Effects of replacing alfalfa hay with malt sprouts and corn stover on milk production and nitrogen partitioning in dairy cows

The aim of this investigation was to study the effect of replacing alfalfa hay with malt sprouts and corn stover on feed intake and apparent digestibility, rumen fermentation, milk production and composition, and N partitioning in dairy cows. Six multiparous Holstein dairy cows were used a replicated 3 × 3 Latin square design with each period lasting 27 d. The cows were assigned randomly to one of three treatment groups: (1) 0 g/kg malt sprouts and 0 g/kg corn stover (0MS), (2) 49.1 g/kg malt sprouts and 34.4 g/kg corn stover (5MS), and (3) 133 g/kg malt sprouts and 49.1 g/kg corn stover (13MS). The diets were isonitrogenous and contained identical corn silage and concentrate mixtures, but different proportions of corn stover and malt sprouts. The in situ effective degradability of dry matter, neutral detergent fiber and crude protein were higher in cows fed 13MS or 5MS diets than in those fed the 0MS diet. The respective intake and total-tract apparent digestibility of dry matter, crude protein, neutral detergent fiber, and acid detergent fiber were greater for 13MS than for 5MS or 0MS. Cows fed the 13MS diet had greater milk production, energy-corrected milk, milk protein and lactose yields and percent milk protein than cows fed other diets, but fat yield, percentage of milk fat, lactose, somatic cell count, milk urea nitrogen concentration and feed efficiency were similar for the three treatments. Compared with the 0MS diet, cows fed 5MS or 13MS diets had higher rumen ammonia nitrogen and total volatile fatty acids concentration, PD to creatinine ratio. Moreover, the cows that consumed a MS diet had a higher rate of manure excretion. Thus, it appeared that the combination of malt sprouts and corn stover effectively replaced a portion of alfalfa hay in diets without affecting the performance of dairy cows.