[Summer mastitis: pathogenesis, losses, incidence and prevention]

Area of Science:

• Veterinary Microbiology
• Insect-borne Diseases
• Bovine Health

Context:

• Summer mastitis is a significant economic concern for cattle farmers, causing substantial annual losses.
• The incidence of summer mastitis fluctuates annually and monthly, with a notable correlation to soil type (sandy, peat, clay).
• The bacterium Corynebacterium pseudotuberculosis (C. pyogenes) is a key pathogen, often isolated with other bacteria, particularly anaerobes.

Purpose:

• To review and evaluate current and potential prevention and treatment strategies for summer mastitis in cattle.
• To identify the primary vector and contributing environmental factors associated with summer mastitis outbreaks.
• To assess the efficacy of various control measures, including repellents, vaccines, antibiotics, and treatment protocols.

Summary:

• The Hydrotaea irritans fly, also known as the 'sheep head fly,' is identified as the principal vector for summer mastitis.
• Prevention methods like fly repellents and teat protectants show moderate success, while synthetic pyrethroids offer long-term potential.
• Vaccine efficacy for C. pyogenes has been disappointing; however, long-acting antibiotics and a specific dry cow treatment regimen (repeated twice) show promising results for disease control.

Impact:

• Effective management of summer mastitis can significantly reduce economic losses in the cattle industry.
• Understanding the role of Hydrotaea irritans and environmental factors aids in targeted prevention efforts.
• Implementation of recommended treatment protocols, particularly for dry cows and yearlings, can improve herd health and productivity.