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2. Magistritööd

Selle kollektsiooni püsiv URIhttp://hdl.handle.net/10492/2498

Sirvi

Sirvi 2. Magistritööd Märksõna "ADF test" järgi

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    Assessing surgically implanted temperature sensors to measure body temperature in dairy calves during individual- and group period
    (Eesti Maaülikool, 2022) Breukers, Thomas; Niine, Tarmo
    Monitoring cattle welfare in ever increasing herd sizes brings challenges to the cattle producers. Measuring core temperature of cattle rectally is one of the main ways to determine the health status of the animal, but requires restraining of the animal, and needs to be done manually. New techniques to measure temperature are being developed one of them being subcutaneous temperature measuring sensors. Our hypothesis was that there should be significant difference in correlation between individual- and group pen periods hourly temperature measurements, and as calves are homeothermic animals and have circadian rhythm the second hypothesis was that daily temperature measurements (taken hourly) would have non-stationary nature. To assess the microchips in dairy calves, 10 calves each had 3 temperature sensors surgically implanted, one in the neck, one in front of the shoulder and one behind the elbow and had continuously their temperature measured for 68 days from November to February in common husbandry environment. Measurements between individual- and group pen periods were compared to each other using lag scatter plots to check significant differences between them, and Augmented Dickey-Fuller (ADF) test was used to determine the stationarity of the temperature measurements by day. The temperature readings showed seasonality demonstrated with the lag scatter plots, and they showed fluctuation throughout the day, both in individual-and group pens. The individual period showed less correlation and more randomness compared to the group pen period, which could be due to the inflammatory period post-implantation. Out of all the ADF tests performed 7.5% were stationary, and 92.5% were non-stationary, indicating that mostly (92.5%) temperature measurement depends on the time of the day, however there were small proportions of days (7.5%) where daily temperature did not seem to follow the expected circadian rhythm. The hypothesis could mostly be proven using ADF test, as the data was mostly non-stationary. The use of subcutaneous temperature sensors in dairy calves as welfare monitoring devices needs further research and considering other factors which might affect calves body temperature.