Droopy Ears and Drunken Behavior

Over the last couple weeks, I’ve been working with a farm having calves suffering from droopy ears and head tilts. This week I was called to a second farm, for a calf with the same symptoms, so I thought it was time to discuss.

Let’s start with a background. Farm A houses their calves in groups and feeds them milk replacer for the first month of life then switches them to waste milk that has been pasteurized. The calves that have been getting droopy ears are about 1 month old and are on the pasteurized waste milk.  Farm B had a calf that was about 3-4 months old, is weaned and is being fed hay, grain and water. 

One of the patients with droopy ears

Many times farmers will say to us “Doc- her ear is droopy and she’s walking like she is drunk!” Calves that have droopy ears and head tilts, suffer from what we call “otitis media,” a fancy way of saying and inner-ear infection.  The inner ear is responsible for hearing, obviously, but balance as well. There is an intricate system of bone and cartilage in the inner ear that works together with the brain, eyes and rest of the body to allow an animal, and a human, to know which end is up. When there is an infection in the inner part of this ear, the entire system is disrupted and the calves walk unbalanced, stumble and can fall down. 

The body is such an amazing unit that works so in synch, that we often take it for granted.  When these calves with inner ear infections are blind-folded, the head tilt is exacerbated and the balance is worsened.  We don’t realize how important eye sight is, and how much it helps compensate for deficiencies in other areas! So amazing! Anyway, I digress…

Most commonly we associate otitis media with the bacteria Mycoplasma.  Although this is a very common causative agent, it’s not the only bacteria involved in these situations. Farm A had been treating these calves with an antibiotic that Mycoplasma is susceptible to, but the calves were not getting any better, in fact they seemed to be getting worse.  Farm B had also treated the calf with the same antibiotic and this calf was not getting worse, but was slow to improve.  Because there are other bacteria that can be involved in otitis media situations, it was time to  take some real sample and submit them to the lab for analysis. 

 Farm A had a calf that was severely neurologic, was falling down consistently and had already had the appropriate treatment. Her prognosis was grave, so we chose to euthanize her and perform a necropsy. When I removed the ear, there was brown, thick discharge in the ear canal. Using a sterile swab and special culture media, I sampled the discharge, from both ears and sent it into the lab. I also sent in the other standard necropsy samples such as lung, liver, spleen, kidney, intestines, thymus, lymph node and heart muscle.  Usually in neurologic cases, we also submit the brain, however, I was confident that the neurologic signs were coming from the inner ear infection, so did not add the brain to my samples.

The results came back with several different bugs. There was indeed Mycoplasma cultured from one of the ear swabs that I sent in. The lab also cultured Trueperella pyogenes, Proteus Mirabilis, and Pseudomonas Aeruginosa.  So, where do all these bugs come from????

Let’s start with Mycoplasma. This is a bacterium that is commonly associated with pneumonia in calves and mastitis in cows.  It is found in the respiratory secretions of calves and is considered part of the “Bovine Respiratory Disease Complex” that I’ve discussed before. It is a contagious bacterium that can be transmitted from animal to animal in the milking machines, nose to nose contact, or from the environment. It has been shown to live for months in sand, ponds and in other cool, humid conditions.  As I mentioned earlier, it is susceptible to a few different antibiotics and when it’s the only bacteria involved in the situation, it can be cured.  Because cows shed the bacteria at different times, many farms routinely sample their milk to check for Mycoplasma. Due to its contagious nature and the trouble it causes for cows and calves, most farms will sell any infected cattle. Proper pasteurization does kill the bacteria so animals fed waste milk, or milk sold for human consumption is clean.

Abscessed udder from Trueperella pyogenes

Trueperella pyogenes is a common mastitis bacterium.  The bacteria are found on the skin of the cow and can be spread by flies and fly bites. It can also infect the udder if the teat end is damaged, the cow was not treated with clean hands or the cow is in a dirty environment. The bacteria form little abscesses in the udder of a cow. Because of the abscesses formed in the udder, these animals are very difficult to treat as very few antibiotics are able to penetrate the wall of the abscess to get to the bacteria. 

The other two bacteria that were isolated from the culture are very difficult bacteria to kill. They are resistant to many drugs and the bacteria have little flagella that allow them to move or “swim” around.  Again, they are found in a dirty environment and commonly associated with fecal material.  They may not have been the true causative agent, but rather took advantage of the opportunity of an infected ear and are wreaking havoc along the way.

So now that I know what bugs I’m dealing with, what’s next? Well, we have been sampling Farm A milk for a couple weeks now, trying to see if the pasteurization of the waste milk is adequate and see if we can culture Mycoplasma from the waste milk. If we find a positive, she will automatically be culled. We know there are Trueperella mastitis cows, and they may be more of an issue than the Mycoplasma alone.  As I mentioned earlier, many of these bugs are found in a dirty environment.  Cleaning up the environment for these calves and the cows will go a LONG way in preventing these diseases from occurring.  We need to minimize, if not eliminate, the source of the bacteria for these calves. If you start with dirty milk, there is only so much you can do, to make it clean. Pasteurization helps reduce bacteria load, but it does not sterilize the milk.

Finding what is causing the issue is easy. It’s getting people to change their practices that cause more stress than anything in a veterinarian’s life!

Farm B’s calf seems to be more of a respiratory issue than dirty milk. She has had a fever that has coincided with the droopy ear. We have decided to try to flush her ear out with hydrogen peroxide and if there is no improvement, we can pop her ear drum to allow the “gunk” to drain. Overall I feel like she on the mend and has a decent prognosis. There does not seem to be any other calves affected so it’s not a “herd issue,” rather an isolated case.  She may always have the droopy ear, but as long as she continues to eat and grow, she can go on to be a productive animal.