6 Signs of Calf Wellness - Understanding Ear Positioning
Assessment of ear positioning is another piece of the puzzle when evaluating calf wellness. Normal positioning of ears should be erect and alert. Calves that flick their ears, shake their head, tilt their head, or have one or more droopy ear, should be examined more closely to determine the presence of a foreign body or an infection.
Diagnosis
The diagnosis of an infected ear is usually obvious. However, the infection may have existed for quite some time before the symptoms appear. Infected calves will have one or more droopy ears, and may exhibit smelly discharge if the ear drum has ruptured. In some instances, damage to the facial nerve is apparent and the eyelid on the same side as the infected ear may be paralyzed. This may result in drooping of the eyelid and possibly mild eye lesions because the calf cannot blink.
The hair around the infected ear may be matted and the calf may shake it’s head or rub it against other objects. If the infection is mostly in the inner ear, the calf’s balance may be affected.
Common Causes
A calf can contract an ear infection many ways. Bacteria can invade the middle ear when an infection from the outer ear breaks through the ear drum. Bacteria can also migrate to the middle ear from the bloodstream from an infection somewhere else in the body.
Another path of infection is when bacteria travel from the mouth to the ear through the Eustachian tube. This tube in an essential structure that can stabilize the pressure between the outer air and the middle ear. This is the same tube that helps equalize pressure when you yawn as you travel to higher elevations. Once a pathogen has colonized the oral cavity it can travel through this tube and invade the middle ear.
Over 50% of calves exhibiting an ear infection also have concurrent pneumonia. Many calves that have a droopy ear, have had an ongoing infection for several days, and should be treated as soon as possible to prevent spread of pneumonia and the ear infection.
A variety of pathogens can cause an ear infection, including Pasteurella multicoda, Mannheimia hemolytica, and Histophilus somnus. Some pneumonia vaccines may help to prevent some of these infections, however, we don’t know how affective the vaccine is in preventing an ear infection.
Mycoplasma bovis (Myco) has become a common cause of calf inner infections. Myco can also cause mastitis in cows. If calves nurse from an infected cow, or are fed infected milk, the infection may ascend up their Eustachian tube and cause an inner ear infection. Myco is a common infection in dairy calves around two to eight weeks of age, but we also see occasional outbreaks in beef herds as well. Other symptoms of Mycoplasma include, pneumonia, arthritis, heat tilt, lameness, and swollen joints.
Sometimes ear infection outbreaks occur in beef herds around weaning time. Usually these outbreaks are accompanied by pneumonia. These outbreaks are difficult to explain as they often happen in well vaccinated herds. Cold, wet weather may be a factor in this kind of outbreak.
Treatment and Prevention
Because ear infections are bacterial they usually respond well to antibiotics if treated early in the disease process. Work with your veterinarian to determine which antibiotic is the best choice for treatment. Your veterinarian may want to take a swab of discharge from the animal’s ear to have it cultured and identify which bacteria is causing the infection, and which antibiotic will be most effective to fight it.
Treatment of Mycoplasma is more challenging as it may not be responsive to antibiotic therapy. Work closely with your veterinarian to determine the best treatment for calves with Myco.
Prevention of infection is done best by working with your veterinarian to establish a good vaccination program for respiratory disease. Also identify and cull cows with chronic mastitis, and avoid feeding infected milk to calves.
Written by: Mariah Gull, M.S.