Growth and development in beef cattle. 2. Direct and residual effects of plane of nutrition during early life on the chemical composition of body components

Abstract

SUMMARYLow, medium and high planes of nutrition were imposed on Friesian calves from 1 to 13 weeks of age (Period 1) and factorially arranged with low and high planes of nutrition in the 13–25 week period (Period 2). In the final (residual) period, from 25 weeks to slaughter, all animals were given the same high plane diet. The different planes of nutrition were achieved by offering restricted allowances of milk replacer or concentrates with roughage ad libitum. The roughage was grass hay during the milkfeeding period and grass silage thereafter. Representative animals were slaughtered at 1, 13 and 25 weeks of age while the remaining animals were slaughtered at mean liveweights of 503 and 553 kg. The ME intake of the low plane animals in Period 1 was 0·55 that of the high plane animals and produced daily accretions of protein, fat and energy in empty body which were respectively 0·43, 0·29 and 0·36 of the gains of the high plane animals. The ME intake of the low plane in Period 2 was 0·69 of the high plane and daily accretions of protein, fat and energy in empty body were 0·46, 0·59 and 0·54 of the gains of the high plane animals.Within Period 2 compensatory protein growth was observed in both carcass and non-carcass components in response to nutritional restriction in Period 1. Compensatory protein growth was also obtained in the carcass component in the residual period as an indirect effect of nutritional restriction in Period 2.Nutritional restriction in early life produced relatively small non-significant direct effects on body and carcass composition and while early restriction subsequent produced a considerable degree of compensatory growth, there were no significant differences in carcass measurements or chemical composition of the carcass by the final slaughter weight.