Anestrus is one of the most important production limiting disorders in dairy buffaloes and its underlying causes have been a current topic of studies. The objectives of this study were to explore the causes of anestrus in buffaloes with the application of ultrasonography. Two examinations were performed by transrectal ultrasonography at 12 days apart in buffalo cows that were not seen in oestrus at 60 or more days postpartum. As high as 54.5% buffaloes had silent ovulation and 45.5% suffered from the true anestrus with ovarian dysfunction. The duration of anestrus after calving was 60～90, 91～120, 121～180 and 181～365 days in 27%, 32%, 18% and 23% buffalo cows, respectively. Treatment with prostaglandin of cyclic buffalo cows with a corpus luteum (72.7%) resulted in higher estrous rate as compared with close observation of estrus (23.1%) by the farmer (p=0.021). Acyclic buffalo cows without any corpus luteum on ovaries were successfully treated with gonadotropin releasing hormone (70%), resulting in higher estrous detection rate than those treated with a vitamin-mineral mixture (20%) (p=0.035). In conclusion, poor heat detection due to silent ovulation is the most important cause of apparent anoestrus in buffaloes; however the percentage of the true anestrous is also quite high in postpartum buffaloes.

ABSTRACT   INTRODUCTION   MATERIALS AND METHODS    Animal Selection and Management    Data Collection    Reproductive Examination    Experimental Design (Fig. 1)    Statistical Analysis   RESULTS    Prevalence of Anestrus    Treatment of Anestrus   DISCUSSION    Prevalence of Anestrus    Treatment of Anestrus   REFERENCES

• Md Saidur Rahman(Department of Surgery and Obstetrics, Bangladesh Agricultural University, Department of Animal Science & Technology, School of Bioresource & Bioscience, Chung-Ang University) Corresponding author
• Abu Said Shohag(Department of Surgery and Obstetrics, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh)
• Md Mostafa Kamal(Department of Reproduction, Obstetrics and Herd Health, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium)
• Nasreen Parveen(Department of Livestock Services, Dhaka, Bangladesh)
• Mohammed Shamsuddin(Department of Surgery and Obstetrics, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh)