Factors affecting the pregnancy rate of Bangladeshi ewes following Laparoscopic Artificial Insemination (LAP-AI)

Abstract

The study was conducted to determine the effects of different factors on increased pregnancy rate of Bangladeshi ewes through LAP-AI. A total of 24 indigenous ewes and 4 rams were selected. Frozen semen with a concentration of 100×106 spermatozoa/ 0.25 ml straws were produced. The selected ewes were synchronized using two doses of PGF2α @ 175µg per ewe at 9 days intervals intramuscularly. Estrus was confirmed by the vasectomized ram. The LAP-AI was performed at two different times from the onset of estrus, two angles of placement on the laparoscopic cradle, and two different puncture sites. Pregnancy was confirmed by ultrasonography on days 45-50 following insemination. The pregnancy rate of ewes 2.5-4 years of age and 16-20 kg bodyweight was higher (75% vs. 41.67%) than ewes 1-2 years and 9-13 kg. However, this was not significant (p>0.05). The pregnancy rate of ewes having BCS >3 was significantly higher (p<0.05) (78.57% vs. 30%) than BCS 2-2.5. The 20-24 hours insemination time from the onset of estrus yielded a significantly higher (p<0.05) (75% vs. 25%) pregnancy rate than 12-16 hours. The pregnancy rate was higher (66.67% vs. 50%) at 45° than 30°angle of placement of ewes on the laparoscopic cradle. However, there was no significant difference (p>0.05). The puncture point, 4-5 cm away from the udder resulted from a significantly higher pregnancy rate (p<0.05) (83.33% vs. 33.33%) than 7-10 cm. The present study indicates that the pregnancy rates following LAP-AI using frozen semen could be increased if the significant factors are considered.