Performance and Metabolic Responses of Nellore Cows Subjected to Different Supplementation Plans during Prepartum.

This study assessed the effects of different prepartum supplementation plans on Nellore cows' performance, metabolic responses, and early offspring development. Thirty-nine pregnant Nellore cows (224 ± 2.67 days of pregnancy, 5.3 ± 0.29 years of age, body weight 520 ± 15.2 kg, initial body condition score 6.0 ± 0.07) were assigned to one of four treatments: a control group receiving only mineral mixture ad libitum, and three groups receiving daily protein-energy supplements of 2, 4, or 6 g/kg BW for 60 days prepartum. Weights and body condition scores were evaluated at the start of the experiment, 7 days before calving, and at 45 and 90 days postpartum. Cows supplemented with 4 and 6 g/kg BW showed improved body weight and body condition scores prepartum and postpartum and had a shorter service period ( p < 0.05). The highest blood urea nitrogen concentrations were observed in cows receiving 6 g/kg BW ( p = 0.0124). There was a reduction in blood urea nitrogen at calving for the 6 g/kg BW group, while the control group showed an increase ( p < 0.001). Non-esterified fatty acids concentrations were lower 21 days before calving for the 4 and 6 g/kg BW groups compared to the control ( p < 0.05) and decreased postpartum for all treatments ( p < 0.001). No significant differences were observed in calf birth weight or performance. Supplementing with 4 g/kg BW of protein-energy is recommended to enhance metabolic health and overall performance.