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Related to proestrus: metestrus, estrous


The period immediately before estrus in most female mammals, characterized by development of the endometrium and ovarian follicles.

pro·es′trous adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(prəʊˈɛstrəs; -ˈiːstrəs)
(Zoology) the usual US spelling of pro-oestrus
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


or pro-oes•trus

(proʊˈɛs trəs)

the period immediately preceding estrus.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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References in periodicals archive ?
As shown in Figure 1, real-time RT-PCR analysis showed that the expression of LIF in the endometrium increased at late diestrus and proestrus phases during the estrous cycle (linear effect of day, p<0.05), while the expression of LIFR did not change during the cycle.
Smears were scored as follows: proestrus (P) contained primarily nucleated epithelial cells with no or few cornified cells, estrus (E) consisted of mostly cornified cells, metestrus (M) contained epithelial cells with leucocyte attacks, and diestrus (D) consisted of few cells that were leucocytes with some rounded or cornified epithelial cells.
(1996) found that a single exposure to the fungicide thiram (50 mg/kg) during the critical period of proestrus prior to mating, resulted in a decrease in the rate of fetal development, as well as a reduction in the number of live fetuses and an increase in the number of resorptions on GD 20.
These morphological changes due to the desquamation depict four major phases of the oestrus cycle which include the Proestrus (P), Oestrous (O), Metestrous (M) and Diestrous (D) (Long & Evans, 1922).
Influence of the length of proestrus on fertility and endocrine function in female cattle.
Changes in the superoxide radical and superoxide dismutase levels in the uterus of Rattus norvegicus during the estrous cycle and a possible role for superoxide radical in uterine oedema and cell proliferation at proestrus. Biochemistry and Cell Biology 69, 313-316.
The estrus cycle of mice is approximately 4-5 days, including proestrus, estrus, metestrus and diestrus (15).
Dilatation of uterine horns was considered a neurohormonal phenomenon associated with the proestrus phase of the inner reproductive organs [40].
Based on vaginal cytology, females were divided into two groups: diestrous (those in diestrus and metaestrus) and estrous (those in estrus and proestrus).
Uterine blood flow shows a characteristic pattern in cows with the highest time averaged maximum velocity values during proestrus and estrus and remains at a fairly constant during diestrus (Bollwein et al., 2016).
Vaginal smears from control group, which was subjected to sham-OVX, showed one of the regular estrous cycles including diestrus, proestrus, estrus, and metestrus.