The concept that a breast cancer patient's menstrual stage at the time of tumor surgery influences risk of metastases remains controversial. The scarcity of comprehensive molecular studies of menstrual stage-dependent fluctuations in the breast provides little insight in this observation. To gain a deeper understanding of the biological changes in mammary tissue and blood during the menstrual c...

Analyses of ovulation rates in consecutive estrous cycles with multiple-trait and repeated-records animal models resulted in different estimates of heritability. The estimate from the repeated-records model was seen to be approximately the product of the average genetic correlation and the average heritability from the multiple-trait procedure. A simple model is used to show algebraically that ...

To investigate uterine fluid and serum calcium (Ca) and Magnesium (Mg) variations during the estrus cycle in water buffaloes, 71 genital tracts and blood samples were collected from the abattoir in Urmia. The phase of the estrous cycle was determined by examining ovarian structures. 18 animals were pro-estrous, 15 estrous, 16 met-estrous and 22 diestrous. The uterine fluid was collected by gent...

the present study was carried out to investigate the effect of different seasons on length and duration of estrus as well as to observe the behavioral changes and physiological peculiarities during estrus period. three climatic seasons and age groups were considered: summer (march-june), rainy (july-october) and winter (november-february); a (6-9 month), b (9-12 month) and c (>12 month). estrus...

Intestinal calcium (Ca) absorption was measured under noninvasive conditions in both normally cycling and ovariectomized rats by determining the decrease in 47Ca/47Sc ratio between diet and feces. In 32-wk-old rats fed a 1.4% Ca diet, both fractional and total intestinal Ca absorption varied during the estrous cycle (p < 0.03), being highest during estrus and lowest during the second day of die...

The possible signaling role of prokineticin 2 (PK2) and its receptor, prokineticin receptor 2 (PKR2), on female reproduction was investigated. First, the expression of PKR2 and its co-localization with estrogen receptor (ERα) in the hypothalamus was examined. Sexually dimorphic expression of PKR2 in the preoptic area of the hypothalamus was observed. Compared to the male mice, there was more wi...

Fluctuations in ovarian hormones throughout the estrous cycle may underlie sex differences in behavior. In this study, estrogen plus progesterone were coadministered at different ratios to determine whether the interaction of those hormones during the estrous cycle contributes to cocaine-induced alterations in behavior. Before cocaine (15 mg/kg) or saline administration, ovariectomized female r...

Reproductive efficiency is the most important factor impacting the economics of a cow calf operation. The economic value of reproduction for commercial beef producers was reported to be five times greater than calf growth (Trenkle and Willham, 1977). Maximizing reproductive efficiency depends upon the successful completion of the following events: a heifer must reach puberty before the start of...

American Society of Animal Science members, publishing in Journal of Animal Science (JAS), completed research that resulted in understanding the estrous cycle of cattle, which led to the ability to inseminate cattle on a given day with pregnancy rates similar to those achieved by 21-d breeding by a fertile and sound bull. Research published in JAS led to understanding estrus, ovulation, the est...