title: Evaluation of a ruminally protected methionine product for lactating dairy cows.
abstract: In Experiment 1, three ruminally and duodenally cannulated cows were used to assess the extent of ruminal protection and postruminal release of Met from ruminally protected Met using a polyester bag technique. The ruminally protected Met contained 85.1% DL-Met (wt/wt). Ruminal disappearance of Met averaged 5.8, 8.1, 21.8, 37.5, and 87.5% after 3, 6, 12, 24, and 96 h of incubation, respectively. Postruminal disappearance of Met from bags inserted in the duodenum after treatment with pepsin-HCl averaged 63.4, 62.6, 51.6, 43.6, and 8.8% for bags incubated in the rumen for 3, 6, 12, 24, and 96 h, respectively. In Experiment 2, 12 cows were fed either 0 or 20 g/d of ruminally protected Met from 7 to 10 d prepartum until 18 wk postcalving. Cows were fed the same total mixed diet. The DMI; yields of milk, CP, and SNF; and percentages of fat, CP, and SNF in milk were not affected by treatment. However, yields of fat and 3.5% FCM increased when ruminally protected Met was fed. Milk N components were not affected by treatment. Concentrations of Met increased in plasma when ruminally protected Met was fed. The mechanism for the increased production of milk fat and 3.5% FCM when ruminally protected Met was fed is unknown.
authors: Department of Animal Sciences, University of Illinois, Urbana 61801, USA.
authors: T R
authors: TR
authors: Overton
authors: D W
authors: DW
authors: LaCount
authors: T M
authors: TM
authors: Cicela
authors: J H
authors: JH
authors: Clark
mesh_terms: D000596:Amino Acids / Q000097:blood; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight; D002417:Cattle; D004386:Duodenum / Q000378:metabolism; D004435:Eating; D005260:Female; D007700:Kinetics; D007774:Lactation / Q000502:physiology*; D050356:Lipid Metabolism; D008715:Methionine / Q000378:metabolism*; D008892:Milk / Q000737:chemistry / Q000378:metabolism; D008894:Milk Proteins / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D012417:Rumen / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D008894:Milk Proteins; D008715:Methionine; D010434:Pepsin A