Lipolytic response of New Zealand and overseas Holstein-Friesian dairy cows challenged with epinephrine

E.S. KOLVER, J.R. ROCHE, M.J. DE VETH AND T.R. MACKLE

Dexcel Ltd., Private Bag 3123, Hamilton, New Zealand

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Proceedings of the New Zealand Society of Animal Production 2001. 61: 48-51

Sixteen New Zealand Holstein-Friesians (NZ HF) and 15 overseas HF (OS HF) grazing pasture or fed a total mixed ration (TMR) were subjected to an epinephrine challenge during early lactation. A genotype x diet interaction trend (P=0.10) was observed; when grazing, OS HF displayed the greatest glycerol response, with the reverse occurring on TMR. No genotype or diet differences were observed for the glycerol or non-esterified fatty acid response. Dairy cows of both genotypes fed TMR produced a glucose response 31% greater than both genotypes grazing pasture. These preliminary results suggest that genotype x diet-induced differences in the rate of lipolysis may occur in Holstein-Friesians during early lactation. These differences may be a function of small differences in energy balance. Feeding TMR was associated with a greater glucogenic response to epinephrine, which probably resulted from greater hepatic reserves of glycogen or simply a greater energy demand by the mammary gland.

Keywords: NZSAPAB; Holstein-Friesian; genotype; diet; epinephrine; body reserves

Last Updated 7/08/01