The objective of this research work was to know ovarian dynamics and pregnancy rate of cyclic Murrah buffalo cows with induced estrus by administration of prostaglandin F2α (PGF2α) and timed artificial insemination (TAI) with frozen thawed semen. A total of 31 female buffaloes were selected for the study. The buffalos having matured CL observed by ultrasonography were given one intra muscular injection of cloprostenol 500 μg and TAI was performed using frozen thawed semen of Indian Murrah buffalo bull. Results showed that 90.32% (significantly, at p < 0.05) cows explore the sign of heat after injection of PG and 67.85% (significantly, at p < 0.05) cows were become pregnant out of 28 inseminated (TAI) cows. In the 28 inseminated (TAI) cows, average number of smaller and larger size of follicles were non-significantly (p > 0.05) higher at day 3 post PG injection, but the medium size of follicles was non-significantly (p > 0.05) higher at PG injection. At day 3 post PG injection the diameter of follicles was significantly (p < 0.05) higher, but the diameter of CL was significantly (p < 0.01) lower compared at PG injection. At PG injection the diameter of largest follicle was non-significantly differences (p > 0.05) in between pregnant and non-pregnant cows. But at day 3 post PG injection it was significantly (p < 0.01) higher in pregnant cows compared to non-pregnant cows. The number of small, medium, and large follicles at PG injection and at day 3 post PG injection were non-significantly (p > 0.05) difference in between pregnant and non-pregnant buffalo cows. Finally, it is concluded that the CL was effectively regresses and induced the sign of heat in buffalo cows and after AI the cows were become pregnant with significant rate. The study will help to the veterinarian and researcher to know the efficacy of PG injection and AI for reproductive efficiency in buffalo cows.

ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
RESULTS AND DISCUSSION
CONCLUSION
ACKNOWLEDGEMENTS
AUTHOR CONTRIBUTIONS
AUTHOR’S POSITION AND ORCID NO
REFERENCES

• Rakesh Kumar Sharma(Division of Animal Physiology and Reproduction, Central Institute for Research on Buffalo (CIRB), Hisar, Haryana 125001, India)
• Nasrin Sultana Juyena(Department of Surgery and Obstetrics, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh)
• Mohammad Musharraf Uddin Bhuiyan(Department of Surgery and Obstetrics, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh)
• Mir Md. Iqbal Hasan(Department of Surgery and Obstetrics, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh, Department of Physiology, Sylhet Agricultural University, Sylhet-3100, Bangladesh)
• SK Phulia(Department of Livestock Services, Krishi Khamar Sarak, Farmgate, Dhaka-1215, Bangladesh)
• Mohammad Harun-or-Rashid(Department of Surgery and Obstetrics, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh, Department of Livestock Services, Krishi Khamar Sarak, Farmgate, Dhaka-1215, Bangladesh) Corresponding author