Effects of feeding Aspergillus oryzae fermentation product to transition Holstein cows on performance and health

Two experiments examined the effects of Aspergillus oryzae fermentation product (AO; Amaferm®; BioZyme Inc., St. Joseph, MO, USA) on productive variables in transition dairy cows. In experiment 1, 33 Holstein cows (22 multiparous and 11 primiparous) were enrolled from −21 to 60 days in milk (DIM). Cows were individually fed either a control total mixed ration (TMR) diet consisting of primarily alfalfa hay and steam-flaked corn [62:38 and 59:41, forage:concentrate (F:C) for prepartum and postpartum phases, respectively] or the control diet along with 15 g d−1 of AO. In experiment 2, 455 multiparous Holstein cows were enrolled from −21 to 121 DIM. Cows were group-fed either a control TMR diet (n = 228) consisting primarily of corn silage and rolled corn (44:56, F:C) or the control diet (n = 227) with 15 g d−1 of AO. In experiment 1, cows fed AO had increased (P < 0.05) milk production compared with controls (37.7 vs. 34.6 kg d−1). Milk composition, dry matter intake, body weight (BW), and BW loss both prepa...