title: Response of lactating dairy cows to a cellulase and xylanase enzyme mixture applied to forages at the time of feeding.
abstract: Fifty Holstein cows (20 primiparous and 30 multiparous) were used in an experiment to evaluate the dose response to a direct-fed cellulase and xylanase enzyme mixture applied to the forage portion (60% corn silage and 40% alfalfa hay) of a total mixed ration just prior to feeding. Cows were fed one of five treatment diets for 12 wk. Diets 1 through 4 were 55% forage: 45% concentrate and consisted of an untreated control and the control diet plus 0.7, 1.0, or 1.5 L of enzyme concentrate/tonne of forage dry matter, respectively. Diet 5 was an untreated 45% forage: 55% concentrate diet. Actual production of milk increased as much as 10.8% relative to the control diet with 1.5 L of enzyme, and production of fat and protein increased as much as 20 and 13%, respectively. The lowest concentration of enzyme treatment (0.7 L/tonne) accounted for approximately one-half of the production increases. The responses to enzyme-treated forages occurred 2 to 4 wk after the cows started to consume the treated forages, and the same responses were maintained throughout the remainder of the experiment. Cows that started to receive enzyme-treated forage during the first 100 d postpartum produced 9 to 15% more milk and 16 to 23% more energy-corrected milk than did cows fed the control diet. However, production was not increased when cows were in midlactation at the start of the experiment. Responses to enzyme-treated forages fed in 55: 45 forage to concentrate rations were similar to the response to increased proportions of concentrates fed with untreated forages at the 45:55 forage to concentrate ratio.
authors.affiliation: Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Schingoethe
authors.forename: G A
authors.initials: GA
authors.lastname: Stegeman
authors.forename: R J
authors.initials: RJ
authors.lastname: Treacher
mesh_terms: D000821:Animal Feed / Q000191:economics; D000818:Animals; D001835:Body Weight; D002417:Cattle / Q000502:physiology*; D002452:Cell Count; D002480:Cellulase / Q000008:administration & dosage*; D003362:Cost-Benefit Analysis; D005260:Female; D007774:Lactation; D008055:Lipids / Q000032:analysis; D000455:Medicago sativa; D008892:Milk / Q000737:chemistry / Q000166:cytology; D008894:Milk Proteins / Q000032:analysis; D012820:Silage; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000008:administration & dosage*; D003313:Zea mays
chemical_list: D008055:Lipids; D008894:Milk Proteins; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; D002480:Cellulase