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Research article - Peer-reviewed, 1995

Clinical Changes in Ovariectomized Ewes Exposed to Phytoestrogens and 17β-Estradiol Implants

Nwannenna, Agnes I.; Lundh, T. J-O.; Madej, A.; Fredriksson, G.; Björnhag, G.


Eight Swedish Finewool Landrace ewes, ovariectomized 5 months earlier and kept on nonestrogenic hay, were each fed 3.5 kg red clover silage, corresponding to 6.1 g phytoestrogens (of which 3.5 g was formononetin) per day, for 14 days in November (short days). In January (short days), two groups (3 each) of these ewes received one or two 17 beta-estradiol sc implants. In May (long days), one of two new groups (4 each) of these ewes was reexposed to phytoestrogens for another 14 days while the other served as a control. Physical examination of ewes for changes in reproductive organs was carried out two or three times per week during each feeding/treatment, and continued until observed changes disappeared. Clinically significant changes occurred in the reproductive organs of ewes fed red clover. Vulva color changed from pale to pink and red, and there were enlargements of the vulva, uterus, and udder. In addition, test length and circumference increased, and secretion of milky fluid began. These changes were similar, but more pronounced during treatment with 17 beta-estradiol, particularly teat circumference. The changes in vulva were more dramatic in May than in November and resembled those observed in ewes treated with estradiol. Our data show that a daily intake of 3.5 g formononetin for 14 days caused the increase of teat sire and changes in the color of the vulva and in uterus weight in ovariectomized ewes.

Published in

Proceedings of the Society for Experimental Biology and Medicine
1995, volume: 208, number: 1, pages: 92-97

Authors' information

Nwannenna, A. I.
SLU - Swedish University of Agricultural Sciences
Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management
Madej, Andrzej
Swedish University of Agricultural Sciences, Department of Physiology
Fredriksson, Gunnar
Swedish University of Agricultural Sciences, Department of Obstetrics and Gynaecology
Björnhag, Göran
Swedish University of Agricultural Sciences, Department of Animal Physiology

UKÄ Subject classification

Clinical Science
Medical Bioscience

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