Effective estrus detection and artificial insemination (AI) are necessary for profitable management of dairy herd. In current study, 45 crossbred lactating cows have been selected with the complaint of unobserved oestrus for more than sixty days postpartum. All cows had functional corpus luteum as examined by transrectal ultrasonography. Cows were treated with PGF2α analogue and AI was performed with observed oestrus and then single dose of GnRH was administered. Similar synchronization protocol has been repeated after 14 days in cows that did not repose to first treatment. Remaining cows received additional PGF2α after 14 days of second treatment and timed AI was performed following GnRH administration. Among 45 cows, 28.89% showed estrus after first treatment and 78.79% responded to second hormonal intervention. A higher conception rate (88.89% vs 26.66 and 72.72%) was observed in cows after triple administration of PGF2α and timed AI. We noticed a significant differences in body condition score (BCS, 1～5 scale), postpartum period, and daily milk production between cows that either responded of non-responded following first and second hormonal treatment. In addition, there was a significant positive correlation between daily milk production and BCS, age and postpartum days, milk production and estrus/BCS, and milk production/BCS/estrus and conception rate. Depending upon the findings we conclude that hormonal intervention with PGF2α and GnRH enhances postpartum ovarian cyclicity and help decreasing the days open of dairy herd. Therefore, this finding might provide an excellent guideline for target breeding system for profitable dairy herd management.

The study focuses on the quality assessment of Black Bengal buck semen preserved at chilled condition. In this in vitro trial, collected semen from Black Bengal bucks was preserved at chilling temperature (4▲5줛) in tris-glucosecitrate yolk medium of 1:5 ratios for four days. Artificial Vagina (AV) method was utilized to collect semen from buck. General evaluation of semen includes the color, mass activity and density were measured by direct visual examination. However, computer-assisted sperm analysis (CASA) and phase contrast microscopy were used to figure out the motility (%), hyper-activated (HYP) motility (%) and number of abnormal spermatozoa (%) initially, and at every 24 h intervals. The result revealed that spermatozoa preserved at chilling temperature showed significantly (P<0.05) lower motility and HYP motility with the progression of preservation. The number of phenotypically abnormal spermatozoa significantly (P<0.05) increased following preservation. Although significant positive correlation (r=0.945; P<0.05) was existed between % motile and % HYP motile spermatozoa however, the % of morphologically abnormal spermatozoa was negatively correlated with % motile (r=긏0.997; P<0.05) and % HYP motile spermatozoa (r=긏0.946; P<0.01). Therefore, we concluded that the quality of chilled semen progressively losses its viability and doesn…t remain useable after certain period of preservation with respect to its motility and morphology.

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.