Changes in nutritional characteristics and performance of grazing Nellore cows during the peripartum phase receiving or not protein supplementation

Abstract

We objective was to understand the changes in nutritional characteristics and performance of grazing Nellore cows during the peripartum receiving or not supplementation. Forty multiparous cows were used, divided into two treatments: CON - mineral mixture and SUP – protein supplementation. Digestibility trial was performed (-45,-30,-15, + 20, +40; days relative to calving). The average daily gain (ADG) pre and postpartum of the cows were measured and, in gestational and maternal tissues in the prepartum, in addition of body condition score (BCS). The calves were weighed at birth and at 30 days of age. There was an effect of treatment and period (P ≤ 0.10) for dry matter, organic matter and crude protein intake, while forage intake was similar (P ≥ 0.10), but with a period effect (P ≤ 0.10). There was 14.37% decrease in dry matter intake from day − 30 to day − 15 of prepartum. In the postpartum period, at 20 days of lactation, there was increase of 72.66% in relation to the period − 15. There was interaction between period and treatment for all digestibilities (P ≤ 0.10). No differences were observed in postpartum ADG (P ≥ 0.10), BCS at calving and postpartum (P ≥ 0.10). However, higher total ADG and in maternal tissues (P ≤ 0.10) were observed on supplemented animals, but with ADG in gestational tissues similar (P ≥ 0.10). It is concluded that there is a decrease in voluntary intake in grazing pregnant cows close to parturition and greater performance of animals supplemented in prepartum.