Behavioural responses of white and bronze turkeys (Meleagris gallopavo) to tonic immobility, gait score and open field tests in free-range system

Abstract

This study was carried out to investigate the behavioural responses of white and bronze turkeys to tonic immobility (TI), gait score (GS) and open field (OF) tests in a free-range system. 144 female turkeys (72 white and 72 bronze) were studied for 23 weeks. They were 32 weeks old. The stocking density was 2 birds/m(2) indoors and 0.66 birds/m(2) outdoors. Both bird genotypes were fed on a diet containing 16% crude protein and 11.7 ME MJ/kg. The birds were weighed in the 32nd, 35th, 48th and 55th week. The turkeys' behaviour was determined by TI, GS and OF tests. Behavioural parameters were established for each applied test. Although the mortality rates of white and bronze turkeys during the study were 6% and 3%, respectively, the white turkeys showed better results in the TI and OF tests suggesting that are more native breed than bronze ones. The results indicate that bronze turkeys are more suited for use in free-range systems than white turkeys with respect to GS and the consequent mortality rates in latter ones.