Agriculture Reference
In-Depth Information
•
Selection 2 carcasses have moderate muscling, with
slightly thick and slightly bulging leg muscles, slightly
full
Longissimus dorsi
muscling in the loins and ribs,
slightly thick shoulders, and lack of muscling in the loin
and leg junction.
•
Selection 3 carcasses have defi cient muscling and
produce low yields of lean meat relative to the body size
and weight. The carcasses are narrow and lack depth,
with moderate leg muscling, shallow rib and loin mus-
cling, and slightly thin shoulder muscling. The defi cient
muscling may contribute a shrunken appearance to the
carcass and a well-defi ned depression along the top of
the back and at the junction of the loin and leg.
The side and rear views of carcasses representing the
midpoint in each selection classifi cation are shown in
Figure 13.1 .
The weight of carcasses can be determined relatively
easily, often before chilling to give the hot carcass weight.
The back muscle (
Longissimus dorsi
) is highly related to
the degree of muscling in the remainder of the carcass.
The measurement of the cross-sectional area of this
loineye or ribeye muscle, 12th rib in beef carcasses, forms
the basis for estimating the degree of muscling. Lamb
carcasses and pork carcasses are seldom split into fore-
quarters and hindquarters commercially. The leg confor-
mation and muscling score are subjectively evaluated to
provide an indication of the relative amount of muscling
on lamb and pork carcasses, respectively. Measurement of
the loineye area at the 10th rib in pork carcasses is some-
times used to provide a more accurate measure of percent-
age muscle in the carcass. Goat carcasses are not separated
into forequarters and hindquarters. The cross-sectional
area of the
Longissimus dorsi
in kid goat carcasses and
many adult goat carcasses is suffi ciently small to result in
inaccurate measurement. The Institutional Meat Purchase
Specifi cations for Fresh Goat (USDA, 2001) use a carcass
conformation score to gauge the degree of muscling in the
goat carcass.
Carcass yield of goat carcasses is highly related to the
amount of KPH fat and subcutaneous fat. KPH can be
estimated by visual evaluation of the internal carcass fat,
as shown in Figure 13.2. Deposited fat around the heart is
different in goats as compared to cattle and sheep; there-
fore, KP is estimated in goats. The KP fat is commonly
removed after evisceration in lamb and pork carcasses, but
it is sold as part of beef and goat carcasses.
The measurement of subcutaneous fat covering the
Longissimus dorsi
on lamb or beef carcasses at the 12th
rib (back fat) or the 10th rib for pork carcasses (rib fat)
Figure 13.1
Rear and side views of meat goat
carcasses depicting the midranges of selection
conformation classes 1, 2, and 3. For color
detail, see Appendix A.
allows estimation of the proportion of fat to muscle and
the relative amount of fat that will be trimmed from the
carcass in making cuts. Goats do not generally deposit fat
over the
Longissimus dorsi
muscle unless nutritional
energy levels are much higher than the need for growth
and maintenance. Fatness over the ribs and behind the
shoulder is used as a relative indicator of waste fat that will
be trimmed from the carcass and result in lower yields of
lean meat.
