Resumen

DUARTE-VERA, F.; SANDOVAL-CASTRO, C.  y  SARMIENTO-FRANCO, L.. SRNS Model adequacy for body weight gain predicting in growing Pelibuey lamb males. Arch. zootec. [online]. 2009, vol.58, n.224, pp.671-681. ISSN 1885-4494.

The objective of the present study was to evaluate adjustments in the maturity index, the value for basal metabolism and the empty live weight proposed for the Small Ruminant Nutrition System (SRNS) model on its capacity to predict the daily weight gain (DWG) of growing Pelibuey rams. The work was carried out at the Faculty of Veterinary Medicine and Animal Science of the University of Yucatan, Mexico. A data base composed by 26 experiments, 77 diets, with a total of 1112 male Pelibuey lambs was used. In order to calculate the index of body maturity, the mature weight was taken as 66 kg. The Model Evaluation System software was used to evaluate the model by means of: Linear regression analysis; the standard error of the estimation (MSE); the coefficient of agreement of the correlation (CCC); the mean standard error of the prediction, (MSEP); the model efficiency (MEF), and model coefficient of determination (CD). The model without adjustments underestimated DWG. Adjustment for maturity (mature weight) and a basal metabolism of 0.039 Mcal ME/ kg^0.75, improved the model's precision and accuracy for DWG prediction of growing Pelibuey males. It was concluded that basal metabolism in Pelibuey sheep is lower than in wool breeds. Using the adjusted basal metabolism value in the equation to estimate maintenance requirements improved the SRNS DWG prediction and the adjustments for estimated gastrointestinal content did not improved model predictions.

Palabras clave : Prediction models; Basal metabolism; Maturity index.

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