Age- and Sex-Related Changes in Body Weight, Muscle, and Tibia in Growing Chinese Domestic Geese ( Anser domesticus )

This study evaluated the changes in body weight (BW), muscle mass, and tibial parameters of growing domestic geese from hatching to 63 days. A total of 256 Jiangnan White geese (128 males and 128 females) were assigned to 16 pens (8 pens of males and 8 pens of females) and fed with the same diet until the age of 63 d. Geese were weighed at hatch and then at 7-d intervals by pen, and then sixteen birds (8 males and 8 females) were selected for measuring breast and leg muscle weights and tibial characteristics. The BW of goslings increased with age throughout the whole study, with males being significantly heavier than females after 28 d. The breast muscle (pectoral major and minor) weight increased slowly before 42 d and then increased rapidly after 42 d regardless of the sex of goslings. At 42 d, the breast muscle weight of males was significantly lower than that of females. Goose leg muscle (thigh and drumstick) weight increased slowly from 0 to 14 d, rapidly from 15 to 49 d, and almost flat from 50 to 63 d. At 63 d, the leg muscle weight of males was higher than that of females. The leg muscle of goslings grew synchronously with their BW, while the growth of the breast muscle lagged behind the leg muscle and BW. The tibia length and width increased with age, especially from hatching to 35 d and then remained with little change from 35 d onward. The fat-free weight and breaking strength of the tibia significantly increased with age, especially from 0 to 49 d. The tibia ash content of goslings increased rapidly before 28 d and gradually flattened after 28 d. During the growth of the tibia, changes in ash were considerably more advanced, followed by morphology and finally by fat-free weight and breaking strength. In summary, the BW, muscle mass, and tibial parameters of goslings showed sex differences after 28 d. After hatching, geese rapidly grew leg muscle and tibia to support their increased BW and movement.