Sandplain lupins (Lupinus cosentinii) as a summer feed for yearling steers

Abstract

The response of 9-month-old Angus steers, grazing sandplain lupins during summer and autumn and fed oat and oat plus urea supplements, or grazing hay made from the lupins and fed no supplement, was studied in two experiments. In the first experiment there were 3.3 t DM/ha present at the start of grazing. Average daily weight changes over 84 days were -0.548, -0.274 and 0.333 kg/day (P<0.05) for steers fed 0, 1 and 2 kg oats/steer.day respectively. The steers grazing lupin hay averaged -0.417 kg/day. There were 8.4 t DM/ha present at the start of the second experiment and the daily weight changes by steers fed 0, 2 and 6 kg oats plus urea/head.day were - 0.012, 0.524 and 0.952 kg/day (P<0.05), respectively. The steers grazing lupin hay gained 0.215 kg/day. No obvious clinical signs of lupinosis were observed in either experiment. However, in the first experiment the lupins were toxic, liver damage occurred and lupinosis may have contributed to the lower growth rates. In both experiments steers not fed a supplement made compensatory weight gains during winter and spring, when all steers were run together on mixed clover-grass pasture.