Morfofisiologia ruminal de vacas leiteiras alimentadas no pré-parto com dietas de diferentes teores energéticos

Abstract

Dairy cows after calving, receiving diets rich in reticulorumen rapidly fermentable carbohydrates, leading to VFA production at high speed. This high VFA production could lead to ruminal acidosis (RA). The aim of this study was to determine whether transition diet, given in the last weeks of pregnancy, contributes effectively to the control of post partum RA in dairy cows. Six Holstein cows divided in a randomized block design, according to the expected date of birth. Six weeks before the expected calving were fed a standardization diet. Four weeks before calving were subjected to diets with low or high content of non-fiber carbohydrates (NFC).. After calving, all cows were fed a highly energetic lactation diet. Cows fed the diet high NFC had higher dry matter intake and increased milk production. Diet high in NFC caused greater extension of the rumen absorptive surface than the diet low in NFC. This suggesting that transition diet has positive effect on the VFA ruminal absorption, which is important in RA controlling. The extent of the absorptive surface before parturition was lower than after delivery, probably reflecting the effect of high energy lactation diet. Providing a diet with high content of NFC in the pre-partum may be a good alternative in controlling postpartum RA in dairy cows of high milk production. Promoting the further development of the absorptive surface of the rumen can thus avoid the accumulation of AGV in this compartment. The higher dry matter intake and increased milk production associated with diets high in NFC in the pre-birth seem to have been a reflection of better physiological condition of the rumen of these animals.