Development and evaluations of equations to predict empty body weight in pre-weaned hair sheep lambs

[Desenvolvimento e avaliação de equações para predizer o peso do corpo vazio em cordeiros deslanados na fase de cria]

ABSTRACT

This research aimed to assess the relationships among shrunk body weight (SBW) and empty body weight (EBW) to develop equations to estimate EBW in 121 pre-weaned hair sheep lambs from different genotypes (Pelibuey, n=39; Katahdin, n=27 and crossbred Pelibuey × Black Belly, n=55), sex (non-castrated male, n=65 and female, n=56) and litter size (single, n=42 and double, n=79). Linear model with intercept, Linear model without intercept and exponential regression models were used for data analysis. The correlation coefficients among SBW and EBW was high (r = 0.89). The regression equations had high determination coefficients (r²) of 0.97. The final model fitted to estimate the EBW as a function of SBW was: EBW (kg) = 0.0065 (±0.14*) + 0.88 (±0.0124***) ×SBW, since it presented better fit values and was statistically significant (P<0.001). The equation developed and evaluated in the present study revealed that the linear relationship between SBW and EBW can be used to predict EBW in pre-weaned hair sheep lambs.

Keywords:
body weight estimation hair sheep; sheep requirements; mathematical models; nutritional requirements