Feeds and feeding methods for assembly of sheep before export

Abstract

Sheep are assembled in Australian feedlots before export and given time to adapt to the pelleted diet they will receive on board ship. In Western Australia, lupins are normally included in the diet at levels up to 30% as a source of digestible energy which is low in starch. It is also common to feed hay during assembly. We examine the use of pellets based on barley and containing either lupins or virginiamycin to overcome problems of acidosis, and the importance of hay during assembly. There were 9 dietary treatments each with 3 pens of 30 sheep. The study was conducted over 8 days simulating assembly feedlot conditions. Measurements were made of numbers of sheep visiting troughs (paint-marking technique) and accumulation of lactic acid in the rumen. 'Barley' pellets were formulated with 33% barley, 18% oats, 47% hay/straw and 2% minerals and vitamins. Replacing about half of the barley with lupins resulted in more sheep paint-marked on days 3-6 (P<0.05) and higher levels of feed intake on days 4-8 (P<0.001) than feeding pellets without lupins. The inclusion of lupins was also associated with a less pronounced drop in feed intake on day 4 than measured in sheep fed barley pellets alone. Adding virginiamycin at 40 g/t to the basal barley-based pellet also significantly increased the numbers of sheep paintmarked. Virginiamycin appeared to have a similar effect to the inclusion of lupins in terms of reducing the number of sheep which were not paint-marked. Sprinkling a small quantity of lucerne chaff onto the pellets had no effect on feeding behaviour. The use of hay in racks resulted in fewer sheep (3 v. 12%, P<0.05) not eating during the first 3 days but there was no significant effect thereafter. We concluded that the inclusion of either lupins or virginiamycin is effective in improving the adaptation to cereal-based pellets in export feedlots. The use of hay either in racks or sprinkled over the pellets appears to be of limited value.