CHARACTERISTICS OF YOUTHFUL BEEF CARCASSES IN RELATION TO WEIGHT, AGE AND SEX: I. ORGAN WEIGHTS, SLAUGHTER LOSS AND COOLER SHRINK IN PRODUCTION OF THE DRESSED CARCASS

In a study of youthful slaughter cattle comprising 168 steers, 147 heifers and 259 bulls, minor but statistically significant (P < 0.05) sex differences were observed for percent hide, shanks and head (steers > bulls > heifers) and percent kidney and cod or udder fat (heifers > bulls > steers). Bulls dressed approximately 1% higher and heifers 1% lower than steers, these sex differences apparently arising from items not recorded on the killing floor (including blood, lungs, digestive tract and contents and reproductive tract of females). Sex differences, particularly the bull versus steer comparisons, may have been influenced by differences in breed and/or pre-test treatment. Percentage internal fat trim and unrecorded slaughter loss were positively, and percent head, hide, shanks and internal organs negatively, correlated with liveweight at slaughter. However, slaughter weight accounted for less than 5% of the variance in dressing percentage, and age independent of slaughter weight had little influence on any of the traits studied. Total recorded slaughter loss expressed as a proportion of carcass weight decreased 0.1 to 0.4% per 100 kg increase in slaughter weight. The importance of pre-slaughter shrink in determining total slaughter loss was discussed.