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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #322274
Title: Reproductive Management for Optimal Uterine Preparedness for Pregnancy

Author
item Geary, Thomas
item FERNANDA, ABREU - The Ohio State University

Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/1/2015
Publication Date: 3/19/2015
Citation: Geary, T.W., Fernanda, A. 2015. Reproductive Management for Optimal Uterine Preparedness for Pregnancy. 19th Conference on New Techniques in Bovine Production and Reproduction. Brazil. CD:111-125.

Interpretive Summary: The uterus is the organ of pregnancy. There are many components involved in preparing the uterus for pregnancy. In beef cattle, the most important component is estrogen around the time the egg is released. High estrogen levels are critical for the embryo to attach 18 days later. Also, high progesterone levels are need from day 5 of pregnancy until calving. Progesterone is especially important from day 5 to 20. Without these 2 hormone signals, embryo growth will be delayed. The embryo must produce IFN to signal its presence. Thus, anything that slows embryo growth will decrease pregnancy success. Embryo quality was the only thing that improved pregnancy success in an earlier study. Scientists and producers need to ensure the cow’s uterus is prepared for pregnancy. This will lead to greater pregnancy success.

Technical Abstract: It is clear that decreased serum concentrations of preovulatory estradiol create uterine deficiencies that prevent the maintenance of pregnancy and losses are related to reduced ability of the developing embryo to implant. The uterine deficiencies in response to reduced post-ovulatory progesterone concentrations have been partially defined. Reducing progesterone concentrations in early gestation alters the normal regulation of PGR and results in numerous alterations in the transcriptome of the endometrium, specifically those genes involved with histotroph production and composition, and preparation of the uterus for conceptus attachment. Ultimately these changes translate into retarded conceptus development and, in many instances, conceptus death, or at least maternal recognition of pregnancy failure. Anything that impedes an embryo’s growth or production of interferon-tau or anything that interferes with the uterine ability to recognize this signal or block prostaglandin release could disrupt maternal recognition of pregnancy and result in return to estrus, even though an embryo is present. Because superior embryo quality was the only variable that improved pregnancy maintenance from d 27 to 72 in the study by Atkins et al. (2013), oviductal limitations to pregnancy success may also exist. From a practical standpoint, animal scientists and producers must be aware of these potential uterine deficiencies induced by alterations in reproductive steroid concentrations when developing and implementing reproductive management technologies and strategies in cattle.