Proceedings of the New Zealand Society of Animal Production.
1965, 25: 26-42
Proceedings of the New Zealand Society of Animal Production.
1965, 25: 26-42
Live animal ultrasonic backfat measurements were strongly correlated (r=0.83, 0.76) with the percentage off at in the carcass, thus offering a sound basis for estimating these components in the live animal. Carcass mid-line back-fat measurements were relatively inefficient indicators of percentage fat, compared with measurements taken over the eye muscle. Eye muscle measurements were not satisfactory as indicators of percentage lean, but fat measurements and ratios of eye muscle measurements to fat depth, were promising. Carcass length and depth measurements were poorly correlated with carcass composition.
Specific gravity (S.G.) was strongly correlated with percentage fat (r=-0.95, -0.92), and the corresponding residual standard deviations (R.S.D.) were low (1.53%, 1.75%). These R.S.D.s were further reduced to 1.39% and 1.63% by combining S.G. and carcass measurements. In another trial, exaggerated thyroid activity appeared to lower the correlation between S.G. and percentage fat. The rib end was the individual joint giving the best prediction of whole carcass composition using S.G. The fillet end appeared the best sample joint to use in dissection.
Weight of trotters, combined with S.G., was a useful indicator of percentage bone (R.S.D.=0.34%). The use of S.G. of the trotters as a third variate reduced the R.S.D. to 0.31%. The cannon bone weight is not recommended for the estimation of percentage bone (r=0.69; R.S.D.=0.51%).
Keywords: NZSAPAB;
