The potential of the tail tip as animal health indicator in dairy cows

Objectives

Tail tip inflammation and necrosis is a well-recognised condition in several species that can have a significant impact on overall health. Fattening cattle, bulls and calves have often been prone to severe tail tip problems, often related to their housing conditions or environmental factors. In addition, a high frequency of tail tip lesions has recently been observed in dairy cattle. Tail tip changes have also been studied in pigs in relation to the newly defined Swine Inflammation and Necrosis Syndrome (SINS). Pathological changes including inflammation and necrosis of ears, teats, claws and tails have been observed in pigs as a result of systemic inflammation and reduced blood flow to the acra. This raised the question of whether changes in the tip of the tail were also associated with other health indicators in dairy cows. The aim of this study was therefore to investigate whether there is a correlation between changes in the tail tip, its temperature measured by thermography, and performance and health traits in Holstein Friesian dairy cows.

Material and methods

The study was conducted on a commercial dairy farm in Germany between May 2021 and June 2022. Every 14 days groups of 19-43 cows were examined. A total of n=530 observations from 351 different Holstein cows (lactation = 1 - 6) were analysed during the study period. Cows were examined at 150 days post partum and/or just before drying off. Data collection included examination of the tail tip for tail tip lesions (TT), annular lesions (AN), hyperkeratosis (HK), swelling (SW) and axis deviation (AD); pain sensation at the tail tips, body condition score (BCS) of the cow, the locomotion score (LMS) and the somatic cell count obtained from a current California Mastitis Test (CMT). Rectal temperature (BT) was measured and cows were clinically examined with particular attention to ruminal filling (Rum_fill) and intensity of contractions (Rum_int). In addition, a thermographic image of each tail tip was taken to record the maximum (Temp_Max), minimum (Temp_Min) and average temperature (Temp_Ave) of the tail tip. The claws were trimmed and the diagnoses were converted to a claw score (Sum_Claw). Data from the milk performance testing as milk solids (MS), protein % (MP), fat % (MF) and somatic cell score (SCS) were also included in the statistical analysis. Cluster analysis using SAS version 9.4 was performed to identify possible patterns among the variables and resulted in 4 clusters.

Results

The highest coefficient of determination, i.e. the greatest effect on clustering, was Sum_Claw (R²=0.68), followed by Temp_Ave (R²=0.63), Temp_Min (R²=0.60), Temp_Max (R²=0.55) and CMT values by quarter (R²=0.26-0.47). The first cluster stood out with the worst values for CMT and SCS. MP and MF were high due to low MS. Meanwhile, AN, HK and BCS were highest. Rumen values were above average, as were tail tip temperature and the LMS, but Sum_Claw was low. The cluster with the highest Sum_Claw also had the worst LMS, the lowest values for Rum_fill and Rum_int, and the highest values for TT, SW, AD and PS. Tail temperatures were well above average. Milk yield was low and udder health was the second worst of all groups. The cluster with the highest MS, and therefore lowest MF and MP, also showed lowest CMT and SCS. Tail alterations were below average, except for HK. In this group, tail tip temperatures were highest and so were Rum_fill and Rum_int. For the last cluster, the coldest tail tip temperatures were outstanding in contrast to the highest BT. TT, SW, AD were the second highest, while AN and HK were the lowest. In addition, Sum_claw, LMS and Rum_fill and Rum_int had low values.

Conclusions

An important finding was that Sum_Claw and tail tip temperatures strongly influenced cluster categorisation, both of which could have a significant impact on animal health. Furthermore, in cases of udder and claw issues, the tail tips presented the most severe alterations and the lowest temperatures. The tail tips of cows with good performance and minimal health issues remained warm and unaltered. Therefore, the results of this study indicate a correlation between the tail tip and different animal health traits that requires further investigation.

Funding

Parts of this research were funded by the Tönnies Forschung, Rheda, Germany.