Effects of energy-protein supplementation frequency on performance of primiparous grazing beef cows during pre and postpartum.

Objective: Twenty-four pregnant Nellore primiparous grazing cows were used to evaluate the effects of energy-protein supplementation and supplementation frequency during pre (105 d before calving) and postpartum (105 d after calving) on performance and metabolic characteristics.
Methods: Experimental treatments consisted of a control (no supplementation), daily supplementation (1.5 kg/d of concentrate/animal) and infrequent supplementation (4.5 kg of concentrate/animal every three days). During the pre and postpartum periods, concentrations of blood metabolites and animal performance were evaluated. Ureagenesis and energy metabolism markers were evaluated at prepartum period.
Results: Supplementation frequency did not alter (P > 0.10) body weight (BW), average daily gain (ADG), and carcass traits during pre and postpartum. The BW (P = 0.079), adjusted BW at day of parturition (P = 0.078), and ADG (P = 0.074) were greater for supplemented cows during the prepartum. The body condition score (BCS; P = 0.251), and carcass traits (P > 0.10) were not affected by supplementation during prepartum. On postpartum, supplementation did not affect animal performance and carcass traits (P > 0.10). The dry mater (DM) intake was not affected (P > 0.10) by supplementation and supplementation frequency throughout the experimental period. Daily supplemented animals had greater (P < 0.001) glucose levels than animals supplemented every three days. Supplementation and supplementation frequency did not alter (P > 0.10) the levels of blood metabolites, neither the abundance of ureagenesis and energy metabolism markers.
Conclusion: In summary, our data show that the reduction of supplementation frequency does not cause negative impacts on performance and metabolic characteristics of primiparous grazing cows during the prepartum.