EFFECT OF FEEDING AN ASPERGILLUS-ORYZAE EXTRACT ON MILK-PRODUCTION AND RELATED RESPONSES IN A COMMERCIAL DAIRY-HERD

The objective of this study was to examine the effects of an Aspergillus oryzae extract on milk production and composition, rectal temperatures, and rumen metabolites in a commercial dairy herd. Holsteins (110 cows with two or more lactations) in midlactation averaging 140 DIM were used in a 120-d trial from May to August 1991. Treatments were control (no additive) and A. oryzae (3 g of culture plus 136 g of rice mill byproduct daily). Both groups were fed a TMR composed of alfalfa silage, alfalfa hay, corn silage, rolled barley, whole cottonseed, beet pulp, liquid supplement, and a protein-mineral mix. No differences were detected in actual milk or 3.5% FCM production. Mean milk protein (3.12 vs. 3.05%) and SNF percentages (8.63 vs. 8.51%) were higher for the group fed A. oryzae. Rectal temperatures taken weekly between 1300 and 1500 h were lower for cows fed A. oryzae (38.7 vs. 38.8-degrees-C). Cows supplemented with A. oryzae had lower blood urea N concentrations than control cows (13.4 vs. 18.1 mg%).