Welfare of food restricted male and female turkeys.

1. The welfare of male and female male-line turkeys fed ad libitum or food-restricted was determined at 4, 8, 12, 16, 20, 24, 28, 36(38) and 46(48) weeks of age using behavioural and physiological indices of well-being. Traditional turkeys fed ad libitum were kept as a control treatment. Restricted male and female male-line turkeys were fed to 0-5 during rearing and subsequently to 0-8 of sex-specific ad libitum-fed body weight. In another treatment, male-line males were fed ad libitum to 18 weeks and 0.8 of ad libitum thereafter. 2. Traditional turkeys and restricted male-line turkeys were more active than ad libitum-fed birds of both sexes. Restricted turkeys showed a high incidence of wall pecking. In the breeding period, about 0.4 of the observations of male-line males were of strutting behaviour whereas traditional male turkeys showed no strutting behaviour at the end of the breeding period. 3. The heterophil lymphocyte ratio (HLR) and the proportion of basophils were not increased in food-restricted turkeys. The HLR was relatively low in traditional birds, compared with male-line turkeys during the rearing period. 4. Plasma corticosterone concentrations were increased by food restriction during the rearing period. Corticosterone concentrations were relatively high in traditional turkeys at 4 and 8 weeks of age only. 5. Plasma lactate dehydrogenase (LIDH) activity was higher from 12 to 24 weeks of age in ad libitum-fed male-line turkeys and was consistent with mortality from cardiovascular disease in this group of turkeys. The pattern of activity of aspartate transaminase was similar, and alkaline phosphatase was inversely related to that of LDH. 6. It was concluded that turkeys may be better able to adjust physiologically to the demands of food restriction than broiler breeders and that there were few deleterious consequences of restricting male turkeys after 18 weeks of age. Male-line turkeys were less active than traditional turkeys.