title: Effects of providing two forms of supplemental methionine to periparturient Holstein dairy cows on feed intake and lactational performance.
abstract: Eighteen primiparous and 42 multiparous Holstein cows were blocked according to parity and expected calving date and assigned randomly to 1 of 3 dietary treatments: 1) a basal diet (negative control), 2) the basal diet plus 2-hydroxy-4-methylthio butanoic acid isopropyl ester (MetaSmart, Adisseo Inc., Antony, France), or 3) the basal diet plus rumen-protected Met (Smartamine M, Adisseo Inc., Alpharetta, GA). Treatments were initiated 21 d before expected calving and continued through 140 d postpartum. Diets were similar in ingredient and chemical composition, except for the content of Met in metabolizable protein. MetaSmart [0.35% prepartum and 0.54% postpartum in diet dry matter (DM)] and Smartamine M (0.06% prepartum and 0.10% postpartum in diet DM) were added to the basal diet in amounts needed to achieve a 3.0:1 ratio of Lys to Met in metabolizable protein. Prepartum DM intake (DMI; 13.5 kg/d), body weight (687 kg), body condition score (3.81), postpartum milk yield (42.0 kg/d), milk fat yield (1,549 g/d), milk fat content (3.66%), milk true protein yield (1,192 g/d), and milk urea N content (12.9 mg/dL) were not different among treatments. Postpartum DMI and body condition score were greater and the ratios of milk:DMI and milk N:feed N were less for cows fed the MetaSmart diet than for cows fed the control and Smartamine M diets. Milk protein content was greater for the Smartamine M (2.87%) and MetaSmart (2.81%) treatments than for the control treatment (2.72%). Concentrations of Met and Met + Cys in total plasma AA were different among treatments, with values for the Smartamine M treatment being the highest, followed by the MetaSmart and control treatments. The results indicated that both MetaSmart and Smartamine M are effective in providing metabolizable Met, but clarification of their relative contributions to metabolizable Met is still needed.
authors.affiliation: Blue Seal Richer Dairy Nutrition Inc, Sandy Creek, NY 13145, USA. ryan.ordway@blueseal.com
authors.forename: R S
authors.initials: RS
authors.lastname: Ordway
authors.forename: S E
authors.initials: SE
authors.lastname: Boucher
authors.forename: N L
authors.initials: NL
authors.lastname: Whitehouse
authors.forename: C G
authors.initials: CG
authors.lastname: Schwab
authors.forename: B K
authors.initials: BK
authors.lastname: Sloan
mesh_terms: D000596:Amino Acids / Q000097:blood; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004032:Diet; D019587:Dietary Supplements; D004435:Eating / Q000502:physiology*; D005223:Fats / Q000032:analysis; D005260:Female; D007774:Lactation / Q000502:physiology*; D008715:Methionine / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D008892:Milk / Q000737:chemistry; D008894:Milk Proteins / Q000032:analysis; D009584:Nitrogen / Q000032:analysis; D036801:Parturition; D011247:Pregnancy; D014508:Urea / Q000032:analysis
chemical_list: D000596:Amino Acids; D005223:Fats; D008894:Milk Proteins; C008391:alpha-hydroxy-gamma-methylmercaptobutyric acid; D014508:Urea; D008715:Methionine; D009584:Nitrogen