Energy and protein requirements of non-descript breed hair lambs of different sex classes in the semiarid region of Brazil

• Published in: Tropical animal health and production Vol. 48; no. 1; pp. 87 - 94
• Main Authors: Rodrigues, Rafael Torres de Souza, Chizzotti, Mario Luiz, Martins, Samara Rodrigues, da Silva, Ivonete Ferreira, Queiroz, Mário Adriano Ávila, Silva, Tiago Santos, Busato, Karina Costa, Silva, Aderbal Marcos de Azevêdo
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-01-2016; Springer Nature B.V
• Subjects: Animal Feed - analysis; Animal Nutritional Physiological Phenomena; Animals; Biomedical and Life Sciences; Body Composition; Body weight; Brazil; Diet - veterinary; Dietary Proteins - administration & dosage; Dietary Proteins - analysis; Energy balance; Energy Intake - physiology; Energy Metabolism - physiology; Female; Hair; Life Sciences; Male; Nutritional Requirements; Orchiectomy; Regular Articles; Semiarid lands; Sheep - genetics; Sheep - physiology; Veterinary Medicine/Veterinary Science; Weight Gain; Zoology; Brazil; Sheep; Gender; Comparative slaughter; Body composition; Nutritional requirement
• ISSN: 0049-4747; 1573-7438
• DOI: 10.1007/s11250-015-0924-2

The aim of this study was to determine the energy and protein requirements of non-descript breed hair lambs (NDB) reared under Brazilian semiarid conditions. Sixty animals from three sex classes (20 intact males, 20 castrated males, and 20 females) with an average initial body weight of 18.1 ± 0.4 kg and an average age of 5 months were used. The nutritional requirements were estimated using the comparative slaughter. The animals in the final slaughter group were distributed in a completely randomized design with a 3 × 3 factorial scheme (three sex classes and three feeding levels: ad libitum feeding (positive energy balance), 70 % feed restriction (maintenance level), and 80 % feed restriction (negative energy balance)). The net energy requirement for maintenance (NEm) did not differ between sex classes (P > 0.05) and it was 68 kcal/kg of metabolic empty body weight (EBW⁰.⁷⁵)/day (P < 0.05). The coefficients for the nonlinear regression of retained energy (RE) on the empty body weight gain (EBWG) were not different among the different sex classes (P > 0.05). The net energy requirement for weight gain (NEg) was estimated by NEg (Mcal/day) = 0.29 × EBW⁰.⁷⁵ × EBWG⁰.⁸⁶ for all sex classes (P < 0.05). The net protein requirement for weight gain (NPg) was estimated by NPg (g/day) = 224.45 × EBWG − 0.025 × RE for all sex classes (P < 0.05). The NEg increased and the NPg decreased with the increase in body weight of NDB lambs.