Prof. Dr. Christine Schmidt

Feedlot cattle are frequently affected by inflammation and necrosis of the tail tips, resulting in impeded animal welfare and economic losses. In a recent study it was demonstrated that dairy cows are also affected by different lesions of the tail tip, among others alopecia, annular constrictions, crusting, scaling and swelling. Despite the frequent occurrence of these lesions, the underlying etiology and pathomechanisms are unclear to date. To gain insight into this malady, we histopathologically examined 16 tail tips of slaughtered dairy cows, representing the entire bandwith of different lesions. While macroscopically alopecic areas were characterized by the formation of granulation tissue in the dermis with unconspicuous epidermis, we found not only dermal granulation tissue but also purulent-necrotizing inflammation with breakdown of the basement membrane in encrusted lesions. Interestingly, in some cases we found herds of coagulation necrosis of epidermal and dermal layers in the crusts. Tails with macroscopical scaling were affected by ortho- and/or parakeratotic hyperkeratosis and in tails with macroscopical swelling, we observed a low-protein edema of the central longitudinal connective tissue of the tail. We conclude that the observed lesions might be caused by ischemia of the skin in distal parts of the tail.

The welfare of dairy cows is becoming increasingly important. While diseases like mastitis and lameness are common ailments, injuries to the tail tip go largely unnoticed. The study aimed at investigating whether tail tip lesions, which are mostly described in beef cattle, also occurred on n = 5 dairy farms and, if so, what type and frequency? The study consisted of two phases. During the first part of the study tail tips of 78 dairy cows were examined over a period of six months; based on these results, we developed a training card on tail tip lesions in dairy cows, which was used in part two of the study to train further examiners to inspect four more flocks. In total, we collected n = 3587 tail records from n = 513 Holstein and n = 128 Simmental dairy cows. The overall frequency regarding all types of lesions ranged between 84.0 % (± 2.0) and 94.1 % (± 1.8) in Holstein herds and between 97.0 % (± 2.2) and 99.0 % (± 2.2) in Simmental herds. To our knowledge, this is the first investigation of tail tip lesions in German dairy cows. We concluded that tail tip lesions might be a frequent yet unnoticed condition in German 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 (Rumfill) and intensity of contractions (Rumint). In addition, a thermographic image of each tail tip was taken to record the maximum (TempMax), minimum (TempMin) and average temperature (TempAve) of the tail tip. The claws were trimmed and the diagnoses were converted to a claw score (SumClaw). 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 SumClaw (R2=0.68), followed by TempAve (R2=0.63), TempMin (R2=0.60), TempMax (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 SumClaw was low. The cluster with the highest SumClaw also had the worst LMS, the lowest values for Rumfill and Rumint, 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 Rumfill and Rumint. 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, Sumclaw, LMS and Rumfill and Rumint had low values. Conclusions An important finding was that SumClaw 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.FundingParts of this research were funded by the Tönnies Forschung, Rheda, Germany.

Objectives In our previous work, we observed a variety of tail tip lesions in dairy cows, which we classified into 7 different clusters. Prevalences of severe lesions such as bleeding or necrotic tail tips reached up to 26 %. These results might indicate that we are dealing with an animal health and welfare issue that has gone unnoticed by now. In fattening cattle, histopathological examination of affected tails led to the presumption that the observed lesions might be caused by cutaneous ischemia. The objective of this study was therefore to find out which histopathological changes underlie the different tail tip lesions in dairy cows in order to contribute to a better understanding of this malady. Material and methods We collected 16 tails of dairy cows of different breeds (Holstein Friesian, Simmental, Brown Swiss and crossbreeds between beef- and dairy breeds) at a slaughterhouse in South Germany after slaughtering. The tail tips were selected to cover all types of macroscopically visible lesions that we have observed in previous studies. Selected samples originated from cows aged two to ten years. After collecting, the tails were packed on ice during the one hour transport. Immediately after arrival, tail tips were shorn, washed, photo documented and examined macroscopically. For histopathological examination, observed lesions were fixed in 10 % buffered formalin for at least four days. Subsequently, all samples were embedded in paraffin, processed routinely for histologic examination, and stained with hematoxylin and eosin (H&E). Selected sections were also stained with periodic acid Schiff reaction (PAS) or Masson-Goldner trichrome for examination of connective tissue. The slides were examined using light microscopy. Results In all cases of macroscopically visible constrictions as well as in hairless areas of the tail tips we found dermal granulation tissue of different age stages that extended to the central longitudinally arranged connective tissue of the tail. In six out of ten tail tips with macroscopically visible annular constrictions, the epidermis was without any particular finding. In the other four cases, we found inflammation of the epidermis with underlying cell-rich granulation tissue. The epidermis of samples showing alopecic tail tips was either free from pathological findings or showed signs of orthokeratotic hyperkeratosis. In tail tips macroscpically exhibiting hyperkeratosis, we observed predominantly orthokeratotic and partly also parakeratotic hyperkeratosis. In one macroscopically unremarkable tail, histological examination also revealed hyperkeratosis. Tail tips with macroscopically visible swelling of the central longitudinal connective tissue were histologically characterized by extracellular and low protein edema. Intracellular edema could be observed in the marginal areas of constrictions with bloody encrustations and in hairless areas. In tail tips which showed macroscopically visible thinning, all layers of the tail were reduced in thickness. Only in one tail tip, we found a concrete thinning of the dermis on only one side of the tail distal to a constriction. Another frequent histopathological finding was the partly focal, partly diffuse hyperemia of the papillary bodies in the dermis, which was found in ten samples. We observed hyperemia in areas affected by hyperkeratosis and in annular constrictions, but also in macroscopically unconspicuous tail tips, in hairless areas and in tail tips showing hyperkeratosis or necrosis. In some cases, the hyperemia was accompanied by free erythrocytes, whereas no accumulation of inflammatory cells could be detected in these areas. Conclusions Our histopathological examination of tail tip lesions in dairy cows revealed amongst others granulation tissue formation, ortho- and parakeratotic hyperkeratosis and hyperemia of the papillary bodies with free erythrocytes. These results resemble those found in fattening cattle. Based on the macroscopical and histological appearance of the lesions, trauma as the sole cause seems unlikely. Future research is required to clarify the underlying etiology and to determine risk factors associated with the observed lesions.FundingParts of this research were funded by the Tönnies Forschung, Rheda, Germany.

Objectives Tail tip lesions have been observed in fattening cattle with prevalences varying from 35 % to 76 %. These lesions include hairless areas of the tail tip, laceration and / or infection leading to inflammation of larger parts of the tail as well as necrosis. This often results not only in economic loss but has also adverse effects on animal health and welfare. While there are several studies on this issue in fattening cattle, data on tail tip lesions in dairy cows are scarce. However, own previous studies have shown that a variety of lesions on the tip of the tail also occur in dairy cows. The objective of this study was to investigate the prevalence of tail tip lesions in dairy cows. Material and methods A developed overview of different tail tip lesions in dairy cows and their manifestations was used to examine cows on six different German dairy farms. After shaving the tail in the region of the switch, cows were examined for the prevalence of 1) lesions on the very tip of the tail, 2) annular lesions, 3) hyperkeratosis, 4) swelling, 5) axis deviation, 6) thinning or 7) fibroma on the distal part of the tail. Examination was performed by one single person. All cows were kept in loose housing conditions on slatted or solid floors, with or without automatic scrapers. Herd sizes varied between 51 and 162 cows. A total of 500 Simmental or Holstein Friesian dairy cows were examined. To calculate the prevalence per lesion, the number of animals affected by the corresponding lesion or lesion manifestation was divided by the total number of animals examined. Mean prevalences were calculated per farm and for the total sample. Results Only one cow, out of all 500 examined cows, was free from the above mentioned lesions. 499 animals, however, were affected by at least one lesion. The most prevalent lesions were hyperkeratosis, ranging from 72.9 % to 97.3 % between herds (mean prevalence = 85.1 % ± 7.9) and swelling, with prevalences between 54.2 % and 95.9 % (mean prevalence = 73.4 % ± 18.3). Every lesion could be observed in every herd. The most severe manifestations of lesions at the very tip of the tail, according to our previously established overview, are bleeding or necrosis up to part loss of the distal part of the tail. We found bleeding or necrotic tail tips in four of the six farms, with prevalences ranging from 0.66 % to 26.03 % (mean prevalence = 8.36 % ± 11,39). Conclusions To our knowledge, this is the first study to show prevalences of different tail tip lesions in Simmental and Holstein Friesian cows on German dairy farms. The high prevalence of the lesions in all farms evaluated, under different housing conditions and in both breeds, and the occurrence of severe manifestations such as bleeding or necrotic tail tips, may indicate an animal welfare problem that has apparently gone unnoticed until now. Further research is needed to assess whether this phenomenon occurs on other farms and in different regions and countries as well, and to elucidate the aetiology, pathogenesis and risk factors of the lesions observed.Funding: Parts of the research wer funded by the Tönnies Forschung, Rheda, Germany