title: Requirements of protein for maintenance and growth in ram hair lambs.
abstract: The experiment was conducted to determine the protein requirements for maintenance (PM) and weight gain (NPg) in Brazilian Somali lambs (n = 48). A database of information on non-castrated rams (n = 48) with an initial body weight (BW) of 13.47 ± 1.76 kg was obtained, and the comparative slaughter technique was used to assess protein requirements. Eight lambs were initially slaughtered and used as a reference for estimation of the empty body weight (EBW) and initial body composition of the remaining animals. The lambs (n = 40) were distributed in a completely randomized block design involving five experimental diets, containing 4.93, 8.65, 9.41, 10.12, and 11.24 MJ/kg dry matter (DM). Daily nitrogen retention (DNR) was calculated as the difference between the final N content in the body minus the initial content estimated from the reference animals, divided by the number of experimental days. PM was estimated from the retained N regression equation as a function of ingested N (g per kg(0.75) EBW/day), extrapolating the equation to the zero level of N intake, followed by multiplication by a factor of 6.25. The protein content of the EBW was reduced from 119.72 to 102.07 g/kg of empty body weight gain (EBG) when BW increased from 13 to 28.70 kg, respectively. The requirement of protein for maintenance was 0.80 g per kg(0.75) EBW/day. Based on information described in the present study, we recommend the value of PM 0.80 g per kg(0.75) EBW/day, for hair sheep Brazilian Somalis raised in tropical regions. We also suggest that hair sheep have different requirements for protein maintenance and gain.
authors.affiliation: Department of Animal Science, Federal University Ceara, Fortaleza City, Ceara State, postal code 60455760, Brazil. elzania@hotmail.com.
authors.forename: Elzania Sales
authors.initials: ES
authors.lastname: Pereira
authors.affiliation: Department of Animal Science, Federal University Ceara, Fortaleza City, Ceara State, postal code 60455760, Brazil.
authors.forename: Rildson Melo
authors.initials: RM
authors.lastname: Fontenele
authors.affiliation: Department of Animal Science, Federal University of Paraiba, Areia, Paraiba, postal code 583970009, Brazil.
authors.forename: Ariosvaldo Nunes
authors.initials: AN
authors.lastname: de Medeiros
authors.affiliation: Department of Animal Science, School of Veterinary Medicine and Animal Science/Federal University of Bahia, Salvador City, Bahia State, postal code 41170110, Brazil.
authors.forename: Ronaldo Lopes
authors.initials: RL
authors.lastname: Oliveira
authors.affiliation: Department of Animal Science, Federal University Ceara, Fortaleza City, Ceara State, postal code 60455760, Brazil.
authors.forename: Ana Claudia Nascimento
authors.initials: AC
authors.lastname: Campos
authors.affiliation: Department of Animal Science, Federal University Ceara, Fortaleza City, Ceara State, postal code 60455760, Brazil.
authors.forename: Eduardo Luiz
authors.initials: EL
authors.lastname: Heinzen
authors.affiliation: Department of Animal Science, Federal University of Piaui, Bom Jesus City, Piaui State, postal code 6490000, Brazil.
authors.forename: Leilson Rocha
authors.initials: LR
authors.lastname: Bezerra
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000831:Animals, Newborn; D001823:Body Composition; D001835:Body Weight; D001938:Brazil; D004032:Diet / Q000662:veterinary*; D004044:Dietary Proteins / Q000008:administration & dosage*; D004734:Energy Metabolism; D008297:Male; D012756:Sheep / Q000502:physiology*; D014329:Tropical Climate; D015430:Weight Gain
chemical_list: D004044:Dietary Proteins
keywords: Comparative slaughter; Growth; Maintenance; Protein; Sheep