Abstract

Forty-eight Friesian cows were subjected to ad libitum grazing (pasture allowance 45 kg/cow/day) or restricted grazing (pasture allowance 16-18 kg/cow/day) in a cross-over experiment during spring. Mean milk yields for ad libitum and restricted cows after 10 day treatment periods were 21.4 and 16.2 l/day respectively. All cows were then subjected to once-daily milking (ODM) for 2 days. ODM reduced milk yield and casein:whey protein ratios but increased concentrations of fat, serum albumin, immunoglobulin G, whey protein and somatic cells. Effects of ODM were greater in fully fed and thus higher-producing cows. In blood, ODM decreased concentrations of non-esterified fatty acids and urea, but increased concentrations of glucose. Milk yield and composition were significantly affected by short-term ODM, but the effect was less in cows producing below their peak due to feed restriction. There were metabolic indications that ODM reduced the nutritional demands of milk production.

MJ, Auldist, and CG Prosser

Proceedings of the New Zealand Society of Animal Production, Volume 58, , 41-43, 1998