Factors Affecting Estrus Response and Conception Rates Following Artificial Insemination in Dairy Farms of Northeast Algerian

Introduction: Fertility in dairy cows is determined by accurate hormonal control and welltimed insemination, which depend on genetic background, parity, and the period between calving and insemination. Optimizing these factors is associated with efficient ovulation, clear estrus behavior, and improved conception outcomes. This study examined how breed, parity, and the interval from calving to first insemination (IC-FI) influence estrus expression and conception rate after hormonal synchronization and artificial insemination (AI) in Algerian dairy herds.Materials & Methods: A total of ۱۰۵ healthy cows aged ۲–۵ years (۶۶ Montbéliarde [MB] and ۳۹ Prim’Holstein [PH]) with body condition scores (BCSs) ≥۲ were enrolled from two intensive farms in Setif, northeastern Algeria. Animals received prostaglandin F₂α (PGF₂α) alone or combined with gonadotropin-releasing hormone (GnRH). Estrus detection was performed visually, and pregnancy was confirmed by ultrasonography at ۳۰ days followed by rectal palpation at ۴۵ days.Results: Overall, estrus expression was moderate (۵۳%), while conception success reached ۷۰%, aligning with results from efficiently managed herds. The PGF₂α-only treatment yielded the best performance. Parity significantly affected estrus manifestation (P<۰.۰۵), with multiparous (MP) cows exhibiting more visible heat signs, whereas longer IC–AI۱ intervals were associated with higher conception rates (P<۰.۰۵). Breed had no significant influence.Conclusion: These findings indicate that a simple PGF₂α-based protocol can produce satisfactory fertility outcomes under Algerian conditions. Considering parity and insemination timing may further enhance reproductive success. Broader studies integrating nutritional and health factors are recommended to better understand their combined effects on fertility.

کلیدواژه ها:

Artificial insemination (AI) ، Breed ، Conception rate ، Dairy cow ، Estrus rate ، Interval from calving to first insemination (IC-FI) ، Parity