Agriculture Reference
In-Depth Information
and cattle. Lasalocid increased weight gain by 20 g per day
in kid goats after weaning at 50 days of age by increasing
propionate and decreasing butyrate concentrations in the
rumen (Hadjipanayiotou et al., 1988 ).
more carcass fat, but usually have less fat unless on a high-
energy diet. Concentrate feeding or concentrate supple-
mentation increases carcass fat deposition compared with
browsing or grazing (Warmington and Kirton, 1990).
Breed, diet, age, sex, weight, growth rate, and other factors
will cause differences in the chemical composition of
moisture, fat, protein, and ash and the physical composi-
tion of lean, fat, and bone in meat goat carcasses (Table
13.4). Fat is deposited in visceral depots rather than carcass
depots. The low proportion of subcutaneous fat on goat
carcasses makes subcutaneous fat thickness measurement
a poor criterion for meat yield (Webb et al., 2005). The
relatively higher proportion of kidney and pelvic fat in goat
carcasses makes this factor more important in determining
meat yield, particularly since many goat carcasses are sold
with the kidney and pelvic fat remaining with the carcass.
Data from the 9-11 rib section showed similar trends in
chemical composition as chemical composition of the half
carcass, except for protein content (Solaiman et al., 2006).
The body chemical composition of three-fourths Boer one-
fourth Saanen male goats weighing 20-35 kg could be
estimated (r
2
= 0.94) by determining the combined chemi-
cal composition of the organs, blood, and 9-11 carcass rib
section. The 9-11 rib section was accurate to estimate
carcass fat percentage (Fernandes et al., 2008).
CARCASS CHARACTERISTICS
Dressing Percentage
Dressing percentage is an important determinant of the
potential yield of meat from an animal. Dressing percent-
age is the carcass weight divided by the live weight times
100. Often the hot carcass weight, the weight taken after
skinning and evisceration and before chilling, is used to
calculate dressing percentage. The chilling process removes
heat from the carcass but also removes moisture, so the
shrinkage from carcass chilling may be 3-5% of the initial
hot carcass weight. Dressing percentage will vary with the
type of slaughter procedures. Leaving the cannon bones
(trotters), kidney and pelvic fat, and skinned head on the
hot carcass will increase the dressing percentage. Goats
that are not withheld from feed before slaughter will have
a lower dressing percentage than goats that only had access
to water overnight before slaughter. Dressing percentages
of kid and yearling male and female meat goats with dif-
ferent body conformations were relatively constant at 48-
52% when the goats were withheld from feed overnight
before sacrifi ce (McMillin et al., 1998).
Dressing percentages of kid goat carcasses with the head
on, the trotter on, and kidney and heart fat left inside will
be 50-55%. Removal of the head will result in 5-7% less
dressing percentage. The dressing percentages of kid goats
of most species will be 42-48%. Carcasses with more inter-
nal or external fat will have higher dressing percentages, so
carcasses from older goats will usually have slightly higher
dressing percentages than kid goats unless the older animals
are cull breeding stock that are very thin.
Dressing percentages of Spanish doe and buck kid goats
were higher after alfalfa hay and supplement diets (52.9%)
than on grass hay and supplement diets (50.4%), with the
same trends observed with yearling Boer and Boer
Carcass Evaluation
F
ACTORS
A
FFECTING
M
EAT
Y
IELD
Carcasses of meat animals are often evaluated to determine
the relative ratios of lean, fat, and bone, and to provide an
estimation of the palatability of the meat to be produced.
Beef, lamb, and pork carcasses have offi cial United States
Department of Agriculture grades that segregate carcasses
according to yield or cutability characteristics and quality
or palatability characteristics. There has been insuffi cient
data collection of goat carcass traits to estimate the yield or
palatability of goat meat. Yield of meat, usually expressed
as the amount of lean or cuts that have been closely
trimmed to remove some of the fat, is highly related to the
weight of the carcass, the degree of muscling relative to
bone, and the amounts of subcutaneous external fat and
internal kidney and pelvic (KP) fat. Heavier carcasses
would be expected to result in more meat than lighter car-
casses, and carcasses with heavier muscling would give
more lean meat than carcasses with less muscling. Meat
cuts are sold with a designated amount of fat or with all fat
removed. The KP fat has no functional value for meat cuts,
so greater amounts of subcutaneous fat and KP fat reduce
the expected lean proportion of carcasses.
×
Spanish
wethers (Wildeus et al., 2007).
Carcass Composition
The physical and chemical composition of the carcass will
determine the value and subsequent desirability of goat
meat. Does contain less bone in their carcass than bucks
and yield more edible tissue at the same carcass weight.
Does also have less muscle than males at most weights
because they have a greater tendency to deposit fat
(Johnson et al., 1995b). Mature goats can contain 30% or
