Effects of an Aspergillus oryzae Extract Containing ɑ-Amylase Activity on Lactational Performance in Commercial Dairy Herds

The effects on milk production and composition of an Aspergillus oryzae extract (Amaize, Alltech Biotechnology Inc., Nicholasville, KY) containing ɑ-amylase activity were examined in 45 commercial dairy herds across the United States and Canada (approximately 8,150 cows). Number of cows, days in milk, milk production, and composition data were collected from monthly DHI test records. Fat-corrected and energy-corrected milk were calculated from milk yield and composition measurements. Cows were fed supplemental ɑ-amylase at a rate of 12 g/d per cow after the first monthly DHI test and continued to receive the supplement through a second DHI test. Whole herd and individual cow record analyses yielded similar results. Milk production tended to increase during the supplementation test month (32.0 vs. 31.7 kg, P = 0.059) when herd was used as the experimental unit in the analysis. When individual cow data were analyzed on a subset including 1,079 cows (initial DIM greater than 60 d and 3 consecutive DHI tests), a trend towards greater milk yield was observed during the supplementation month (33.3 vs. 32.2 kg, P = 0.097). Milk fat percentage was lower during the supplementation month (3.77 vs. 3.90, P = 0.013), whereas milk fat yield was not affected by supplemental ɑ-amylase. Inclusion of an Aspergillus oryzae extract containing ɑ-amylase activity in diets of commercial dairy herds tended to improve milk yield in a compilation of field studies.