Hormonal profiles and etiological factors associated with abortion in ewes: A case-control study in Salah Al-Din Province, Iraq

The economic implications of abortion among ewes in Salah Al-Din Province (Iraq) have a significant negative impact on the livestock industry. Therefore, it is important to understand the hormonal changes associated with abortion, as well as the potential causative agents to devise adequate and practical prevention strategies of abortion in ewes. The objective of this study was to investigate the hormonal changes in aborted ewes and to identify the primary causes of abortion in sheep throughout Salah Al-Din Province during the breeding season of 2024. A total of 180 ewes were examined, including 120 ewes with confirmed abortions, whereas the remaining 60 ewes with healthy pregnancies served as a control group. Blood samples were taken from each ewe for hormonal analysis (progesterone, estradiol-17β, cortisol, and prolactin) using enzyme-linked immunosorbent assay. Samples from aborted ewes were microbiologically cultured, serologically tested, and histologically examined to determine the causative agents. There was a statistically significant difference between aborted and control ewes in the concentration of progesterone (1.82±0.34 ng/mL vs 4.15±0.52 ng/mL, p < 0.001), and estradiol-17β levels (12.45±2.18 pg/mL vs 28.67±3.45 pg/mL; p < 0.001). The concentration of cortisol was significantly higher in the serum of aborted ewes (45.32±6.78 ng/mL vs 22.15±3.42 ng/mL; p < 0.001). The aborted group revealed slightly lower levels of prolactin compared to controls on average. The leading causes of abortion identified were brucellosis (33.2%), toxoplasmosis (25.8%), chlamydia (19.2%), and nutritional deficiencies (15.8%). The findings from this study indicate that abortion in ewes in Salah Al-Din Province is associated with significant hormonal changes, the most notable of which were decreased progesterone and increased cortisol levels. Infectious diseases, especially brucellosis and toxoplasmosis, represented the leading causes of abortion. These observations suggest a need for comprehensive vaccination programs, improved nutritional management, and strategies to reduce stress to lower the incidence of abortion in ewes.