Lactation performance, nitrogen utilization, and profitability in dairy cows fed fermented total mixed ration containing wet corn gluten feed and corn stover in combination replacing a portion of alfalfa hay

Abstract To effectively use corn by-products for ruminants, lactation performance, nitrogen utilization, and profitability in lactating dairy cows fed fermented total mixed ration (FTMR) that contained wet corn gluten feed (WCGF) and corn stover in combination replacing a portion of alfalfa hay were studied. Thirty-six multiparous Holstein dairy cows (602 ± 46.8 kg of body weight; 109 ± 18.5 day in milk; 30.1 ± 1.53 kg of milk production; and 2.44 ± 0. 51 of parity; mean ± SD) were blocked into 12 groups based on DIM, milk production, and parity and were allocated randomly to 1 of 3 diets for a 14-week period, with the first 2 weeks allowed for adaptation to the diets. The TMR was prepared with same mixed ration of concentrate mixtures and corn silage but different proportions of alfalfa hay, corn stover and WCGF. The treatments were designed as (1) TMR A containing 220 g/kg DM alfalfa hay; (2) TMR B containing 118 g/kg DM alfalfa hay, 68.8 g/kg DM WCGF, and 34.4 g/kg DM corn stover; and (3) Fermented TMR (FTMR) prepared with same ingredient as TMR B. The FTMR diet had higher crude protein (CP) and lactic acid contents content, the ratio of ammonia nitrogen to total N while decreased pH value, neutral detergent fiber (NDF), acid detergent fiber (ADF) and dry matter (DM) content compared to other two diets. The milk fat concentration, milk fat yield, DM and CP degradation, estimated microbial CP yield and feed efficiency were higher (P