There are some things modern medicine does not yet have all figured out, and udder sores certainly seem to be one of those issues. 

The Merck Veterinarian Manual states: “Udder Sores are scientifically known as Necrotic Dermatitis.” The manual defines udders sores as “Moist, foul-smelling, necrotic lesions [defined as dead skin tissue] may be observed in areas of tightly adjacent skin of some animals. In heifers, the lateral aspect of the udder [to the sides] and medial aspect of the thigh are often involved. In this area, the udder is pressed tightly against the leg, resulting in chafing, dermatitis, and necrosis [death of tissue]… The Merck Manual also states, “In multiparous cows, a similar condition, which may be associated with mite infestation, is seen at the anterior portion of the udder between the two forequarters” (retrieved from

While some believe that udder sores may have links to tail mange and mites, others consider the possibility that a type of bacteria called a spirochete is responsible. 

Dr. Forian Ledermann wrote in an April 9, 2005 Dairy Star article, “Current thinking on the cause of the [Udder] Rot is that it is caused by a bacteria called Fusobacterium necrophorum that also causes Foot Rot. There is also strong evidence that the mange mite is responsible for initiating this disease in many cows.” 

Dave Wilson, Dairy Extension Veterinarian, Utah State University, said, “The cause of udder sores, sometimes called udder necrosis, especially in the fore udder, has been reported as Chorioptic mange caused by Chorioptesbovis, the parasitic worm Stephanofilaria, and simply pressure and rubbing.” (Retrieved from 

Dr. Leo Timms of Iowa State University believes that mange and/or mites have nothing to do with udder sores. He said the common reason for udder sores is much simpler: a combination of an irritant and moisture. Timms said sometimes yeast or dermatophilus (a fungus) can be found in the sores but they are not solely responsible. 

“These organisms are often found on farms, but an abraded, irritated, moist situation on the udder sets up an ideal growth situation for the organisms,” he said. 

Even though the definite cause is not know, udder sores seem to be becoming more common, possibly because of the link with irritation caused by sand bedding. In almost every case, moisture and some type of irritant are involved. It is also know that post-freshening edema is a contributing factor.

As many different ideas are behind the cause of udder sores, there are even more ideas on how to treat it. 

The Merck Veterinarian Manual says “The necrotic [dead] skin should be cleaned daily with an antiseptic solution and thoroughly dried. Mild astringents should be applied… The swollen, necrotic area may be treated topically with an approved miticide; however, appropriate milk withholding periods must be observed.”

Utah State University’s Wilson wrote: “Treatments described and advertised include various ointments and gels. Anti-parasitic therapy is not often described as a treatment. However, experience and most recent expert advice suggest that cleaning the sores (usually the easiest way to do this is with a cloth towel) followed by application of a dry powder, usually including talcum, is the best therapy. On some cows, the sores are very frustrating and hard to clear up. They can smell bad enough to make milking unpleasant.”

Dr. Ledermann wrote in his 2005 Dairy Star “From the Cow Doctor” column, “Our goal is to remove all dead tissue crusting and skin sloughing to expose the bacterial field of action ... Every veterinarian probably has a favorite treatment to cure this disease. Here is my favorite. First off, pour-on an approved insecticide on the animal’s back to kill mites and lice … This rids the possibility of mite infestation causing the lesion to fester. Secondly, instead of using disinfectant, soapy water, etc to clean the lesions, I would use a product called Granulex (Pfizer) to spray on the lesion twice daily to digest the dead skin. This could take up to five days but does a nice job of cleaning up the wound because of its digestive enzymes. 

“Once the wound has been cleaned up, there are some choices but I like an ointment from Stewart Labs called Udder Heal. This is a natural healant that promotes healthy skin growth and seems to create a bactericidal environment that is non-irritating. Applying twice a day with a gloved hand seems to work well.”

Ledermann noted not to stop treatment too soon as the lesions will come back aggressively. 

Dr. Timms said, “For years a lot of people would disinfect the sores. If the area was kept disinfected that would sometimes work, but the real key to treatment is keeping the area dry.” 

Timms said using a type of disinfectant that keeps the area dry is essential. “The more moisture that is in there the more that area will fester.”

Timms said the normal protocol used with the Iowa State University herd includes cleaning the area as well as practical, drying the area, and then using a spray disinfectant that will seal in dryness. He notes splashing the disinfectant will not get it to where it needs to go and that a spray is needed.

“People understand anti-bacterial part of it, but they don’t always get the importance of keeping it dry, said Timms.

Timms said products that promote healing can be helpful, but he discourages use of anything oily which will keep the area too moist and cause irritants such as sand or other bedding to stick. 

Charlie Regan who farms with his family at ReganCrest farms near Waukon, Iowa, has developed a treatment protocol that works well for them. He said they take a good dishsoap such as Dawn, and wash out the sores really well, getting the area good and sudsy and then rinsing it off. They do this for about three days, or until the sores stop oozing. 

Regan said they then apply a product such as Integrity’s “udderCARE,” or Udder Heal by Stewart Labs to the sores daily. 

“I think that is the big key to it. The medication [products mentioned] work better and are better for the cow than other treatments.”

ReganCrest milks 550 cows twice daily, and the cows are bedded on kiln-dried sawdust.

Dan Mormann farms with his son Glen near New Vienna, Iowa. They have also developed a good protocol for dealing with udder sores. When sores are discovered they are wiped out with a dry towel and the underbelly of the cow is marked so that all milkers know she is being treated for udder sores. After the area is cleaned they start applying Udder Heal by Stewart Labs. They apply that product at each milking, three times a day, until they clear up. The treatment sometimes can last a month or two, but most do heal up really well, he said.

Mormann noted they tried many different ways of dealing with udder sores, such as hosing off the sores and treating with peroxide, before they decided upon this system which works well for them. 

Ruth A. Bryant , author of Acute& Chronic Wounds (2nd edition, Mosby, Inc. 2000) writes, “Wounds heal best if they have a moist surface. New cells and the components that replace the damaged or missing tissue migrate over the wound surface in an aqueous or water medium. If the wound surface is dry or a tight scab is in place that process is inhibited. One concern with a moist surface on a wound is that it will harbor pathogenic organisms which may have initially caused the wound at least will acerbate the inhibition of the healing process. However, using antibacterial or antiseptic agents on a wound surface will inhibit the growth of new tissue by virtue of the fact that the cidal agents will also kill or inhibit the new mammalian cells. The challenge is to cleanse the wound surface and to prevent re-infection of the site.” 

Unfortunately the ideal healing conditions do not naturally occur on the underbelly of a cow, and sometimes finding the balance between keeping things moist enough to heal and dry enough to prevent the reproduction of yeast, fungi and microorganisms that thrive in damp conditions can be a challenge. 

Dairy farmers should work with their veterinarian to develop a program that works well on their farm.