title: Determination of when during the lactation cycle to start feeding a cellulase and xylanase enzyme mixture to dairy cows.
abstract: We used 48 multiparous Holstein cows to compare the response of dairy cows to a direct-fed mixture of cellulase and xylanase enzymes (1.25 L of enzyme concentrate/tonne of forage dry matter) applied to the forage portion (60% corn silage and 40% alfalfa hay) of a total mixed diet starting either in the close-up dry period, at calving, or at peak milk production. Cows were blocked by calving date and, within blocks, randomly assigned to one of four treatment diets. Treatments were: 1) an untreated control diet, 2) enzyme addition to the forage from wk 6 to 18 postpartum, 3) enzyme addition to the forage from calving to wk 18 postpartum, and 4) enzyme addition to the forage from wk 4 prepartum to wk 18 postpartum. Total mixed diets were 65% forage and 35% concentrate prepartum, and 50:50 forage:concentrate postpartum. The production of milk, solids-corrected milk, fat-corrected milk, and energy-corrected milk was higher for cows fed enzyme-treated diets than for cows fed control diet. Production was similar for cows in all enzyme-treated groups, although numerically highest for cows that started receiving enzyme-treated forages right after parturition and numerically lowest when started prepartum. Concentrations of fat, protein, and lactose in milk were similar for all treatments; yields of protein and fat were higher for cows fed enzyme-treated forages. Dry matter intake and body condition scores, both prepartum and postpartum, were similar for all diets. Eating rates, as determined in two 24-h studies, were similar for control and enzyme-treated diets. The feeding of enzyme-treated forages increased milk production. While the effect of when the feeding of enzyme-treated forages started was not statistically significant, we recommend starting soon after parturition because of the greatest total milk production when starting at that time.
authors.affiliation: Dairy Science Department South Dakota State University Brookings, 57007-0647, USA.
authors.forename: W
authors.initials: W
authors.lastname: Zheng
authors.forename: D J
authors.initials: DJ
authors.lastname: Schingoethe
authors.forename: G A
authors.initials: GA
authors.lastname: Stegeman
authors.forename: A R
authors.initials: AR
authors.lastname: Hippen
authors.forename: R J
authors.initials: RJ
authors.lastname: Treachert
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000502:physiology*; D002480:Cellulase / Q000008:administration & dosage*; D005260:Female; D007743:Labor, Obstetric; D007774:Lactation / Q000502:physiology*; D007785:Lactose / Q000032:analysis; D008055:Lipids / Q000032:analysis; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000032:analysis; D011247:Pregnancy; D013997:Time Factors; D043325:Xylan Endo-1,3-beta-Xylosidase; D014995:Xylosidases / Q000008:administration & dosage*
chemical_list: D008055:Lipids; D008894:Milk Proteins; D014995:Xylosidases; D043325:Xylan Endo-1,3-beta-Xylosidase; D002480:Cellulase; D007785:Lactose