Effect of Sometribove on Rumen Fermentation, Rate of Passage, Digestibility, and Milk Production Responses in Dairy Cows

• Published in: Journal of dairy science 1991-10, Vol.74 (10), p.3518-3523
• Main Authors: Winsryg, M.D., Arambel, M.J., Kent, B.A., Walters, J.L.
• Format: Article
• Language: English
• Subjects: Animals; Bacteria - drug effects; Biological and medical sciences; Cattle - physiology; DIGESTA; DIGESTIBILIDAD; DIGESTIBILITE; DIGESTION; Digestion - drug effects; Female; FERMENTACION; FERMENTATION; Fermentation - drug effects; Food industries; Fundamental and applied biological sciences. Psychology; Growth Hormone - administration & dosage; Growth Hormone - analogs & derivatives; Growth Hormone - pharmacology; HORMONAS PITUITARIAS; HORMONE HYPOPHYSAIRE; Hormones - administration & dosage; Hormones - pharmacology; Human Growth Hormone; Injections, Subcutaneous - veterinary; INTESTIN; INTESTINOS; Lactation - drug effects; MICROORGANISME; MICROORGANISMOS; Milk and cheese industries. Ice creams; milk yield; Recombinant Proteins - administration & dosage; Recombinant Proteins - pharmacology; RENDEMENT LAITIER; RENDIMIENTO LECHERO; RUMEN; Rumen - drug effects; Rumen - metabolism; Rumen - microbiology; ruminal parameters; sometribove; VACAS LECHERAS; VACHE LAITIERE
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(91)78543-3

Six ruminally and duodenally fistulated Holstein cows 60 d postpartum were assigned randomly to each of two treatments in a single reversal design. Treatments consisted of placebo or 25mg of sometribove (bST) injected daily. Treatments were initiated at 60 d±7 postpartum and maintained for 6 wk with a 3-wk adjustment between treatment periods. All cows received a TMR consisting of 16% CP and 1.67Mcal of NEL/kg of DM. Influence of bST on rumen fermentation characteristics, digesta rate of passage, apparent nutrient digestibility, and milk production was evaluated. Milk yield of treated animals was 4.0 kg/d higher than controls. The 3.5% FCM and milk production efficiency (3.5% FCM/DMI) were significantly higher in treated animals than in controls (29.0 vs. 25.4kg/d and 1.38 vs. 1.21kg/ kg, respectively). Percentage of rumen cellulolytic bacteria (of total viable bacteria) was not significantly different for bST-treated animals (6.4 vs. 3.4%). Total number of rumen protozoa tended to be higher (7.25 vs. 6.55×103/ml) in bST-treated animals. Ruminal percentages of CP, NH3 N, α-amino N, VFA, and pH were unaffected by treatment. Sometribove treatment did not significantly affect liquid dilution or solids turnover rates. Percentages of CP, α-amino N, and NH3 N content in duodenal samples were unaffected by treatment. Total tract apparent digestibility of nutrients and mean daily DMI were unaffected by treatment.