Estrus Detection Using Background Image Subtraction Technique in Tie-Stalled Cows

• Published in: Animals (Basel) Vol. 11; no. 6; p. 1795
• Main Authors: Higaki, Shogo, Horihata, Kei, Suzuki, Chie, Sakurai, Reina, Suda, Tomoko, Yoshioka, Koji
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 16-06-2021; MDPI
• Subjects: Animals; background subtraction; Cameras; Cattle; Communication; Data analysis; Estrus; estrus detection; Frames per second; Labor costs; Livestock; Manpower; Monitoring; Moving object recognition; Ovulation; Pixels; precision agriculture; Sensitivity; Software; Subtraction; tie-stall housing; Ultrasonic imaging; Wearable technology; Webcams; Japan
• ISSN: 2076-2615; 2076-2615
• DOI: 10.3390/ani11061795

In this study, we determined the applicability of the background image subtraction technique to detect estrus in tie-stalled cows. To investigate the impact of the camera shooting direction, webcams were set up to capture the front, top, and rear views of a cow simultaneously. Video recording was performed for a total of ten estrous cycles in six cows. Standing estrus was confirmed by testing at 6 h intervals. From the end of estrus, transrectal ultrasonography was performed every 2 h to confirm ovulation time. Foreground objects (moving objects) were extracted in the videos using the background subtraction technique, and the pixels were counted at each frame of five frames-per-second sequences. After calculating the hourly averaged pixel counts, the change in values was expressed as the pixel ratio (total value during the last 24 h/total value during the last 24 to 48 h). The mean pixel ratio gradually increased at approximately 48 h before ovulation, and the highest value was observed at estrus, regardless of the camera shooting direction. When using front-view videos with an appropriate threshold, estrus was detected with 90% sensitivity and 50% precision. The present method in particular has the potential to be a non-contact estrus detection method for tie-stalled cows.