Effects of faba bean, blue lupin and rapeseed meal supplementation on nitrogen digestion and utilization of dairy cows fed grass silage-based diets

There is increasing interest in using locally produced protein supplements dairy cow feeding. The objective of this experiment was to compare rapeseed meal (RSM), faba beans (FBs) and blue lupin seeds (BL) at isonitrogenous amounts as grass silage cereal based diets. A control diet (CON) without supplement included the experiment. Four lactating Nordic Red cows were used a 4 × Latin Square design with four 21 d periods. milk production increased supplementation but when expressed energy corrected milk, response disappeared due substantially higher fat concentration CON compared supplemented Milk output by 8.5, 4.4 2.7% RSM, FB BL CON. main changes rumen fermentation propionate lower butyrate proportion total volatile fatty acids diets Protein also clearly ruminal ammonia N concentration. improved organic matter NDF digestibility efficiency microbial synthesis per kg truly digested not affected. Flow greater fed. All decreased nitrogen use production. marginal (amount additional feed captured protein) 0.110, 0.062 0.045 for BL, respectively. current study supports evidence that RSM good cows, effect least partly mediated degradability BL. relatively small responses simultaneous decrease suggest economic environmental consequences feeding need be carefully considered.