BRIEF COMMUNICATION: Insulin response to a glucose tolerance test in 18-month-oId pregnant heifers as a predictor of subsequent herd survival

摘要

A decline in dairy cow fertility in the USA and in the UK (Beam & Butler 1999; Royal et al. 2000) has also been noted in New Zealand. Calving rate, the proportion of cows re-calving within the first 42 days of the subsequent seasonal calving period, in New Zealand decreased from approximately 70% in 1991 to 60% in 2004 (Harris et al. 2006). There has been no further deterioration in subsequent years.A number of studies have indicated that circulating insulin concentrations influence reproductive performance of dairy cows (Garnsworthy et al. 2009; Wathes et al. 2011). The objective of this paper was to investigate the relationship between response parameters to a glucose tolerance test (GTT) administered to pregnant Friesian-Jersey crossbred heifers and their subsequent survival in the herd, especially those aspects associated with fertility.