Effect of insemination dose on pregnancy rate in mares.

The research paper investigates the impact of varying insemination dosage on the pregnancy rate in horses during artificial insemination. Researchers found that reducing the dosage from 500 x 10(6) to 300 x 10(6) progressively motile spermatozoa did not significantly affect the pregnancy rate when using fresh extended semen with stallions known to have good-quality semen.

Objective and Methodology of the Study

• The main aim of the study was to determine if the insemination dosage, which is generally considered to influence the pregnancy rate during artificial insemination (AI), can be reduced while maintaining an acceptable pregnancy rate.
• Thirteen stallions with proven fertility and sixty-four mares randomly assigned to two insemination groups were used in the study. The insemination groups were differentiated based on the dosages of 500 x 10(6) and 300 x 10(6) progressively motile spermatozoa.
• The mares’ pregnancy was evaluated approximately 16 days post insemination using ultrasonography per rectum.

Findings of the Study

• The research revealed that the pregnancy rate when using an insemination dosage of 300 x 10(6) progressively motile spermatozoa was 75%. This figure was higher than the 64% pregnancy rate observed with a dosage of 500 x 10(6) progressively motile spermatozoa.
• However, the results indicated no statistically significant difference in the pregnancy rate between the two insemination doses, with P = 0.341.

Conclusion of the Study

• The study concluded that reducing the insemination dosage of progressively motile spermatozoa from 500 x 10(6) to 300 x 10(6) was unlikely to result in a decreased pregnancy rate, provided that the semen used was of good quality and was fresh extended.
• This conclusion implies that the quality of the semen used in AI is more critical than the quantity, at least within the range examined in the study.