Study the effect of number of parturitions on the measurements of reproductive performance of dairy cows

This study is conducted in Latifiya station for dairy cows in south east of Baghdad. Which have Holstein and Friesian and cross breed among them, from the first of April 2012 until the first of August 2014. Dystocia rate 69.81% recorded and also 26.8% retained placenta with 16% ovarian problem and 53% uterine problems for (386) cows. The cows of research are divided into four group according the number of parturition and four reproduction performance parameters are used.(calving interval) ,(open day) ,(conception from first service) and finally (services per conception).The results are in the first group (2parturitions) (121) cows were 423.7 day for calving interval ,107.1 days open ,27.4% conception from first service and 2.3 services per conception ,the result of second group (3parturitions) (106)cows were ,458.3 day calving interval ,188.1 day open days, 25.3% conception from first service and 2.28 services per conception that statically significant. The result of third group (4 parturition ) (120)cow record 427.6 days calving interval ,156.2 days open ,37% conception from first service ,and2.15 services per conception. with statistical significant difference at p< 0.01. The last group (5 parturitions) (58) cow also record 378.8 days calving interval ,101.8 days open ,49% conception from first services and 1.76 services per conception .The results of last two groups have statically significant at p