Net requirements of energy, protein and macrominerals for weight gain of grazing beef cattle castrated at different ages, with and without supplementation

Revista Brasileira de Zootecnia

Anilza Andréia Da Rocha²  Mário Fonseca Paulino¹  Henrique Jorge Fernandes¹  Lívia Vieira De Barros²  Sidnei Antonio Lopes²  Leandro Galon¹  Aline Gomes Da Silva²  Daniel Mageste De Almeida² 

[1] ,Universidade Federal de Viçosa

关键词: castration;    supplementation;    Zebu cattle;   

DOI  :  10.1590/S1516-35982012000200025

来源: SciELO

【 摘 要 】

The objective of this experiment was to estimate the requirements of energy, protein and macrominerals of grazing crossbreds calves, in Brachiaria decumbens Stapf pasture, castrated at different ages, with and without supplementation. Forty-seven young calves at initial age of 120±30.1 days and 115.3±1.97 kg of live weight were used. To estimate net energy requirements for weight gain, a regression equation between energy retained in the gain and empty body weight gain and metabolic empty body weight was obtained. For estimation of net protein requirements for weight gain, a regression equation was adjusted between protein retained in gain and empty body weight gain and energy content of this gain. Net requirements of Ca, P, Mg and Na for weight gain were determined by the equation Y' = a.b. Xb-1, in which a and b represent the intercept and the coefficient of the alometric equation of macromineral body content prediction, respectively. Neither castration nor concentrate supplementation affects body weight gain net requirements, except the ones of Ca, which were higher for non-castrated animals.

【 授权许可】

CC BY   
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