There was a decline in the peripheral progesterone concentrations with increasing ration. The pregnancy rate in ewes fed a high ration was significantly reduced when compared with those of ewes fed a medium or low ration (48% vs 68 and 67% respectively; P < 0\m=.\05). In ewes fed the high ration exogenous progesterone increased the pregnancy rate from 48 to 76% (P < 0\m=.\01).Progesterone treatment did not influence pregnancy rates in ewes fed medium or low rations. The number of fetuses per ewe pregnant was not influenced by level of nutrition or progesterone treatment.
Recent studies have reported a substantial increase in the incidence of reproductive cycle problems in modern dairy cows (Opsomer et al., 1998; Royal et al., 1999). This increase is often attributed to the ever-increasing metabolic demands placed upon these cows by continually increasing milk yields. In this study we have monitored a variety of metabolic parameters in lactating dairy cows and related these to reproductive function in an attempt to establish metabolic predictors of impending reproductive failure.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.