Estimates of repeatability for growth traits of pure and crossbred turkeys in the tropics
Growth traits and their repeatability estimates were studied in a flock of 300 turkeys made up of 120 indigenous, 120 crossbred and 60 exotic turkeys. Weekly body weights and their conformation traits (breast girth (BG), body length (BL), thigh length (TL), shank length (SL) and keel length (KL)) were taken from week 1 to 20. The mean values for body weight and other conformation traits for the three groups of turkeys increased with age with exotic turkey having the best performance while the least was observed in indigenous turkey. Low repeatability estimate for body weight at week 1 of 0.01 and 0.16 were obtained for exotic and indigenous turkey while medium estimate (0.30) was obtained for crossbred turkey. As their age increases, the repeatability estimates of 0.95 to 0.99 were obtained for body weight in exotic and indigenous turkey from week 5 to 20 while the estimate in crossbred turkey ranged from low (0.11) to high (0.46). High repeatability estimates for breast girth ranging from 0.50 to 0.90 from week 5 to 20 were obtained for exotic and indigenous turkey while that of crossbred ranges from 0.11 to 0.46. Repeatability estimate ranges for BL (0.38-0.99, 0.34-0.99, 0.11-0.64), TL (0.50-0.98, 0.72-0.99, 0.01-0.97), SL (0.51-0.99, 0.57-0.99, 0.72-0.93) KL (0.44-0.98, 0.43-0.99, 0.24-0.98) were obtained for indigenous, exotic and their crossbred turkey respectively. This is the first study to estimate repeatability for growth traits in turkey in the tropics. The crossbred turkey although is better in terms of growth performance than their indigenous counterpart, more measurements will be required to realise expected response from selection.
Keywords: Turkey, Body weight, Conformation traits, Repeatability estimates