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MEAT GOAT PRODUCTION HANDBOOK
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Factors
Affecting Goat Carcass Yield and Quality |
Frank Pinkerton |
Introduction |
Carcasses of meat animals are
generally evaluated commercially in terms of yield
and quality of lean. In beef carcasses, yield refers
to the percentage of closely trimmed, boneless retail
cuts (edible lean) on a carcass weight basis. Quality
of lean refers to the palatability (taste appeal)
of the lean and is perceived as being strongly influenced
by the degree of marbling (intramuscular fat deposition).
Since most goat carcasses are not presently marketed
in typical retail cuts and since goat meat is primarily
valued for its unmarbled lean, this evaluation scheme
seems somewhat inappropriate for goats, at least for
now. |
Instead, goat processors seem
to pay particular attention to dressing percent and
to "muscling" or "meatiness",
both terms reflecting an assessment of meat-to-bone
ratios. However, processors do prefer young goats
(less than 40 lb live weight) to show considerable
fat deposition around the kidneys and heart. Experienced
goat buyers are quite adept at palpating the loin/rib
area of a live kid and predicting degree of muscling
and kidney fat and, accordingly, the visual and commercial
appeal of the carcass to buyers. Contrarily, older,
heavier carcasses are discriminated against if they
have more than a (poorly defined) minimum of fatness.
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Carcass Characteristics |
The dressing percentage of slaughter
goats may be influenced by age, weight, sex, body
condition, amount of gut fill at slaughter, whether
the carcass is weighed hot or cold and, of course,
by the number of body components included in the yield
calculation. Dividing the unshrunk liveweight into
the weight of the hot carcass with liver, heart and
kidney but without skin, head, feet and viscera will
yield dressing percent values in the 45-52% range.
The interactions among the individual factors affecting
dressing percentage are great, making it rather difficult
to accurately predict carcass yield or quality by
visual examination of the live goat. |
Table 1, taken from a review
by Shelton, Snowder and Figueiredo (1984), compares
slaughter characteristics of castrated vs. intact
meat type kids (columns 1 and 2, 4 and 5), Angora
vs. meat type intact males (columns 3 and 4) and aged
Angora females vs. aged meat type females (columns
6 and 7); column 8 shows the averages for the 92 head
in the study. Table 1 also indicates the percent of
the live weight found in the hanging carcass (with
kidneys) and in various body components. Certain of
these components are considered to be edible by various
groups of consumers; any calculation of "dressing
percent" would necessarily have to denote which
component is to be included. |
The effects of castration are
also shown in Tables 2 and 3 (Shelton, Snowder and
Figueiredo, 1984). These and other studies indicate
that intact males are heavier per day of age, make
more efficient gains but have a higher percent of
their weight in the lower value hindquarters. Castrates
show more carcass quality (improved fat cover) and
generally sell for more per lb, except in specialized
markets taking larger, more mature bucks. Castration
may have an adverse impact on daily gain as documented
in Table 2. |
The effect of breed on carcass
characteristics of goats has not been extensively
reported. The recent arrival of the meat type Boer
goat has sparked much interest in its potential for
crossing with dairy and Spanish goats. Table 4 reports
a study in England which compares two dairy breeds,
Saanen and Nubian, with Boer x Saanen goats, all slaughtered
at various body weights (Gibb, Cook & Tresher,
1993). All were on a hay and concentrate ration after
weaning at 8 weeks of age. The numbers of animals
used were quite small and so apparently was the genetic
diversity within breed; readers should be aware of
these experimental limitations. |
In this study there were no
significant differences between breeds in 8 week weights
or in daily feed intake. With regard to daily weight
gains, at heavier slaughter weights, the Saanen kids
were superior to the Boer x Saanen crosses which,
in turn, were superior to the Nubian kids. Nubian
and, to a lesser extent, Boer x Saanen crosses produced
superior carcasses in terms of muscling. The Boer
x Saanen crosses had more fat overall all slaughter
weight than the Nubian kids; Saanen kids had the least
fat. |
The energy density of diets
fed to goats can influence carcass characteristics
across various slaughter weights. Table 5 illustrates
this point using Boer goats in South Africa (Ueckerman,
1969). Dressing percent rises with slaughter weight
and length of time on feed. Feed efficiency (lb of
feed required to put on lb of gain) decreases as heavier
carcasses are produced. An all-roughage ration required
more time on feed and required more lb of hay per
lb of gain than the rations containing concentrates.
Apparently, the responses to 60:40 R:C and 40:60 R:C
ratios were rather similar. The relative costs of
hays and concentrates and reduced time on feed at
the higher concentrate level would determine the economic
choice among R:C ratios. |
Conclusions |
1. Carcass characteristics of
slaughter goats may be affected by a number of genetic
and environmental conditions as well as specific herd
management decisions.
1. Muscling, not body fat, is the most important goat
carcass characteristic.
1. The goat industry could likely benefit from the
creation of a set of grade standards somewhat similar
to those now used by the sheep and lamb trade. |
| Table 2. Results of Castration
of Meat Type Male Kid Goats. |
| Treatment |
No. |
Initial
Wt., lb |
Gain
lb2 |
Condition
Score3 |
Sale
Price 4 (1984)
US $ Per Head
|
| Intact Males |
46 |
43.3 |
16.1 |
3.5 |
15.75 |
| Castrated by Knife |
48 |
42.5 |
15.1 |
3.9 |
17.00 |
| Castrated by Burdizzo1 |
48 |
42.6 |
14.8 |
3.9 |
18.00 |
1 One kid died
after castration by burdizzo and four showed
signs of improper or incomplete castration.
2 Weight gains following 103 days on pasture.
3 Condition scores were assigned on a 1-6 basis,
with the high values being fatter.
4 Twelve (12) animals were randomly kept from
each group of slaughter and the remainder were
sold at a local auction. The prices shown are
that received for the remaining animals which
were sold. |
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| Table 3. Slaughter data
from castrate vs. intact males. |
| Treatment |
No. |
Slaughter Wt. |
Hide Wt. |
Carcass Wt.
|
Dressing % |
Backfat Thickness
|
Ribeye Area |
| |
--------- lbs---------- |
|
---- in--- |
- sq. in |
| Intact Males |
12 |
60.7 |
7.7 |
27.5 |
45.3 |
0.003 |
4.47 |
| Castrates |
24 |
54.1 |
6.2 |
24.6 |
45.5 |
0.100 |
3.97 |
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| Table 5. Meat Production and Carcass
Yields in Boer Goats. |
| |
Roughage:Concentrate
Ratio |
100:0 |
|
60:40 |
|
40:60 |
| Slaughter Wt., lbs |
70.0 |
100.1 |
|
70.0 |
100.1 |
|
70 |
100.1 |
| Number of goats |
231 |
336 |
|
182 |
308 |
|
168 |
301 |
| Weeks to slaughter |
33 |
48 |
|
26 |
44 |
|
24 |
43 |
| Feed to gain ratio |
10.3 |
13.3 |
|
8.1 |
9.5 |
|
8.6 |
9.5 |
| Average daily gain, lb |
.27 |
.27 |
|
.34 |
.30 |
|
.37 |
.31 |
| Dressing percent |
49.4 |
52.4 |
|
51.8 |
56.3 |
|
54.6 |
56.5 |
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| References |
Gibb, J.J., J. E. Cook, and
T. T. Tresher, 1993. Performance of British Saanen,
Boer X British Saanen and Anglo-Nubian Castrated Male
Kids from 8 weeks to Slaughter at 38,33 or 38 kg liveweight.
Anim. Prod. 57:263-271.
Shelton, Maurice, Gary Snowder, and E.A.P. Figueiredo,
1984. Meat Production and Carcass Characteristics
of the Goat. USAID Title XII. Small Ruminant Collaborative
Research Support Program, Texas A & M University,
San Angelo.
Ueckerman, L., 1969. Master of Science Ag. Thesis,
University Pretoria, Republic of South Africa.
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