TY - JOUR

T1 - Composição do ganho e exigências de energia e proteína para ganho de peso em bovinos Nelore puros e mestiços

AU - De Freitas, José Antônio

AU - De Queiroz, Augusto César

AU - Dutra, Alecssandro Regal

AU - Mendonça Vieira, Ricardo Augusto

AU - De Paula Lana, Rogério

AU - De Paula Leonel, Fernando

AU - Henrique, Douglas Sampaio

AU - De Lima, Adhemar Ventura

AU - De Souza, Júlio César

PY - 2006

Y1 - 2006

N2 - The objectives of this trial were to estimate gain composition and energy and protein requirements for weight gain of purebred and crossbred Nellore. Sixty young bulls averaging 10 to 11 months of age from four genetic groups: Nellore, F1 Nellore x Angus, F1 Nellore x Brown Swiss and F1 Nellore x Simental and initial average body weights of 286, 309, 333 and 310 kg, respectively, were used in this study. A completely randomized design was adopted and bulls from the four genetic groups were fed diets containing: 30, 40, 60 and 70% of concentrate. Three animals from each genetic group were slaughtered at the beginning of the trial and used as reference for initial body composition. The net protein and energy requirements for gain of 1 kg of empty body weight (EBW) were estimated by the equation Y′ = a. b. X (b-1), where a and b are the parameters of the regression equations and X is the EBW of the animals. The identity test of the models indicated no significant differences among genetic groups for the net energy and protein requirements for weight gain. It was observed a decrease of 10.6% and an increase of 37.8%, respectively, in the protein and energy requirements for body weight gain between 250 and 550 kg. These changes are result of the increase in the content of fat and reduction in that of protein as EBW increased. The net requirements of protein and energy for body weight gain were estimated as 143.5 g and 4.7 Mcal, respectively, for a body weight of 450 kg.

AB - The objectives of this trial were to estimate gain composition and energy and protein requirements for weight gain of purebred and crossbred Nellore. Sixty young bulls averaging 10 to 11 months of age from four genetic groups: Nellore, F1 Nellore x Angus, F1 Nellore x Brown Swiss and F1 Nellore x Simental and initial average body weights of 286, 309, 333 and 310 kg, respectively, were used in this study. A completely randomized design was adopted and bulls from the four genetic groups were fed diets containing: 30, 40, 60 and 70% of concentrate. Three animals from each genetic group were slaughtered at the beginning of the trial and used as reference for initial body composition. The net protein and energy requirements for gain of 1 kg of empty body weight (EBW) were estimated by the equation Y′ = a. b. X (b-1), where a and b are the parameters of the regression equations and X is the EBW of the animals. The identity test of the models indicated no significant differences among genetic groups for the net energy and protein requirements for weight gain. It was observed a decrease of 10.6% and an increase of 37.8%, respectively, in the protein and energy requirements for body weight gain between 250 and 550 kg. These changes are result of the increase in the content of fat and reduction in that of protein as EBW increased. The net requirements of protein and energy for body weight gain were estimated as 143.5 g and 4.7 Mcal, respectively, for a body weight of 450 kg.

KW - Beef cattle

KW - Body protein

KW - Crossbred

KW - Energy requirements

UR - http://www.scopus.com/inward/record.url?scp=33746824614&partnerID=8YFLogxK

U2 - 10.1590/s1516-35982006000300035

DO - 10.1590/s1516-35982006000300035

M3 - Tidsskriftartikel

AN - SCOPUS:33746824614

VL - 35

SP - 886

EP - 893

JO - Revista Brasileira de Zootecnia

JF - Revista Brasileira de Zootecnia

SN - 1516-3598

IS - 3

ER -