Prediction of grasscutters (Thryonomis swinderianus) body weight from linear body measurements

Abstract

A study was conducted to investigate the relationship between linear body measurements (LBMs) and body weights of grasscutters at 2, 4 and 6 weeks of age. Simple linear correlation procedure was used to establish the strength of linear relationships and associations between the different linear body measurements with body weight. These parameters were also subjected to step-wise regression analysis. The goodness of fit (R2) was tested to determine the contribution of each independent variable measured to the prediction of the dependent variable, the body weight of grasscutters at different ages of 2, 4,6, 8, 10, 12, 14, 16, 18 and 20 weeks. One hundred and thirty-nine (139) juvenile grasscutters obtained from 24 parents comprising of 18 does and 6 bucks were used for the study. Experimental animals were raised under a mixed feeding regime throughout the experimental period of 20 weeks. The linear body measurements assessed are head length (HL), body length (BL), heart girth (HG), ear length (EL) and tail length (TL). Correlation coefficients (r) between body measurements and weights were generally positive and significant (p < 0.01) at 2 weeks, demonstrating strong relationships between variables. At 4 weeks, correlation coefficients ranged from 0.013 to 0.829 whereas at 6 weeks values ranged from -0.230 to 0.859. Coefficient of determination (R2) varied from 0.926 to 0.997, 0.965 to 0.989 and 0.930 to 0.991 at 2, 4 and 6 weeks, respectively The positive correlation coefficients observed for body length and heart girth shows that these parameters can be improved upon for grasscutters raised under intensive management. Results from this study further revealed that body weight of grasscutters can be estimated under field condition using the ear,head, body lengths and heart girth in the absence of a weighing balance.