Effects of immobilization on the biomechanical properties of the broiler tibia and gastrocnemius tendon.

Researchers have provided much insight into the various factors that influence the incidence of musculoskeletal problems in the poultry industry. However, a better understanding of the mechanobiology of broiler bone and tendon can have a positive effect on the welfare of the production bird and assist in the development of improved production practices. This study investigated the mechanical adaptability responses due to disuse on the biomechanical properties of the broiler tibia and gastrocnemius tendon. Beginning at 3 wk of age, broilers were placed in a harness system designed to eliminate load bearing of the leg. After 2 wk of this treatment, the average values for body mass and shank length of the birds were 58 and 85% of the values for the controls, respectively. The treatment reduced the mineral content of the tibia by approximately 50%, tibia structural strength by 40%, and tibia material strength by 8%. The structural strength and toughness of the gastrocnemius tendon were reduced by 10 and 30%, respectively, whereas the material strength, material toughness, and material stiffness of the tendon increased by approximately 75, 65, and 70%, respectively.