Composição corporal de garrotes inteiros de três grupos genéticos nas fases de recria e terminação

Abstract

RESUMO -Com os objetivos de avaliar a composição corporal e identificar características corporais mensuráveis capazes de estimar o tamanho relativo de componentes corporais, foram utilizados 36 garrotes inteiros, sendo 12 Nelore, 12 ½ Holandês x ½ Zebu e 12 ½ Caracu x ½ Zebu. Em cada grupo genético, havia seis animais de cada fase de produção: recria e terminação, com peso inicial próximo a 225 kg e 330 kg, respectivamente. Os animais foram mantidos em regime de confinamento até o abate, realizado de acordo com o peso: 310 a 340 kg PV para os animais na fase de recria e 420 a 470 kg PV para aqueles na fase de terminação. Foi fornecida a mesma dieta a todos os animais, com 50% da matéria seca à base de concentrado e 50% de silagem pré-seca de coastcross. Utilizou-se um fator geral de 0,8693 para conversão do peso vivo em peso de corpo vazio (obtido a partir dos dados de todos os animais do experimento). Animais provenientes de seleção para corte na categoria terminação apresentaram maiores rendimentos de carcaça (59,2%) que aqueles de origem leiteira (56,33%). Grupos genéticos de raças com aptidão leiteira mostraram tamanhos relativos de órgãos 9% maior, 21% menos tecido adiposo na carcaça, bem como maior participação da gordura interna no total de tecido adiposo corporal. Em razão das baixas correlações encontradas, não parece confiável estimar os tamanhos relativos dos componentes corporais estudados a partir das características corporais mensuráveis analisadas.Palavras-chave: carcaça, composição física, cortes comerciais, mestiços, Nelore Body Composition of Young Bulls of Three Genetic Groups in the Growing and Finishing PhasesABSTRACT -To evaluate the body composition, and to identify measurable body characteristics capable to estimate the relative size of body components, 36 young bulls (12 Nellore, 12 ½ Holstein x ½ Zebu, and 12 ½ Caracu x ½ Cebu) were used. In each genetic group, six animals of each production phase were used: growing animals with initial weight of 225 kg and the finishing ones with initial weight of 330 kg. The animals were maintained in confinement regime to reach 310 to 340 kg of weight for the growing animals and 420 to 470 kg of weight for the finishing ones. The same diet was fed to all the animals, with concentrate level of 50% in the dry matter and 50% of coastcross hay. A general factor of .8693 was adopted to conversion of live weight in empty body weight (obtained with the records of all the animals in the experiment). Animals from a beef selection origin, in finishing group, presented higher dressing percentage (59.2%) that those of milk selection origin (56.33%). Genetic groups originating from breeds with milk aptitude showed higher relative sizes of organs (9% more), 21% smaller total fatty tissue in carcass, as well as higher participation of internal fatty tissue in total fatty tissue. Despite of the low correlations, it is not reliable to estimate the relative sizes of the body components studied from the analyzed measurable body characteristics.

Performance and fatty acid profile of Holstein calves slaughtered at different weights

“…Among cattle, low carcass yield is a shortcoming unique to dairy breeds. According to Fernandes et al (2004), animals selected for meat production generally have carcass yields 7% higher than those of dairy breeds. However, carcass production improved with the increase in carcass yield, because the vital organs, and not the initial stage of life of the animal, represent a greater proportion.…”

Quantitative carcass traits of Holstein calves, finished in different systems and slaughter weights

“…It is highly affected by the fasting period before slaughtering, making it difficult to compare the results of authors who used different periods of fasting. According to FERNANDES et al (2004), the selected animals for cutting have carcass yields 7% higher than those of dairy. In the present experiment the carcass yield ranged from 48.18 to 51.32%, while the cold carcass yield ranged from 46.59 to 49.46%.…”

Slaughter body weights of Jersey young bulls finished on feedlot

“…Among cattle, low carcass yield is a shortcoming unique to dairy breeds. According to Fernandes et al (2004), animals selected for meat production generally have carcass yields 7% higher than those of dairy breeds, because of less fat present in the carcass, viscera, and gastrointestinal tract (Coleman et al, 2016). Slaughter of very young animals fed high amounts of concentrate could minimize this problem.…”