چکیده (انگلیسی):

Objective: To investigate the conception rate when cows showing clear signs of estrus
and having both normal sized follicles and cystic follicles were artificially inseminated.
Methods: Thirty parous Holstein cows showing clear signs of estrus and having both
normal sized follicles (diameter <25 mm) and cystic follicles (diameter
25 mm)
simultaneously in their ovaries were artificially inseminated. Changes in the ovaries were
observed using real-time ultrasonography for 25 d after artificial insemination. The
concentration of plasma progesterone (P4) was measured simultaneously to monitor the
function of the corpus luteum.
Results: The normal sized follicles ovulated in 21 out of 30 cows (ovulation rate:
70.0%), and 11 of these cows successfully conceived (conception rate: 36.7%) (Group C)
while 10 cows did not conceive (Group NC). The maining 9 cows, normal sized follicles
did not ovulate (Group NO). The change in P4 in cows that ovulated was similar to that in
normal cows. Although there were no significant differences in median number and size
of cystic follicles among the groups, all cows in Group C only had one cystic follicle.
Conclusion: These results support artificially inseminated of cows that show clear signs
of estrus even if they have both cystic follicles and normal sized follicles, and especially
when the cows have only one cystic follicle.