Predição do peso de ovinos da raça Morada Nova a partir de medidas corporais

Abstract

The use of regression models for prediction of animal weight from morphometric measurements can be an important strategy in sheep management. In this sense, the present work aimed to find regression equations for prediction of body weight of Morada Nova sheep. The experiment was conducted in two locations, the Experimental Farm Lavoura Seca, in the municipality of Quixadá - CE, and the Center for Teaching and Studies in Forage (NEEF-UFC), in Fortaleza-CE. We used 221 sheep of the breed morada nova, of these: 169 females and 52 males. The measurements were performed with the aid of a morphometric ruler, and with it the following measurements were measured: Sternal Height (HS), Body Length (LC), Chest Width (WL), Croup Height (HC), Croup Width (WL), Croup Length (CL), and a tape measure was also used for the following measurements: Thoracic Perimeter (TP), Forearm Circumference (AC) and Shin Circumference (SC). The equations for females had a lower fit than that of males, several factors may explain this situation, and the different growth curve of males and females is one of these factors. Equations were also generated for red and white varieties, which should be generated independently because the two varieties are from different genetic groups. The morphometric measure that showed the greatest relationship with body weight was Thoracic Perimeter (TP), which was present in all equations, for both sexes and varieties. The equations with a greater number of variables have a higher coefficient of determination (R²), however, the execution is more laborious. Based on the results of the present study, the equations PC = -3.67 + 0.0067.PT² for the red variety and PC = 3.42 + 0.000062.PT³ for the white variety should be used, as they present high and positive R², in addition to greater practicality.