Effects of strain, maternal age and sex on morphological characteristics and composition of tibial bone in broilers

1. This study was to determine the effects of strain, age of the maternal f lock and sex on morphologic:ll characteristics and composition of tibial bo ne of broilers horn hatch to 48 d of age. 2. A total of 600 chicks was obtained from 2 strains of broiler breeder flo cks (150/chicks/strain/maternal age). Maternal flock age was classified as young (32 to 35 weeks of age) or old (56 to 58 weeks of age). Birds were re ared under standard feeding and lighting regimes. 3. On day 1, 16, 32 and 48, twelve birds were selected at random from each maternal group, strain and sex and killed. The wet bone weight and volume w ere measured. Morphological characteristics of tibia were determined using radiography. Bone breaking strength was tested. Tibia dry matter, ash conte nt, mineral density and collagen level were determined. 4. A quadratic increase occurred with increase in age of broilers fur all v ariables, except proximal width, medial cortex thickness and distal condyle width which increased in a linear manner. 5. Maternal age had a significant effect only on the variably measured at t he time of hatch. On day of hatch bone weight, ash content and hone volume were affected by maternal age, but the extent of this also depended on the strain. 6. The differences observed between strains for bone anatomy and bone miner alisation during the rapid growth period of 16 d were not significant at la ter ages, with the exception of bone volume. Differences between sexes were evident from 16 to 49 d of age with females having lower values.