Aym. Nour et Ml. Thonney, CHEMICAL-COMPOSITION OF ANGUS AND HOLSTEIN CARCASSES PREDICTED FROM RIB SECTION COMPOSITION, Journal of animal science, 72(5), 1994, pp. 1239-1241
Seventy-four small-framed Angus and sixty-nine Holsteins were used to
evaluate the classic Hankins and Howe equations for predicting percent
ages of water, protein, and lipid of steer carcasses varying in weight
and breed type. Animals were fed either corn grain or corn silage die
ts, housed inside or outside, and slaughtered at one of five predeterm
ined weights within breed. Soft tissues from a carcass side and the fr
om the 9-10-11th rib section were separated from bone, and the percent
ages of water, protein, and lipid were measured. The Hankins and Howe
equations predicted .81 +/- .181 percentage units more (P < .001) wate
r and .99 +/- .213 percentage units less (P < .001) lipid than was mea
sured in the carcasses. The residual difference for protein depended o
n breed anddiet (P < .028) and decreased .22 +/- .078 percentage units
for each percentage unit increase in predicted protein. During develo
pment of equations from our data, no statistical difference was found
between Angus and Holstein in the relationship of carcass water to rib
water. The relationship of carcass protein to rib protein had a lower
(P < .1) intercept with a steeper (P < .055) slope for Angus than for
Holstein steers, whereas for lipid there was no difference between th
e slopes, but Holsteins had one percentage unit more (P < .038) carcas
s lipid than Angus at the same percentage rib lipid. These results con
firm that composition of the 9-10-11th rib section can be used accurat
ely to predict carcass composition with minor adjustments for breed ty
pe.