Effect of yeast culture and Aspergillus oryzae extract on milk yield in a commercial dairy herd.

The objective of this study was to examine the effects of an Aspergillus oryzae extract in combination with a yeast culture (Saccharomyces cerevisiae) on milk yield and composition, rectal temperatures, and rumen parameters in a commercial dairy herd. Pluriparous Holstein cows (n = 521) in early lactation were assigned to a 130-d trial from May to September 1992. Treatments were control (no additive) and yeast culture (56 g/d) plus A. oryzae (3 g/d). Both groups were fed a TMR composed of alfalfa silage, alfalfa hay, corn silage, rolled barley, rolled corn, grass screenings, whole cottonseed, wet citrus pulp, molasses supplement, protein pellet, and minerals. No differences were detected in actual milk, 3.5% FCM, or percentages of milk fat or protein. Percentages of lactose and SNF were lower for the group fed yeast culture plus A. oryzae. Rectal temperatures were lower for cows fed yeast culture plus A. oryzae for 7 of 17 readings made during the summer. The greatest difference occurred during hotter months.