Effect of administration of lesireline five days after artificial insemination on pregnancy rates and luteal function in cows

Abstract

The aim of this study was to increase pregnancy rates by administering lesireline five days after artificial insemination (AI). Five days after AI, lesireline acetate (2 ml) and physiologic saline solution (2 ml) were injected intramuscularly in Group I (n=29) and Group It (n=27), respectively. Blood samples were collected at Al (day 0) and 5, 10 and 20 days after Al to determine serum progesterone concentrations. Pregnancies were diagnosed via palpation per rectum at day 60 after Al. Pregnancy rates were 24.1% and 22.2% in lesireline (Group 1) and control (Group II) groups, respectively, and these pregnancy rates did not significantly differ between groups (p>0.05). Serum progesterone concentrations ten days after Al were not significantly different between experimental and control groups (p>0.05). Although serum progesteron concentration in lesireline group (6.3 +/- 0.9 ng/ml) was higher than those in control group (5.2 +/- 1.0 ng/ml), it did not significantly differ between groups (p>0.05). In spite of the fact that administration of lesireline resulted in significant rise in progesterone levels in the middle of the cycle, pregnancy rates did not differ between groups.