Abstract:
Animal Production in Australia Vol. 15 LUPINS OR OATS AS SUPPLEMENTS FOR COWS FED PASTURE IN EARLY LACTATION P.J. MOATE*, G.L. ROGERS*, I.B. ROBINSON* Lupins have been suggested to be superior to cereal grains as a feed supplement for cows in early lactation because they provide more protein (Bartsch and Wickes 1980). Rogers et al. (1980) have shown that lactating cows grazing high quality spring pasture can yield more milk and milk constituents in response to post ruminal protein supplements. A common claim is that the heating of proteinaceous feeds decreases their ruminal proteolysis (Ferguson 1974). In this experiment lupins (DMD, 0.86; N, 0.048) were crushed and heated (3 hours at 13O'C) and compared with crushed oats (DMD, 0.69; N, 0.014) as a feed supplement to lactating cows. Four groups of seven cows grazed temperate ryegrass/white clover autumn pasture`(DMD, 0.735; N, 0.035) and were offered either 0 or 2.2 kg/cow/day of crushed oats; or isocaloric supplements of either 4.4 kg/cow/day of crushed oats or a mixture of 2.2 kg of crushed oats and 2.0 kg of lupins. Table 1 Effects of oat and lupin supplements on milk production Means not followed by common letters differ significantly (P<O.O5) With both oats and the lupin-oats mixture there were significant increases in milk and milk protein yields (Table 1). There was no associated increase in milk fat yield because milk fat concentration was significantly depressed by concentrate feeding. As a feed supplement for lactating cows grazing good quality pasture, crushed-heated lupins were no better than crushed oats. Twenty-four hour NH3-N productions from crushed and crushed-heated lupins digested in rumen fluid in vitro, were 0.33 and 0.31 g NH3-N/g lupin N respectively. This indicated the heating did not significantly protect lupin protein from ruminal digestion. The results show that crushed-heated lupins were not superior to oats as a supplement for cows grazing high quality pasture. On the basis of cost, oats would generally be preferred. BARTSCH, B.D. and WICKES, R.B. (1982). Proc. Aust. Soc. Anim. Prod. 14 :628. Z FERGUSON, K.A. (1974). Proc. 4th International Symposium on Ruminant Physiology. Sydney p. 448. ROGERS, G.L., PORTER, R.H.D., CLARKE, T. and STEWART, J.A., Aust. J. Agric. Res. z 31:1147. c (1980) * Department of Agriculture, Dairy Research Institute, Ellinbank, Vic. 3820. 721
