Effects of providing two forms of supplemental methionine to periparturient Holstein dairy cows on feed intake and lactational performance

• Published in: Journal of dairy science Vol. 92; no. 10; p. 5154
• Main Authors: Ordway, R S, Boucher, S E, Whitehouse, N L, Schwab, C G, Sloan, B K
• Format: Journal Article
• Language: English
• Published: United States 01-10-2009
• Subjects: Amino Acids - blood; Animals; Cattle - physiology; Diet; Dietary Supplements; Eating - physiology; Fats - analysis; Female; Lactation - physiology; Methionine - administration & dosage; Methionine - analogs & derivatives; Methionine - pharmacokinetics; Milk - chemistry; Milk Proteins - analysis; Nitrogen - analysis; Parturition; Pregnancy; Urea - analysis
• ISSN: 1525-3198
• DOI: 10.3168/jds.2009-2259

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.