Short communication: Effect of increasing levels of corn bran on milk yield and composition.
Thirty-nine lactating Holstein cows (23 multiparous and 16 primiparous) were randomly assigned to 1 of 3 dietary treatments in a crossover design. Dietary treatments differed by the proportion of corn bran [10, 17.5, and 25% dry matter (DM); designated as low, medium, and high] replacing corn silage and alfalfa. The corn bran coproduct contained 8.2% moisture and 12.9% crude protein, 30.4% neutral detergent fiber (NDF), and 45.0% nonfiber carbohydrate, 9.9% ether extract, and 0.70% P (DM basis). The low treatment consisted of 15.8% NDF from forage (fNDF) and 33.1% total NDF; the medium treatment consisted of 12.9% fNDF and 32.5% total NDF; and the high diet contained 9.9% fNDF and 31.8% total NDF. Dry matter intake was not affected by treatment. The percent milk fat decreased by 0.26% with the inclusion of corn bran from 10 to 25% of the diet DM, but total milk fat yield was not affected. In comparison, corn bran increased yield of milk protein 0.12 kg/d when bran increased from 10 to 25% of the diet DM. Total milk yield tended to increase when bran increased from 10 to 25% of the diet DM, but no differences were observed on 3.5% fat-corrected milk. Lastly, feed conversion significantly improved with increasing inclusion: 1.39, 1.39, and 1.55 +/- 0.05 kg of milk/kg of DMI for low, medium, and high, respectively. Observed effects were likely due to the increase in energy intake associated with increasing levels of corn bran.
Janicek
B N
BN
Department of Animal Science, University of Nebraska, Lincoln 68583-0908, USA.
Kononoff
P J
PJ
Gehman
A M
AM
Karges
K
K
Gibson
M L
ML
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004043:Dietary Fiber / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage; D005260:Female; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000737:chemistry*; D012639:Seeds; D003313:Zea mays
D004040:Dietary Carbohydrates; D004043:Dietary Fiber; D004044:Dietary Proteins