Measuring the effects of estrus on rumen temperature and environment, behavior and physiological attributes in Korean Native breeding cattle

In this study, we evaluated rumen temperature and environment in estral and non-estral Korean Native breeding cattle using a bolus sensor. We also assessed behavioral and physiological changes in study animals. To assess the rumen temperature and environment, we inserted bolus sensors into 12 Korean Native cattle with an average age of 35.5 months. We then measured temperature and activity within the rumen using the wireless bolus sensor. We recorded drinking, feeding and mounting behavior, and measured vaginal temperature and levels of intravaginal mucus resistance. We found that cattle in estrus exhibited more acts of mounting (37.4 vs. 0 times/day), increased vaginal temperature (39.0℃ vs. 38.4℃), and decreased vaginal mucus resistance (136.3Ω vs 197.4Ω), compared with non-estral animals. We further determined that increased levels of rumen activity were most significant in estrus cattle at the highest activity levels (<italic>p</italic> &lt; 0.01). Overall, the estrus group exhibited increased rumen temperature (<italic>p</italic> = 0.01), compared with the non-estrus group. In conclusion, the results of this study not only provide basic physiological data related to estrus in improved Korean Native breeding cattle, but also suggest that monitoring of rumen temperature and activity might be used as an effective smart device for estrus detection.