Differences in growth and carcass composition of growing male and female turkeys

An experiment was conducted with 1 680 one-day-old turkey poults (720 males and 960 females) of the Hybrid ConverterTM genotype to compare the growth performance of male and female turkeys. The experiment lasted until 119 days of age for males and 126 days for females, during which 6 commercial-type feeds were administered, with changes occurring at 21, 42, 63, 84 and 102 days of age. Performance was evaluated by weekly weighing and measuring feed consumption in each pen at weekly intervals. At 1, 7, 14, 21, 35, 56, 77, 119 (males) and 126 (female) days, 12 birds from each sex were sampled for weights of carcass, liver, gizzard, heart, thighs and breast. The Gompertz equation fitted separately to male and female growth data suggested that the mature weight of males would be by 16 kg heavier than in females (34.6 vs 18.7 kg) and that the females would mature 36% faster than males (0.023 2 vs 0.017 0/day). The weights of liver, gizzard and heart were similar in males and females in the early part of the growth period but they diverged from 35 days for the gizzard, 56 days for the liver and 77 days for the heart. However, the allometric coefficients describing the growth of each of these internal organs in relation to body weight were the same for males and females. Thigh weight was allometrically related to body weight, with males and females sharing the same relationship, but although the slope of the allometric relationship for breast weight in males and females was the same, breast weights in females were heavier than in males at any given body weight. Female turkeys became fatter than males from 56 days onwards.