Thrush is a very common bacterial infection that occurs on the

hoof The hoof (: hooves) is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits; the ruminants with ...

of a

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 mi ...

, specifically in the region of the

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

. The bacterium involved is'' Fusobacterium necrophorum'', and occurs naturally in the animal's environment—especially in wet, muddy, or unsanitary conditions, such as an unclean stall—and grows best with low

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

. Horses with deep clefts, or narrow or contracted heels are more at risk of developing thrush. The word ''thrush'' is the same term as used for oral candidiasis.“Thrush, N. (2).” Oxford English Dictionary, Oxford UP, July 2023, https://doi.org/10.1093/OED/1201547560.

Symptoms

The most obvious sign of thrush is usually the odor that occurs when picking out the feet. Additionally, the infected areas of the hoof will be black in color (even on a dark-horned hoof), and will easily break or crumble when scraped with a hoof pick. When picking the hooves around thrush areas, the differences between healthy and infected areas can be seen when white or gray tissue (healthy frog) is surrounding a dark, smelly (infected) area. Most horses do not become lame if infected with thrush. However, if left untreated, the bacteria may migrate deeper into the sensitive parts of the hoof, which will result in

lameness A limp is a type of asymmetric abnormality of the gait. Limping may be caused by pain, weakness, neuromuscular imbalance, or a skeletal deformity. The most common underlying cause of a painful limp is physical trauma; however, in the absence ...

. Then, the horse may also react when its feet are picked out, and blood may be seen.

Treatment and prevention

Treatment for horses with thrush includes twice-daily picking of the feet, taking special care to clean out the two collateral grooves and the central sulcus. The feet may then be scrubbed clean using a detergent or disinfectant and warm water, before the frog is coated with a commercial thrush-treatment product, or with iodine solution, which may be soaked into cotton balls and packed into the clefts. Several home remedies are used, such as a hoof packing of a combination of sugar and betadine, powdered

aspirin Aspirin () is the genericized trademark for acetylsalicylic acid (ASA), a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and inflammation, and as an antithrombotic. Specific inflammatory conditions that aspirin is ...

borax The BORAX Experiments were a series of safety experiments on boiling water nuclear reactors conducted by Argonne National Laboratory in the 1950s and 1960s at the National Reactor Testing Station in eastern Idaho.

, or diluted bleach. It is best, however, to speak with the horse's veterinarian, to be sure these home remedies are effective and, more importantly, safe for use on horses. Horses with thrush, or those at risk for contracting it, are best kept in a dry, clean environment. Daily cleaning of the hooves also contributes to the prevention of thrush. In general, thrush is relatively easy to treat, although it can easily return and it can take up to a year for a fully healthy frog to regrow after a severe infection.

References

{{reflist

Symptoms

Treatment and prevention

References

Further reading