As is common every year about this time, I have been getting calls and emails regarding hoof problems producers are seeing in their cattle. Generally, this starts with “I’ve been having several cases of foot rot over the last few weeks” and the follow-up discussion covers potential treatment and prevention.
Cattle Hoof Issues
I think we can all agree that there are few problems as miserable as foot pain. In this cattle are no different than we are. It’s not uncommon to look out across a group of cattle only to see one animal or another limping to some degree? These situations are not unique to any part of the country and there are no singular causes. In some cases this is related to a minor injury, other times it is more serious. Additionally, it’s almost impossible to estimate the countless dollars lost annually by cattle producers in terms of labor, medicine cost, performance and in extreme situations, animal loss.
This article will review this problem and discuss methods to prevent and treat the condition. Aside from simple injuries to the animal’s foot or hoof, foot rot tends to be the largest primary problem although these can be other related conditions that have similar symptoms. Approximately 20% of all diagnosed lameness in cattle is foot rot.
Economically in stocker cattle, weight gain is significantly reduced when grazing cattle contract the disease. In one multi-year study, Brazle (1993) reported that affected steers gained 2.3 lbs. per day, while steers not affected gained 2.76 lbs. per day. This disease is usually sporadic in occurrence, but the disease incidence has been reported as high as 25% in high-intensity beef or dairy production units.
Foot Rot
It is a subacute or acute necrotic (decaying) infectious disease of cattle, causing swelling and lameness in one or more feet. The disease can become chronic, with a poorer likelihood of recovery if treatment is delayed, resulting in deeper structures of the toe becoming affected.
Causes of foot rot can vary. Normally, an injury of some type, mechanical or otherwise occurs or there is a softening and thinning of the interdigital (between the toes) skin by continuous exposure to wet conditions (common in Spring and late Fall). These situations typically create entrance points for infectious agents. A common bacteria, Fusobacterium necrophorum is the organism most commonly isolated from infected feet.
Regardless of the source, once the loss of tissue integrity occurs, bacteria gain entrance into tissues, begin rapid multiplication and produce toxins that stimulate further continued bacterial multiplication and penetration of infection into the deeper structures of the foot.
Spreading of the Disease
Feet infected with F. necrophorum serve as the primary source of infection for other cattle by contaminating the environment. Researchers and veterinarians disagree on the length of time F. necrophorum can survive off of the animal, but estimates range from one to ten months. This means that the condition can crop up again in a given area even after no cattle or no observed cases appear for a period of time.
Signs and Symptoms
While this foot disease occurs in all ages and classes of cattle, the greater incidence is commonly observed during wet, humid conditions. When incidences increase in hot and dry conditions, attention must be directed to areas where cattle gather, which are often crowded and may be wet from urine and feces deposited in shaded areas.
The first signs are lameness, acute swelling of interdigital tissues, and swelling evenly distributed around the hairline of both hoof claws. This follows a growth and development period of the organism over a period of five to seven days. Eventually, the interdigital skin cracks open, revealing a foul-smelling, necrotic material. Untreated, the swelling may progress up the foot to the fetlock or higher. More critically, an infection may invade the deeper structures of the foot and lower leg which can result in more extensive damage to the leg as well as the foot and hoof.
Related Problems
A potential problem is that there are other conditions that can cause lameness in cattle. It can be mistaken for foot rot and would require different treatment. These include interdigital dermatitis, sole ulcers, sole abscesses, sole abrasions, infected corns, fractures, septic arthritis, as well as inflammation or infection of tendons and tendon sheaths. All of which generally only involve one claw of the foot and not the areas of skin or soft tissues between the toes or claws.
Another common foot condition, digital dermatitis (hairy heel warts) is often confused with foot rot. It happens because of foot swelling and severity of lameness. Digital dermatitis affects only the skin, beginning in the area of the heel bulbs. It is progressing up to the area of the dewclaws. Whereas, foot rot lesions occur in the interdigital area and invade the subcutaneous tissues. Cattle grazing endophyte-infected fescue pastures that develop fescue toxicity. This is causing loss of blood circulation to the feet and subsequent lameness. That’s why it is sometimes mistaken as having foot rot.
Treating Foot Rot
Treatment is usually successful, especially when caught and started early. Treatment should always begin with cleaning and examine the foot. It helps to establish that lameness is actually due to foot rot. The most important is not to confuse it with not one of the other conditions discussed. At this point, a topical treatment should be applied. Some very mild cases will respond to topical therapy only. But most cases require the use of a systemic (injectable) antibiotic. There a number of antibiotic products on the market that can be useful. Consult your veterinarian for his recommendation. Since many of these now require a prescription he can provide this as well.
Affected animals should be kept in a dry area until healed. If improvement is not evident within three to four days, it may mean the infection has invaded the deeper tissues. Infections that do not respond to initial treatments need to be re-evaluated by your veterinarian sooner rather than later. He or she will want to determine if re-cleaning, removing all infected tissue, application of a topical antimicrobial, and bandaging are appropriate, along with a different antibiotic.
An Ounce of Prevention
Preventive measures are focused on the prevention of mechanical damage to the foot as caused by frozen or dried mud, shredded weeds or brush (resulting in stubble). It also helps and minimizing the time cattle must spend standing in wet areas. Other preventive measures presently used include the use of footbaths which include Zinc or Copper solutions. Unfortunately, footbaths are not very practical in range cattle situations. Other preventative measures include feeding low levels of chlortetracycline. As well as an addition of organic and inorganic zinc and organic iodine to the feed or mineral mixes.
Feeding of chlortetracycline (CTC) is labeled through the Food and Drug Administration for beef cattle. As discussed above, F. necrophorum is the major infective agent in liver abscesses and foot rot in cattle. CTC is labeled at 350 mg per head per day in beef cattle under 700 lbs. And 0.5 mg per head per day in cattle over 700 lbs., for the prevention of anaplasmosis. Consequently, many mineral mixes and commercial supplements are formulated to provide 350 mg per head per day. It helps to control those diseases listed on the CTC label. Since foot rot is caused by the same organism as liver abscesses, some control of foot rot should occur at the 350 mg per head per day level. As of Jan 1, 2017, the use of CTC in mineral or feed mixes now requires a veterinarian prescription.
Micros
Supplemental zinc may reduce the incidence of foot rot. Improvements have been seen in foot health even when zinc is not deficient in the diet. Even when organic sources are included and overall zinc concentrations in supplements are increased. Zinc is important in maintaining skin and hoof integrity; therefore, adequate dietary zinc should be provided to help minimize foot rot and other types of lameness. In one three-year study, zinc methionine added to a free-choice mineral supplement reduced the incidence of foot rot by 55% (P<.05) in steers grazing early summer pasture.
Feeding of organic sources of iodine has also been shown effective in this type of system. Iodine from EDDI (ethylenediamine dihydriodide), is believed to be effective in preventing foot rot. Although it should not be routinely fed at elevated levels year-round. Studies have reported good results of organic I fed at a rate of 10 to 15 mg per head per day. It certainly was helpful in the control of foot rot on some farms.
Conclusion
Foot rot is one of many conditions of the foot that cause lameness in cattle. For treatment to be effective it must be started early in the course of the disease. It is normally necessary to have a break in skin integrity for foot rot to occur. The most important preventive measures are centered on the protection of interdigital skin health. All this said, however, solid preventative measures can dramatically reduce the expense of a foot rot outbreak. In general, it may be the most cost-effective method available to the cattleman.