Herbage allowance effects on the characteristics of Brachiaria brizantha cv. Marandu pastures and the production and economic viability of Nellore heifer.

摘要

This study aimed to evaluate the effect of three herbage allowances (5, 10, and 15 kg dry matter [DM] 100-1 of body weight [BW]) for Brachiaria brizantha cv. Marandu pastures in a continuous grazing system on the morphological and nutritional characteristics of forage, animal performance, and economic viability in Nellore heifers. The total experimental area was 60 ha, divided into 12 paddocks of 5 ha each, with 4 paddocks per treatment. The experimental animals were Nellore heifers (260 in total), with average BW of 301.16 ± 9.12 kg, receiving 0.4 % BW in multiple supplements. We evaluated the production, structural characteristics, and nutritional value of the forage, productive performance, carcass characteristics, and economic viability of each allowance. There were significant effects for the production, structural characteristics, and nutritional value of the forage treatment. The proportions of leaves were 42.40, 38.20, and 30.88 % and the leaf:stem ratios were 1.22, 1.03, and 0.83 for the 5, 10, and 15 kg DM 100-1 BW herbage allowances, respectively. The average daily weight gain (mean 0.42, 0.75, and 0.63 kg daily-1) and stocking rate (3.35, 1.87, and 1.26 animal unit ha-1) had a significant effect for the 5, 10, and 15 kg DM 100-1 BW forage allowance, respectively. The herbage allowances were evaluated as being economically viable with a profit margin of 10.37, 23.65, and 14.43 % for the 5, 10, and 15 kg DM 100-1 BW allowances, respectively. The greatest pasture response was found in the 5 kg DM 100-1 BW allowance and was related to better nutritional values and morphological characteristics of the pasture and greater stoking rate and weight gain per area. The herbage allowance of 10 kg DM 100-1 BW be applied to obtain higher animal performance and better economic viability of heifers in B. brizantha cv. Marandu pastures in a continuous grazing method that are receiving protein-energy supplementation.