ALBERT

Beschreibung: SummaryDissection data for 753 steer carcasses from 17 breed-type × feeding system groups were used to examine the distribution of bone weight between 11 standardized commercial joints, and the prediction of bone content in side (half carcass) from the bone content of individual joints. Breed types included Ayrshire, Friesian, Friesian × Ayrshire and crosses out of Friesians by Angus, Charolais, Hereford, Limousin, Simmental and South Devon sires. Group means for bone weight in the side ranged from 14·9 to 21·0 kg with a pooled within-group S.D. of 1·97 kg.The increase in bone weight in each joint relative to that in the side was examined using the allometric equation. Pooled within-group growth coefficients (b values) were lowest for the leg (hind shin) and shin (fore shin) joints (b = 0·86 ± 0·02 and 0·94 ± 0·02 respectively) and highest for the sirloin (b = 1·10 ± 0·05).At equal total bone weight, there were significant (P 〈 0·001) but relatively small differences between groups in the weight of bone in each of the joints tested.Bone weights in the top piece, shin and coast joints gave the most precise prediction of bone weight in the side: the pooled within group residual standard deviations were 0·62, 0·67 and 0·71 kg respectively. The limited variation between groups in bone weight distribution was reflected in the robustness of common prediction equations across groups.

Beschreibung: SUMMARYDissection data for 753 steer carcasses from 17 breed-type x feeding system groups were used to examine the prediction of lean content in the side (half carcass) from the lean content of standardized wholesale joints. Different prediction equations were examined and the joints compared both in terms of predictive precision and the stability of their prediction equations between groups.The relative precision of the joints for predicting weight of lean in the side depended on whether or not the prediction equation included joint weight. With side weight and weight of lean in joint as independent variates, there was little difference between most joints in precision, and the smaller joints, shin and leg (hind shin) appeared to be best because they are convenient and easy to dissect. The addition of joint weight to the equation improved considerably the precision of all the joints except the shin and leg. The coast and top piece gave the most precise predictions with the trivariate equation (residual standard deviations about the common regression line computed ignoring groups, RSD overall, were 1·44 and 1·48 kg respectively) and the fore rib probably offered the best compromise between cost and precision (RSD overall = 1·82 kg).The stability of prediction equations between groups was influenced in a similar way by the inclusion of joint weight as an independent variate. The joints which gave the most precise predictions tended to have the most stable equations. The average biases between the actual group means and the means predicted using the trivariate equation computed ignoring groups were ± 0·46, ± 0·49 and ± 0·76 kg for the top piece, coast and fore rib respectively.