Abstract

This study investigated the immediate and long-term effects of temporary alterations to milking frequency post-partum in grazing cows. Multiparous Holstein-Friesian cows (n = 150) were assigned to one of five groups at calving: milked twice daily (2X, Control), or either once daily (1X) or thrice daily (3X) for three or six weeks, and 2X thereafter. During Weeks 1-6 post-calving, 1X for six weeks resulted in greater decreases in milk, fat, protein and lactose yields (P <0.05) relative to 2X than 1X for three weeks. Furthermore, 1X for three or six weeks reduced fat, protein and lactose yields (P <0.05), and tended to reduce milk yields (P = 0.08), for the remainder of lactation (Weeks 8-32). Body condition was greater for 1X cows at Weeks 6 and 8 (P <0.05) and tended to be greater during Weeks 8-32 (P = 0.09). Milking 3X for three or six weeks increased milk yield (P <0.05) relative to 2X during Weeks 1-6 and milk yields were numerically greater during Weeks 8-32 (P = 0.17); however, fat and protein yields were not affected. Once-daily milking for three or six weeks postcalving had lactation-long negative effects on milk production, whereas 3X increased milk yield but did not result in short- or long-term benefits in fat and protein yields.

CVC, Phyn, JK Kay, AG Rius, SR Morgan, CS Roach, TM Grala, and JR Roche

Proceedings of the New Zealand Society of Animal Production, Volume 71, Invercargill, 45-49, 2011