The corpus luteum on the ovaries of dairy cows, the secretions of the uterine horns, and lactation all have an impact on the development of follicles. During lactation, the number of developing follicles on the ovaries of dairy cows is not only small in number and size, but also the amount of estrogen secreted is low. During lactation, follicle development is inhibited by prolactin, and follicles only begin to develop 3-5 days after weaning.

The presence of the corpus luteum is very beneficial to follicular development. Although many reports point out that the follicles on the ovaries on the corpus luteum side are small in size and the estrogen content in the follicular fluid is low, this is the result obtained under the conditions of using slaughterhouse materials and histological examination and estrogen determination, and its reliability is far less than the current research on live cows using the B-ultrasound imaging method of dairy cows. The dynamic study of cow follicle development using the B-ultrasound imaging method of dairy cows confirmed that the follicle development of the ovaries on the corpus luteum side is better than that of the ovaries on the opposite side of the corpus luteum.

The effect of the cow uterus on follicular development is mainly manifested as an inhibitory effect. In early pregnancy, the conceptus and/or the uterus on the same side of the conceptus can secrete some substances that change the production of steroid hormones and reduce the growth capacity of follicles. Injecting PGF after giving birth to cows can reduce the activity of the ovary on the opposite side of the pregnant horn, even if the uterus does not change. In production, it is also often found that when the cow is in estrus for the first time after giving birth, ovulation often occurs in the ovary on the opposite side of the pregnant horn, indicating that follicle development often occurs in the ovary on the opposite side of the pregnant horn.