| 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. |
