Practical experience with artificial insemination (AI) using fresh chilled and frozen semen in mares.

This research article studies the efficiency of artificial insemination (AI) in horses under field conditions, comparing the results of using both fresh chilled and frozen semen. The findings suggest that while both methods lead to successful pregnancies and birth of foals, the use of frozen semen requires more insemination attempts and extends the insemination period.

Objective and Design of the Study

• The main aim of the study was to evaluate the effectiveness of artificial insemination (AI) using both frozen and fresh, diluted and chilled semen under practical conditions.
• One hundred and twenty-nine mares of varying breeds were included in the analysis.
• The study design was a comparative analysis of the two AI methods in terms of the resulting pregnancies, abortions, foal births and insemination cycles.

Comparison of the Two Methods

• Of the 107 mares inseminated with fresh, chilled semen, 81 became pregnant. Following seven abortions, 74 foals were born successfully.
• Compared to this, 17 out of 22 mares inseminated with frozen semen became pregnant. After two abortions, 15 healthy foals were born.
• The ratio of foals born did not show a significant difference between the two groups. This suggests that both methods were equally successful in leading to birth of foals.
• Further, the number of insemination cycles also did not showcase any significant difference between fresh chilled and frozen semen methods.

Difference in the Number of Inseminations and Duration of Insemination Period

• A significant difference was observed in the number of inseminations per conception, favouring frozen semen (2.5 vs. 1.8 with fresh chilled and frozen semen, respectively).
• This implies that more attempts were required to achieve conception when using frozen semen.
• Cox regression analysis further revealed that the type of semen has a significant impact on the duration of the insemination period. Using frozen semen was associated with a longer insemination period.
• This could potentially be due to management issues, as re-insemination with frozen semen happened after only one or a few missed oestrous cycles that were not used for artificial insemination.