title: Energy and protein requirements of non-descript breed hair lambs of different sex classes in the semiarid region of Brazil.
abstract: 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 (EBW(0.75))/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 × EBW(0.75) × EBWG(0.86) 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.
authors.affiliation: Department of Animal Science, Universidade Federal do Vale do São Francisco - UNIVASF, Petrolina, Pernambuco, 56300-990, Brazil. rafael.nutricao@hotmail.com.|Department of Animal Science, Universidade Federal de Lavras - UFLA, P.O. Box 3037, Lavras, Minas Gerais, 37200-000, Brazil. rafael.nutricao@hotmail.com.
authors.forename: Rafael Torres de Souza
authors.initials: RT
authors.lastname: Rodrigues
authors.affiliation: Department of Animal Science, Universidade Federal de Lavras - UFLA, P.O. Box 3037, Lavras, Minas Gerais, 37200-000, Brazil.
authors.forename: Mario Luiz
authors.initials: ML
authors.lastname: Chizzotti
authors.affiliation: Department of Animal Science, Universidade Federal do Vale do São Francisco - UNIVASF, Petrolina, Pernambuco, 56300-990, Brazil.
authors.forename: Samara Rodrigues
authors.initials: SR
authors.lastname: Martins
authors.affiliation: Department of Animal Science, Universidade Federal do Vale do São Francisco - UNIVASF, Petrolina, Pernambuco, 56300-990, Brazil.
authors.forename: Ivonete Ferreira
authors.initials: IF
authors.lastname: da Silva
authors.affiliation: Department of Animal Science, Universidade Federal do Vale do São Francisco - UNIVASF, Petrolina, Pernambuco, 56300-990, Brazil.
authors.forename: Mário Adriano Ávila
authors.initials: MA
authors.lastname: Queiroz
authors.affiliation: Instituto Federal de Educação, Ciência e Tecnologia do Sertão Pernambucano - IF Sertão, Petrolina, Pernambuco, 56314-520,, Brazil.
authors.forename: Tiago Santos
authors.initials: TS
authors.lastname: Silva
authors.affiliation: Department of Animal Science, Universidade Federal de Lavras - UFLA, P.O. Box 3037, Lavras, Minas Gerais, 37200-000, Brazil.
authors.forename: Karina Costa
authors.initials: KC
authors.lastname: Busato
authors.affiliation: Departament of Animal Science, Universidade Federal de Campina Grande - UFCG, Patos, Paraíba, 58700-970, Brazil.
authors.forename: Aderbal Marcos de Azevêdo
authors.initials: AM
authors.lastname: Silva
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001823:Body Composition; D001938:Brazil; D004032:Diet / Q000662:veterinary; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000032:analysis; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D008297:Male; D009751:Nutritional Requirements; D009919:Orchiectomy; D012756:Sheep / Q000235:genetics / Q000502:physiology*; D015430:Weight Gain
chemical_list: D004044:Dietary Proteins
keywords: Body composition; Comparative slaughter; Gender; Nutritional requirement; Sheep