Data from the three-year breeding records of a dairy cattle farm were obtained and the monthly distribution of artificial insemination (AI) was analyzed. The conception rate of dairy cattle artificially inseminated after natural and induced estrus was also compared. More AIs were done after natural estrus during November to March compared to induced estrus for the same period. On the contrary, more AIs after induced estrus were done during April to October. During these months, the cows were said to exhibit silent estrus due to heat stress. Conception rate varied according to type of estrus within the year. Conception rates from April to September after natural estrus were higher (P<0.05) than those of induced estrus. Regardless of the month, AI after natural estrus did not adversely affect the conception rate. For AI after induced estrus, there was a tendency for the conception rate to decline during April to October. The conception rate of AI after natural estrus were higher (P<0.05) than those of induced estrus. It can be concluded that AI after natural estrus gave higher conception rate compared to induced estrus but it is recommended to induce estrus during the period when incidence of silent estrus is high.