Physiological adaptation of local, exotic and crossbred turkeys to the hot and humid tropical environment of Nigeria.

A total of 300 birds consisting of 120 local, 120 crossbred and 60 exotic turkeys were used to compare physiological adaptation of birds raised under the high-heat stress environment of Nigerian tropical humid climate. Genotype significantly (PB0.05) affected heat tolerance traits with the highest mean values for rectal temperature, pulse-rate and heat stress index observed in exotic turkeys. Genotype also had significant (PB0.05) effect on serum biochemical parameters such as glucose (GLU), potassium (K ) and Chloride (Cl ). The haematological indices of the birds such as haemoglobin, white blood cell count and heterophyl/lymphocyte ratio (H/L) were equally affected by the different genetic groups (PB0.05). The significantly higher (PB0.05) H/L ratio of the exotic turkeys was an indication of heat stress. The better performance exhibited by local and crossbred turkeys could be exploited in management, conservation and selection decisions of animal genetic resources under tropical conditions.