Influence of Forage Type, Ratio of Forage to Concentrate, and Methionine Hydroxy Analog on Performance of Dairy Cows

Abstract

In a 2-yr study, 44 primiparous and 77 multiparous cows were assigned to one of 12 dietary treatments (2 × 3 × 2 factorial). Treatments were two forages (alfalfa or smooth bromegrass), three percentages of grain (40, 50, or 60% of diet DM), and two percentages of methionine hydroxy analog (0 or .15% of diet DM). Feeds were offered as total mixed diets. Data collection began 4 d postpartum and continued through 116 d postpartum. Dry matter intake was not affected by percentage of concentrate or forage source even though NDF of the diets ranged from 25.6 to 48.8% and ADF ranged from 15.7 to 36.8%. Cows fed bromegrass hay produced 1.5 kg/d more FCM and 1.2 kg/ d more SCM than those fed alfalfa hay. Concentrate percentage in the diet increased milk yield (28.9, 30.4, and 31.3 kg/d at 40, 50, and 60%, respectively). Methionine hydroxy analog increased milk fat percentage and yield for cows fed diets of 50 and 6096 concentrate with alfalfa hay but not for those fed diets of 50 and 60% concentrate with bromegrass hay. Effect of methionine hydroxy analog was not significant for milk fat or yield when diets of 40% concentrate were fed. © 1991, American Dairy Science Association. All rights reserved.