Bioscientifica Proceedings

Abstract. The efficiency of milk production in pasture-based systems is heavily influenced by calving pattern, necessitating excellent reproductive performance in a short breeding season. Where grazed pasture is the major component of the diet, cows are underfed relative to their intake potential. A number of studies have identified body condition score measurements that are related to likelihood of both submission and conception. In general, fertility variabl...

Summary. Reduced reproductive performance of lactating cows during the summer is associated mainly with intensive genetic selection for high milk production, which places a great load on the thermoregulatory mechanism. Today, cooling is the predominant strategy used to alleviate the effects of heat stress. However, it cannot eliminate the decline in reproduction. A better understanding of the mechanism by which heat stress compromises fertility is required to ...

Summary. Declining fertility and perturbations in reproductive development in a variety of species have been linked to exposure to endocrine disrupting chemicals (EDCs), which are ubiquitous in the environment. Ruminants are largely exposed to such chemicals in sewage sludge fertiliser widely used in animal production systems. This has been investigated experimentally through the deliberate exposure of pregnant ewes to sewage sludge fertilised pastures or cont...