Resumo
Os objetivos deste estudo foram estimar as exigências nutricionais e desenvolver equações para predizer a composição química do corpo e da carcaça. Trinta e quatro cabritos Boer o Saanen, não castrados, foram utilizados, dos quais sete foram abatidos no início do experimento, com 21,2 kg PV. Outros seis foram abatidos ao atingirem 28,2 kg PV. Os 21 restantes foram distribuídos aleatoriamente em sete grupos de três animais. Os tratamentos foram definidos por três níveis de consumo de matéria seca (CMS): à vontade e restrição de 30 ou 60% do CMS. Cada grupo foi abatido quando o animal do tratamento à vontade atingiu 35 kg de PV. Foi utilizado o método da abate comparativo para o cálculo das exigências. A exigência líquida (EL) diária de energia e proteína para mantença foram estimadas em 78,2 kcal/kg0,75 de peso do corpo vazio (PCV) e 2,4 g/kg0,75 PCV. Com relação aos macrominerais, a EL diária para mantença foi estimada em 32,3 mg Ca; 30,8 mg P; 1,31 mg Mg; 8,41 mg K e 5,14 mg Na por kg de PCV. A EL para ganho de energia, para animais pesando entre 20 a 35 kg PV, variou entre 2,5 a 3,0 Mcal/kg ganho PCV (GPCV); a de proteína variou entre 178,8 e 185,2 g/kg GPCV e a de macrominerais variou de 6,5 a 7,0 g Ca; 5,3 a 5,4 g P; 0,29 a 0,31 g Mg; 0,67 a 0,62 g Na e 1,18 a 1,05 g K por kg GPCV. A composição química (CQ) do corpo e da carcaça foram melhores estimadas por meio da CQ dos componentes não carcaça e das costelas, respectivamente
Meat production of goats has become an important livestock enterprise in several parts of the world. Nonetheless, energy and protein requirements of meat goats have not been defined thoroughly. The objective of this study was to determine energy and protein requirements for maintenance and growth and to develop equations to predict the chemical composition of body and carcass using chemical composition of body components of Boer and oSaanen crossbred, intact male kids. In the first trial, 34 Boer and oSaanen crossbred, intact male kids were used. The baseline group (BL) was comprised of seven randomly selected kids, averaging 21.2 l 0.36 kg of BW. An intermediate group consisted of six randomly selected kids that were slaughtered when they reached 28.2 l 0.39 kg BW. The remaining kids (n = 21) were allocated randomly to three levels of DMI (treatments: ad libitum and restricted to 30 or 60% of the ad libitum intake) within seven slaughter groups. A slaughter group consisted of one kid from each treatment and was slaughtered when the ad libitum treatment kid reached 35 kg BW. Individual body components were weighed, ground, mixed, and subsampled for chemical analyses. The calculated daily NEm requirement was 78.2 kcal/kg0.75 of empty BW (EBW). A value of 2.44 g of net protein/kg0.75 of EBW for daily maintenance was determined. Net energy and protein (NPg) requirements for growth ranged from 2.55 to 3.0 Mcal/kg of empty weight gain (EWG) and 178.8 to 185.2 g/kg of EWG for 20 and 35 kg of BW, respectively. The daily net requirement of macrominerals for maintenance was 32.3 mg of Ca; 30.8 mg of P; 1.31 mg of Mg; 8.41 of K and 5.14 mg of Na per kg of EBW. Net macrominerals requirements for growth ranged from 6.5 to 7.0 g of Ca; 5.3 to 5.4 g of P; 0.29 to 0.31 g of Mg; 0.67 to 0.62 g of Na and 1.18 to 1.05 g of K per kg of EWG. The chemical composition of the non-carcass components