Compensatory Gain by Holstein Calves After Underfeeding Protein

Abstract

A total of 110 Holstein steer calves 8 wk to 12 wk old were used in two trials to quantify feed energy and protein utilization by calves recovering from underfeeding protein. Three treatments (low protein, energy restriction and high protein) were imposed during the first two periods of growth (Period 1 was 154 d in Trial 1 and 112 d in Trial 2; Period 2 was 98 d in both trials). At the end of Period 1, calves in each treatment were fed either the low or high level of protein. All were full-fed a high-energy diet from the end of the second period until slaughter (estimated 26% body fat). Initial, end-of-period and final body composition were determined to calculate energy and protein retention. Compensatory gain was observed in all but one previously restricted group during realimentation; growth rates were 14 to 30% higher than controls. Degree of restriction altered the amount of compensatory gain; those that gained less during low-protein feeding gained faster during recovery. Compensating calves consumed more feed per unit metabolic body weight. Efficiency of gain (gain/feed) always was higher for the compensating groups, with no differences (P > .10) in overall efficiency. The restricted groups required 12 to 117 more days to reach a similar percentage final body fat. Final weight at a constant fatness was reduced by 44 kg when growth was restricted for 112 d at .12 kg/d followed by 98 d at .18 kg/d. Copyright © 1988. American Society of Animal Science . Copyright 1988 by American Society of Animal Science