Relationship between Estrus Signs and Subsequent Fertility Rates in Buffaloes Subjected to Estradiol based Synchronization Treatments

The study was carried out on 60 postpartum cyclic buffaloes subjected to Presynch-Heatsynch (n=30) and Heatsynch (n=30) synchronization treatments. In Presynch-Heatsynch group, two injections of PGF₂α analogue were administered at 12 days apart (Day-14 and-2) with last injection two days before GnRH administration (Day 0). A third PGF₂α alpha was given on day 7 followed by estradiol benzoate injection on day 8 and fixed time artificial insemination (FTAI) on day 10. In Heatsynch group, first two PGF2 alpha injections were not given; however, rest of the treatment was same. Frequent urination, vulvar swelling and bellowing were prominent estrus signs observed in all buffaloes of both groups at the time of FTAI. The study revealed significantly pronounced (p<0.01) cervico-vaginal mucus (CVM) discharge and high uterine tonicity in buffaloes that became pregnant (100.00 and 70.00%) than those failed to become pregnant (60.00 and 20.00%) in group I and II, respectively. Further, it was observed that none of the buffaloes that became pregnant had low uterine tonicity, whereas 40.00 and 55.55% buffaloes which failed to become pregnant showed low uterine tonicity on rectal examination. In conclusion, appearance of CVM at vulva and rectal finding of high uterine tonicity at the time of AI had positive influence on the pregnancy rates in buffaloes subjected to estradiol based synchronization protocols. Thus, successful pregnancy may be predicted if a buffalo shows above two estrus signs at the time of FTAI.