The effects of insulin on the milk production of pasture-fed
Jersey cows
P.J. BACK, D.D.S. MACKENZIE, S.R. DAVIS, P.M. HARRIS AND J. LEE
AgResearch Grasslands Research Centre, Palmerston North, New
Zealand
E-Mail:
NZSAP 2003 Abstract No. 10
Proceedings of the New Zealand Society of Animal Production
63: 35-39
The aim of this experiment was to determine the effects of
insulin on milk protein production in lactating, pasturefed dairy cows.
Five lactating rumen-fistulated Jersey cows were subjected to a
hyperinsulinaemic euglycaemic clamp (HEC) with and without an abomasal
infusion of casein (310g/d) in a two period cross-over design
experiment. The HEC significantly reduced milk yield in the control cows
compared to casein-infused cows (9.9 ± 0.5 vs 13.2 ± 0.5
kg/ d, P<0.001). Milk protein yield was significantly higher in the
casein-infused cows compared to the control cows (482 ± 16 vs 421
± 16 g/d, P<0.05). The HEC significantly reduced milk protein
yield in the control cows compared to casein-infused cows (311 ±
16 vs 459 ± 16 g/d, P<0.001). The use of the HEC technique in
pasture-fed cows did not result in the milk protein response reported in
concentrate-fed cows.
Keywords: NZSAPAB;
dairy cows; milk protein; insulin
Last Updated 8/07/2004
