Bisphenol A (BPA) is a common industrial chemical that has been used extensively to make certain plastics and resins since the 1960s. As a potential endocrine disruptors, BPA has been investigated for its impact on fertility/reproduction in animals and humans. However, the molecular mechanisms of BPA action and standard method for detecting BPA-related health hazards are unclear. Considering in-vitro experimental model, we investigated the effects of BPA (0.0001 to 100 μM) exposure on mouse spermatozoa. We revealed that BPA affects several sperm functions by triggering the mitogen-activated protein kinase, phosphatidylinositol 3-kinase, and protein kinase-A (PKA) activity. High doses of this chemical was also likely for the activation of protein tyrosine phosphorylation in a PKA-dependent signaling consequently induced a precocious acrosome reaction. Simultaneously, BPA has been found to decrease the rate of fertilization and early embryonic development. In addition, BPA induced differential protein expression in spermatozoa were responsible for the pathogenesis of many diseases. Considering in vivo experimental model, we deliberate the effects of gestational BPA exposure (TDI, NOAEL, and LOAEL doses) on both ejaculated and capacitated spermatozoa in F1 adult mice. We confirmed that BPA affects several sperm function in F1 male. These effects appeared to be caused by reduced numbers of stage VIII seminiferous epithelial cells in testis and decreased PKA activity and tyrosine phosphorylation (non-capacitated) in spermatozoa. We also noticed that BPA decreased average litter size as well as compromise the rates of cleavage and blastocyst formation. Proteins differentially expressed in both capacitated/ejaculated spermatozoa play a critical role in energy metabolism, stress responses, and fertility, finally predispose to the development of several diseases. On the basis of these results, we suggest that BPA alter spermatozoa function and the proteomic profile, ultimately affecting their fertility potential. Therefore, it is of critical public health significance to reevaluate the levels of BPA exposure that are currently deemed to be acceptable.

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 decreased fertility is frequently thought to be problem of cattle production. However, studies figure out that number of these problems is related to bull factors especially in artificial insemination setting. Therefore, this study was designed to investigate the fertility status of bull by their estimated relative conception rate of cows that were inseminated by frozen semen from Korean proven bulls. Here we use the non-return rate (NRR) to access the bull fertility whereas, the NRR was define as the proportion of bulls that semen were used to inseminate cows and the number of cows that did not return for another service within 60 days. The data from 54,388 artificial inseminations (AI) were analyzed from 88 KPN semen. The NRRs of highest and lowest fertile bull were 83.81 and 51.33%, respectively. And mean NRR was 68.27%. In comparison to previously reported study, our data shows 17.38% higher NRR and the absolute value of difference in 50%>NRR and 50%<NRR group was 22.17 and 10.51, respectively (p< 0.001). In conclusion, the decreased fertility might consider as key aspect in achieving considerable conception of cows in existing integrated farming system at Korea.