GROSS MORPHOMETRICAL CHANGES IN LEG BONES OF POST-HATCH MALE BROILER CHICKENS WITH SPECIAL REFERENCE TO GROWTH PLATE CARTILAGE

Forty-five (45) ‘Vencob' day old male broiler chicks were reared up to day 42 (market age) to carry out gross morphometrical studies on the long leg bones (femur, tibiotarsus and tarsometatarsus) and associated growth plate cartilages at different ages (on days 1,7, 14, 21, 28, 35 and 42). It was found that the average weight of the bones in day old chicks gradually increased up to day 7, followed by a marked increase from day 14 up to day 42. There was simultaneous increase in length of the bones throughout the experimental period. The thickness of marrow cavity and cortical bone gradually increased with age of the broiler birds. The diameter (width) of all the bones in broiler birds showed a steep increase from day 7 up to day 21 and a steady increase thereafter till day 42. The proximal and distal end widened more than the mid shaft and the distal end was the widest. The growth of the gross dimensions of the bones slowed down a bit towards the end of the experiment (days 35 and 42). Though initially mid shaft cortical bone was thinner than epiphyseal ends, it gradually became thicker from day 21 (in femur and tarsometatarsus) or from day 28 (in tibiotarsus) till day 42. The gross anatomical observation did not reveal the presence of growth plate cartilages in all day- old chicks. In femur, presence of growth plate cartilages was reported for the first time. These gross morphometrical parameters (data) could be well correlated with the musculoskeletal growth of the birds as well as with the common deformities of the long leg bones.