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Critser JK, Miller KF, Gunsett FC, et al. Seasonal LH profile in ovariectomized cattle. Theriogenology. 1983;19(2):181-91doi: 10.1016/0093-691x(83)90004-3.
Critser, J. K., Miller, K. F., Gunsett, F. C., & Ginther, O. J. (1983). Seasonal LH profile in ovariectomized cattle. Theriogenology, 19(2), 181-91. https://doi.org/10.1016/0093-691x(83)90004-3
Critser, J K, et al. "Seasonal LH profile in ovariectomized cattle." Theriogenology vol. 19,2 (1983): 181-91. doi: https://doi.org/10.1016/0093-691x(83)90004-3
Critser JK, Miller KF, Gunsett FC, Ginther OJ. Seasonal LH profile in ovariectomized cattle. Theriogenology. 1983 Feb;19(2):181-91. doi: 10.1016/0093-691x(83)90004-3. PMID: 16725785.
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Theriogenology. 1983 Feb;19(2):181-91. doi: 10.1016/0093-691x(83)90004-3.

Seasonal LH profile in ovariectomized cattle.

Theriogenology

J K Critser, K F Miller, F C Gunsett, O J Ginther

Affiliations

  1. Department of Veterinary Science University of Wisconsin Madison, WI 53706 USA.

PMID: 16725785 DOI: 10.1016/0093-691x(83)90004-3

Abstract

Two experiments were conducted to examine seasonal changes in circulating LH concentrations in ovariectomized heifers. In experiment 1, four Holstein heifers were ovariectomized in April 1977 during middiestrus. Blood samples were collected daily for 30 days surrounding each equinox and solstice for one year to examine changes in plasma LH levels at the time of seasonal photoperiod changes. The LH concentrations were highest during the winter solstice period and lowest during the summer solstice period. In addition, samples taken at two-week intervals indicated a distinct LH profile with maximal LH concentrations during November-April and minimal concentrations during May-October. In experiment 2, eight Holstein heifers were ovariectomized in June-July, 1979 and given an estradiol or a control implant in October. A distinct LH profile for the interval extending from January, 1980 to February, 1981 was found in the heifers that were not treated with estradiol. Concentrations were maximal during December-April and minimal during May-November. The LH profile followed a similar pattern in the estradiol-treated heifers; however, the overall profile was at a higher level. These data indicate that underlying seasonal reproductive mechanisms are present in cattle even though the species ovulates and breeds throughout the year.

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