 |
0.765 |
1.230 |
0.340 |
0.610 |
1.035 |
||||||
Muscle |
1.390 |
2.813 |
3.043 |
1.160 |
2.285 |
3.425 |
||||||
Fat tissue |
0.267 |
0.707 |
1.383 |
0.200 |
0.370 |
1.895 |
||||||
Weight loss |
0.030 |
0.032 |
0.057 |
— |
0.010 |
0.010 |
||||||
Total |
2.197 |
4.317 |
5.713 |
1.700 |
3.275 |
6.365 |
||||||
Hindquarters |
Loin
and rump |
Leg
and thigh |
Loin
and rump |
Leg
and thigh |
||||||||
Bone |
0.390 |
1.273 |
0.320 |
1.100 |
||||||||
Muscle |
2.153 |
4.543 |
2.125 |
4.315 |
||||||||
Fat tissue |
1.270 |
1.577 |
1.210 |
1.555 |
||||||||
Weight loss |
0.037 |
0.057 |
0.015 |
0.015 |
||||||||
Total |
3.850 |
7.450 |
3.670 |
6.985 |
||||||||
Forequarters, total |
||||||||||||
Bone |
2.505 |
1.985 |
||||||||||
Muscle |
7.246 |
6.870 |
||||||||||
Fat tissue |
2.357 |
2.465 |
||||||||||
Weight loss |
0.119 |
0.020 |
||||||||||
Total |
12.227 |
11.340 |
||||||||||
|
Male |
Female |
||||||||||
Hindquarters, total |
Bone |
1.663 |
1.420 |
|||||||||
|
Muscle |
6.696 |
6.440 |
|||||||||
|
Fat tissue |
2.847 |
2.765 |
|||||||||
|
Weight loss |
0.094 |
0.030 |
|||||||||
|
Total |
11.300 |
10.655 |
|||||||||
Carcass, total |
Kg |
% of
live weight [48.8 kg] |
Kg |
% of
live weight [45 kg] |
||||||||
Bone |
4.168 |
8.54 |
3.405 |
7.57 |
||||||||
Muscle |
13.942 |
28.57 |
13.310 |
29.58 |
||||||||
Fat tissue |
5.204 |
10.66 |
5.230 |
11.62 |
||||||||
Weight loss |
0.213 |
0.44 |
0.050 |
0.11 |
||||||||
Total |
23.527 |
48.21 |
21.995 |
48.88 |
||||||||
Fat tail |
||||||||||||
Tail fat |
3.890 |
7.97 |
3.060 |
6.80 |
||||||||
Tail |
0.140 |
0.29 |
0.120 |
0.27 |
||||||||
Total |
4.030 |
8.26 |
3.180 |
7.07 |
||||||||
Head, feet and inner organs |
|||
|
Male |
Female |
|
Head (without skin) |
Total |
2.027 |
1.675 |
|
Tongue |
0.108 |
0.115 |
|
Brain |
0.100 |
0.115 |
|
Horns |
0.382 |
0.010 |
Feet (without skin) |
0.747 |
0.725 |
|
Inner organs |
Liver |
0.757 |
0.645 |
|
Lungs with trachea |
0.650 |
0.410 |
|
Spleen |
0.103 |
0.060 |
|
Heart |
0.163 |
0.130 |
|
Kidneys |
0.127 |
0.110 |
|
Diaphragm |
0.153 |
0.093 |
|
Oesophagus |
0.045 |
0.040 |
|
Oesophagus fat tissue |
0.220 |
0.190 |
|
Thymus |
0.020 |
0.020 |
|
Testes |
0.280 |
— |
|
Udder |
— |
0.200 |
Skin and intestines |
|||
Weight of wet skin |
Body |
5.500 |
6.200 |
|
Head and ears |
0.610 |
0.520 |
|
Legs |
0.360 |
0.340 |
|
Total |
6.520 |
7.060 |
Length of intestines (m) |
Small intestine |
32.630 |
28.650 |
|
Large intestine |
6.700 |
7.850 |
|
Total |
39.330 |
36.500 |
TABLE 5-6. Live and carcass
weights of male Awassi lambs (kg) |
||||||||
Group |
Number |
Age
(days) |
Live
weight |
Warm
carcass weight |
Carcass
yield (%) |
|||
On
farm |
Before
slaughter (in wool) |
Before
slaughter (shorn) |
||||||
I |
14 |
312 |
65.2 |
61.3 |
59.1 |
28.9 |
48.0 |
|
II |
7 |
303 |
71.8 |
67.4 |
65.5 |
32.5 |
48.5 |
|
III |
10 |
298 |
72.8 |
69.0 |
66.6 |
33.1 |
48.6 |
|
Mean |
31 |
306 |
69.1 |
65.1 |
63.0 |
31.1 |
48.3 |
TABLE 5-7. Mean weights of inner
organs, kidney and caul fat, and fat tail in male Awassi lambs (kg) |
||||||||
Group |
Number
of lambs |
Live
weight |
Liver,
lungs and heart |
Kidneys |
Kidney
fat |
Caul
fat |
Total
kidney and caul fat |
Fat
tail |
I |
14 |
61 |
2.0 |
0.137 |
0.6 |
1.4 |
2.0 |
6.3 |
II |
7 |
67 |
2.2 |
0.155 |
1.0 |
2.9 |
3.9 |
6.9 |
III |
10 |
69 |
2.1 |
0.153 |
1.1 |
2.9 |
4.0 |
8.0 |
Mean |
31 |
65 |
2.1 |
0.146 |
0.8 |
2.2 |
3.1 |
7.0 |
Figure 5-1. Weight of caul and kidney fat and
fat tail in relation to live weight. (Source: Goot, Folman & Eyal, 1967)
The mean fleece
weight of the 31 lambs examined by Goot, Folman and Eyal (1967) was 2.1 kg, or
3.2 percent of the weight of the unshorn lambs. The cold carcass weight was
estimated at 2 percent less than the warm carcass weight. The slaughter yield
without inner organs and fat tail amounted to 48.3 percent; the addition of the
edible inner organs increased it to 51.8 percent, and of the inner organs and
fat tail to 62.6 percent.
From among the
heavy lambs of group III, the three heaviest ones were selected for an analysis
of their carcass composition, for which one-half of each carcass was used. The
average live weight of these lambs on the farm was 81.0 kg (see Table 3-60) ; shearing and shrinkage in transit and during the period
of abstention from feed and water prior to slaughter reduced it to 73.8 kg.
(See Tables 5-8 to 5-11.) The ratio of subcutaneous to intermuscular fat in the
trunks of the Awassi lambs was 63:37.
|
|
In addition to the
subcutaneous and intermuscular fat, there also exists intramuscular fat, the
quantity of which can only be determined by chemical analysis. Table 5-12 gives
the composition of the 'eye-muscles' of heavy male Awassi lambs (Goot, Folman
& Eyal, 1967).
The effect of
docking on the carcass of fat-tailed sheep has been examined in the Awassi,
Ausimi, Rahmani and Karakul. Epstein (1957) docked the tail of a three-day-old
male Awassi lamb below the first caudal vertebra. The animal was castrated with
an emasculator at the age of five months and slaughtered at 11 months when it had
reached a live weight of 51 kg. The lamb was shorn before slaughter to show the
fat development on the hindquarters of the live animal and the line of
TABLE 5-10. Distribution
of bone, muscle and
fat tissue in various parts of the carcass of three male Awassi lambs (%) |
||||||
|
Bone |
Muscle |
Subcutaneous
fat |
Intermuscular
fat |
Total
fat |
Weight
loss |
Neck |
12.1 |
45.5 |
15.5 |
24.9 |
40.4 |
2.0 |
Breast |
14.3 |
39.2 |
19.7 |
26.0 |
45.7 |
0.8 |
Right shoulder |
12.1 |
52.0 |
25.5 |
10.1 |
35.6 |
0.3 |
Loin |
6.2 |
33.8 |
46.4 |
13.6 |
60.0 |
— |
Psoas muscles |
— |
79.7 |
— |
19.4 |
19.4 |
0.9 |
Pelvis |
8.7 |
38.2 |
39.8 |
11.6 |
51.4 |
1.7 |
Thigh |
12.1 |
57.5 |
22.6 |
6.8 |
29.4 |
1.0 |
|
amputation
which is clearly marked along the border of the woolly and woolless parts of
the buttocks (Fig. 5-2). The rump of the live animal and the carcass after
removal of the skin showed that the large mass of fat concentrated in the tail
of a well-fed Awassi sheep had not moved up to the hindquarters. Only two small
fat moieties, each weighing not more than 200 g, remained on the
buttocks (Fig. 5-3). When the carcass was halved longitudinally, these fat deposits, which in
the undivided carcass appeared very small, expanded outwards and became more
prominent (Fig. 5-4). In Awassi sheep in which the fat tail has been docked
below the third caudal vertebra or farther down and in which the superior part
of the lateral skin folds of the tail has remained on the rump, the fat
accumulations are considerably larger than in the present case, their size
depending on the extent of the skin folds near the tail butt.
In twelve
91-day-old male fat-tailed Awassi lambs and 12 lambs of the same breed, sex and
age, which had been docked on the third day after birth, Epstein (1961)
recorded the mean live and carcass weights, the weights of the head, feet,
edible inner organs and pelt, and of the bone, muscle and fat
Figure 5-4.
Halved hindquarters of a docked Awassi lamb.
External and internal views
tissue in
the forequarters and hindquarters (Tables 5-13 and 5-14 and Fig. 5-5). Prior to
slaughter the lambs had been deprived of feed for 18 hours and were weighed
empty (see also Chapter 3, 'Effect of docking', Tables 3-114 and 3-115).
While docking had
only a slight negative effect on the weight of the lambs at the age of 91 days,
the mutton conformation of the live docked lambs was superior to that of the
undocked controls. In particular, the forequarters and hindquarters had a more
balanced appearance, approaching the conformation desired in a mutton breed.
Outwardly there was little evidence of fat accumulation on either side of the
tail butt. During the 18-hour fasting period prior to slaughter, the docked
lambs lost 2.7 kg or 9 percent and the undocked controls 3.3 kg or 10.7 percent
in live weight.
In the slaughtered
lambs there was hardly any difference between those docked and those undocked
in the average weight of the head, feet and edible inner organs. The slightly
larger weight of the heads of the undocked lambs may have been a result of
fortuitous differences in horn weight; there were nine horned and three polled
lambs in each of the two groups. The relative weight of the feet was the same
in both groups. In the docked lambs, the mean weight of the edible organs was 86
g above
TABLE 5-13. Mean weights of carcass, head, feet, edible inner
organs and pelt of 12 docked and 12 undocked male Awassi lambs (kg and as % of mean live weights) |
||||||
|
Docked |
Undocked |
||||
Kg |
SD± |
% of
live weight (27.2 kg) |
Kg |
SD± |
% of
live weight (27.5 kg) |
|
Total carcass |
13.59 |
3.69 |
50.0 |
13.87 |
2.45 |
50.4 |
Forequarters |
6.96 |
1.73 |
25.6 |
6.48 |
0.90 |
23.6 |
Hindquarters |
6.64 |
1.97 |
24.4 |
7.39 |
1.61 |
26.8 |
Head |
1.23 |
0.18 |
4.5 |
1.17 |
0.08 |
4.2 |
Feet |
0.58 |
0.08 |
2.1 |
0.58 |
0.06 |
2.1 |
Liver |
0.47 |
0.11 |
1.7 |
0.49 |
0.05 |
1.8 |
Lungs |
0.36 |
0.11 |
1.3 |
0.32 |
0.05 |
1.2 |
Spleen |
0.06 |
0.01 |
0.2 |
0.05 |
0.01 |
0.2 |
Heart |
0.12 |
0.02 |
0.5 |
0.12 |
0.02 |
0.4 |
Kidneys |
0.10 |
0.01 |
0.4 |
0.10 |
0.02 |
0.4 |
Testicles |
0.04 |
0.02 |
0.2 |
0.04 |
0.02 |
0.2 |
Diaphragm, etc. |
0.39 |
0.10 |
1.4 |
0.33 |
0.07 |
1.2 |
Total edible inner organs |
1.54 |
0.28 |
5.7 |
1.45 |
0.17 |
5.4 |
Pelt |
3.63 |
0.62 |
13.3 |
3.76 |
0.72 |
13.7 |
TABLE 5-14. Mean weights of bone
muscle and fat tissue in forequarters, hindquarters and total carcass of 12
docked and 12 undocked male Awassi lambs (kg and as % of mean live weights) |
|||||||
|
Docked |
Undocked |
|||||
Kg |
SD± |
% of
live weight (27.2 kg) |
Kg |
SD± |
% of
live weight wt (27.5 kg) |
||
Forequarters |
|||||||
|
Bone |
1.45 |
0.29 |
5.3 |
1.45 |
0.19 |
5.3 |
|
Muscle |
4.10 |
0.76 |
15.1 |
4.01 |
0.47 |
14.6 |
|
Fat tissue |
1.34 |
0.77 |
4.9 |
0.94 |
0.34 |
3.4 |
|
Weight loss |
0.07 |
0.04 |
0.3 |
0.08 |
0.04 |
0.3 |
|
Total |
6.96 |
1.73 |
25.6 |
6.48 |
0.90 |
23.6 |
Hindquarters |
|||||||
|
Bone |
1.03 |
0.20 |
3.8 |
1.00 |
0.10 |
3.6 |
|
Muscle |
3.51 |
0.73 |
12.9 |
3.35 |
0.40 |
12.1 |
|
Body fat tissue |
2.04 |
1.12 |
7.5 |
1.03 |
0.35 |
3.7 |
|
Tail fat |
— |
— |
— |
1.90 |
0.90 |
6.9 |
|
Tail |
— |
— |
— |
0.07 |
0.02 |
0.3 |
|
Weight loss |
0.06 |
0.03 |
0.2 |
0.04 |
0.03 |
0.2 |
|
Total |
6.64 |
1.99 |
24.4 |
7.39 |
1.61 |
26.8 |
Total carcass |
|||||||
|
Bone |
2.48 |
0.47 |
9.1 |
2.45 |
0.29 |
8.9 |
|
Muscle |
7.61 |
1.47 |
28.0 |
7.36 |
0.82 |
26.7 |
|
Body fat tissue |
3.37 |
1.87 |
12.4 |
1.97 |
0.68 |
7.1 |
|
Tail fat |
— |
— |
— |
1.90 |
0.90 |
6.9 |
|
Tail |
— |
— |
— |
0.07 |
0.02 |
0.3 |
|
Weight loss |
0.13 |
0.06 |
0.5 |
0.13 |
0.03 |
0.5 |
|
Total |
13.59 |
3.69 |
50.0 |
13.87 |
2.45 |
50.4 |
Figure 5-5. a) Carcass of docked fat-tailed
lamb (weight 14.650 kg); b) Carcass of fat-tailed lamb (weight 14.950
kg)
TABLE 5-15. Ratio of
forequarters to hindquarters in docked and undocked fat-tailed Awassi lambs |
||
|
Forequarters |
Hindquarters |
Docked lambs |
100 |
95.4 |
Undocked lambs, including fat tail |
100 |
114.1 |
Undocked lambs, excluding fat tail |
100 |
83.7 |
that of
the control animals. The skin of the docked lambs weighed 133 g less on average than the skin of the
undocked lambs, owing to the presence of the tail covering in the latter.
The dressed weight
of the docked lambs was 50 percent and that of the undocked lambs 50.4 percent
of the live weight. Docking had, however, a marked influence on the weight
ratio of forequarters to hindquarters. The forequarters of the docked lambs
were absolutely and relatively heavier than the forequarters of the undocked
lambs. Similarly, and to a greater extent, the hindquarters of the docked lambs
were absolutely and relatively heavier than the hindquarters of the undocked
lambs minus the fat tail, though the difference in favour of the docked lambs
was less than the weight of the fat tail (1.97 kg).
The forequarters
of the docked lambs were 317 g, or 4.8 percent, heavier than the hindquarters.
The forequarters of the undocked lambs were 916 g, or 12.4 percent, lighter
than the hindquarters including the fat tail; but they were 1 056 g, or 19.5
percent, heavier than the hindquarters minus the fat tail, a very undesirable
proportion from the mutton point of view. Taking the weight of the forequarters
as 100, the ratio of forequarters to hindquarters was as given in Table 5-15.
The carcasses of
the docked lambs had a superior appearance to those of the undocked control
animals, although in several of the former accumulation of fat on both sides of
the tail butt detracted from their appearance. The superiority of the docked
carcasses was due to the better condition and more favourable balance of the
forequarters and hindquarters. The hindquarters of the docked lambs, more
especially the thighs and buttocks, were fuller and heavier than those of the
undocked; they were thus superior in economic usefulness since to the consumer
the legs of mutton and the loin chops are the best part of the sheep
(Fig. 5-5).
The loss in
carcass weight caused by docking was much less than the weight of the fat tail.
Additional nutrients in amounts not far short of those normally stored in the
tail of fat-tailed lambs were deposited in the docked lambs in both the
forequarters and the hindquarters. Dissection demonstrated in which forms these
deposits had taken place.
In the
forequarters, the proportion of bone to live weight was not affected by the
docking of the fat tail. However, muscle tissue in the forequarters of the
docked lambs exceeded that of the undocked controls by 94 g and fat tissue by 392 g. In other words, the fat, which would
normally have been deposited in the tail, was partly made good by the deposits
of extra muscle and fat in the forequarters in the ratio of 1:4.2. In terms of
live weight, the percentages of lean meat and fat in the forequarters of the
docked lambs exceeded those of the undocked lambs by 0.5 percent (15.1 versus
14.6) and 1.5 percent (4.9 versus 3.4), respectively. However, only about
one-fourth of the fat normally deposited in the tail was represented by the
extra meat and fat in the forequarters of the docked lambs.
In the
hindquarters, bone growth was affected by docking to a negligible extent, the
bone in the docked lambs weighing 33 g more than in the undocked. However, the growth of muscle and body
fat tissue was markedly increased by docking. In the docked lambs the lean meat
weighed 162 g more and the
body fat tissue 1 004 g more
than in the undocked lambs. In the docked animals the fat that would normally
have been deposited in the tail was partly made good by deposits of extra
muscle and fat in the hindquarters, in the ratio of 1:6.2. In terms of live
weight, the hindquarters of the docked lambs contained 0.8 percent more muscle
tissue (12.9 versus 12.1) and 3.8 percent (7.5 versus 3.7) more body fat than
the hindquarters of the undocked control animals. Approximately three-fifths of
the 'inhibited' tail fat was made good by extra meat and fat in the
hindquarters of the docked lambs, the share of the hindquarters as a depository
of the extra meat and fat deposited thus being 2.4 times that of the
forequarters. Were it possible in docking the fat tail under conditions of
ordinary farm management to remove the skin folds on both sides of the tail
completely, the two fat cushions near the butt of the tail would be of
negligible size in the 91-day-old lamb, and the ratio of extra muscle to extra
fat tissue deposited in the hindquarters following docking would probably be as
narrow as that for the forequarters.
The ratio of lean
meat to total fat was 2.26:1 in the whole carcass of the docked lambs, and
1.91:1 in that of the undocked control animals. As it is the protein of the
muscle that gives meat its special nutritional value, the superiority of the
docked carcasses to the undocked was to some extent a result of the higher
relative share of lean meat (Epstein, 1961).
In a study on the
growth and carcass characteristics of 19 docked and 19 normal male Awassi lambs
conducted at the experimental farm of the American University of Beirut, the
average dressing percentage of the intact lambs was found to exceed that of the
docked ones by a statistically significant margin (Table 5-16). Following
removal of the fat tail, a tendency was observed for the fat to spread forwards
over the loin, shoulder, brisket and sternum, with only a slight indication of
increased internal deposits (McLeroy, Ananian & Kurdian, 1959). There was
only a limited, if any, increase in marbling owing to docking. The difference
in iodine number (grams of iodine absorbed by 100 g of fat) of back fat in favour of docked
lambs is representative of a mobile fat similar to that normally deposited in
the tail (Table 5-17) (McLeroy & Kurdian, 1958).
|
In Iraq, Asker, El-Khalsy
and Juma (1964) examined the carcasses often male Awassi lambs that had been
docked by the rubber ring method during the second week of their lives and had
been slaughtered at 13 months when they had reached an average live weight of
38.9 kg (Table 5-18) (see also pp. 132-3 and
Table 3-116 and Fig. 3-17). The
average dressing percentage was 38.6-2.6 percent less than that of the ten
undocked control animals that weighed 43.6 kg at the same age. The carcasses of
the docked lambs had a larger fat accumulation around the tail root and thicker
subcutaneous fat deposits
on the brisket, back, loins, neck and legs than the control lambs. All cuts of
the docked lambs showed thicker layers of fat, and the kidney, heart and caul
fat was also more copious. Owing to the marked development of the subcutaneous
fat, the carcasses of the docked animals had a whiter appearance than those of
the control group.
TABLE 5-18. Average weights of carcasses and carcass cuts of 10
docked and 10 undocked male Awassi lambs in Iraq (kg) | |||
|
Docked lambs |
Undocked lambs |
|
Live weight |
38.90 |
43.60 |
|
Carcass weight |
15.00 |
18.00 |
|
(Killing-out percentage |
38.6 |
41.2) |
|
Shoulders |
3.67 |
4.24 |
|
Breast and shank |
2.00 |
2.19 |
|
Loins |
1.96 |
2.21 |
|
Ribs |
1.66 |
1.91 |
|
Legs |
4.59 |
5.13 |
|
Fat tail |
— |
1.32 |
TABLE 5-19. Mean weights of carcass, head, feet, tail, stomach,
intestines, edible inner organs, and pelt of 5 docked and 6 undocked male
Awassi lambs in Iraq (in kg and
as % of mean live weights) | ||||
|
Docked |
Undocked |
||
|
Kg |
% of live wgt(37.4kg) |
Kg |
% of live wgt(40.5kg) |
Carcass |
20.600 |
55.10 |
23.100 |
57.00 |
Fat tail |
0.724 |
1.94 |
2.715 |
6.70 |
Head |
3.01 |
8.05 |
3.23 |
7.98 |
Feet |
1.10 |
2.94 |
1.12 |
2.77 |
Liver |
0.666 |
1.78 |
0.728 |
1.80 |
Lungs |
0.592 |
1.58 |
0.714 |
1.76 |
Spleen |
0.081 |
0.22 |
0.145 |
0.36 |
Heart |
0.170 |
0.45 |
0.162 |
0.40 |
Kidneys |
0.112 |
0.30 |
0.119 |
0.29 |
Testicles |
0.277 |
0.74 |
0.339 |
0.84 |
Stomach |
1.47 |
3.93 |
1.44 |
3.56 |
Intestines |
1.47 |
3.93 |
1.56 |
3.85 |
Pelt |
5.23 |
14.00 |
5.67 |
14.00 |
Source: Farhan,
Al-Khalisi & Hameed, 1969 |
The carcasses of
the docked lambs had an average length of 46.4 cm and a heart girth of 64.0 cm,
versus 49.9 and 68.4 cm, respectively, in the undocked lambs (Asker, El-Khalsy
& Juma, 1964).
In another
experiment at Abu-Ghraib, Farhan, Al-Khalisi and Hameed (1969) compared the
carcass characteristics of five male Awassi lambs that had been docked with
rubber rings during the first week of age with six undocked control lambs
(Table 5-19). The lambs were slaughtered at 7½-8½ months, ten days after completion of a
feeding trial of 81 days. Before slaughter they were deprived of feed and water
for 16 hours.
The docked lambs
had an average live weight of 45.8 kg before fasting and 37.4 kg after fasting,
losing 8.4 kg (or 18.3 percent) weight during this period. The undocked control
animals weighed 48.7 kg before
fasting and 40.5 kg after, losing 8.2 kg (or 16.8 percent) by fasting.
The dressed weight of the docked lambs was 44.1 percent, and that of the
fat-tailed control lambs 46.0 percent of the live weights recorded before the
fasting period. After slaughter the stomach and intestinal contents of the
docked lambs weighed 5.93 and 2.49 kg, and of the undocked controls 6.17 and
2.03 kg, respectively. The average length of the small intestine was 9.5 m in
the docked lambs and 10.5 m in the undocked animals. The composition of the
carcasses was recorded after 48 hours of chilling.
Docking reduced
the fat content of the carcass and the killing-out percentage, but increased
the percentages of kidney fat and muscle and the depth of fat tissue over the Musculus
longissimus dorsi. In the docked sheep the fat tissue amounted to 15.9
percent and the muscle tissue to 52.1 percent of the total carcass weight
excluding the fat tail, and in the undocked animals to 17.5 and 51.1 percent,
respectively. The kidney fat in the docked lambs weighed 244 g, or 1.21 percent
of the carcass weight without the fat tail, versus 204 g, or 0.91 percent of
the carcass weight of the undocked sheep. The fat cover over the seventh-rib
section of the M. longissimus dorsi on the right loin side measured 5.1
mm in thickness in the docked lambs and 4.6 mm in the fat-tailed control
animals.
The killing-out percentage of fat
adult Awassi sheep of unimproved type in the summer was estimated by Hirsch
(1933) at 52 percent, ranging from 50 to 54 percent. The dressed carcass yield
of rams was somewhat higher. However, adult slaughter ewes from bedouin flocks,
of an average live weight of 40 kg and in rather poor condition, had a warm
dressed weight of only 15.6 kg, or 39 percent of the live weight. Adult Awassi
slaughter sheep, purchased by the Mandatory Government of Palestine in Syria
and Iraq during the Second World War, were graded according to the dressed
weights and dressing percentages, including the fat tail, given in Table 5-20.
|
The
mean live and slaughter weights and the weights of the edible inner organs of
20 unshorn sheep of grade B (carcass yield 38.8 percent) were as given in Table
5-21.
In 1951, five unimproved
Awassi ewes of an average live weight of 40.2 kg were kept at a slaughterhouse
for four days without adequate feed. Normally such ewes kill out at 42 percent,
but in this instance, owing to the emptiness of the alimentary tract, the mean
dressing percentage was 44.3. Table 5-22 gives the mean weights of the
different parts and organs of the carcasses.
In 1970 the author
recorded the body composition of five six- to eight-year-old Awassi ewes in
good condition and of an adult stud ram in rather lean condition, culled from a
highly improved flock (Tables 5-23 and 5-24). The shrinkage in transit and
during the fasting period prior to slaughter was 3.68 percent in the ewes and
4.32 percent in the ram.
TABLE 5-22. Mean weights of carcass parts
and inner organs of adult, unimproved Awassi ewes (in kg and as % of
mean live weight) | ||
|
|
Weight |
Kg |
% of live weight |
|
Live weight on delivery to slaughterhouse |
42.4 |
— |
Live weight before slaughter |
40.2 |
100.0 |
Forequarters |
9.2 |
22.9 |
Hindquarters (with kidneys and fat tail) |
8.6 |
21.4 |
Total carcass |
17.8 |
44.3 |
Head |
0.960 |
2.39 |
Brain |
0.106 |
0.26 |
Tongue |
0.366 |
0.91 |
Liver |
0.570 |
1.42 |
Lungs and trachea |
1.010 |
2.51 |
Spleen |
0.112 |
0.28 |
Heart |
0.192 |
0.48 |
Udder |
0.150 |
0.37 |
Fat tail |
0.660 |
1.64 |
Alimentary tract |
1.340 |
3.33 |
TABLE 5-23. Mean weights of carcass, head,
feet, inner organs, and pelt of 5 adult Awassi ewes and 1 ram (in kg and
as % of mean live weights) | |||||
|
Ewes |
Ram |
|||
Kg |
SD ± |
% of live weight |
Kg |
% of live weight |
|
Live weight on farm before fasting |
70.600 |
5.12 |
— |
81.000 |
— |
Live weight before slaughter |
68.000 |
4.85 |
— |
77.500 |
— |
Carcass weight |
34.050 |
2.39 |
50.10 |
44.410 |
57.40 |
Forequarters |
15.716 |
2.23 |
23.10 |
22.820 |
29.50 |
Hindquarters with fat tail |
18.334 |
1.89 |
27.00 |
21.590 |
27.90 |
Head |
2.326 |
0.21 |
3.42 |
3.330 |
4.30 |
Brain |
0.124 |
0.02 |
0.18 |
0.240 |
0.31 |
Tongue |
0.142 |
0.03 |
0.21 |
0.310 |
0.40 |
Feet |
0.926 |
0.12 |
1.36 |
1.330 |
1.72 |
Liver |
1.208 |
0.15 |
1.78 |
0.700 |
0.90 |
Lungs and trachea |
0.718 |
0.16 |
1.06 |
0.910 |
1.17 |
Spleen |
0.156 |
0.06 |
0.23 |
0.150 |
0.19 |
Heart |
0.280 |
0.06 |
0.41 |
0.270 |
0.35 |
Kidneys |
0.196 |
0.06 |
0.29 |
0.180 |
0.23 |
Udder |
1.072 |
0.43 |
1.58 |
— |
— |
Testicles |
— |
— |
— |
0.510 |
0.66 |
Oesophagus and thymus |
0.182 |
0.09 |
0.27 |
0.240 |
0.31 |
Diaphragm |
0.284 |
0.09 |
0.42 |
0.320 |
0.41 |
Pelt |
7.146 |
1.27 |
10.50 |
10.150 |
13.10 |
TABLE 5-24. Mean weights of bone, muscle and fat tissue in forequarters,
hindquarters and total carcass of 5 adult Awassi ewes and 1 ram
(in kg and as % of mean live weights) |
|
Ewes |
Ram |
||
Kg |
SD ± |
% of live weight |
Kg |
% of live weight |
|
Forequarters |
|
|
|
|
|
Bone |
3.103 |
0.44 |
4.56 |
6.050 |
7.81 |
Muscle |
8.574 |
1.34 |
12.61 |
13.720 |
17.70 |
Fat tissue |
3.902 |
0.71 |
5.74 |
2.570 |
3.32 |
Weight loss |
0.137 |
0.27 |
0.20 |
0.480 |
0.62 |
Total |
15.716 |
2.23 |
23.10 |
22.820 |
29.50 |
Hindquarters |
|
|
|
|
|
Bone |
1.778 |
0.26 |
2.61 |
2.600 |
3.35 |
Muscle |
7.216 |
0.68 |
10.61 |
9.910 |
12.79 |
Body fat tissue |
5.580 |
0.88 |
8.21 |
3.850 |
4.97 |
Tail fat |
3.382 |
0.75 |
4.97 |
4.820 |
6.22 |
Tail |
0.220 |
0.07 |
0.32 |
0.210 |
0.27 |
Weight loss |
0.158 |
0.10 |
0.23 |
0.200 |
0.26 |
Total |
18.334 |
1.89 |
27.00 |
21.590 |
27.90 |
Total carcass |
|
|
|
|
|
Bone |
4.880 |
0.78 |
7.18 |
8.650 |
11.16 |
Muscle |
15.790 |
1.23 |
23.22 |
23.630 |
30.49 |
Body fat tissue |
9.482 |
1.16 |
13.94 |
6.420 |
8.28 |
Tail fat |
3.382 |
0.75 |
4.97 |
4.820 |
6.22 |
Tail |
0.220 |
0.07 |
0.32 |
0.210 |
0.27 |
Weight loss |
0.296 |
0.22 |
0.44 |
0.680 |
0.88 |
Total |
34.050 |
2.39 |
50.10 |
44.410 |
57.40 |