Meeting Abstract
As a result of selective breeding, domestic poultry grow very rapidly and reach elevated body masses. The turkey, Meleagris gallopavo, has been bred to massive proportions, with some broad-breasted white (BBW) strains reaching over 24 kg at adulthood, while wild turkeys reach only 8 kg on average. It is reasonable to predict that this dramatic increase in body mass should affect locomotor biomechanics, and indeed, a prior study noted large lateral oscillations during walking in domestic turkeys. This “waddle” has been attributed to the need for domestic turkeys to bring their heavier bodies squarely over the stance foot for balance. The goal of this study is to understand how the lateral oscillations affect the ground reaction forces and gait kinematics of domestic turkeys. Five wild and five BBW turkeys locomoted down a trackway with a force plate positioned midway. The domestic turkeys’ average speed was very slow, 0.48 m s-1 compared to the wild turkeys, 1.93 m s-1. BBW’s average peak vertical force was 1.04 times body mass, much lower than even their domestic poultry counterpart, the broiler chicken. Mediolateral forces were significantly higher in the BBWs at any given speed (P< 0.001), while fore-aft forces were significantly lower than wild turkeys (P= 0.012). Normalized step width was larger in both wild and BBW males compared to females (P=0.013, P=0.030, respectively), however step length was not different. These results indicate that artificial selection for increased body mass results in locomotor changes that are apparent in the ground reaction force signature and influence fundamental mechanics, such as the motion of the center of mass.
