Relationship between live weight, age and dry-matter intake for beef cattle after different levels of food restriction

Abstract

Five groups of 24 Aberdeen Angus steers, initially 8 months old and 185 kg in weight were subjected to varying degrees of restriction of energy intake, by feeding them on diets containing 1·45 to 2·85 Meal metabolizable energy (ME)/kg dry matter (DM) for 16 weeks. During the realimentation period that followed, all animals were fed ad libitum on the diet containing 2·85 Meal ME/kg DM. When realimentation began the feed consumption of all animals, which had been markedly different, rapidly became similar. When compared at equal live weight the restricted animals had higher intakes than the controls; at an equal age, however, feed intakes were practically the same. This led us to discard compensatory feed intake as a possible explanation for compensatory growth. Age explained 65% of the variability in feed intake, live weight explained 43% and both parameters jointly explained 73%. It is concluded that in restricted and realimented animals, age is a better predictor of feed intake than live weight. Compensatory growth is attributed to a lower maintenance requirement in restricted animals because of their lower live weight at the beginning of the realimentation period.