Multifactorial discriminant analysis of morphological and heat-tolerant traits in indigenous, exotic and cross-bred turkeys in Nigeria

Abstract

This investigation explored the ability to distinguish the morphological and heat-tolerant traits of Nigerian indigenous, exotic and cross-bred turkeys using multivariate discriminant analysis. A total of 228 turkeys that were 20 weeks old were utilized in the study. The body parameters measured were body weight (BW), body length (BL), shank length (SL), thigh length (TL), keel length (KL), breast girth (BG), rectal temperature (RT), pulse rate (PR), respiratory rate (RR) and heat stress index (HI). Analysis of variance revealed that the exotic turkeys had significantly (p < 0.05) higher values than Nigerian indigenous and cross-bred turkeys in all the morphological traits with the exception of TL. However, the indigenous and cross-bred turkeys appeared to have more adaptive capability than the exotic ones based on their low HI. Sexual dimorphism was observed only in the morphological traits with male birds having significantly (p < 0.05) higher BW, BL, SL, TL and KL than that in females. However, the stepwise discriminant analysis revealed that BW, TL and HI were the most discriminating variables to separate the three genetic groups. The longest Mahalanobis distance was observed between the indigenous and exotic turkeys (36.68) while the shortest distance was recorded for the indigenous turkeys and their cross-bred counterparts (7.97). The canonical plot revealed the heterogeneity of the turkey populations as the birds clustered separately. In the nearest-neighbour discriminant analysis, 100.00, 98.73 and 96.43 percent of exotic, cross-bred and indigenous turkeys were correctly assigned into their source genetic groups. The present findings could aid the implementation of a conservation and improvement strategy of indigenous turkeys towards sustainable development of animal genetic resources.