Application of infrared thermography for identification of estrus in Sahiwal females (Bos indicus).

Estrus detection is the primary concern related to dairy animals, which accounts for poor reproductive efficiency and increased calving interval in Zebu cattle. The present study shows the application of Infrared Thermography (IRT) for estrus detection in indigenous Sahiwal females. A total of 22 Sahiwal females were induced to estrus by prostaglandin (PGF2α) protocol after ensuring the presence of functional corpus luteum (CL). The day of treatment, estrus, and three days post-estrus were designated as days − 3, 0, and 3, respectively. Infrared thermography (IRT) of the muzzle, eye, ear, and vulva was monitored from day − 3 to 3, with maximum temperatures recorded on day 0, showing a significant increase (0.35–0.84 °C; p < 0.05) compared to days − 3 and 3. With the cut-off vulvar temperature, the true positivity rate was 70%, with the positive predictive value 100%. Estrus was confirmed using ultrasonography examination (USG) with a dominant follicle (13.13 ± 0.39 mm), cervical mucus fern pattern (typical 54.54%; atypical 36.36%; and nil patterns 9.09%), spinbarkeit value (23.50 ± 0.76 cm), and serum progesterone (P4) concentration (0.31 ± 0.01 ng/ml) on the day of estrus. So, it is concluded that IRT can be used as an efficient, supportive tool to monitor the eye and vulva temperature as an estrus indicator in Sahiwal females.