Tail tip temperature measured by thermography as an indicator of animal health in Holstein cows

There is an increasing focus on animal health in research, and a growing public interest in transparent animal welfare practices. Several indicators are already used to assess animal health. Recently, the health of the tail tip has gained attention in animal welfare studies. Previous research suggests that circulatory problems may cause alterations in the tail tip. The aim of this case study was to evaluate whether tail tip temperature, measured using IR thermography, can be used as an indicator of animal health and whether visible or palpable alterations in the tail tip are associated with the tail temperature. We also compared the results with known animal health indicators using a cluster analysis. This study was conducted on a dairy farm in Germany. Data from 530 observations of 351 Holstein Friesian cows were collected over a 14-month period. The variables included the minimum, maximum, and average tail tip temperature; multiple tail tip alterations; the somatic cell score; the rectal temperature score; ruminal health indicators; the locomotion score; the body condition score; milk performance test results; and the sum of the claw diagnosis score. We used cluster analysis to identify patterns among these variables, resulting in the formation of four distinct clusters. The analysis revealed that the claw diagnosis score followed by tail tip temperature had the strongest influence on cluster categorisation, suggesting their notable influence on animal health. In the case study, cows with good performance and no obvious health problems showed unaltered and warm tail tips (non-standardised average temperature of 31.55 °C), whereas lower tail tip temperatures and altered tail tips tended to be associated with udder and claw issues, reduced rumen filling, and indications of potential health restrictions. Overall, a change in tail tip temperature was observed, supporting the previously hypothesised circulation issues. In addition, the correlations between the tail tip condition and several health traits in dairy cows suggest that the tail tip can be considered as an animal health indicator, and this issue warrants further investigation.