Growth Curves for Different Body Traits of Lagune Cattle

This study was carried out at Samiondji breeding farm in Benin. A total of 1, 414 age-data sets of Height at Withers (HW), Heart Girth (HG), Scapulo-Ischial Length (SIL) and Live Body Weight (LBW) from 707 Lagune cattle (373 males and 334 females) were individually fitted to Brody, Gompertz and Logistic Growth Models using the NLIN procedure of SAS. The growth parameters consist of mature weight or body size (A), the constant of integration (B) and the maturity rate (k). The most appropriate model through the goodness of fit was determined by higher adjusted determination coefficient (R2), lower Mean Squares Errors (MSE) and Bayesian s Information Criteria (BIC). Among the competing models and within sexes, the Brody show the best adjustment of data followed by Gompertz and Logistic. According to the range of the parameters A (81.36-137.07), B (0.46-2.94) and k (0.0019-0.102), the value of A derived from the Brody model (82.41-137.07) was higher (p<0.05) whereas B (0.46-0.95) and k (0.0019-0.0065) lower (p<0.05) than in Gompertz and Logistic. The plot from birth up to 1, 320 days of age of LBW, HW, HG and SIL using Brody model provide the higher growth profiles of males than females (p<0.05). Polynomial regressions to predict LBW from HW, HG and SIL showed that HG alone or with the inclusion of HW and SIL was the reasonable fit according to R2 (between 68 and 81%). The degree of maturity show that except for LBW both sexes are fully developed (≥90%) at 720 days of age. Under field condition where farmers do not usually have weighing facilities this study present several applications such as management purposes, selling animals for slaughter and medicine dosage. Among the fitting equations to predict LBW, the simplest possible indication for male and female was respectively, LBW = - 92.39+0.86HG and LBW = -49.72+1.26HG.