Survival feeding of pregnant and lactating cows under simulated drought conditions on all-sorghum grain rations with and without added calcium

Abstract

Eleven pairs of twin cows were fed a drought ration of either 3 kg or 4 kg of sorghum grain per head per day. The grain fed to one member of each twin pair was supplemented with 1 per cent limestone whereas the other twin received the same quantity of grain without limestone. The rations were fed to the cows during the last 100 days of pregnancy and first 10 weeks of lactation. Cows fed 3 kg sorghum grain a day had a significantly greater rate of body weight loss than those fed 4 kg grain during pregnancy but not during lactation. No clinical signs of calcium deficiency were observed in cows fed the all-grain ration without 1 per cent limestone nor was rate of body weight loss affected. Neither the birth weight nor the growth rate of the calves was affected by the addition of calcium to the ration ; however, calves suckling cows fed 4 kg grain a day had a significantly greater rate of body weight gain than those suckling cows fed 3 kg grain.