Effect of Seasons and Management Practices on Reproductive Performance of Crossbred Cows Artificially Inseminated in Khartoum and Gezira States

Abstract

This study was conducted to evaluate the effects of some environmental factors and managemental practices on some reproductive traits (calving interval (CI), day's open (DO) number of services per conception (NSPC), and over all pregnancy rate (P.R).) of crossbred dairy cattle artificially inseminated (AI) in Khartoum and Gezira states. Nineteen farms were surveyed using structure questionnaire and data of 520 artificially inseminated cows for the period from January 2007 to December 2008 was collected and screened. The data was classified into three periods according to season of insemination (dry summer, wet summer, and winter) and then subjected to statistical analysis by (SAS,2004) program. The results revealed that season of insemination exerted significant effect on CI , DO and NSPC .Cows that were inseminated in dry summer had the longest CI (466.16 days) and DO (185.96 days). The NSPC was higher in dry summer 2.03; similar values were obtained in both winter and wet summer. The parity number also secured significant (p<0.05) effect on CI, DO and NSPC. The highest values of CI and DO were obtained in the second parity 462.51and 182.40 days respectively, while the lowest values were obtained for parity four 431.92 and 150.76 days respectively. The highest values of NSPC were obtained in fifth parity 1.9 and the lowest in parity one 1.7. The type of nutrition regime showed significant (p<0.05) effect on CI, DO and NSPC. The highest values were obtained for those farms with poor feeding regime 461.65 days, 180.89 days and 1.88 respectively. The inseminator techniques significantly (p<0.05) affected CI, DO and NSPC. The location of the farm showed insignificant effect (p>0.05) on CI and DO, while the NSPC was significantly affected by location. Khartoum state obtained the higher value 1.8 and the lower value vii was recorded in Gezira state 1.6.The herd size and veterinary monitors didn't show any significant (p>0.05) effect on the traits. On the other hand location of the farm significantly (p<0.05) affected number of cow serviced and number of cow receiving over one service per conception, Khartoum state recorded the higher mean values 56.50 and 26.16 respectively, while the lower values were obtained in Gezira state 13.38 and 3.38 respectively. Also the type of the farm significantly (p<0.05) affected number of cow serviced and number of cow receiving over one service per conception. Semi tradition scale farms had the higher mean values 47.16 and 16.67 respectively, while the lower mean values were obtained in traditional scale farms 17.69 and 7.76 respectively. The over all pregnancy rate was insignificantly (p>0.05) affected by location and type of farm. The inefficiency in reproductive performance is caused by many factors, however in the tropics, under nutrition plays a major role in depressing reproduction .