Alteration of the Endometrial EGF Profile as a Potential Mechanism Connecting
the Alterations in the Ovarian Steroid Hormone Profile to Embryonic Loss in Repeat
Breeders and High-producing Cows |
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Authors: | Seiji KATAGIRI Masaharu MORIYOSHI |
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Institution: | 1)Laboratory of Theriogenology, Department of Large Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu 069-8501, Japan |
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Abstract: | Poor reproductive efficiency is a worldwide problem that has affected the dairy industry
during the last several decades. In an attempt to explain the changes in reproductive
physiology caused by high milk production, a model of elevated steroid metabolism in
lactating dairy cows has been proposed. A slow increase in levels and low peak levels of
estradiol (E2) and progesterone (P4) characterize endocrine changes
in high producing cows. Similar changes have been reported in the repeat breeder cows. The
abnormal changes in E2 and P4 concentrations of these cows may cause
an improper uterine environment due to disturbed expression of growth factors and
cytokines in the endometrium. This review focuses on the alteration in epidermal growth
factor (EGF) profile in the endometrium during the estrous cycle. The normal cow has two
peaks of EGF concentrations on days 2–4 and 13–14. Low concentrations of EGF on these days
distinguished both high-producing and repeat breeder cows from normal cows. Alteration of
the EGF profile could be found in 70 and 40% of the repeat breeder and high-producing
cows, respectively. Treatment with a high dose of estradiol benzoate and an intravaginal
progesterone-releasing device restored the normal EGF profile in about 70% of the affected
cows. The cows having a normal EGF profile after treatment showed a higher pregnancy rate
than the cows with the altered profile. Further studies to understand the etiology of the
alteration in the EGF profile are needed to develop another treatment option and
preventive management for this problem. |
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Keywords: | Embryonic loss Endometrial biopsy Estrogen Infertility Progesterone |
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