An evaluation of whole lupin grain, hammer-milled barley, and mixtures of the two as concentrates in a ration for yearling steers fed in pens

Abstract

Forty yearling Hereford x Friesian steers (237 kg initial liveweight) were paired in pens and fed for 77 days a ration of pasture hay ad libitum, plus either whole lupins, hammer-milled barley or mixtures of the two. Included also was a change-over ration where the concentrate commenced as whole lupins, but was changed progressively to hammer-milled barley. In each of the five treatments the concentrate was fed at 1.6 per cent of liveweight, and represented a mean of 45 per cent of the rations. Steers fed rations with whole lupins and hammer-milled barley in the proportions 100 : 0, 50 : 50 and 25 : 75 did not differ significantly in their liveweight gain, carcase weight, feed intake or feed conversion ratio. Depth of subcutaneous fat was, however, significantly (P < 0.05) greater where lupins were alone in the concentrate (4.8 mm vs, a mean of 2.7). There were no significant effects of the changeover ration. Feeding the concentrate as hammer-milled barley alone produced significantly (P < 0.01 ) lower liveweight gains and carcase weight than all other treatments (0.78 kg head-1 day-1 vs. a mean of 1.05; and 145.6 kg vs. a mean of 160.4 respectively). The reduced performance may have been related to the incidence of mild D-lactic acidosis, or to the lower than recommended protein level in the diet.