Determination of the mature weight of intact male hair sheep

Abstract

The objective of this study is to provide approaches to determine the mature weight of intact male hair sheep using body composition data. To estimate empty body weight (EBW) at maturity, we used information from eight independent studies comprising a total of 250 intact males in growing and finishing phases. The quantitative data used for each animal were body weight (BW), EBW, water-free EBW protein content, water-free EBW fat content, water-free EBW ash content and EBW water content. The water, protein, fat and ash contents in the EBW and water-free EBW were predicted by non-linear regressions. The best model was chosen considering the achievement of convergence and capacity for biological explanation. The standard deviation of the asymptotic EBW was computed using a simulation method based on a Monte Carlo approach. Among the non-linear evaluations, only the allometric function converged with the parameters within the expected biological limits. To estimate mature EBW, only protein and fat were suitable to predict estimates with the capacity to biological explanation. The water and protein contents in the EBW were closely associated. Animal maturity can be estimated mathematically using body composition. Maturity was reached at an EBW of 47.3 and 57.5 kg when protein and fat were used as a predictor, respectively. We conclude that protein is a good predictor of maturity for intact male hair sheep.