Concentrate supplementation, and the herbage intake and milk production of heifers grazing Cenchrus ciliaris

Friesian heifers grazing Cenchrus ciliaris cv. Biloela were supplemented with 0, 3 or 6 kg concentrates daily during weeks 10–34 (±1·7) of lactation during either the rainy or the dry season. The overall responses to concentrate were identical between seasons at 0·27 kg extra milk and solids corrected milk per kg. Supplementation increased total feed intake and modified the grazing behaviour of cows. For each kg concentrate organic matter eaten, herbage organic matter intake was reduced by 0·64 and 0·42 kg in the rainy and dry seasons respectively and the time spent grazing by 11 min. Higher intakes in the dry season were the result of an increased rate of biting and were reflected in liveweight change but not milk yield.