Feed additives for attracting sheep to eat a pelleted diet during assembly for live export

Abstract

The failure of some sheep to eat pelleted feed in feedlots prior to export may result in subsequent problems in their health and welfare. We investigated ways of improving feeding behaviour by adding chaffed hay or aromatic compounds to the pelleted feed. A control ration of pellets was compared with the same diet sprayed with solutions of butyric acid, aniseed oil or molasses, or fed with chaff (lucerne or oaten). Measurements of the number of sheep eating and total feed intake were made over a 10-day period. Merino wethers from 3 properties were mixed and allocated into 2 replicate groups of 39 animals per yard (1 3 m2/sheep) for each of the 6 treatments. The patterns of feed intake over time fell into 2 distinct groups. Over 70% of sheep fed pellets with either type of chaff visited the feed trough during the first 24 hours. When no chaff was fed, this level of feeding was achieved only after 4 days. All groups fed pellets without chaff showed the same pattern of feed intake, reaching a peak intake on day 3 or 4 before reducing intake until day 6 and then an increasing intake up to day 10. Little sign of this fluctuation was seen in the animals fed pellets with chaff, suggesting that, when only pellets were fed, an unstable pattern of rumen fermentation may have caused a build-up of lactic acid in the rumen and reduced feed intake. Molasses and aniseed reduced (P<0.01) the percentage of sheep per day visiting feed troughs to 5 1 and 53% respectively (6-day mean) compared with 63 and 62% for sheep on unsprayed pellets and pellets sprayed with butyric acid. Over the 10 days, intake of total feed per sheep putting its head in the trough was 1.10 kg/day for sheep fed pellets only while aniseed caused a reduction (P<0.01) to 0.85 kg/day and lucerne chaff resulted in an increase (P< 0.05) to 1.27 kg/day. There were significant differences in the eating pattern between different sources of sheep (P< 0.001) but there were no interactions between source and dietary treatments. We conclude that adding chaffed hay to the feed troughs can maximise the proportion of sheep eating from the first day in the feedlot. In addition, mixing chaffed hay with pellets on the first few days may assist the transition from roughage to cereal based diets. The use of aromatic compounds was not successful in attracting animals to the feed or in encouraging an increased intake.