Dietary nitrogen concentration in growing cattle: the effect on growth rate, feed utilization and body composition

Abstract

Thirty-six British Friesian castrated male cattle (steers) were included in an experiment to measure the response in live-weight gain and body composition to feeding barley-based diets containing increasing levels of formaldehyde-treated soya bean meal. The response was measured between 100 kg and 350 kg or 450 kg live weight. The basal diet of pelleted whole barley and 10% ground oat straw contained 16·6g to 38·5 g nitrogen per kg dry matter. There were no overall differences in live-weight gain or in feed intake. Between 100 kg and 250 kg live weight, live-weight gain increased significantly from 1 08 to 1·24 kg/day when the lowest and highest nitrogen diets respectively were fed (PPPP<0·05). When similar animals were slaughtered at 465kg there was a non-significant trend for omental fat weight and fat depth at the 12th rib to decrease as the nitrogen content of the diet increased.