Abstract

Six lactating abomasally cannulated ewes were subjected to a hyperinsulinemic euglycemic clamp with or without casein supplementation in a two period crossover design experiment. There was a significant response in milk (1169 ± 46 g/d vs 952 ± 46 g/d, P<0.001) and milk protein (66.4 g/d ± 2.7 g/d vs 54.2 g/d ± 2.7 g/d P<0.006), yield from casein supplemented ewes. There was no overall effect of the clamp on milk and milk protein yield, while the interaction was also non-significant. However, there was a significant reduction in feed intake (P<0.001) as the clamp continued, which may have compromised milk and milk protein response. There was also a significant period effect across all the measured parameters, which could also be a stage of lactation effect, due to the rapid decline of milk production during ewe lactation. In this study, in contrast to concentrate-fed cows, the utilisation of this technique did not increase milk protein yield in pasture fed lactating ewes.

PJ, Back, DDS MacKenzie, SR Davis, and PM Harris

Proceedings of the New Zealand Society of Animal Production, Volume 58, , 205-208, 1998