Effects of incorporating yellow lupins into concentrate diets compared with soya on milk production and milk composition when offered to dairy cows

An experiment investigated the hypothesis that incorporating lupins (Lupinus spp.) compared with soya bean (Glycine max) meal into concentrate diets would not alter the yield or composition of milk from dairy cows. There were 2 dietary treatments: yellow lupin (cv. Wodjil) and soya bean meal. The experiment consisted of a continuous design with 3 phases: a covariate period (weeks 2 and 3 of lactation), an adaptation period (7 days; week 4 of lactation) and a measurement period (weeks 5 to 12 of lactation). Twenty-four mature autumn-calving dairy cows were used. During the covariate period, feed intakes and milk yields were recorded whilst cows were offered ryegrass silage ad libitum plus 6 kg d-1 of a standard dairy concentrate. Cows were allocated to treatment and adapted to their respective diet over 7 days, during which the concentrate offered was increased up to 9 kg d-1. During the measurement period, cows received ryegrass silage ad libitum using individual feeders. Concentrates of each treatment (9 kg d-1) were fed 3 times d-1. Milk yields were measured and 50 ml sub-samples of milk from two consecutive milkings were collected from all cows every week for measurement of fat, protein, lactose and somatic cell counts. Dairy cows offered the soya bean meal concentrate had a higher DM intake, and therefore, ME intake than cows offered the lupin dietary treatment but there was no difference in the N intake by cows on the two treatment diets. As animals on both dietary treatments consumed the same (9 kg) amount of concentrates each day, the intake data showed that dairy cows offered concentrates containing soya bean meal consumed more ryegrass silage than those offered concentrates containing yellow lupins. There were no significant differences in the milk yield or milk composition from dairy cows offered concentrate diets containing either yellow lupins or soya bean meal during weeks 5 to 12 of lactation (P>0.05). Overall, the findings from this study indicate that yellow lupins could be used as a home-grown alternative to imported soya in dairy diets in the UK but further studies are needed to determine the long-term effects of yellow lupins on dairy cow health and fertility.