Protein and energy requirements of castrated male Saanen goats

• Published in: Small ruminant research 2015-01, Vol.123 (1), p.88-94
• Main Authors: Dias Ferreira, Angela Cristina, Yáñez, Enrique Alejandro, de Medeiros, Ariosvaldo Nunes, de Resende, Kleber Tomas, Pereira Filho, J.M., da Rocha Fernandes, Márcia Helena Machado, Almeida, Amélia Katiane, Molina de Almeida Teixeira, Izabelle Auxiliadora
• Format: Article
• Language: English
• Subjects: Body composition; Comparative slaughter; Efficiency; Gain; Maintenance
• ISSN: 0921-4488; 1879-0941
• DOI: 10.1016/j.smallrumres.2014.10.017

•We determined energy and protein requirements of Saanen castrated males.•We used comparative slaughter technique.•Net energy for gain increased by 40% as body weight increased from 20 to 35kg.•Net protein for gain decreased by 3% as body weight increased from 20 to 35kg.•We report requirements which diverge from previous studies. A comparative slaughter trial was conducted to determine the energy and protein requirements for growth of castrated male Saanen goats weighing from 20 to 35kg body weight (BW). Regarding maintenance requirements, 36 castrated male Saanen goats with an initial BW of 20.7±0.5kg, and aged 3.3±0.6 months, were used. Nine animals were randomly chosen and slaughtered at the beginning of the experimental phase (BW of 21.0±0.4kg), representing the baseline (BL) group. The 27 remaining castrated male goats were pair-fed into nine groups (blocks) of three animals each, fed either ad libitum or restricted to 30 or 60% of ad libitum intake. A group was slaughtered when the animal fed ad libitum reached 35kg BW. Regarding requirements for gain, 27 castrated male Saanen goats were fed ad libitum and nine were slaughtered at 21.0±0.4kg BW, nine at 27.7±0.5kg BW and nine at 35.1±0.3kg BW. The BL and ad libitum-fed animals used to determine maintenance requirements were also used to estimate gain requirements. The net energy (NE) requirement for maintenance was 261.5kJ/kg0.75 BW. The metabolizable energy (ME) requirement for maintenance was 404.2kJ/kg0.75 BW; therefore, the partial efficiency of use of ME for NE was 0.65. The minimal endogenous N losses were 262±48.4mgN/kg0.75 empty BW (EBW), corresponding to a net protein requirement for maintenance of 1.39±0.257g/kg0.75 BW. The net energy for gain increased by approximately 40% (from 12 to 17MJ/kg EBW gain) and the net protein for gain slightly decreased by 3% (from 166 to 160g/kg EBW gain) as the BW increased from 20 to 35kg. Our study contributes to the improvement of goat nutrition because it provides estimates of the protein and energy requirements of castrated male Saanen goats.