Energy nutrition of the pasture-based transition cow--a review.

Abstract

A restriction in energy intake during the final weeks pre-calving is believed to depress milk production post-calving. The requirements of the non-lactating periparturient cow for energy, and in particular for glucose, have been shown to increase dramatically as parturition approaches. However, a decline in precalving dry matter intake has also been measured during this period. One solution to this problem has been to reduce the forage to concentrate ratio, thereby substituting feeds that are greater in energy density for feeds that are less dense. However, the pre-calving decline in dry matter intake appears greater as the amount of concentrates in the diet increases or alternatively as the fibre concentration of the diet declines. Previous reviews of transition cow nutrition have largely dealt with the nutrition of cows offered a total mixed ration or diets containing primarily lucerne or maize silage, and have not accounted for differences in farming systems, the base diet offered, or differences between cows within breeds. In this paper the effect of nutrition during the transition period on the metabolism of the periparturient cow offered a pasture-based diet was examined.