author(s)
BC Naha, AK Chakravarty, MA Mir, BL Saini, P Boro and Supradip Das

abstract
The concept of bulls is half of the herd has changed to more than half of the herd”. The factors viz., season, period, stage of lactation, breed, parity, number of services per conception, age of cows at the time of insemination affect the conception rate of breeding bulls. Age of the bull at the time of mating was the major factor influence conception rate. Infertility problems of a breeding bulls has a longer impact on herd productivity. Therefore, fertility of breeding bulls is of great concern for herd profitability. Non-genetic factors may be maintain for better conception rate in breeding bulls. The non- genetic factors are having a significant effect on conception rate of the breeding bulls. The main factors includes season, age and period mainly. The present review compiles effect of different non-genetic factors on conception rate of breeding bulls.