# Clinical Presentation, Bacteriologic Findings and Possible Risk Factors for Ischemic Teat Necrosis in Cattle—A Case Series

## TL;DR

This study explores the causes and clinical signs of ischemic teat necrosis in dairy cows, finding that it involves both infectious and non-infectious factors.

## Contribution

The study identifies specific pathogens and risk factors for ischemic teat necrosis in dairy cows, highlighting its multifactorial nature.

## Key findings

- Treponema spp. and Staphylococcus aureus were significantly more prevalent in affected teats.
- First- and early-lactation heifers are particularly at risk for ischemic teat necrosis.
- Non-infectious factors like pre-damaged teats and milking practices contribute to the condition.

## Abstract

This study addresses ischemic, i.e., oxygen-deprivation-induced, teat necrosis in dairy cows, a disease that causes significant economic and animal welfare problems in the dairy industry. The aim was to investigate the clinical presentation, possible risk factors, and microbial involvement in teat necrosis. The necrosis can be recognized by an initial reddish-bloody change from the teat to the base of the udder and the eventual development of dead, dark areas and even loss of the teat, usually caused by licking by the cow. In addition to the visual change, severe itching is a particularly noticeable clinical sign. The researchers analyzed milk and swab samples from affected cows and collected questionnaires from farmers and veterinarians. The study revealed that ischemic teat necrosis predominantly affects first- and early-lactation heifers and identified infectious pathogens such as Treponema spp. and Staphylococcus aureus as well as non-infectious factors such as pre-damaged, chapped, dry, or thickened teats and certain milking factors as contributors. The results suggest that the necrosis has a multifactorial cause, combining both infectious and non-infectious factors. Understanding these factors is critical to the development of prevention and treatment strategies that aim to reduce the economic impact and improve animal welfare.

Ischemic teat necrosis (ITN) is a growing problem in the dairy industry characterized by teat lesions, necrosis, pruritus and automutilation. Despite the economic and welfare consequences, there is no treatment, and the etiology of the disease remains poorly understood. The aim of this study was to investigate ITN by analyzing its clinical presentation, potential risk factors and microbial involvement. Methods included collection of milk and swab samples from affected cows over a period of one-and-a-half years and completion of questionnaires by veterinarians and farmers. Microbial testing included PCR testing for Treponema spp. and cultural testing by anaerobic and aerobic incubation on blood agar. The results showed a high and significant prevalence of Treponema spp. and Staphylococcus aureus in affected teats compared to non-ITN-affected control teats, indicating their potential role in the development of ITN. Other factors such as edema and milking practices also appear to contribute to the tissue damage. First-lactation and early-lactation heifers are particularly at risk. In conclusion, ITN appears to have a multifactorial etiology with both infectious and non-infectious factors playing a role. Further research is needed to better understand the complex interplay of these factors and to develop effective prevention and management strategies.