Beitrag zur Verbesserung des Tierschutzes und der Tiergesundheit in der Milchviehhaltung durch Untersuchungen zu Prävalenz und Ätiologie von Schwanzspitzenveränderungen bei Milchkühen (TINCa Dairy - Tail Inflammation and Necrosis in Dairy Cattle)

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

Research investigating necrotic tail tips in dairy cows resulting in necrotic tissues is scarce. However, there is evidence that in dairy cattle tail tip necroses exist with high prevalence. In piglets, the latest research described tail and ear necroses not because of tail and ear biting only, but because of swine inflammation and necrosis syndrome (SINS). Besides tails and ears, SINS includes inflammation of claws, heels, and teats. In cattle, tail tip necroses are described mainly in fattening bulls. As known so far, these findings are often discussed related to slatted flooring, intensive housing systems and management strategies. However, an association with subacute rumen acidosis and laminitis is described. In order to investigate what kind of and how often tail tip alterations appear in dairy cattle, data of 87 German Holstein dairy cows were collected over a period of 12 months. All cows were evaluated for tail tip alterations, body condition score (BCS), and locomotion score (LMS) every two weeks. In addition, milk yield data resulting from performance testing were included. Thermographic images of the tails were taken once. Firstly, all kind of tail tip alterations were described and collected. After 6 months, we categorized the observed alterations and developed a tail scoring system. The scoring for each specified trait (tail tip, tail ring) ranged from 0 to 4. The overall prevalence for tail alterations was 94%. Especially tail tip alterations had a constantly high prevalence of 56%. Cows affected by an increased average tail tip score, showed higher locomotion scores compared to others (P = 0.02). The prevalence of ring-like tail alterations increased from first to second lactation cows from 9 to 46%. Regarding the BCS, lighter cows showed higher scores due to ring-like alterations than heavier cows (P = 0.054). The most often occurring anomalies of the tail were sports or scurf (21.6%), followed by verruca-like mass (10.2%), swelling (8.4%), and thinning (4.3%). The results and especially the scoring system can serve as a template for further studies considering larger samples sizes, to investigate prevalence for tail necroses and other tail anomalies in different herds and management systems. It was hypothesized, that an inflammatory condition in dairy cows showing up in altered/necrotic tail tips or rings exists, which is in relationship with claw disorders indicated by lameness. If so, the tail score of a cow could be used as health indicator to evaluate the health status in dairy production systems.

ObjectivesTail injuries and pathological alterations have been reported in many species. In cattle, they were investigatedmainly in fattening bulls and feedlot cattle. In dairy cows high prevalences for different tail alterations werefound. However, aetiology and pathogenesis of this health trait are still unclear and need further investigation.Out of 4443 phenotypes of different tail alterations we assorted seven groups common in dairy cows: 1. verytip of the tail , 2. ring-like, 3. scurf, 4. swelling, 5. thinning, 6. axis anomaly, and 7. verruca-like mass. Theobjective of this study was to identify genomic regions that may influence the occurrence of different tailalterations in dairy cows, which could be useful for a potential implementation of a genomic selection tool formore robust and healthy cows in the future.Material and methodsData collection started in December 2019 from a German 75 German Holstein (HOL) cows dairy herd. All cows wereexamined every two weeks during six months regarding any kind of tail alterations. The findings were described andphotographed. Data analysis resulted in seven different kinds of tail alterations: 1. very tip of the tail, 2. ring-like, 3. scurf,4. swelling, 5. thinning, 6. axis anomalies, and 7. verruca-like mass.Hereinafter, prevalences for the observed tail alterations were calculated based on monthly data collection from fivedifferent dairy herds: 3 HOL herds, counting average herd sizes of 75, 300, and 1300, respectively; 2 German Fleckvieh(FV) herds, counting 60 cows, each. All cows were housed in free stall barns with conventional (HOL, FV) or automaticmilking systems (FV).In total, 4443 Dairy Cows' Tail Scores were recorded. Data preparation and analysis were performed using R version4.1.2. Prevalences for tail alterations were calculated by dividing the number of observations within by the total number ofobservations of each kind of tail alteration and was given in percent. For calculating the total prevalence per breed andfarm, the occurrence of at least one tail alteration counted as an observation, was divided by the total number of cowsunder investigation and given in percent.ResultsThe overall prevalence for any kind of tail alteration was 88% in German Holstein and 99% in Fleckvieh cows; it variedbetween farms from 74% to 99%. Prevalences for HOL and FV regarding alterations of the very tip of the tail were 26%and 71%, ring-like alterations 24% and 30%, swelling 26% and 42%, scurf 55% and 60%, thinning combined with axisanomalies 16% and 21%, and verruca-like mass 10% and 21%, respectively. Number per tail ranged for ring-likealterations and thinning/axis anomalies from 1 to 5 and for verruca-like mass from 1 to 3.ConclusionsDuring this study, high prevalences for different tail alterations in HOL and FV dairy cows were found out. The grouping ofdifferent alterations as described above can be useful to phenotype tail alterations in dairy cows. However, furtherinvestigations regarding pathogenesis, aetiology, and genetics of the observed alterations in dairy cows' tails are neededto understand their origin and impact on animal health and welfare.FundingThis research was funded by the Tönnies Forschung, Rheda, Germany.

ObjectivesTail injuries and pathological alterations have been reported in many species. In cattle, they were investigatedmainly in fattening bulls and feedlot cattle. In dairy cows high prevalences for different tail alterations werefound. However, aetiology and pathogenesis of this health trait are still unclear and need further investigation.Out of 4443 phenotypes of different tail alterations we assorted seven groups common in dairy cows: 1. verytip of the tail , 2. ring-like, 3. scurf, 4. swelling, 5. thinning, 6. axis anomaly, and 7. verruca-like mass. Theobjective of this study was to identify genomic regions that may influence the occurrence of different tailalterations in dairy cows, which could be useful for a potential implementation of a genomic selection tool formore robust and healthy cows in the future.Material and methodsData collection started in December 2019 from a German 75 German Holstein (HOL) cows dairy herd. All cows wereexamined every two weeks during six months regarding any kind of tail alterations. The findings were described andphotographed. Data analysis resulted in seven different kinds of tail alterations: 1. very tip of the tail, 2. ring-like, 3. scurf,4. swelling, 5. thinning, 6. axis anomalies, and 7. verruca-like mass.Hereinafter, prevalences for the observed tail alterations were calculated based on monthly data collection from fivedifferent dairy herds: 3 HOL herds, counting average herd sizes of 75, 300, and 1300, respectively; 2 German Fleckvieh(FV) herds, counting 60 cows, each. All cows were housed in free stall barns with conventional (HOL, FV) or automaticmilking systems (FV).In total, 4443 Dairy Cows' Tail Scores were recorded. Data preparation and analysis were performed using R version4.1.2. Prevalences for tail alterations were calculated by dividing the number of observations within by the total number ofobservations of each kind of tail alteration and was given in percent. For calculating the total prevalence per breed andfarm, the occurrence of at least one tail alteration counted as an observation, was divided by the total number of cowsunder investigation and given in percent.ResultsThe overall prevalence for any kind of tail alteration was 88% in German Holstein and 99% in Fleckvieh cows; it variedbetween farms from 74% to 99%. Prevalences for HOL and FV regarding alterations of the very tip of the tail were 26%and 71%, ring-like alterations 24% and 30%, swelling 26% and 42%, scurf 55% and 60%, thinning combined with axisanomalies 16% and 21%, and verruca-like mass 10% and 21%, respectively. Number per tail ranged for ring-likealterations and thinning/axis anomalies from 1 to 5 and for verruca-like mass from 1 to 3.ConclusionsDuring this study, high prevalences for different tail alterations in HOL and FV dairy cows were found out. The grouping ofdifferent alterations as described above can be useful to phenotype tail alterations in dairy cows. However, furtherinvestigations regarding pathogenesis, aetiology, and genetics of the observed alterations in dairy cows' tails are neededto understand their origin and impact on animal health and welfare.FundingThis research was funded by the Tönnies Forschung, Rheda, Germany.

Vortragstagung der DGfZ und GfT am 21./22. September 2022 in Kiel Auf der Suche nach neuen Phänotypen - Untersuchung zur Prävalenz von Schwanzveränderungen bei Milchkühen K. Schubert, S. Meier, P. V. Kremer-Rücker1 1Hochschule Weihenstephan-Triesdorf, Markgrafenstraße 16, 91746 Weidenbach 1 Einleitung Schwanznekrosen bei Mastbullen wurden bereits in den 1970er Jahren beobachtet und beschrieben. Diese gehen in den meisten Fällen mit einem gestörten Allgemeinbefinden, reduzierter Futteraufnahme und Gewichtsverlust einher. Bei schweren Verläufen weitet sich die Entzündung auf das Rückenmark und andere Organe aus und führt im Extremfall zum Tod durch frühzeitige Schlachtung (Drolia et al., 1991; Heers et al., 2017). Zu den Ursachen wurden bis zum aktuellen Zeitpunkt lediglich Hypothesen verfasst. Dabei werden Betonspaltenböden, mangelnde Hygiene, Trittverletzungen durch Artgenossen sowie Mykotoxine und Strukturmangel in der Ration als Einflussfaktoren angesehen (Dirksen et al., 2006; Heers et al., 2017; Metzner, 2019). Dahingegen ist bei Milchkühen zum aktuellen Zeitpunkt die Datenlage noch gering. 2 Material und Methoden Für die vorliegende Untersuchung wurden die Schwänze von 213 Kühen über einen Zeitraum von zehn Monaten (11.04.2021 bis 20.01.2022) untersucht. Dabei wurden Tiere ausgewählt, welche zwischen dem 01.03.2021 und dem 30.04.2021 gekalbt haben. Die Datenerhebung fand in einer ostdeutschen Milchviehherde mit 1300 Holsteinkühen, jeweils zeitgleich mit der Milchleistungsprüfung (MLP) statt. Hierfür wurden die Schwänze von allen Tieren mit Hilfe eines Tailwell2® geschoren. Im Anschluss daran erfolgte die Beurteilung der Schwänze nach dem Dairy Tail Score von Kremer-Rücker (unveröffentlicht) sowie die Lahmheitsbeurteilung nach Sprecher et al. (1997) und die Körperkonditionsbeurteilung nach Edmonson et al. (1989). Folgende Parameter flossen außerdem mit in die Datenauswertung ein: Laktationsnummer, Melktage, Milchmenge (kg/Tag), Fett-Eiweiß-Quotient (FEQ), Zellzahl (1.000 Zellen/ml), Rasse und Vater. Mit Beginn der Datenerhebung haben außerdem zwei Tinytag Datenlogger installiert und so alle dreißig Minuten Temperatur und Luftfeuchtigkeit aufgezeichnet, woraus der Temperatur-Humiditäts-Index (THI) errechnet wurde. Die statistische Analyse erfolgte mittels Chi²-Test und RStudio Version 2021.09.2. 3 Ergebnisse und Diskussion Veränderungen traten an der Schwanzspitze selbst, aber auch im darüberliegenden Bereich des Schwanzes auf. Hierzu zählten Schuppenbildung, Achsabweichung, ringartige Veränderungen, Schwellung, haarlose bis blutige Schwanzspitzen sowie warzenähnliche Zubildungen (Abbildung 1). Von den insgesamt 213 Einzeltieren im Versuch gab es kein Tier, welches über den gesamten Beobachtungszeitraum frei von Schwanzveränderungen war. Abbildung 1: Arten von Schwanzveränderungen. A: leichte Schuppenbildung und Achsabweichung, B: starke Schuppenbildung, C: Warzenähnliche Zubildung, D: haarlose Ringe, E: Ringeinschnürung, F: blutiger Ring, G: haarlose, geschwollene Schwanzspitze, H: geschwollene, nekrotische Schwanzspitze Für die Veränderung „Schuppen“ konnte im Versuch die größte Prävalenz (51,95 %) ermittelt werden, während „Verdünnungen“ am seltensten vorkamen (0,19 %). Gleichzeitig war der Bereich 15 bis 20 cm oberhalb der Schwanzspitze am häufigsten (41,57 %) von Veränderungen betroffen. Die Prävalenz von Schuppen war in der ersten Laktation (P < 0,05) und im ersten Laktationsdrittel (P < 0,01) am größten und nahm mit steigender Tagesleistung zu (P < 0,05). Gleichzeitig traten Schuppen vermehrt bei einem FEQ unter 1 und über 2 auf (P < 0,05). Dahingegen kamen Ringartige Veränderungen mit steigendem Laktationstag (P < 0,01) häufiger vor. Schwellungen gingen mit steigender BCS-Note zurück (P < 0,01) und wurden in der ersten Laktation am seltensten erfasst. Allerdings stieg deren Prävalenz bei einer somatischen Zellzahl ≥ 800.000 Zellen/ml (P = 0,05). Des Weiteren bestand ein statistisch signifikanter Zusammenhang zwischen Schwanzveränderungen und der Rasse sowie des Vaters der Tiere, was auf einen genetischen Einfluss schließen lässt. Schuppen oder Hyperkeratosen wurden bei Mastbullen ebenfalls verzeichnet. Hier treten diese zu Beginn der Veränderung auf (Drolia et al., 1991; Hofmann, 2005; Dirksen et al., 2006; Ural et al., 2007; Kordowitzki, 2015; Salib und Farghali, 2016; Freitag et al., 2017; Metzner, 2019). Dabei erscheinen Schuppen dann, wenn die Haut und deren umliegendes Gewebe nicht mehr vollumfänglich durchblutet wird. Je länger dieser Zustand anhält, umso schlechter wird die Haut mit Nährstoffen versorgt, was schlussendlich zu einer Nekrose führt (Drolia et al., 1991; Kordowitzki, 2015). Dahingegen gehören Schwellungen zu den klassischen Entzündungszeichen und gehen mit einer Erweiterung der Blutgefäße in Folge der unspezifischen Immunabwehr einher (Reiner, 2015). Mastbullen wiesen dieses Merkmal ebenfalls auf, wobei die Autoren den Grund hierfür in einer Infektion bereits verletzter Haut sehen (Dirksen et al., 2006; Thomson et al., 2007; Salib und Farghali, 2016). Beim Schwein wurden jedoch Entzündungsanzeichen am Schwanz erfasst, obwohl die betroffenen Tiere eine nachweislich unverletzte Epidermis hatten. Die Autoren sehen dies als Hinweis auf eine endogene Erkrankung an (Reiner et al., 2021). Beim Rind wird auch der Einfluss von Endotoxinen, resultierend aus Pansenacidosen, diskutiert (Freitag et al., 2017; Heers et al., 2017). So ruft bei Milchkühen ein zu geringer Strukturanteil in der Ration, gepaart mit dem Energiedefizit und Stress in der Transitphase klinische und subklinische Pansenacidosen hervor (Wilken, 2003; Heers et al., 2017; Stein, o. D.). Sinkt daraufhin der pH-Wert im Pansen sterben gram-negative Bakterien der Pansenflora ab, wodurch Lipopolysaccharide (LPS) als Zerfallsprodukt zurückbleiben (Monteiro und Faciola, 2020). Befinden sich LPS im Blutkreislauf, lösen diese eine Immunantwort mit Entzündungsreaktion im Körper aus. Um einer weiteren Ausbreitung der LPS entgegenzuwirken werden die Kapillaren im Gewebe verschlossen (Reiner, 2015). Die reduzierte Durchblutung führt jedoch sowohl bei Schweinen als auch bei Rindern zu Schwanznekrosen (Harlizius und Hennig-Pauka, 2014; Reiner, 2015, Heers et al., 2017; Stein, o.D.). Ferner wird das Allgemeinbefinden betroffener Tiere gestört, was wiederum eine reduzierte Futteraufnahme und Leistungseinbruch zur Folge hat (Wilken, 2003). Diese Studie liefert daher Hinweise, dass sich das Schwanzende von Kühen als neuer Phänotyp zur Bewertung und zur züchterischen Verbesserung der Tiergesundheit bei Kühen eignen könnte. 4 Literatur Dirksen, G., Gründer, H., Stöber, M. (2006): Innere Medizin und Chirurgie des Rindes, 5. Auflage, unveränderter Nachdruck der 4. Auflage, Parey in MVS Medizinverlage Stuttgart GmbH & Co. KG, Oswald-Hesse-Str. 50, D-70469 Stuttgart. Drolia H., Luescher, U. A., Meek, A. H., Wilcock, B. P. (1991): Tail tip necrosis in Ontario beef feedlot cattle, Can Vet J, 32:23 – 29. Edmonson, A. J., Lean, I. J., Weaver, L. D., Farver, T., Webster, G. (1989): A Body Condition Scoring Chart for Holstein Dairy Cows, J Dairy Sci 72, 1:68-71. Freitag, M., Heers, P. A., Beune, H. (2017): Schädigt falsche Fütterung die Schwanzspitzen? top agrar, 9/2017, 26-28. Harlizius, J., Hennig-Pauka, I. (2014): Farbatlas Schweinekrankheiten. Eugen Ulmer KG, Wollgrasweg 41, 70599 Stuttgart (Hohenheim). Heers, P., Beune, H., Freitag, M. (2017): Schwanzspitzennekrosen, Weil sich die Mastbullen bei enger Haltung auf den Schwanz treten? AVA Haupttagung 2017, in Nutztierpraxis Aktuell, 84 – 88. Hofmann, W. (2005): Rinderkrankheiten – innere und chirurgische Erkrankungen, 2. Auflage, Eugen Ulmer KG, Wollgrasweg 41, 70599 Stuttgart (Hohenheim). Kordowitzki, P. (2015): Untersuchungen zum Auftreten der Schwanzspitzennekrose bei Mastbullen. Inaugural-Dissertation, Freie Universität Berlin. Kremer-Rücker, P. V. (2021): Dairy Tail Score. Persönliche Mitteilung. Metzner, M. (2019): Schwanzspitzennekrose / Schwanzspitzenentzündung. Klinik für Wiederkäuer, Ludwig-Maximilians-Universität München, URL: https://www.rinderskript.net/skripten/b7-1.html (abgerufen am 16.02.2022). Monteiro, H. F., Faciola, A. P. (2020): Ruminal acidosis, bacterial changes, and lipopolysaccharides. J Anim Sci, 98, 8:1–9. Reiner, G. (2015): Krankes Schwein – kranker Bestand. Eugen Ulmer KG, Wollgrasweg 41. 70599 Stuttgart (Hohenheim). Reiner, G., Kühling, J., Löwenstein, F., Lechner, M., Becker, S. (2021): Swine Inflammation and Necrosis Syndrome, (SINS). Animals, 11, 1670. Salib, F. A. und Farghali. H. A. (2016): Epidemiological, therapeutic and surgical studies on Tail necrosis in Egypt. Inter J Vet Sci, 5/2: 58-6 Sprecher, D. J., Hostetler, D. E., Kaneene, J. B. (1997): A lameness scoring system that uses posture and gait to predict dairy cattle reproductive performance, Theriogenology 15;47(6): 1179-87 Stein, M. (o. D.): Endotoxine: Ein Problem von ungeahnter Tragweite. Fakten für die Tierproduktion von Boehringer Ingelheim. URL: https://www.tiergesundheitundmehr.de/endotoxine.pdfx (abgerufen am 15.04.2022) Thomson, D. U., Taylor, W., Noffsinger, T., Christopher, J. A., Wileman, B. W., Ragsdale, J. (2009): Case Report – Tail Tip Necrosis in a Confined Cattle Feeding Operation. The Bovine Practitioner, 43, 1:18-22. Ural, K., Alic, D., Karakurum, M. C., Aktas, M. S., Haydardedeoglu, A. E., Cingi, C. C. (2007): Tail-Tip Necrosis in Beef an Dairy Cattle: A Report of Seven Cases in Ankara. Kafkas Üniv Vet Fak Derg, 13 (2):203-207. Wilken, H. (2003): Endotoxin-Status und Antioxidative Kapazität sowie ausgewählte Stoffwechselparameter bei gesunden Milch- und Mutterkühen. Inaugural-Dissertation. Veterinärmedizinische Fakultät der Universität Leipzig.

Vortragstagung der DGfZ und GfT am 21./22. September 2022 in Kiel Analyse der bei Deutschen Holstein Kühen mit Schwanzläsionen assoziierten Kandidatengene L. Volkert, S. Meier, K. Schubert, P.V. Kremer-Rücker1 1Fakultät Landwirtschaft, Lebensmittel und Ernährung, Hochschule Weihenstephan-Triesdorf, 91746 Weidenbach 1 Einleitung Verschiedene Aspekte des Tierwohls rücken seit einiger Zeit mehr und mehr in den Fokus. Zahlreiche neue und alte Label sollen die Transparenz im Markt für den Verbraucher in Bezug auf das Wohlergehen der Tiere erhöhen. Hierzu zählt inzwischen auch die Kennzeichnung der Haltungsform. Gerade die Laufstallhaltung beim Milchvieh mit allen Vor- und Nachteilen wird in Zukunft eine wichtige Rolle spielen. Ein bereits lange beschriebenes Problem auf perforierten Böden mit frei laufenden Tieren sind. Schwanzspitzennekrosen. Diese treten z.B. bei Masttieren häufiger auf Vollspaltenböden als in der Anbindehaltung auf (Kordowitzki, 2015). Bei eigenen Untersuchungen an Milchrindern zeigte sich jedoch, dass Veränderungen der Schwänze auch bei diesen Tieren ein häufiges Problem darstellen. Neben den bekannten, entzündlichen Läsionen der Schwanzspitze, konnte eine Vielzahl von unterschiedlichen Veränderungen beobachtet werden (Meier et al., 2021). Laut Literatur spielen als Ursache von Schwanzläsionen Haltungsbedingungen, Haltungsform, Besatzdichte, Management und der Umgang mit dem Tier eine Rolle (Kordowitzki, 2015). Häufig als ursächlich beschrieben werden außerdem Mykotoxine. Dabei wird zwischen dem von Mutterkorn-Alkaloiden ausgelöstem Ergotismus und durch nicht weiter definiertes pilzbelastetes Futter ausgelöste Erkrankungen wie fescue foot oder Deg Nala Disease unterschieden (Cowan, 2020; Rahimabadi et al., 2022). Als dritte potenzielle Ursache kommt die Fütterung in Frage (Freitag et al., 2017). Dabei wird ein ähnlicher Pathomechanismus wie bei SINS (Swine Inflammation and Necrosis Syndrome) vermutet: Acidosen im Pansen oder Dickdarm führen zu einer massenhaften Vermehrung gram (-) Bakterien, die wiederum Lipopolysaccharide (LPS) freisetzen. Diese gelangen durch ein geschwächtes Epithelgewebe in die Blutbahn und sorgen in feinen Blutgefäßen für Durchblutungsstörungen (Plaizier et al., 2012). Ziel der Arbeit war es herauszufinden, ob bei zuvor in Bezug auf Veränderungen des Schwanzes phänotypisierten Deutsch Holstein Kühen genetische Unterschiede bestehen und diese eventuell Hinweise auf eine der potenziellen Ursachen liefern können. 2 Material und Methoden Für die Studie wurden 167 Deutsche Holstein Kühe in Bezug auf die Merkmalskomplexe 1) Schwanzspitzenentzündungen und -nekrosen, 2) Ringartige Veränderungen, 3) Hyperkeratosen, 4) Schwellungen, 5) Verdünnungen, 6) Achsabweichungen, 7) Warzenähnliche Zubildungen untersucht und binär bewertet. Der Genotyp wurde bei 118 Tieren über den Illumina EuroG10k (V5, V7, V8), ein SNP-Chip mit 7k bzw. 10k SNP-Analysepunkten, erfasst und bei 51 Kühen mit dem lllumina EuroG_MD (V1, V1.1, V2). Dieser SNP-Chip erlaubt die Analyse von 45k SNPs, während die Daten der 118 Kühe auf 45.613 SNPs mittels FImpute (Gene Set Enrichment Analysis) imputiert wurden. Für jedes der oben genannten Merkmale wurde separat eine genomweite Assoziationsstudie (GWAS) mittels der Software GEMMA (Zhou & Stephens, 2014) durchgeführt. Innerhalb des univariaten linearen gemischten Modells wurde eine standardisierte Verwandtschaftsmatrix verwendet, die anhand der SNP-Marker berechnet wurde und somit die Populationsstratifikation berücksichtigte. Die Laktation (1., 2., ≥3.) wurde als Kovariate betrachtet. Die Genotyp-Matrix wurde zudem im Modell verwendet und die daraus resultierenden SNP-Effekte wurden mittels Likelyhood-ratio-Test auf Signifikanz geprüft. Die genomweite Signifikanzschwelle von α = 0,05 wurde bei einem -log10(p)-Wert von 5,91 erreicht. Da es sich um eine kleine Stichprobe handelt wurden die Top-Marker bereits ab -log10(p) ≥ 3,5 weiterer Betrachtung unterzogen. Dabei wurde jeweils der höchste Wert unter den einzelnen GWAS für einen SNP herangezogen. In der Linkage Disequilibrium decay Analyse (Laido et al., 2014) wurde ein r² > 0,6 im Abstand von 325 kbp festgestellt. Dieser Abstand wurde zur Kandidatengenanalyse (Positionelle Kandidatengene) verwendet. Die Analyse der Kandidatengene erfolgte auf ENSEMBL (http://oct2018.archive.ensembl.org/Bos_taurus/) mit dem hinterlegten Referenzgenom Bos taurus UMD3.1. Die Kandidatengene wurden auf gemeinsame Funktion in der Zelle und im Organismus mittels Genontologie-Analyse (GO-Analyse) über g:Profiler (https://biit.cs.ut.ee/gprofiler/gost) und String (https://string-db.org) durchgeführt. Einzelne GOen wurden ausgewählt und alle dazu zugeordneten Gene wurden auf deren Funktion in der Zelle und im Organismus überprüft. Hier wurde auch auf Studien anderer Tierarten und des Menschen zurückgegriffen. Zuletzt wurden die oben genannten SNPs mit ihrem Untersuchungsfenster in der AnimalQTLdb (https://www.animalgenome.org/cgi-bin/QTLdb/BT/index) auf bekannte QTL untersucht. Beachtet wurden dabei nur Merkmale, die nicht das Exterieur, die Milchleistung/-inhaltsstoffe oder Fruchtbarkeitskennzahlen beschreiben. 3 Ergebnisse und Diskussion Über alle sieben Merkmale fanden sich 92 zu analysierende Marker damit 682 zugeordnete Gene bzw. 562 Kandidatengene. Beim Merkmal „Verdünnung“ konnten mit 24 SNPs mit -log10(p) ≥ 3,50 die meisten SNPs für die Kandidatengenanalyse festgestellt werden. Zwei Marker für dieses Merkmal überschreiten die genomweite Signifikanzschwelle. Auf BTA5 liegt rs41618168, mit einem Wert von 6,40 für -log10(p). Mit ihm konnte Kandidatengen ADAMTS20 und die Merkmale Zellzahl, Zwillingsgeburten, Trockenmasseaufnahme und Reaktion auf Parasitenbefall über den QTL-Abgleich in Verbindung gebracht werden. Das Gen ist für Fruchtbarkeitsprobleme beim Menschen bekannt. May et al. (2022) untersuchten die Erstlaktationsdaten von ca. 14800 HF Kühen in Ostdeutschland auf Fruchtbarkeitsstörungen. ADAMTS20 ist in dieser Untersuchung ein Kandidatengen für Endometritis des dritten Schweregrads. Auf BTA1 liegt rs42577957 mit -log10(p) = 9,43, es konnte das Kandidatengen TBL1XR1 und die Merkmale Hitzestress und Länge des produktiven Lebens über den QTL-Abgleich mit ihm in Verbindung gebracht werden. TBL1XR1 konnte als einzelnes Gen ebenfalls mit Hitzestress bei HF Kühen und anderen Wiederkäuern assoziiert werden (Carabaño et al., 2016). Durch die GO-Analyse über g:Profiler wurden 23 GO und über String 20 GO in den gleichen Kategorien ermittelt. Über beide Plattformen konnte die GO „lipopolysaccharid binding“ (LPS Bindungsvermögen) identifiziert werden. Die hier gehäuft auftretenden Gene gehören zur Familie der Cathelicidine und werden in der vorliegenden Studie mit dem Marker rs109960160, auf Chromosom 22 und mit dem Merkmal Schwellung assoziiert. Cathelicidine zeigten bei Rindern Wirkung gegen Bakterien, Viren und Parasiten und sind in der Lage Lipopolysaccharide (LPS) zu binden und damit deren Wirkungen zu unterbinden (Flores, 2011). Diese Gruppe ist somit ein Teil der Immunantwort und wird auch in vielen Studien mit Mastitiden in Verbindung gebracht. LPS sind Membranbestandteile von gram (-) Bakterien, die sich z.B. bei einer Pansenacidose stark vermehren können. Dies stellt einen potenziellen Zusammenhang zwischen Fütterung und Veränderungen am Rinderschwanz dar. Tomasinsig et al. (2010) konnten die antimikrobielle Wirkung von Cathelicidinen in vitro bestätigen. Überprüft wurden Vergleichsstämme und Isolate aus Mastitisfällen und damit die Erreger: E. coli, K. pneumoniae, S. aureus, S. epidermidis, Sc. uberis und Sc. agalactiae. Zanetti (2005) gibt einen Überblick über die große Bandbreite von Mikroorganismen, die laut verschiedener Studien durch Cathelicidine bekämpft und abgetötet werden. Dabei wird betont, dass Ergebnisse in vitro aufgrund des komplexen Zusammenspiels verschiedenster Proteine im Organismus oftmals anders ausfallen als die Ergebnisse in vivo. Welche Funktionsweisen der antimikrobiellen Wirkung, besonders gegen gram (-) Bakterien, verwendet werden, zeigen Young-Speirs et al. (2018) in einem Review auf. Dabei ist die amphiphile Natur der Cathilicidine besonders wichtig, da Membranen gram (-) Bakterien selbst auch aus amphiphilen Molekülen aufgebaut sind und so gute Reaktionspartner sind. Insgesamt bieten die analysierten Gene einen Anhaltspunkt dafür, dass genetische Unterschiede einen Einfluss auf Veränderungen der Schwanzspitze haben. Das Krankheitsbild ist zwar nicht geklärt, aber durch die Ergebnisse dieser Arbeit sollten bei weiteren Untersuchungen LPS, Cathelicidine, ADAMTS20 und TBL1XR1 mit betrachtet werden. 4 Literatur Carabaño, M.J., Ramón, M., Díaz, C., et al. 2016: Breeding for resilience to heat stress effects: A comparison across dairy ruminant species. Journal of Animal Science 94 (Suppl_5), 195, DOI: 10.2527/jam2016-0402, Abstract. Cowan, V.E. 2020: Investigation of the subclinical toxicological effects of ergot alkaloid mycotoxin (Claviceps purpurea) exposure in beef cows and bulls. University of Saskatchewan, Dissertation. Flores, E.G. 2011: Characterization of the bovine cathelicidin gene family. Texas A&M University ProQuest Dissertations Publishing, UMI 3486189, Dissertation. Freitag, M., Heers, P.A., Beune, H. 2017: Schädigt falsche Fütterung die Schwanzspitzen?. top agrar 9/2017, R26–R28. Kordowitzki, P. 2015: Untersuchungen zum Auftreten der Schwanzspitzennekrose bei Mastbullen. Freie Universität Berlin, Dissertation, DOI: 10.17169/refubium-15478 . Laido, G., Marone, D., Russo, M.A., et al. 2014: Linkage Disequilibrium and Genome-Wide Association Mapping in Tetraploid Wheat (Triticum turgidum L.). PLoS ONE 9(4), 1–18, DOI: 10.1371/journal.pone.0095211 . May, K., Sames, L., Scheper, C., König, S. 2022: Genomic loci and genetic parameters for uterine diseases in first-parity Holstein cows and associations with milk production and fertility. Journal of Dairy Science 105 (1), 509–524, DOI: 10.3168/jds.2021-20685 . Meier, S., Abel, K., Kremer-Rücker, P.V. 2021: Development of a Tail Scoring as Health Indicator for Dairy Cows. Proceedings of the 44th ICAR Annual Conference virtually held from Leeuwarden, NL 2021 (25), 1-16. Plaizier J.C., Khafipour E., Li S., et al. 2012: Subacute ruminal acidosis (SARA), endotoxins and health consequences. Animal Feed Science and Technology 172 (1-2), 9–21, DOI: 10.1016/j.anifeedsci.2011.12.004 . Rahimabadi, P.D., Yourdkhani, S., Golchin, D., Rad, H.A. 2022: Ergotism in feedlot cattle: clinical, hematological, and pathological findings. Comparative Clinical Pathology 31 (2), 281–291, DOI: 10.1007/s00580-022-03331-7 . Tomasinsig, L., De Conti, G., Skerlavaj, B., et al. 2010: Broad-Spectrum Activity against Bacterial Mastitis Pathogens and Activation of Mammary Epithelial Cells Support a Protective Role of Neutrophil Cathelicidins in Bovine Mastitis. Infection and Immunity 78 (4), 1781–1788, DOI: 10.1128/IAI.01090-09 . Young-Speirs, M., Drouin, D., Cavalcante, P.A., et al. 2018: Host defense cathelicidins in cattle: types, production, bioactive functions and potential therapeutic and diagnostic applications. Review. International Journal of Antimicrobial Agents 51 (6), 813–821, DOI: 10.1016/j.ijantimicag.2018.02.006 . Zanetti, M. 2005: The Role of Cathelicidins in the Innate Host Defenses of Mammals. Current Issues in Molecular Biology 7 (2), 179–196, DOI: 10.21775/cimb.007.179 . Zhou, X., Stephens, M. 2014: Efficient multivariate linear mixed model algorithms for genome-wide association studies. Nature Methods 11 (4), 407–409, DOI: 10.1038/nmeth.2848 .

ObjectivesTail injuries and pathological alterations have been reported in many species. In cattle, they were investigatedmainly in fattening bulls and feedlot cattle. In dairy cows high prevalences for different tail alterations werefound. However, aetiology and pathogenesis of this health trait are still unclear and need further investigation.Out of 4443 phenotypes of different tail alterations we assorted seven groups common in dairy cows: 1. verytip of the tail , 2. ring-like, 3. scurf, 4. swelling, 5. thinning, 6. axis anomaly, and 7. verruca-like mass. Theobjective of this study was to identify genomic regions that may influence the occurrence of different tailalterations in dairy cows, which could be useful for a potential implementation of a genomic selection tool formore robust and healthy cows in the future.Material and methodsOccurrence data of each tail alteration group were collected monthly from 167 German Holstein cows. Thecows originated from a German 1300 cows dairy herd. Data collection was performed from May to December2021, since calving of all included cows was from April to May. The cows were in their first to seventh lactation.The phenotype was encoded binary, where 0 means the absence and 1 the presence of a tail alteration groupwithin the whole timespan.For 118 cows, Illumina EuroG10k genotypes were available and imputed up to 45k (FImpute). The remainingcows were genotyped with the Illumina EuroG MD (V1, V1.1, V2) with 45613 SNPs. After quality check (onlysegregating SNPs, at least two groups with a minimum of 10 observations, no duplicated markers, a minorallele frequency of 1%, and within Hardy-Weinberg-Equilibrium P>0.01), 41062 SNPs remained.A genome-wide association study was performed using the software GEMMA and the univariate linear mixedmodel. Each tail alteration group was treated as a separate phenotype. A standardized relatedness matrix wasincluded in the model and calculated on SNP chip data to consider the population stratification, since manyhalf-sib groups were present. The lactation (1st, 2nd, ≥3rd) was included as covariate. The genotype matrix wasincluded in the model and the effect size per marker was estimated and tested for significance using a Waldtest.For positional candidate gene analysis, genomic regions around top markers (P < 0.0001) of 325kbp wereconsidered,since the linkage disequilibrium decay analysis gave a mean r² of >0.61 within this distance. Themarker positions are given on the ARS-UCD 1.2 Bos taurus genome assembly.ResultsIn total 51 top markers resulted for all seven tail alteration groups, whereof one marker reached Bonferronicorrectedgenome-wide significance threshold for tail alteration group “thinning” (BTA1: rs42577957, −log10(P)= 9.22). The markers were found on 18 different chromosomes. Close to these markers, 65 positionalcandidate genes reside. Among them CCDC122 (rs42421906, −log10(P) = 5.46), which was associated withthe phenotype “scurf” in our analysis. CCDC122 is one of the top differentially expressed genes in livermetabolism in pigs showing swine inflammation and necrosis syndrome (Ringseis et al., 2021). This syndromeresults in severe tail alterations in pigs as well.ConclusionsThis first genetic investigation of tail alterations in dairy cows showed the potential of finding genetic markersfor this novel health trait. Nonetheless, it is recommended to increase the sample size of cows and to furtherinvestigate the cause of tail alterations, to substantiate the reported phenotypes.LiteratureRingseis, R., Gessner, D. K., Loewenstein, F., Kuehling, J., Becker, S., Willems, H., et al. (2021). Swine inflammation and necrosis syndrome is associated with plasma metabolites and liver transcriptome in affected piglets. Animals 11, 1–14. doi:10.3390/ani11030772 Sargolzaei, M., Chesnais, J. P., and Schenkel, F. S. (2014). A new approach for efficient genotype imputation using information from relatives. BMC Genomics 15. doi:10.1186/1471-2164-15-478 Zhou, X., and Stephens, M. (2014). Efficient Algorithms for Multivariate Linear Mixed Models in Genome-wide Association Studies. Nat Methods 11, 407–409. doi:10.1038/nmeth.2848 AcknowledgementWe thank the MASTERRIND GmbH, Verden, Germany, for providing the genotypes from the investigatedcows.FundingPart of the data results from the project TINCa Dairy, which is funded by the Tönnies Forschung, Rheda,Germany.

ObjectivesTail injuries and pathological alterations have been reported in many species. In cattle, they were investigatedmainly in fattening bulls and feedlot cattle. In dairy cows high prevalences for different tail alterations werefound. However, aetiology and pathogenesis of this health trait are still unclear and need further investigation.Out of 4443 phenotypes of different tail alterations we assorted seven groups common in dairy cows: 1. verytip of the tail , 2. ring-like, 3. scurf, 4. swelling, 5. thinning, 6. axis anomaly, and 7. verruca-like mass. Theobjective of this study was to identify genomic regions that may influence the occurrence of different tailalterations in dairy cows, which could be useful for a potential implementation of a genomic selection tool formore robust and healthy cows in the future.Material and methodsOccurrence data of each tail alteration group were collected monthly from 167 German Holstein cows. Thecows originated from a German 1300 cows dairy herd. Data collection was performed from May to December2021, since calving of all included cows was from April to May. The cows were in their first to seventh lactation.The phenotype was encoded binary, where 0 means the absence and 1 the presence of a tail alteration groupwithin the whole timespan.For 118 cows, Illumina EuroG10k genotypes were available and imputed up to 45k (FImpute). The remainingcows were genotyped with the Illumina EuroG MD (V1, V1.1, V2) with 45613 SNPs. After quality check (onlysegregating SNPs, at least two groups with a minimum of 10 observations, no duplicated markers, a minorallele frequency of 1%, and within Hardy-Weinberg-Equilibrium P>0.01), 41062 SNPs remained.A genome-wide association study was performed using the software GEMMA and the univariate linear mixedmodel. Each tail alteration group was treated as a separate phenotype. A standardized relatedness matrix wasincluded in the model and calculated on SNP chip data to consider the population stratification, since manyhalf-sib groups were present. The lactation (1st, 2nd, ≥3rd) was included as covariate. The genotype matrix wasincluded in the model and the effect size per marker was estimated and tested for significance using a Waldtest.For positional candidate gene analysis, genomic regions around top markers (P < 0.0001) of 325kbp wereconsidered,since the linkage disequilibrium decay analysis gave a mean r² of >0.61 within this distance. Themarker positions are given on the ARS-UCD 1.2 Bos taurus genome assembly.ResultsIn total 51 top markers resulted for all seven tail alteration groups, whereof one marker reached Bonferronicorrectedgenome-wide significance threshold for tail alteration group “thinning” (BTA1: rs42577957, −log10(P)= 9.22). The markers were found on 18 different chromosomes. Close to these markers, 65 positionalcandidate genes reside. Among them CCDC122 (rs42421906, −log10(P) = 5.46), which was associated withthe phenotype “scurf” in our analysis. CCDC122 is one of the top differentially expressed genes in livermetabolism in pigs showing swine inflammation and necrosis syndrome (Ringseis et al., 2021). This syndromeresults in severe tail alterations in pigs as well.ConclusionsThis first genetic investigation of tail alterations in dairy cows showed the potential of finding genetic markersfor this novel health trait. Nonetheless, it is recommended to increase the sample size of cows and to furtherinvestigate the cause of tail alterations, to substantiate the reported phenotypes.LiteratureRingseis, R., Gessner, D. K., Loewenstein, F., Kuehling, J., Becker, S., Willems, H., et al. (2021). Swine inflammation and necrosis syndrome is associated with plasma metabolites and liver transcriptome in affected piglets. Animals 11, 1–14. doi:10.3390/ani11030772 Sargolzaei, M., Chesnais, J. P., and Schenkel, F. S. (2014). A new approach for efficient genotype imputation using information from relatives. BMC Genomics 15. doi:10.1186/1471-2164-15-478 Zhou, X., and Stephens, M. (2014). Efficient Algorithms for Multivariate Linear Mixed Models in Genome-wide Association Studies. Nat Methods 11, 407–409. doi:10.1038/nmeth.2848 AcknowledgementWe thank the MASTERRIND GmbH, Verden, Germany, for providing the genotypes from the investigatedcows.FundingPart of the data results from the project TINCa Dairy, which is funded by the Tönnies Forschung, Rheda,Germany.

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 Although inflammation and necrosis of the tail tip has been a well-known problem in fattening cattle for several decades, the etiology of the disease is not fully understood, yet. While some authors hold husbandry conditions such as limited space allotment or slatted concrete floors responsible for the occurrence of tail lesions, other studies point towards a connection with rumen acidosis. Furthermore, tail necrosis has also been described in the context of mycotoxin intake, which leads to vasoconstriction, finally resulting in ischemia. In dairy cows, we observed lesions of the tail, which resemble those described in housed fattening cattle, although husbandry conditions of dairy cows differ from those of fattening cattle. In order to identify possible risk factors, the aim of this study was to investigate whether there are associations between the occurrence of tail tip lesions and selected health and performance parameters in dairy cows. Material and methods For this purpose, we monitored the course of the lesions over 10 months in a German dairy herd consistig of 1,300 cows. The cows were housed on slatted rubber floor in a loose housing system. The cubicles either contained straw manure bedding or were covered with waterbed mattresses. Manure was removed by an automatic scraper system. N = 213 cows that calved within a predetermined period of 2 months were selected for the study to ensure that all cows were at a similar stage of lactation. Number of lactation varied between cows, ranging from one to seven. The sample consisted of 89% Holstein Friesian cows, 10% crossbreds and 1% Brown Swiss cows. Examinations took place at every milk performance testing, starting after calving. One single person assessed tail tip lesions, locomotion score and body condition score of the cows. Number of lactation, days in milk, and data from milk performance testing including milk yield, milk fat:protein ratio and somatic cell count were used for further analysis. The frequencies of the individual tail lesions were calculated by dividing the number of each lesion by the number of all observed lesions. Data were processed using Rstudio version 2021.09.2. Chi2-test and a mixed model procedure were performed for statistical analysis of possible risk factors for the different lesions. Results Over the course of the examination period, every cow was affected by one or several lesions at least once. The examination of n = 213 cows resulted in 4,123 observations. We were able to observe all of the previously described lesions, with varying frequencies, namely: lesions at the very tip of the tail: 8.2 %, annular lesions: 8.5 %, hyperkeratosis: 52.0 %, swelling: 10.7 %, axis deviation: 9.2 %, thinning: 0.2 % and fibroma: 3.7 %. The frequency of tails without any visible lesion was 7.5 %. Regarding the results of the Chi2-test, with the exception of the somatic cell count, all parameters included in this study had a significant influence on at least one lesion. Days in milk significantly influenced all lesions (p < 0.01 or p < 0.001) except of thinnings of the tail. Lactation number had a significant impact on the occurrence of hyperkeratosis (p < 0.05), swellings (p < 0.001), axis deviations (p < 0.01) and fibromas (p < 0.001). Hyperkeratosis and axis deviations were furthermore influenced by milk yield (p < 0.05 and p < 0.001, respectively). Milk fat:protein ratio had a significant impact on hyperkeratosis (p < 0.05) and thinning (p < 0.001). Locomotion score significantly influenced annular lesions (p < 0.05) and axis deviations (p < 0.05), whereas body condition score had a significant impact on the occurrence of swellings (p < 0.001). Conclusions Our results demonstrate that there are multiple associations between tail tip lesions and different health- and performance parameters such as milk yield, locomotion score and body condition score. Based on our results, we conclude that the formation and development of tail tip lesions is a complex, presumably multi-factorial process. Further research is required to examine the individual risk factors in more detail.FundingParts of this research were funded by the Tönnies Forschung, Rheda, Germany.

In fattening bulls tail tip alterations are described as health issues associated with (sub)acute rumen acidosis and lameness. Investigations of dairy cows’ tail tips are scarce; however, there is evidence that tail tip alterations occur as a result of intensive feeding management and metabolic imbalance. In June 2020, we investigated 68 German Holstein cows for tail tip alterations using a handheld thermal camera (FLIR® T1030). Thermal images of the shaved tail tip were taken from two different perspectives: (p1) tail in front of the udder and (p2) held tail in front of the ground. Additionally, all cows were evaluated for any kind of tail tip alterations, body condition score (BCS), and locomotion score (LMS). Milk yield data, resulting from latest performance testing were collected, too. Images were analysed using FLIR Tool+ and a generalised linear model was used to correct measured temperatures for fixed effects. The prevalence of tail tip alterations, regardless the findings, was 94%. Raw temperature data showed high correlations of r² = 0.79 for maximum and average temperature and r² = 0.70 for minimum temperature between p1 and p2 (P < 0.001). Tail tip necroses and BCS > 3 decreased the tail’s temperature, while swelling of the tail tip increased its temperature. Average, maximum and minimum temperatures for perspective 1 and 2 were 34.05 (±0.16) and 33.78 (±0.20) °C, 35.46 (±0.11) and 35.52 (±0.11) °C, and 30.30 (±0.30) and 29.22 (±0.38) °C, respectively. Temperatures of necrotic tissues (n = 4) decreased on average by 8.38 °C compared to the average temperature and were close to the minimum. We concluded thermal imaging can be used for the detection of alterations regarding the tail’s temperature, which could allow an early-warning system for swellings, probably caused by inflammation and possibly resulting in necroses. Further studies are needed to evaluate the praevalence of tail tip alterations in dairy cows on larger samples and to clarify their etiology. However, thermal imaging can be used as an early-warning system for tail alterations. Each early-warning system regarding health issues, improves animal welfare as it allows adapting management strategies early.