Influence of forage type, ratio of forage to concentrate, and methionine hydroxy analog on performance of dairy cows.
In a 2-yr study, 44 primiparous and 77 multiparous cows were assigned to one of 12 dietary treatments (2 X 3 X 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 60% 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.
Hansen
W P
WP
Department of Animal Science, University of Minnesota, St. Paul 55108.
Otterby
D E
DE
Linn
J G
JG
Donker
J D
JD
D000367:Age Factors; D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004043:Dietary Fiber / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D004435:Eating; D005232:Fatty Acids, Volatile / Q000032:analysis; D005260:Female; D006863:Hydrogen-Ion Concentration; D007774:Lactation; D000455:Medicago sativa; D008715:Methionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008892:Milk / Q000737:chemistry / Q000378:metabolism*; D006109:Poaceae; D012417:Rumen / Q000737:chemistry
D004043:Dietary Fiber; D004044:Dietary Proteins; D005232:Fatty Acids, Volatile; C008391:alpha-hydroxy-gamma-methylmercaptobutyric acid; D008715:Methionine