Follicular Dynamics and Corpus Luteum Growth and Function in Pregnant Versus Nonpregnant Dairy Cows

¹ Department of Animal Science, University of British Columbia, Vancouver, BC, Canada

The effects of pregnancy on follicular dynamics and corpus luteum growth and function are somewhat contentious. In an effort to learn more about the effects of pregnancy, the reproductive tracts of 16 bred dairy cows were monitored using an ultrasound device with a rectal probe through the first 60 d of pregnancy or upon a return to estrus. Additionally, blood samples were collected for progesterone determination. Eleven of 16 cows were diagnosed pregnant by 25 d post-breeding. There were two embryonic mortalities between 28 and 32 d. A two-wave pattern of follicular growth and atresia, each wave resulting in a large dominant follicle, was seen in both pregnant and nonpregnant cows during the first 24 d postbreeding. Pregnant cows had more follicles than nonpregnant cows; however, there was no difference in the size of the largest follicle. A wave-like pattern of growth of large follicles continued throughout the study period in pregnant cows. Progesterone profiles, corpus luteum growth rate, and maximum size of the corpus luteum were similar in both pregnant and nonpregnant cows. It is concluded that growth of dominant follicles and of the corpus luteum is unaffected during the first 60 d of pregnancy.

Key Words: follicular dynamics • pregnancy • corpus luteum growth

Submitted on January 5, 1990
Accepted on June 11, 1990

This article has been cited by other articles:

				M. C. Lucy The bovine dominant ovarian follicle J Anim Sci, March 1, 2007; 85(13_suppl): E89 - E99. [Abstract] [Full Text] [PDF]

				A. Gumen, J. N. Guenther, and M. C. Wiltbank Follicular Size and Response to Ovsynch Versus Detection of Estrus in Anovular and Ovular Lactating Dairy Cows J Dairy Sci, October 1, 2003; 86(10): 3184 - 3194. [Abstract] [Full Text] [PDF]