This study aims to explore the various invasive and non-invasive methods employed in identifying estrus in ewes. The estrous cycles of 15 Garut ewes were synchronized through hormone prostaglandin with two injections 11 days apart. The ewes were submitted to measurements of invasive (vaginal and rectal temperature, vaginal pH, and cytology) and non-invasive (rectal temperature with infrared thermography, and automatic heart rate) methods, carried out at the time (D0) until the 3rd day (D3) of the second hormone injection. The results showed that the vaginal pH of ewes on day 0 was acidic and still dominated by parabasal and intermediate cells amounting to 48.61% and 43.74%, respectively, significantly different from day 1 to day 3 was alkaline and the percentage of superficial cells reached 58.06% (p<0.05). The vaginal and rectal temperatures (thermometer or infrared thermography), and heart rate would increase on day 1 and then return to the initial temperature and heart rate marked by the mating process. The selection of non-invasive methods may be a more benign option in facilitating the detection of oestrus symptoms as it can overcome potential stress or welfare issues that have been associated with invasive methods. © 2024 IEEE.