Effects of duration of introductory feeding and barley content of pelleted diets on the feed intake and liveweight of export sheep

Abstract

The liveweights and feed intakes of 409 adult wethers, from 2 pastoral sources, were measured in an experiment that simulated the assembly and shipping stages of the export of live sheep. The sheep were held separately with 17 wethers per group, and were introduced in outdoor yards to pelleted diets containing 0, 25 or 50% barley for either 5 or 9 days (adaptation) during which time lucerne hay or oaten hay were also fed. The wethers were then housed in intensive indoor pens (0.33 m21wether) for 14 days and fed the pelleted diets ad libitum without hay. During indoor feeding, wethers fed pellets containing 50% barley ate less pellets than did other sheep (1127 v. 1376 g DM/day, s.e.m. = 25.2, P<0.001). They had similar intakes of digestible organic matter (DOM) (732 v. 757 g/day, s.e.m. = 15.6), but lost more liveweight than did other sheep (- 1.88 v. -0.54 kg, s.e.m. = 0.200, P< 0.001). Increasing adaptation from 5 to 9 days significantly reduced the liveweight loss of wethers fed the diets containing 0% (-1.22 v. -0.20 kg, s.e.m. =0.283, P<0.05) and 25% barley (-1.35 v. 0.63 kg, s.e.m. = 0.283, P< 0.001) but had no effect on wethers fed diets containing 50% barley. Wethers fed lucerne hay during adaptation lost less liveweight indoors than wethers fed oaten hay (-0.66 v. -1.31 kg, s.e.m. = 0.163, P<0.01). Wethers fed lucerne for 9 days tended (P< 0.06) to eat more pellets indoors than other sheep (1386 v. 1262 kg, s.e.m. = 17.9). The wethers had an estimated intake of 37.9 g digestible organic matter/kg0.75 liveweight, which greatly exceeded expected requirements for maintenance and may be partly due to stress associated with intensive housing of the wethers.