The effect of body-weight loss on the composition of Brahman cross and Africander cross steers

Abstract

Comparative slaughter was used to assess the effects of body-weight loss on Brahman cross (BX) and Africander cross (AX) steers of the F₃ generation with respect to the empty body weight, the hot carcass weight and various offal components. Animals were slaughtered at design weights of 325, 341, 358, 374 and 390 kg, some while during positive body-weight growth (Group A) and others during weight loss from 390 kg at a rate of 0·5 kg per day (Group B).AX animals had less empty body weight (B. B. W.) and dressed carcass weight (H. C. W.) at the same fasted body weight. Weight loss also reduced the amount of E. B. W. at the same fasted body weight but the effect on H. C. E. was not significant.The breeds were very similar with respect to the various components of the offal, except that the AX had heavier heads. The weight loss treatment increased the proportion of the head, tail and feet, because these comparatively bony structures lost relatively little during the weight loss period. The heart was also relatively increased by the weight loss treatment. The liver, gall bladder, kidneys, total gut tissue, spleen and thymus were reduced relative to E. B. W. in Group B animals. The liver showed its most rapid weight loss in the early period of body-weight loss, being the only organ to show any variation in its rate of change during body-weight loss.Body-weight loss caused changes in the distribution of the gut tissue, with a relative loss in the rumen-reticulum and a relative gain in the hind gut.