Desempenho animal, consumo de nutrientes e eficiência do uso do nitrogênio por borregos mantidos em pastagem de aruana e feijão guandu recebendo ou não suplemento energético

Abstract

The cultivation of grasses intercropped with legumes is an alternative for raising small ruminants, as it provides a higher protein concentration, resulting in superior performance, in addition to promoting nitrogen fixation in the soil. The present study evaluated the intercropping of guandu beans (Cajanus cajan (L.) Mills) with aruana (Panicum maximun) for grazing sheep, with or without supplementation with energy concentrate. The research was conducted at the Sheep Farming Teaching and Research Unit (UNEPE) of the Federal University of Paraná (UTFPR), Dois Vizinhos campus, Paraná, from December 2023 to April 2024. Twenty-four Dorper × Santa Inês crossbred sheep were used in a completely randomized design with four treatments and three replicates. The treatments used were: AR = aruana grass pasture; ARGB = aruana grass pasture intercropped with guandu beans; ARGBSUP = aruana grass pasture intercropped with guandu beans and an energy concentrate supplement at 1.0% of body weight; ARSUP = aruana grass pasture and an energy concentrate supplement at 1.0% of body weight. The following parameters were evaluated: forage production (kg DM ha⁻¹), forage mass (FM, kg DM ha⁻¹), forage accumulation rate (FA, kg DM ha day⁻¹), stocking rate (no. of animals), forage supply (FS, kg DM per 100 kg BW), and average daily gain and body weight of the animals (BW and ADG). Additionally, fecal and urine samples were collected to determine N use efficiency and microbial protein synthesis. The results showed that supplementation increased the body condition score and improved the productive performance of sheep, resulting in a higher average daily gain compared to unsupplemented animals. On the other hand, unsupplemented animals exhibited higher forage intake.