|dc.description.abstract||The dairy industry’s profit is dependable on the dairy cows ability to produce high milk yields while reproducing efficiently. Cows undergo dynamitic metabolic changes during late pregnancy and through to the peak of lactation. With lactation the energy output is greater than the cows’ energy intake resulting in a NEB and a subsequent loss in BCS. The herd must be managed to reduce the degree of negative impact that those metabolic changes have on reproductive performance.
Within the studied herd, BCS and several metabolic parameters were found to be unsupportive of fertility. A great loss in BCS through the start of lactation, elevated BHB and increased urea concentrations indicates that the herd is in a NEB. This can negatively affects the reproductive performance and account for the suboptimal conception rate of the herd. Affects on reproduction include delayed uterine involution, decreased LH and progesterone concentrations, decrease oocyte quality, and creating an uterine environment incompatible with embryo survival. Increasing the energy density of the feed for lactating cows and preventing over conditioning of dry cows are critical management changes that can be made to lessen or eliminate the negative metabolic changes.||en