17 September 2011

9 minute read

Lameness in cattle is a serious economic problem. There are many causes for lameness. It is important that the problem be diagnosed correctly and treated quickly to minimise economic losses, said Dee Griffin, Beef Cattle Production Management Veterinarian

A review of the records from five large western feedlots showed 13.1 per cent of 1,843,652 animals were treated for health problems. Lameness accounted for 16 per cent of these health problems and five per cent of deaths of feedlot cattle.

Lame cattle accounted for 70 per cent of all sales of non‐performing cattle. The price received for these salvaged lame animals was only 53 per cent of the original purchase price. While lame cattle in this set of records were sold, on average, 85 days after their arrival, they weighed, on average, only 10 pounds more than their in‐weight.

The NCBA National Quality Audits identify lameness in over 15 per cent of culled cows and over 30 per cent of culled bulls. Additionally, carcase bruising had a high incidence in all marketed lame culled cattle. A close look at NCBA Quality Audits in both finished fed and marketed cows and bulls, trim loss from carcases exceeds a million pounds a year.

Causes of Lameness

Diseases of the feet account for approximately 70 per cent of all cases of lameness.

Other causes include injuries to the upper skeleton or major muscles (15 per cent), septic joints (12 per cent) and injection site lesions (three per cent).

The incidence of each cause will vary by season, source of cattle, environmental management, and cattle handling. However, regardless of the circumstances, an accurate diagnosis is the key to successful treatment and prevention of future cases. Examination of the animal is the key to making an accurate diagnosis. Since most lameness involves the feet, you must pick up the foot to make a proper examination. Never medicate the animal before making a proper diagnosis. Your veterinarian should routinely review your cattle's health problems.

Most foot diseases in feedyards are caused by mechanical injuries from handling equipment, footrot or sole penetration from excessive wear (toe abscesses). In cows and bulls footrot is also common.

In these cattle hoof wall disease associated with genetics and/or nutrition is also a common finding. Hoof sole disease can be an important issue in bulls. This general is found in the medial claw of the front feet and is associated with laminitis.

Toe Abscesses

Young cattle coming from lush pastures are prone to toe abscesses. These abscesses are caused by a sole penetration that leads to an infection under the hoof wall. The hoof is soft and easily worn down into the sensitive tissues, especially in the toe area. The outside front toe is usually the most severely affected. The outside rear toe is the next most common location for this problem.

Fall weaned calves, cattle coming from parts of the country with high annual rain fall, and cattle coming from small grain pastures in the spring are most likely to have problems with toe abscesses. Wild cattle, abrasive surfaces, and rough handling of the cattle often combine to create this problem.

If toe abscesses are a problem in feedlots, the receiving areas may be too clean. Dirt and dried manure provide a cushion to the hoof. Some feedlots only have a problem with toe abscesses after rains have washed the cushion away.

The early symptoms of toe abscesses are very subtle. The cattle will appear sore and short-strided. The foot is not swollen in the early stages. Nearly all animals treated properly at this stage will recover.

If the disease is allowed to progress, the animal will become noticeably lame. The animal may hold the most severely affected foot up, and if the disease continues to progress, a slight swelling may be noticed at the top of the hoof.

When the animals are taken to the hospital area, the feet must be picked up and examined. When pressing your thumb on the side at the end of the toe, you should feel a soft area. You may also notice a crack between the hoof wall and the sole.

There should be no swelling between the toes. Swelling between the toes is a cardinal sign of footrot, and is totally unrelated to toe abscesses. Beef producers often make the mistake of treating all lame cattle for footrot or upper leg injuries when toe abscesses may be part of the problem. If toe abscesses are not treated in time the toe will have to be amputated or the animal sold for salvage.

Toe abscesses are treated by trimming the end of the hoof just enough to relieve the pressure inside the hoof caused by the infection. If the animal bleeds when you trim the end of the hoof, you have trimmed too much. In addition to trimming, animals should be treated with a long-acting tetracycline. Antibiotics alone will not benefit the animal - the hoof must be trimmed.

Mechanical Injury to the Hoof

Hoof injuries are another cause of lameness. They are most often caused by poorly designed facilities or poorly maintained facilities. An animal's toe can be caught in the space between the ground and the wall in crowding facilities. If the animal steps forward with a toe caught, the hoof can be injured.

You can minimise damage by using a pipe instead of square corner metal at the bottom of a side wall. This round finish will minimize damage to the hoof. The ideal condition would be to have no space between the side wall and the ground in the crowding facility. However, the minimum standard is no more than 1/4 inch per 100 pounds of the typical animal handled.

Equipment should be inspected every day before it is used. Loose metal can cause mechanical injuries to dozens of animals before it is detected. Mechanical injuries should not be left to heal on their own. A minor injury can become a severe local infection which can cause loss of animal performance. Mechanical injuries vary widely, as does appropriate management. Your veterinarian can recommend appropriate treatments.

Footrot

While footrot is the most commonly diagnosed cause of lameness in all cattle, it actually accounts for less than 10 per cent of the confirmed cases of lameness. The patterns of occurrence for footrot and toe abscesses are similar. Footrot is most often apparent one to two weeks after the soft tissue between the toes has sustained mechanical damage.

The mechanical damage may come from dried pasture stubble or frozen mud spikes. You should be especially careful during the first two weeks after fall weaning when calves are coming from dried pastures, and during the first two weeks after the temperature drops below freezing following a wet period.

Footrot can be easily and successfully treated. To properly diagnose footrot, pick up the foot and examine the soft tissue between the toes. In footrot cases, the soft tissue between the toes will be swollen and smell very bad.

Footrot is treated with long-acting antibiotics. Topical medications are of very little value. Footrot seldom affects only a few animals in a group. You must be on guard for other cases to develop from the same set of cattle.

It is difficult to prevent footrot. Many producers have used iodine in the feed with questionable results. The level of iodine that is approved for use in the feed (10 mg/head/day) is not considered therapeutic. Research suggests that high levels (50-250 mg/hd/day) of iodine fed for 15-17 weeks can interfere with some immune function tests. However, there is some evidence that zinc methionine in the ration may have some value in preventing footrot. Zinc methionine can be used with other feed additives including antibiotics and ionophores.

Swollen joints

Swollen joints are linked to about 10 to 15 per cent of all cases of lameness. These usually fall into three categories; an infection that settles in the joint after an animal has a generalised infection; an injury to a joint; or an infection that develops in the joint after an infection in the foot was improperly treated. The most common joints involved are the front fetlock, the hock and the elbow. Stifle, hip and shoulder lameness is very rare in cattle.

Regardless of the cause of the swollen joint, the three most common isolated bacteria are Hemophilus somnus, Pasteurella multocida, and E. coli. While the bacteria are often sensitive to common antibiotics, treatment is not very rewarding and should only be considered after visiting with your veterinarian.

Sale for salvage is often the best option for animals with swollen joints. If the swollen joint appears before the animal has cleared its drug withdrawal time from the medications and vaccines used at processing, treatment with antibiotics should be considered. An antibiotic with a short withdrawal time is recommended so that the animal can be marketed as soon as possible. Swollen joints are very painful to an animal, and the animal may not eat enough for minimum body maintenance. If the animal is under a long withdrawal time for a medication when the swollen joint is diagnosed, humane euthanasia should be considered.

Broken Bones

If the animal is not under medication withdrawal time restrictions, it is best to salvage the animal as soon as possible. If time restrictions exist, and the fracture does not break the skin, the animal may get along quite well if kept in a small pen. The fracture will not heal, but it will allow the animal to clear the medication before marketing.

Muscle Damage

Severe muscle damage is common in newly arrived cattle and feedlot bullers. Newly arrived cattle should be allowed to rest before processing to replenish the energy in their muscles. The animals should rest for as few as six hours but for no more than 72 hours.

Muscle damage can often be traced to handling techniques. It is very important to handle only small numbers of cattle at a time and handle them gently.

Muscle damage in feedlot bullers can be severe. It is important to be looking for bullers constantly and to remove them from riding cattle as soon as they are noticed. When bullers are removed from a pen it is common for the animals to be re-tagged, have their implants removed and placed in a "buller pen."

There is no information to support the removal of the implants, but the implants should be checked and replaced if the implant is crushed or abscessed.

Finishing bullers in a buller pen does seem to be an effective management tool. Antibiotic therapy is usually not required in the treatment of bullers. Your veterinarian can prescribe medications to minimise the effects from muscle damage and help you with effective buller management.

Non-ambulatory Animals

Many non-ambulatory animals have sustained an injury to the central nervous system. Response to treatment for this injury is generally poor. There are many causes for these injuries and a veterinarian should be consulted. USDA regulations prohibit slaughter of non-ambulatory cattle! Putting these animals to sleep is almost always the most humane and economical decision.

Injection Site Damage

Injections can cause severe muscle damage. The swelling that results can be painful and can decrease an animal's consumption and daily gains. Most injection site problems can be avoided if the manufacturer's recommendations for use are followed.

Subcutaneous administration of medications, if offered as an acceptable route of administration by the manufacturer, will minimise damage to muscle tissue. Never mix drugs in the same syringe before administration. Never mix medications or accept medications that have been mixed in the same bottle.

September 2011