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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Livestock Bio-Systems » Research » Publications at this Location » Publication #169436

Title: SUPEROVULATORY RESPONSE OF ONE OVARY IS RELATED TO THE MICRO- AND MACROSCOPIC POPULATION OF FOLLICLES IN THE CONTRALATERAL OVARY OF THE COW

Author
item Cushman, Robert - Bob
item DESOUZA, JOSE
item HEDGPETH, VICKIE
item BRITT, JACK

Submitted to: Biology of Reproduction
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/1998
Publication Date: N/A
Citation: Cushman, R.A., Desouza, J.C., Hedgpeth, V.S., Britt, J.H. 1999. Superovulatory response of one ovary is related to the micro- and macroscopic population of follicles in the contralateral ovary of the cow. Biology of Reproduction. 60(2):349-354.

Interpretive Summary: There is large variation between cows in their response to superovulatory treatments with gonadotropins. A better understanding of the mechanisms controlling this variation would allow for greater efficiency when superovulating a cow of high genetic merit. The number of large gonadotropin responsive follicles present on the ovary at the time that superovulation is started is associated with the ovulatory response. Because there are positive correlations between the numbers of microscopic follicles in the ovary and the number of surface follicles, we hypothesized that the ovulatory response of one ovary to gonadotropins would be related positively to the number of microscopic follicles in the other ovary. Nonlactating cows were unilaterally ovariectomized and 2 days later were superovulated. The superovulatory response was classified as Low (< 5 corpora lutea [CL]), Medium (5-14 CL), or High (> 14 CL). Surface follicles on the ovary removed before superovulation were classified as small (1-3 mm), medium (3-7 mm), or large ( > 7 mm), and the ovary was processed for microscopic analysis. Numbers of primordial, tertiary, small surface follicles, medium surface follicles, and total surface follicles were lower (p

Technical Abstract: We hypothesized that the ovulatory response of one ovary to FSH would be related positively to the size of the primordial and growing pools of follicles in the other ovary. Nonlactating cows (n = 26) were unilaterally ovariectomized and 2 days later were superovulated. The superovulatory response was classified as Low (< 5 corpora lutea [CL]), Medium (5-14 CL), or High (> 14 CL). Surface follicles on the ovary removed before superovulation were classified as small (1-3 mm), medium (3-7 mm), or large (> 7 mm), and the ovary was then fixed and serially sectioned. Follicles 250 follicles