The Survey of the effects of maternal, fetal and environmental factors at the calving time of dairy cows

Genetic selection procedures applied to improve broiler performance may negatively impact the subsequent reproductive efficiency of breeders, particularly in males. Identification of traits that reliably indicate individual male fertility would facilitate selection for reproduction. Fertility decline in primary broiler breeder strains is likely attributable to individual males in the flock with extreme subfertility. This differential fertility among males may reduce productivity for the broiler breeder industry. Male broiler breeders must be physiologically and behaviourally mature to successfully elicit the female sexual response and copulate. Fertility problems, particularly those associated with Cornish-derived lines, may result from a physical inability to successfully copulate or from the absence of sexual behaviour. For study of male shank lengths effects on production performances, in a Broiler Breeder farm, males were divided into three groups based on their shank lengths. Fertility and hatchability data’s gathered during next 15 weeks production period (Ages37-51). Data analysis showed that fertility and hatchability of roosters with short shank length were lower than other two groups.