Supplementation levels for suckling female calves under grazing: productive and nutritional performance and metabolic profile

The objective in this study was to evaluate the effects of supplementation levels on productive and nutritional performance and metabolic profile in suckling female calves under grazing. Forty female calves (averaging 3.5±0.06 months and 127.3±2.68 kg), and their respective dams were distributed in a completely randomized design with two treatments and twenty replicates. The treatments were 1) 4 g kg-1 body weight (BW) of supplement or 2) 6 g kg-1 BW of supplement. Forage and organic matter (OM) intake did not affect (P > 0.05) by levels of supplement, though crude protein and non-fibrous carbohydrates intake were greater (P 0.05) the supplementation levels on OM and CP digestibility. The metabolic profile of the animals was not affected (P > 0.05) by supplementation level. Average daily gain, longissimus dorsi area, fat thickness over rump of the animals did not affect (P > 0.05) by levels of supplement. However, there was trend of increasing (P=0.074) in fat thickness over loin by increase the supplementation level. Although the body growth of animals was similar (P > 0.05) between treatments, there was observed a trend of increase (P=0.064) in ratio BW:Height at the withers by increasing supplementation levels. In conclusion, increasing the supplementation level of 4 to 6 g kg-1 of BW, not improve the productive and nutritional performance and metabolic status in female calves under grazing on creep-feeding system.