Autores

Elisa Junqueira Oliveira, Aníbal Eugênio Vercesi Filho, Flavia Fernanda Simili, Tassia Sant’Ana Samora2, Ricardo Lopes Dias Costa, Lenira El Faro, Maria Lucia Pereira Lima, Claudia Cristina Paro de Paz

Body weight estimation in sheep Santa Ines

Resumo

The body weight (BW) determination
is important to evaluate the growth of animals, their nutritional condition and
reproduction and to establish the slaughter time and the sale value of the
animal. The chest girth (CG) could be an alternative to determine the body
weight of sheep on properties that do not have scales. The objective of this
study was to investigate the feasibility of using chest girth to determine the
estimated body weight (EBW). The data file contained 1762 records of body
weight (BW) and chest girth (CG) from 426 Santa Ines breed sheep, belonging to
eight herds located in Southeastern Brazil. The
chest girth was measured using the sternum and the withers as base, passing the
tape measure behind the shoulder. Body weights were related to CG values
through linear regressions using the software Statistical Analysis Systems (SAS Inst., Inc., Cary, NC).
The age classes 1, 2, 3, were defined respectively as: 0 to 12 months; 13 to 22
months; over 34 months. The regression equation used to predict the body weight
through chest girth in different age classes was y = b_{0 }+ b_{1}x,
where y is the dependent variable EBW, x is the independent variable CG, b_{0}
is the intercept, b_{1} is the slope of the equation that defines the
relationship between EBW and CG. The other variables were constant. The
regression equations for specific age groups of animals were: Class 1 EBW = -42.2018
+ 1.0081CG (R^{2} = 0.91); Class 2 EBW = -61.2794 + 1.2660 CG (R^{2}
= 0.79) and Class 3 PCE = -72.6146 + 1.3885PT (R^{2} = 0.84). The BW
average observed and the respective standard deviations for Classes 1, 2 and 3
respectively, were 27.19 (13.37); 49.90 (13.64) and 53.27 (11.83). EBW average
observed and respective standard deviations for Classes 1, 2 and 3,
respectively, were 27.31 (12.72); 49.69 (12.55) and 53.56 (11.11), small
differences were observed between BW and EBW, indicating the regression equations
are adequate to estimate body weight based on chest girth in different age
classes studied. The highest coefficient of determination (R²) was 0.91 for
Class 1. It can be concluded that these regression equations presented can be
used to estimate the body weight of Santa Inês sheep at different ages based on
chest girth.

Estimativa do peso corporal em ovinos da raça Santa Inês

Abstract

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