Macromineral requirements in male and female Saanen goats
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Data
2016-02-01
Autores
Santos Neto, José Mauricio dos [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Objetivou-se determinar as exigências de Ca, P, Mg, K e Na em machos inteiros, machos castrados e fêmeas da raça Saanen. Foram realizados dois experimentos: um para determinar as exigências líquidas para mantença (Exp. 1) e outro para determinar as exigências líquidas para crescimento (Exp. 2). Setenta e cinco caprinos (26 machos inteiros, 25 machos castrados e 24 fêmeas) foram utilizados para determinar as exigências líquidas para mantença. Desses, 21 caprinos (8 machos inteiros, 7 machos castrados e 6 fêmeas) foram abatidos com peso médio de 16,6 ± 0,40 kg e foram utilizados como grupo referência para estimar a composição corporal inicial. Os 54 caprinos restantes (18 machos inteiros, 18 machos castrados e 18 fêmeas) foram alocados em seis blocos ao acaso, no quais foram incluídos três caprinos do mesmo sexo distribuídos em um dos três níveis de alimentação: ad libitum e ingestão de 75% ou 50% em relação aos animais alimentados ad libitum. Quando os animais alimentados ad libitum atingiram 30 kg de PC foram abatidos juntamente com os outros caprinos do mesmo grupo. Os dados das categorias sexuais e dos níveis de alimentação foram analisados em parcelas subdivididas. A parcela principal foi composta pelas três categorias sexuais e as subparcelas pelos três níveis de alimentação. Os requerimentos líquidos para mantença não diferiram entre as categorias sexuais (P > 0.05), resultando em valores de: 35,4 mg de Ca; 24,7 mg de P; 2,5 mg de Mg; 5,0 mg de K e 3,3 mg de Na/kg PC·d. As exigências líquidas para crescimento foram obtidas a partir de 58 caprinos (20 machos inteiros, 20 machos castrados e 18 fêmeas) com peso inicial de 15,8 ± 0,11 kg de PC alimentados ad libitum. Os animais foram distribuídos em um delineamento experimental inteiramente casualizado e alocados em três pesos ao abate: 16,6 ± 0,40 kg de PC; 23,1 ± 1,33 kg de PC; e 31,2 ± 0,58 kg de PC. Os dados utilizados para determinar as exigências líquidas para crescimento foram analisados em um esquema fatorial 3 × 3 (categorias sexuais × níveis de alimentação). As exigências líquidos de Ca, P e Mg para crescimento foram similares entre machos inteiros, machos castrados e fêmeas (P > 0.05). Houve efeito da categoria sexual sobre as exigências líquidas de K e Na para crescimento (P < 0,05). As exigências líquidas de K (g/kg de PC ganho) para crescimento foram superiores nos machos inteiros, sendo verificado um aumento de aproximadamente 16% conforme o PC aumentou de 15 para 30 kg de PC. Já nas fêmeas e nos machos castrados, para a mesma faixa de peso, observou-se redução nos requerimentos líquidos de K para crescimento em aproximadamente 11%. Machos inteiros aumentaram os requerimentos líquidos de Na para crescimento em 9,5%, enquanto as fêmeas diminuíram em 22%. Em caprinos Saanen dos 15 aos 30 kg de PC, a categoria sexual afeta as exigências de líquidas de K e Na para crescimento, mas não influencia as exigências líquidas para mantença.
Our study estimated Ca, P, Mg, K, and Na requirements of intact male, castrated male, and female Saanen goats. Two experiments were performed: one to determine the net macromineral requirements for maintenance (Exp. 1), and another to determine net macromineral requirements for growth (Exp. 2). In Exp. 1, 75 goats (26 intact males, 25 castrated males, and 24 females) with initial BW (iBW) of 15.76 ± 0.10 kg were used. These animals were divided in two groups: baseline animals and pair-fed animals. Twenty-one goats (8 intact males, 7 castrated males, and 6 females) were slaughtered at the beginning of the experiment (16.6 ± 0.40 kg BW) to be used as the baseline group. The 54 remaining goats (18 intact males, 18 castrated males, and 18 females) were pair-fed in 6 blocks of 3 goats per sex. The goats within each block were then randomly allocated to one of 3 different levels of intake: ad libitum, restricted-fed to 75% of the ad libitum intake, and restricted-fed to 50% of ad libitum intake. When the animal fed ad libitum reached 31.2 ± 0.58 kg BW, it and the other goats from the same block were slaughtered. The effects of sex and level of intake were evaluated in a split-plot design, where sex was the main plot observation and level of intake was the sub-plot. Daily net macromineral requirements for maintenance did not differ among the sexes (P > 0.05), and the average values obtained were 35.4 mg Ca, 24.7 mg P, 2.5 mg Mg, 5.0 mg K, and 3.30 mg Na per kg BW. The net requirements for growth in Exp. 2 were obtained using 58 goats (20 intact males, 20 castrated males, and 18 females) with 15.8 ± 0.11 kg iBW, all fed ad libitum. These animals were assigned in a completely randomized design and allocated in three slaughter weight groups: 16.6 ± 0.40, 23.1 ± 1.33, and 31.2 ± 0.58 kg BW. The net Ca, P, and Mg requirements for growth were similar among the sexes (P > 0.05). There was a sex effect on net K and Na requirements for growth (P < 0.05). The net K requirements for growth (g/kg ADG) of intact males was greater and increased approximately 16%, whereas females and castrated males decreased approximately 11% as BW increased from 15 to 30 kg BW. The net Na requirements for growth increased 9.5% for intact males and decreased 22% for females when the goats grew from 15 to 30 kg BW. Sex thus affects net K and Na requirements for growth, but it does not affect net macromineral requirements for maintenance in Saanen goats.
Our study estimated Ca, P, Mg, K, and Na requirements of intact male, castrated male, and female Saanen goats. Two experiments were performed: one to determine the net macromineral requirements for maintenance (Exp. 1), and another to determine net macromineral requirements for growth (Exp. 2). In Exp. 1, 75 goats (26 intact males, 25 castrated males, and 24 females) with initial BW (iBW) of 15.76 ± 0.10 kg were used. These animals were divided in two groups: baseline animals and pair-fed animals. Twenty-one goats (8 intact males, 7 castrated males, and 6 females) were slaughtered at the beginning of the experiment (16.6 ± 0.40 kg BW) to be used as the baseline group. The 54 remaining goats (18 intact males, 18 castrated males, and 18 females) were pair-fed in 6 blocks of 3 goats per sex. The goats within each block were then randomly allocated to one of 3 different levels of intake: ad libitum, restricted-fed to 75% of the ad libitum intake, and restricted-fed to 50% of ad libitum intake. When the animal fed ad libitum reached 31.2 ± 0.58 kg BW, it and the other goats from the same block were slaughtered. The effects of sex and level of intake were evaluated in a split-plot design, where sex was the main plot observation and level of intake was the sub-plot. Daily net macromineral requirements for maintenance did not differ among the sexes (P > 0.05), and the average values obtained were 35.4 mg Ca, 24.7 mg P, 2.5 mg Mg, 5.0 mg K, and 3.30 mg Na per kg BW. The net requirements for growth in Exp. 2 were obtained using 58 goats (20 intact males, 20 castrated males, and 18 females) with 15.8 ± 0.11 kg iBW, all fed ad libitum. These animals were assigned in a completely randomized design and allocated in three slaughter weight groups: 16.6 ± 0.40, 23.1 ± 1.33, and 31.2 ± 0.58 kg BW. The net Ca, P, and Mg requirements for growth were similar among the sexes (P > 0.05). There was a sex effect on net K and Na requirements for growth (P < 0.05). The net K requirements for growth (g/kg ADG) of intact males was greater and increased approximately 16%, whereas females and castrated males decreased approximately 11% as BW increased from 15 to 30 kg BW. The net Na requirements for growth increased 9.5% for intact males and decreased 22% for females when the goats grew from 15 to 30 kg BW. Sex thus affects net K and Na requirements for growth, but it does not affect net macromineral requirements for maintenance in Saanen goats.
Descrição
Palavras-chave
Abate comparativo, Caprinos Saanen, Equações alométricas, Exigência de macrominerais, Nível de ingestão, Retenção mineral, Comparative slaughter, Saanen goats, Allometric equations, Macromineral requirements, Level of intake, Mineral retention