title: Effects of yeast on dairy cow performance, ruminal fermentation, blood components, and milk manufacturing properties.
abstract: Effect of dietary yeast culture on milk production and composition, ruminal fermentation, blood parameters, and milk manufacturing properties of 24 midlactation Holstein-Friesian cows was determined in a 6-wk experiment. The control diet (DM) consisted of 30% corn silage, 22% alfalfa hay, and 48% concentrate. After a 2-wk preliminary period, cows were assigned in equal numbers to either 0 or 10 g/d of yeast culture for the remainder of the 4-wk study on the basis of age, DIM, and pretrial milk production. Production of milk (26.2 vs. 25.4 kg/d), FCM (23.6 vs. 21.6 kg/d), and milk fat (.90 vs. .78 kg/d) was increased significantly by dietary yeast culture. No differences were significant for milk composition. Molar proportion of acetate and acetate:propionate ratio in ruminal liquor tended to be higher in cows fed yeast culture. Total VFA concentration in ruminal fluid was not different between treatments. Manufacturing properties of milk and blood plasma components were not affected adversely by added dietary yeast culture.
authors.affiliation: Istituto di Scienze della Nutrizione, Facoltà di Agraria, Università Cattolica S.C., Piacenza, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Piva
authors.forename: S
authors.initials: S
authors.lastname: Belladonna
authors.forename: G
authors.initials: G
authors.lastname: Fusconi
authors.forename: F
authors.initials: F
authors.lastname: Sicbaldi
mesh_terms: D000641:Ammonia / Q000378:metabolism; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D002417:Cattle / Q000097:blood / Q000502:physiology*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005260:Female; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007774:Lactation; D008892:Milk / Q000737:chemistry; D012417:Rumen / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D015032:Zinc / Q000172:deficiency
chemical_list: D001786:Blood Glucose; D005232:Fatty Acids, Volatile; D000641:Ammonia; D015032:Zinc