10/13/2021
What is Thrush?
Thrush is an anaerobic bacterial and sometimes fungal infection that causes destruction of the horse’s frog and hoof tissue. The commonly associated organisms are Fusobacterium necrophoru and Spherophorus neaophorus. These organisms eat away and kill the frog and hoof tissue. Thrush typically affects the central and lateral sulcus of the frog of the horse’s foot. The central sulcus is more commonly involved if the horse has sheared heels; the lateral sulci are primarily involved in most cases of thrush. Thrush is a somewhat common condition, but it should not be taken too lightly. If left untreated, it can make its way into the delicate structures of the hoof. If this happens it can cause temporary to permanent lameness. In severe cases thrush can invade the white line, sole, and sensitive layers of the foot.
How do you identify it?
It’s black and it stinks
SMELL: Thrush has an easily recognizable, strong-smelling, foul odor.
APPEARANCE: Thrush looks like thick, black, putty-like, or tar-like material on and in the frog and the collateral and central sulci. The borders of the frog are commonly necrotic (dead) from the thrush infection. Most horses with mild cases of thrush are not lame, but if the infection is severe and invades the sensitive layers of the foot, then cleaning and manipulating the frog can cause pain.
What Causes it?
Several possibilities!
Environment, Conformation, Exercise, Diet
Environment: Thrush organisms thrive in moist, dirty environments. Poor stall hygiene (wet, dirty stalls), and muddy conditions attribute to the likelihood of your horse developing thrush. Water alone won’t lead to thrush, but moisture combined with a dirty pen creates prime conditions for thrush.
Conformation: Deep, narrow frog clefts and, upright or contracted heels can leave a horse more vulnerable to a thrush infection. Abnormal hoof growth or lack of regular trimming can result in your horse’s feet becoming infected with thrush. Improper trimming or shoeing resulting in unbalanced feet can also leave your horse to being more vulnerable to thrush.
Exercise: Lack of exercise. Movement/exercise is thought to help “clean out” the sulci. In the normal hoof, continuous movement prevents the build of dirt and muck in the bottom of the hoof that can lead to thrush. When the horse bears weight on the leg, the coffin bone descends, causing the sole to flatten. As the coffin joint descends the navicular bone moves towards the ground. This movement pushes against the navicular bursa and the deep flexor tendon, resulting in the frog expanding as it approaches the ground surface. Essentially pushing out any packed in material. Impairment of this hoof cleaning mechanism appears to be a leading cause of thrush. Thrush is seen in a large percentage of horses that live in primarily in stalls. When horses are confined to a stall, they are not able to “self-clean” their hooves.
Diet: Nutritional deficiencies leave horses more susceptible to thrush infections and can make it challenging for them to fight and recover from thrush. Zinc and Copper deficiencies are linked to higher rates of thrush cases. High iron levels can present many problems for horses including the canceling of absorption of copper and zinc. Finding the correct nutritional balance can help your horse be healthy comes from the inside, out. More in depth information about the importance of copper and zinc:
"Copper supports enzymes that form the strengthening cross-links between collagen and elastin molecules in connective tissue. Deficiencies lead to abnormalities in bone, cartilage, tendons, ligaments, and arterial walls among the most dramatic consequences. In horses, copper deficiency has been linked to uterine artery rupture in mares, a fatal complication of labor. Copper deficiency is known to cause developmental bone disease in foals. From research in other animals, we also know that copper deficiency has adverse effects in hair quality. Although it hasn't been studied in horses, remember that the ingredients and growth mechanisms for hair and the hoof are virtually identical. Zinc performs a host of functions in the body. Structures on proteins called zinc fingers allow them to bind to DNA. Zinc fingers also influence the folding and structure of proteins. In enzyme systems, zinc is essential for pigment formation, antioxidant function, transport of carbon dioxide in the blood, bone building and remodeling, insulin production and release among others." Eleanor Kellon, VMD
"Excess iron cancels the absorption of copper and zinc- even if there is an "adequate" amount of those minerals available. Excess iron has many effects, including predisposition to infection, a predisposition to arthritis and increased risk of tendon/ligament problems, liver disease and altered glucose metabolism, including insulin resistance and overt diabetes." Eleanor Kellon, VMD
Treatment:
Prevention beats treatment any day. Balanced diet, Balanced farrier work, keeping feet picked out, A Clean pen and Plenty of turnout or exercise.
BUT IF YOU are Fighting an infection here are some suggestions
Treatment can be relatively easy and inexpensive, especially if caught early. There are many commercial products available from your local feed store which include: Kopertox, No Thrush Powder and Thrush Buster.
IF you want to skip the Brand Name products here is a simple and effective treatment option as well:
A.) Treat thrush with a germ-killing product, such as iodine or a bleach-and-water mix, diluted 50-50. Get a bucket of water, add the bleach or iodine, scrub the frog and sole with a brush, then let the hooves dry. Then apply Destin (diaper rash cream) into crevasses of frog.
B.) Apply Today or Tomorrow (mastitis cream for cows) to the affected area. The application tube has a tip that makes it easy get it deep in the cracks where thrush lives. Just sq**rt it in and pack with some cotton balls to keep it in place longer.
*You should treat thrush once a day for the first week, every other day for the second week, every third day for the third week, every fourth day for the fourth week, and then leave it alone for two weeks. *
As with any hoof or health issue, if you have questions or concerns, don’t hesitate to call in your farrier or veterinarian.
