Feeding of heifers for survival on whole and cracked sorghum grain under simulated drought conditions

Abstract

Groups of Hereford heifers of a mean (¦ SE.) body weight 187 ¦ 3 kg were fed in yards a sole ration of sorghum grain + one per cent limestone for 26 weeks. Four groups were fed the equivalent of 1.36 kg of sorghum grain per head per day as either whole or cracked grain at either daily or twice weekly intervals. A fifth group was fed 1.64 kg of whole sorghum grain per head per day which provided a digestible dry matter intake comparable to that of 1.36 kg of cracked grain. When heifers were fed the same quantity of dry matter as whole and cracked grain, the rate of body weight loss of those fed whole grain was significantly greater than that of those fed cracked grain; and the rate of body weight loss of those fed daily was significantly greater than that of those fed twice weekly. With similar intakes of digestible dry matter from whole and cracked grain, there was no significant difference in the rate of body weight loss. Heifers from sub-groups of high initial body weight lost significantly more body weight than heifers from sub-groups of low initial body weight. The whole bodies of three heifers that died from undernutrition contained less than 0.3 per cent ether extract on a fresh weight basis, indicating complete exhaustion of body energy reserves.