author(s)
S Sivaramakrishnan, AV Omprakash, S Ezhilvalavan, KG Tirumurugaan and A Varun

abstract
The present study was conducted to investigate the effect of different thermal conditioning on the total erythrocyte count of Nandanam Broiler-3 and Naked Neck. A total of 180 birds (90 from each strain) were randomly assigned in to three treatments with three replicates. The first treatment (T1) served as a control group where birds reared under ambient temperature (AT), birds in second treatment (T2) were exposed to thermal conditioning at 37^oC for 4 hours and third treatment (T3) were exposed to 39^oC for 2 hours from day old to 14 days and 29 to 42 days of age, apart from exposure period birds were reared at ambient temperature. At the end of 12^th week all the treatment birds was challenged for thermal challenge at 38±1^oC for 6 hours. The results indicated that the thermal conditioning had significantly (p<0.01) decreased erythrocyte count, irrespective of the strain. At thermal challenge the preconditioned birds had total erythrocyte count on par with control birds, whereas the sudden exposed group had decreased count. From the present study it was concluded that preconditioned/ thermal conditioned birds were able to maintain the erythrocyte count near to the control birds, which indicated thermal conditioning at an early age resulted in improved thermo-tolerance level.