Evaluation of body weight prediction Equations in growing heifers

Marcia   de Oliveira Franco; Marcos Inácio   Marcondes; José Maurício   de Souza Campos; Denise   Ribeiro de Freitas; Edenio   Detmann; Sebastião   de Campos Valadares Filho

Evaluation of body weight prediction Equations in growing heifers

Autores

Marcia de Oliveira Franco

Marcos Inácio Marcondes

José Maurício de Souza Campos

Denise Ribeiro de Freitas

Edenio Detmann

Sebastião de Campos Valadares Filho

Editor

Universidade Estadual de Maringá

Descripción

This study was realized to evaluate predicti on models for body weight (BW) using body measurements as heart girth (HG), wi ther height (WH), hip width (HW), body length (BL) and hip height (HH), and develop new Equations to predict the BW of Holstein and crossbred heifers. Prediction Equations (1, 2, 3, 4, 5 and 6) proposed in previous studies were tested, while body measurements, which were more significant in te rms of predicting BW, were used to ob tain new Equations. Heart girth was the body measurement with the greater co rrelation with BW. Equation 4 presen ted the best prediction results, showing a low average deviation, high accuracy and precision. Equations 1 and 2 predicted with a high presence of bias, while 2 had the lowest value of the concordance correlation coefficient and a great contribution made by systematic error. The 3 model presented a high variability in predicting BW. For both Holstein and crossbred heifers, the Equations evaluated are inadequate for predicting BW. Among the Equations evaluated, the model using HG presente d the best adjustment and the greater adjusted coefficient of determination. Body measurements re lating to HG and BL were the most significant variables in predicting the BW, resulting in th e following Equation: BW = - 372.89 + 2.8072 × HG + 1.6087 × BL.