title: Effect of rumen protected methionine supplementation on early lactational responses of dairy cows fed a grass silage and cereals diet.
abstract: To investigate the milk production limiting potential of a diet based on grass silage (40%), hay (15%), dried sugar beet pulp (13%) and grain compound mixture (32%), 28 multiparous cows in early lactation were randomly assigned to two treatment groups: a control group and a group receiving supplementary rumen protected methionine (RPMet) treatment (12 g intestinally available methionine/cow/day, given 1-120 days postpartum; Smartamine; RPAN's technology). The diet was formulated to meet the requirements for protein and net energy. RPMet supplementation had no significant effect on DMI (kg/cow/day), milk dry mass, milk lactose and milk urea contents. Responses for mean daily milk yield, mean milk fat and milk protein yields were significantly higher (P < 0.05) in cows supplied with RPMet than in controls. Mean daily milk yield, milk protein and milk fat yields increased by 2.4 kg, 108 g and 124 g, respectively. The mean daily milk protein and casein contents were increased by 1.8 g and 0.9 g and milk fat content by 1.2 g in 1 kg of milk, respectively. The results suggest that in cows fed grass silage and a grain compound mixture milk production is limited by methionine insufficiency, but milk production performance can be increased significantly by the addition of RPMet to the diet.
authors.affiliation: Institute of Animal Nutrition and Feed Management, University of Agriculture and Technology, Olsztyn-Kortowo, Poland.
authors.forename: S
authors.initials: S
authors.lastname: Iwańska
authors.forename: D
authors.initials: D
authors.lastname: Strusińska
authors.forename: B
authors.initials: B
authors.lastname: Pysera
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001798:Blood Proteins / Q000032:analysis; D001806:Blood Urea Nitrogen; D002417:Cattle / Q000378:metabolism*; D002523:Edible Grain / Q000737:chemistry / Q000378:metabolism; D005260:Female; D007774:Lactation / Q000378:metabolism*; D008715:Methionine / Q000008:administration & dosage / Q000378:metabolism*; D008892:Milk / Q000378:metabolism*; D011897:Random Allocation; D012417:Rumen / Q000378:metabolism; D012820:Silage / Q000032:analysis; D013053:Spectrophotometry / Q000662:veterinary
chemical_list: D001786:Blood Glucose; D001798:Blood Proteins; D008715:Methionine