PROSTAGLANDIN (PGF2 ) BASED OESTROUS SYNCHRONIZATION IN POSTPARTUM LOCAL COWS AND HEIFERS IN BAHIR DAR MILKSHED

shed with the objective of evaluating the effect of prostaglandin on oestrus synchronization of postpartum local cattle. Appropriate animal handling facilities were installed in a centralized location and all logistical arrangements were spelled out. There after a total of 534 primiparous, multiparus and nulliparous post partum local cattle (358 of parity 1 to 3 cows and 176 heifers) with good body condition> 4.0 were injected 5 ml prostaglandin intra muscular (Perry et al., 2002 and Gokhan et al., 2010). Within 2 to 5 days after injection, 477 postpartum local cattle in heat were inseminated artificially using 100 % Holstein Frisian bull semen. The average weight of cows and heifers were 239(130-340) kg and 235 (143-308) kg, respectively. Pregnancy diagnoses were undertaken 3 months later through ovarian palpation and foetus size smaller than the suggested size at three months were regarded as bull pregnant. The mean number of cows/heifers responded to prostaglandin injection were 89.3 % with a conception rate of 13.7%. Variations in both response to prostaglandin injection and conception rate was also observed due to a difference in parity and body condition. From the findings of this study it can be inferred that prostagland in was effective to synchronize post partum local cows and heifers. In contrast, the rate of pregnancy was very low. Therefore, selection of dairy belts, farmers and cattle for synchronization should be done carefully. Moreover, strategic feed supplementation of synchronized cattle should not be neglected. Those cows that show standing oestrus should only be inseminated. The maximum expected heat detection date should be extended to 10 days not to miss delayed oestrus