Uso de sistema de monitoramento automatizado na detecção do estro após protocolo de IATF em vacas leiteiras Girolando a pasto

Abstract

The use of precision livestock farming on farms has shown positive results in production, animal welfare, and reduced environmental impact, as it allows for the individual observation of each animal and early alerts on potential health and behavioral changes. The main challenge of utilizing these tools, especially in Brazil with grazing animals, lies in the range of the antennas, due to the power limitations and the vast areas where the animals are located. Therefore, the aim of this study was to evaluate the effectiveness of an automated activity monitoring system, using an accelerometer, for estrus detection compared to visual observation and the tail-base adhesive scraping method in crossbred dairy cows on pasture. The study was conducted at the Technology Center for Zebu Dairy Breeds (CTZL), Embrapa Cerrados, Brasília-DF. The research involved 25 5/8 Girolando dairy cows (n=13 primiparous and n=12 multiparous) kept in rotational grazing on Panicum maximum cv Mombaça paddocks. The animals were milked twice a day and returned to pasture immediately after milking. The experiment took place from September to November 2021, with two estrus cycles, and all animals underwent ultrasound examinations. Sensitivity and specificity for estrus detection were assessed using three methods: 1) Automated Activity Monitoring (AAM) sensors, 2) Visual observations, and 3) Adhesive tape estrus detector. The monitoring collars were applied 15 days prior to the start of the TAI protocol to establish the baseline activity for each animal. After this period, the reproductive protocol began. On day 0 (D0), 2 mL of estradiol benzoate was administered, and a progesterone intravaginal device was inserted. This device was removed on day 8 (D8), followed by the administration of 2 mL of prostaglandin, 2 mL of equine chorionic gonadotropin, and 1 mL of estradiol cypionate, in addition to the placement of the adhesive tape. Visual observations were conducted on days D9, D10, and D11 to detect estrus. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were analyzed across all three methods for each treatment. The average sensitivity of the two reference methods—visual observation and adhesive tape—was 85.1% and 82.9%, respectively. The specificity of the visual method was 66.7% and 28.6% for adhesive tape. Accuracy was 64% for the visual method and 74.4% for adhesive tape. In conclusion, the AAM system demonstrated similar effectiveness to conventional methods for estrus detection. The use of AAM on pasture is a helpful tool for estrus detection, though further adjustments to the system and algorithm are needed for optimal performance.