Thrush (horse)
Thrush is a very common bacterial infection that occurs on the hoof of a horse, specifically in the region of the frog. 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. Horses with deep clefts, or narrow or contracted heels are more at risk of developing thrush. 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. Then, the horse may also react when its feet are picked out, and blood may be seen. Treatment and prevention Treatment for horses with