evaluation of some of the reproductive parameters of holstein cows in kermanshah province

this experiment was conducted to evaluate reproductive indices and provide appropriate solutions to improve the reproductive efficiency of dairy cattle in kermanshah province. with reference to forty-eight dairy industrial herds available at different cities of the province, a questionnaire containing quantitative measures were completed to assessing the reproductive parameters of 5397 dairy cows includes genuine population of dairy and dry productive cattle (holstein) and also pregnant and non-pregnant genuine heifers of over 12 months olds. data analysis was performed based on unbalanced completely randomized design and means were compared using t-test. mean and standard deviation of  the number of open days, the interval from calving to first estrus, the number of insemination to conception, calving rate and length of lactation (days) in total holstein cattle of this province were obtained 90.54 ± 3.55, 46.86 ± 1.32, 1.85 ± 0.06, 0.62 ± 0.03 and 255.59 ± 6.26, respectively. mean of evaluated reproductive traits including the number of insemination to conception and calving rate of holstein dairy herd of various province cities did not show any significant differences (p>0.05). mean of the number of open days of holstein dairy herd of javanrood city showed significant differences with mean of the number of open days of holstein dairy herd of soonghor-o-kolyaei city  (p<0.038). the most of the interval from calving to first estrus mean is related to the dalahoo city and the least of the interval from calving to first estrus mean is related to the kangavar city (54.00 ± 4.30 and 41.80 ± 2.00 day, respectively, p