Ear infections are a common occurrence in young cattle.
They can be seen at various ages, including young suckling calves, in older unweaned calves and also in weaned calves in the feedlot.
The diagnosis of an inner ear infection is usually easy because clinical signs are obvious. However, the problem may have existed for some time before the clinical signs became evident. Affected calves will often have a droopy ear and may have a smelly discharge from the affected ear if the ear drum has ruptured.
In some cases, associated damage to the facial nerve exists and the eyelid on the same side as the infected ear may be paralyzed, which may result in drooping of the eyelid and some mild eye lesions because the calf can’t blink.
The hair around the ear may be matted and the calf will shake its head or rub its ears against other objects.
If the infection is mostly in the inner ear, the calf’s balance may be affected.
The calf will have an obvious head tilt and may walk cautiously to maintain its balance.
We think that most ear infections ascend up into the ear via the eustachian tubes, which are the small tubes that travel from the back of the throat to the inner ear.
Many infections that can cause pneumonia in calves will also colonize the tonsils and the nose and throat regions of the calf.
In calves that are bottle fed, infected milk may cause an infection. Calves nursing on a cow with mastitis may also be infected this way. In up to 75 percent of ear infections, the calf will also have a concurrent pneumonia.
Many calves that show a droopy ear may have had an infection ongoing for several days before clinical signs have occurred. Producers should treat those calves as early as possible before the pneumonia and ear infection becomes more severe.
A variety of bacterial infections can cause ear infections. Common causes include some of the bacteria associated with pneumonia infections in young calves, including Pasteurella multocida, Mannheimia hemolytica and Histophilus somnus.
Some respiratory disease vaccines used in young calves may help protect against these infections, although we don’t know how effective they are in preventing ear infections.
In my experience, most calves suffering from these infections will respond to antibiotic therapy if treated early in the disease process.
Mycoplasma bovis has become a common cause of calf inner ear infections.
It is also a cause of mastitis in cows and if calves are fed infected milk or if they nurse from an infected cow, the infection may ascend to their eustachian tubes and cause an inner ear infection. As a result, in dairy calves between two and eight weeks of age, Mycoplasma bovis has become a common infection.
We occasionally see outbreaks in beef herds as well. Mycoplasma bovis infections can also cause chronic pneumonia and arthritis, and affected calves may show signs of lameness and swollen joints in addition to the ear infections.
These infections are more difficult to treat and may not respond to antibiotic therapy. They present a much more frustrating scenario for both the producer and the veterinarian to handle. In addition, no vaccines are available to help prevent Mycoplasma bovis infections.
Ear infection outbreaks have been seen in some beef herds in older calves just before weaning. These outbreaks are more difficult to explain and in some cases have occurred in well-vaccinated herds.
These animals will typically have pneumonia as well as an ear infection. Many of these outbreaks tend to occur in the winter or at times of inclement weather.
If ear infections occur, talk to a veterinarian about the most appropriate antibiotic therapy and treat calves early.
Veterinarians may want to swab the discharge from the animal’s ear and send it to the laboratory to identify the bacteria causing the infection. Early treatment will help to prevent the complications of a more chronic pneumonia or a spread of the ear infection to other tissues.
The best prevention will be to work with your local veterinarian to ensure you have a good vaccination program in place for respiratory disease in young calves.
Identifying and culling cows with chronic mastitis may also be important, especially for control of Mycoplasma bovis infections in young calves.
Dairy producers must ensure they are not feeding contaminated milk to young calves. Ensuring calves have received adequate colostrum is always an important prevention strategy for any infectious disease in young calves.