Use of Prediction Models for Evaluation of Live Weight and Carcass in New Zealand White Rabbits

Department of Animal Science,Faculty of Agriculture,University of Uyo, Uyo, Akwa Ibom State, Nigeria A total of 40 New Zealand white rabbits were used in a study where prediction models were developed for predicting live weight and evaluating the carcass. In the study, six body measurements namely, body length, thigh circumference, shank length, chest width, body circumference and girth were determined or measured. The determination was carried out using the linear, multiple and allometric equations. The four stages of development assessed for body linear measurements and carcass evaluation were day-old rabbits (0 – 24hr), weaners (0 – 6 weeks), growers (16 – 20 weeks) and the mature stage (24 – 32 weeks). A total of 10 rabbits were randomly selected and used at each stage of the study. In the four stages of growth using simple linear, multiple and allometric equations, the body linear measurements had positive and significant (P<0.05) relationship with liveweight. However, high positive correlation was obtained for liveweight and body circumference with R value of 0.948 using simple linear regression but with allometric equation, the best predictor for liveweight was body length with the R value of 0.990. The results also revealed that body length, shank length, heart girth, thigh circumference, chest width and body circumference had positive and significant (P < 0.05) relationship with the carcass cuts but body length was the best indicator for predicting hindleg, Neck + foreleg, thoracic cage and loin weights with R of 0.936 while shank length recorded the lowest R value of 0.832. Liveweight was also predicted from the retail cuts and the hindleg weight was more effective in estimating liveweight as compared to other retail cuts (R = 0.993 ± 0.007). Ratio of meat/bone of the hindleg gave a reasonable prediction for carcass meat. Among the prediction equations tested, the allometric model proved more reliable in predicting liveweight. This could therefore be incorporated into the breeding programme for breeders during selection most especially in remote areas where weighing scales are not available.