Presence of a Temperature Gradient Among Genital Tract Portions and the Thermal Changes Within These Portions Over the Estrous Cycle in Beef Cows

Abstract

The aim of the present study was to describe the temperature of the different portions of the female genital tract and their relation to rectal temperature and to investigate the effect of steroid hormones profiles on these variables over the estrous cycle in cattle. Four nonpregnant Japanese Black cows were investigated daily over two successive estrous cycles using a digital thermometer with a long probe and rounded-end sensor to record the temperature of the rectum (RT), vagina (VT), cervix (CT), uterine body (UBT) and uterine horns (UHT). Blood samples were collected immediately before temperature recording to assay peripheral levels of progesterone (P4) and estradiol-17β (E2). Moreover, transrectal ultrasonography was carried out after temperature recording to monitor the ovulatory follicle and track ovulation. During the experiment, the ambient temperature and relative humidity were recorded for further calculation of the temperature humidity index (THI). The temperature within the genital tracts in these cows progressively increased towards the uterine horns from the vagina. The VT, CT, UBT and UHTs were significantly higher in association with peripheral P4 concentrations greater than 4 ng/ml (mid-luteal phase) when compared with lower peripheral P4 concentrations. The VT was more significantly (P<0.01) correlated to the CT, UBT and UHTs than RT. In conclusion, a temperature gradient was present among the vagina, cervix and uterus over the estrous cycle, and changes in peripheral P4 concentrations were associated with the thermal variations within these portions. The VT could be more beneficial than RT in monitoring temperature of deeper portions of the female genital tract in bovine.

Effect of summer heat stress on gene expression in bovine uterine endometrial tissues

“…Bovine body temperature is approximately 38.5°C, which increases under high ambient temperature (Sartori et al., 2002). The uterine temperature is typically higher than that of the rectum, vagina, or cervix (El‐Sheikh Ali et al., 2013; Gwazdauskas et al., 1973). An increased uterine temperature reduces blood flow into the uterus (Gwazdauskas et al., 1975; Roman‐Ponce et al., 1978), thus disturbing fetal development.…”

Effects of ambient temperature and humidity on body temperature and activity of heifers, and a novel idea of heat stress monitoring

“…In addition, our team also monitored the body surface temperature of cows by measuring ankle temperature; however, its application is also unsuitable as it is affected by uncontrollable environmental factors (Kou et al 2017). The temperature correlation between rectum and vagina is 0.79, which is higher than that of uterine body, cervix, uterine angle and rectal temperature, and shows that long-term automatic monitoring VT to indicate core temperature is more scientific and reasonable than rectum (El-Sheikh Ali et al 2013). The real-time VT monitoring technique, based on sensor technology, is relatively new, and the automatically measured VT can serve as a strong indicator of bovine rectal temperature, since it is less affected by external factors (Collier et al 2006;Kendall et al 2007).…”

Involvement of calcium channels and intracellular calcium in bull sperm thermotaxis

“…It has also been confirmed that the intravaginal temperature of bovines was elevated 0.4ºC at estrus [ 16 , 17 ]. Therefore, a temperature gradient of 39–41ºC, higher than body temperature (38–39ºC) [ 17 , 18 ], is formed in the reproductive tract of the estrus bovine, and thermotaxis may be involved in supporting the migration of fertilizing sperm. In this in vitro study, the thermotaxis of bull sperm toward the 1–2ºC higher temperature was confirmed.…”