Effects of pituitary-derived bovine growth hormone on production parameters and biokinetics of key metabolites in lactating dairy cows at peak and mid-lactation
1987
McDowell, G.H. | Hart, I.C. | Bines, J.A. (National Inst. for Research in Dairying, Reading (United Kingdom)) | Lindsay, D.B. (Agricultural Research Council, Cambridge (United Kingdom). Inst. of Animal Physiology) | Kirby, A.C. (Sydney Univ. (Australia). Dept. of Genetics and Biometry)
Treatment of 5 cows with pituitary-derived bovine growth hormone (bGH) was investigated at peak (c.40 days) and mid (c.130 days) lactation. At peak lactation, milk yield and milk fat increased, liveweight and milk lactose content decreased with bGH treatment. At mid-lactation milk yield, milkfat yield and milk lactose yield increased, while milk protein decreased and milk lactose content was unaffected, and liveweight was unchanged. Metabolic effects differed with stage of lactation. Plasma glucose, urea, acetates, non-esterified fatty acids and their irreverisble losses were investigated. bGH results in the supply of increased nutrients to support milk synthesis. Metabolic effects reflect differences in physiological and-or nutritional state with stage of lactation.
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