Local and Systemic Inflammation in Finnish Dairy Cows with Digital Dermatitis

Area of Science:

• Veterinary Dermatology
• Immunology
• Pathology

Background:

• Digital dermatitis is a significant cause of lameness and welfare issues in dairy cattle.
• Understanding the inflammatory response is crucial for managing this disease.

Purpose of the Study:

• To assess local and systemic inflammatory responses in dairy cattle with digital dermatitis.
• To compare macroscopic and histological findings with inflammatory markers.
• To develop a novel histopathological grading system for digital dermatitis lesions.

Main Methods:

• Macroscopic evaluation of 104 dairy cow feet.
• Histological examination of skin biopsies.
• Serum analysis for acute phase proteins (serum amyloid A, haptoglobin) and pro-inflammatory cytokines (interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha).

Main Results:

• Cows with active and non-active digital dermatitis lesions showed higher serum interleukin-1 beta levels compared to healthy cows.
• Lesions with necrosis had significantly higher interleukin-1 beta concentrations.
• No significant differences were observed in other cytokine or acute phase protein concentrations between healthy and affected cows.
• A novel histopathological grading system was developed, correlating lesion severity, necrosis, ulceration, and spirochete presence.

Conclusions:

• Digital dermatitis activates pro-inflammatory cytokines, notably interleukin-1 beta.
• The inflammatory response does not appear to trigger systemic acute phase protein release.
• The developed histopathological grading system aids in understanding disease progression, with spirochetes potentially being secondary invaders in necrotic lesions.