Summer Mastitis Prevention in Cattle

Summer mastitis is a painful bacterial infection of dry cows and heifers caused by fly transmission, and prevention through fly control and teat management significantly reduces animal suffering.

Key Facts

Summer mastitis is caused primarily by Trueperella pyogenes transmitted by the head fly Hydrotaea irritans
The infection causes severe acute mastitis with quarter loss, systemic illness, and high welfare impact
Dry cows and heifers at pasture in late summer are most susceptible as they cannot be milked to monitor infection
Prevention includes fly repellent Stockholm tar, post-dipping dry cow therapy, and daily vigilance
Early treatment with antibiotics can save the quarter if initiated before severe tissue destruction occurs

Welfare Considerations

Summer mastitis causes intense pain - the affected quarter rapidly develops severe infection with pus, systemic fever, and toxemia in some cases. Early detection is challenging in dry cows that are not being handled daily for milking. The welfare solution is prevention-focused: minimizing fly burden through targeted repellents, careful teat seal management, and daily monitoring of at-risk animals during the high-risk late summer period.

What You Can Do

Apply Stockholm tar or other fly repellents to dry cow teats during the high-risk summer period
Inspect dry cows and heifers daily for early summer mastitis signs - swollen quarters and systemic illness
Move dry cattle away from fly-prone areas such as woodland edges if possible
Work with your vet on preventive internal teat seal placement for high-risk animals
Seek veterinary treatment immediately if summer mastitis is suspected - early treatment saves quarters