FROM THE FARM REPORT: RETHINKING WHITE LINE DISEASE: EVIDENCE SHOWS HIDDEN BACTERIAL CULPRIT AT WORK

White line disease (WLD) continues to be one of the more frequent and costly hoof problems on our dairy as well as many other dairies. It involves separation of the hoof wall from the sole, which can lead to a lesion, hemorrhage or abscess often in the outer rear claw. It has traditionally been viewed as a mechanical lesion caused by shearing forces when turning, poor flooring, or excessive wear or trimming. Last year, we placed heavy, grooved rubber belting on our flooring going from the parlor to our 2004 freestall since the flooring and grooving was less than ideal and likely contributing to some of our WLD problems.

Often the healing of WLD is slow even when cows receive timely trimming and hoof blocks. The healing may be complicated by an overlooked factor…a secondary infection with Treponema bacteria, the same pathogen involved in digital dermatitis. This connection offers some insights for both treatment and prevention strategies.

A 2025 comprehensive review of WLD in Microorganisms (doi.org/10.3390/microorganisms13092159) highlighted that many problematic cases show a suboptimal response to standard treatments and therapies. The researchers attributed the poor healing, in part, to a secondary infection with Treponema species, which can contribute to inflammation and delayed horn regeneration. If bacteria are invading weakened horn, it provides a biological explanation for why some lesions deepen, abscess, or spread despite quality hoof care. This means that farms with persistent digital dermatitis issues may struggle more with WLD even if their floors, cow traffic, and trimming schedules are well-managed.

The researchers suggested that standard therapeutic recommendation, such as corrective trimming, removing loose or damaged horn, applying a hoof block, and administering NSAIDS as needed remain the foundation of care. In addition, they suggested that in some cases, use of antibiotic therapy is warranted when a secondary bacterial infection is likely.

Prevention remains important. Mechanical forces create the initial lesion. Bacteria worsen it. Addressing both factors give us and other dairies a better change to reduce lameness and improve hoof health. Cow comfort that reduces standing time and stress along with flooring, especially good-quality surfaces that reduce slipping and sharp turns by cows and lessens microabrasions on the hooves continue to be essential. Controlling digital dermatitis through footbaths, hygiene, and early treatment may reduce WLD severity by limiting Treponema exposure. Talk with your hoof trimmer and veterinarian about prevent and treatment strategies that are right for you.

— Heather Dann

dann@whminer.com