Development and evaluation of models to estimate body chemical composition of young Nellore bulls

Joslaine Noely Dos Santos Gonçalves Cyrillo,Renata Helena Branco,Luiz Henrique Oliveira Silva,Sarah Figueiredo Martins Bonilha,Maria Eugênia Zerlotti Mercadante

doi:10.1590/s1806-92902017000200011

Joslaine Noely Dos Santos Gonçalves Cyrillo, Renata Helena Branco + Show 3 more

Open Access

https://doi.org/10.1590/s1806-92902017000200011

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Abstract

ABSTRACT The objective of this study was to develop accurate regression equations to predict body composition of Nellore cattle using chemical composition of the 9th, 10th, and 11th ribs and to evaluate the models proposed by analyzing mean and linear bias. Sixty-seven Nellore bulls were slaughtered and slaughter body weight (SBW), hot carcass weight (HCW), and 9th-, 10th-, and 11th-rib-cut weight (RCW) were measured. Empty body composition was obtained after grinding, homogenizing, sampling, chemical analysis, and pooling (blood, skin, head [...]

Highlights

Determining the body composition of beef cattle permits to study nutritional requirements and efficiency, as well as evaluate performance based on the production of carcasses with good cut yields and adequate amounts of fat in an attempt to reduce the age of the animals at slaughter
The indirect method most widely used for the determination of carcass and empty body composition, proposed by Hankins and Howe (1946), uses the composition of the 9th, 10th, and 11th rib section of animals to develop prediction models
The wide range of variation in slaughter body weight and, in rib weight, hot carcass weight, and empty body weight (Table 1), was mainly due to three reasons: the use of a baseline group of animals, which were slaughtered immediately after the adaptation period and not finished to the standardized fat thickness; the use of animals belonging to different selection lines of Centro Avançado de Pesquisas Tecnológicas do Agronegócio de Bovinos de Corte

Summary

Introduction

Determining the body composition of beef cattle permits to study nutritional requirements and efficiency, as well as evaluate performance based on the production of carcasses with good cut yields and adequate amounts of fat in an attempt to reduce the age of the animals at slaughter. Different methods are available to determine the body composition of cattle, being the direct method the most accurate. This method is very time-consuming and expensive, since it requires the homogenization and sampling of all body organs and tissues and the analysis of their chemical components. The indirect method most widely used for the determination of carcass and empty body composition, proposed by Hankins and Howe (1946), uses the composition of the 9th, 10th, and 11th rib section of animals to develop prediction models. Bias measures how far off the predictions of a model are from the observed values and, serves to determine the accuracy of a model (St-Pierre, 2003)

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