Nutrition and Fertility in Cattle

Nutrition influences fertility of cattle in many ways and improved understanding of the mechanisms involved is leading to new strategies with potential to reverse the trend for declining fertility. The first priority is to minimise the degree and duration of negative energy balance in early lactation by restricting body condition at calving so that feed intake is not impaired. The second priority is to provide good quality diets that meet the animal's energy and nutrient requirements within its appetite limits. When these priorities have been addressed, diet composition can be altered to manipulate metabolic hormones, particularly insulin, which helps to coordinate ovarian function with changes in metabolic status. Increasing insulin concentrations during early lactation can advance the resumption of oestrous cycles by enhancing follicular growth. However, high concentrations of insulin can be detrimental to oocyte quality, which is influenced also by supply of fatty acids. Recent evidence has demonstrated that varying nutrient profile during the reproductive cycle can optimise responses. This enables nutrition to be matched to genotype and milk production, with a positive impact on pregnancy rate.