The effect of bypassing the rumen with supplements of protein and energy on intake of concentrates by sheep

Abstract

1. Two experiments were conducted with young early-weaned lambs to measure the voluntary intake of dry concentrates when additional protein or lactose was given as a fluid preparation from a bottle.2. The voluntary intake of a barley–urea diet (130 g crude protein/kg) was increased by 10–15% as a result of giving 2·3 g nitrogen/d as a fish-protein concentrate in fluid suspension. Amounts greater than 2·3 g N/d did not further increase voluntary intake but increased growth rate and food conversion ratio. Urea given as a solution in water in the same way in amounts equivalent to 4·6 N/d had no effect on voluntary intake.3. The voluntary intake of a high-protein barley–fish-meal diet was decreased by giving 10 or 20% of the estimated intake as lactose by bottle. The results indicated that maximum energy intake was achieved with the basal diet, since the decrease in energy intake was about equal to the amount given in the solution bypassing the rumen.