Energy feeding strategies to shorten the postpartum anoestrous in grazing dairy cows

A prolonged postpartum anoestrus (PPA) is related to a low reproductive efficiency in dairy farms, independently of the calving pattern or feeding system. Postpartum luteal activity resumption is coincident with the onset of lactation when the cow is in negative energy balance, which depending on its magnitude could alter the hypothalamus – pituitary – ovary axis of the animal and prolong the PAA. In this article, some results from experiments that manipulated nutrition as a strategy to shorten the PPA, with emphasis in grazing systems, are briefly reviewed. Available information suggests that manipulation of the level and source of dietary energy are promising tools to reduce the length of the PPA in grazing dairy cows and increase the reproductive efficiency in dairy farms