March 20, 2019

Mycoplasma in Dairy Calves: As easy as 1, 2, 3...4, 5, 6, 7, 8, 9, 10!

Two words that you really don’t want to hear when you’re dealing with pneumonia in your heifers?

Mycoplasma bovis!

I’ve been consulting with a few herds recently where Mycoplasma is high on their list of problems in weaned and unweaned heifers. It has been on my mind recently, so I thought I’d share some thoughts on the disease and its control.

 

What Does Mycoplasma bovis Look Like?

Typically, herds that are having problems with Mycoplasma have higher levels of pneumonia that does not get better with treatment. You may also see tilted heads and drooping ears and swollen joints in calves. Adult cattle can contract mastitis – typically this is chronic, multiple quarters are affected, and does not respond well to antibiotics.

 

Why is Mycoplasma so Difficult to Treat and Control?

Mycoplasma is a very unique bacteria … They are very small, lack a cell wall, and have a membrane that is able to “shape-shift”. What does this mean for the calf?

• Many of the antibiotics that we have to treat bacteria rely on the bacteria to have a cell wall – these antibiotics will not kill Mycoplasma
• Mycoplasma needs special culture media and techniques, so it’s hard to diagnose in the lab
• It is difficult for the immune system to recognize and rid the calf of Mycoplasma
• Many animals might be carrying the bacteria in their nasal and urogenital system and we’ll never know it (they’re “asymptomatic”)

 

 Usually a Mixed Bag

It’s rare to find Mycoplasma as the only cause of disease in a group. Normally, there are other viruses and bacteria involved in the disease. Each of these bugs could potentiate (help out) the other to cause disease. This can make control challenging. This is an important thing to remember when designing a control program.  

 

Control of Mycoplasma in Dairy Heifers

Here’s my take on the most important things to control Mycoplasma in the herd:

1. Don’t let it in. I know, this is the advice of the guy who arrives late to the emergency. It really is best to know the Mycoplasma status of the herd of origin (and incoming animals) before purchased animals make it on your farm.
2. Break the cycle from cow to calf. Mycoplasma can be passed from cow to calf in milk and through contact. Segregate calves early. Don’t feed milk or colostrum from infected cows. Pasteurize milk and colostrum, and consider feeding milk replacer if you know Mycoplasma is an issue in your herd (but it’s never a bad practice to look into a pasteurizer anyway!!).
3. Reduce air exposure. Work on stocking densities (> 35 square feet/calf) and make sure pens are well-ventilated (at least 4 air changes per hour in cold weather, up to 30 changes/hour in the warmest months!).
4. Sanitize, sanitize, sanitize! Rinse (lukewarm water). Wash with liquid detergent and bleach or a dry chlorinated detergent. All surfaces need to be scrubbed. Keep water above 120°F (49°C) at all times – this means frequently changing the water. Too often I see people scrubbing their colostrum equipment in stagnant bog water. Gross. Acid rinse in warm water.
5. Wear gloves and change them often (definitely after handling sick calves).
6. Colostrum management. Focus on Quickness (within 2h after birth), Quantity (10% of body weight), Quality (22% on the Brix), Clean (low contamination – see sanitize, sanitize, sanitize! point). The jury is still out on whether colostrum helps prevent Mycoplasma, BUT excellent colostrum management will decrease the level of other diseases.
7. Quarantine. Get those sick (and shedding) calves out of the population.
8. All-in-all-out management. Easier said than done, but we know that Mycoplasma passes from older to younger calves. Manage calves as a group and you reduce the contact of older animals with younger ones.
9. Have a good vaccination program. Again, this is all about reducing the level of other diseases in your calves, so that they are less susceptible to Mycoplasma. Sorry, no good Mycoplasma-specific vaccine in cattle just yet!
10. Choose antibiotics wisely. Mycoplasma responds poorly to antibiotics, but we want to make sure that we’re not using the drugs to which there is zero chance of cure. Stick with florfenicol, macrolides (like tulathromycin or gamithromycin) as your first line of treatment. Use fluoroquinolones as a secondary line of treatment.

There you have it. All it takes is a LOT of diligent hard work, and it is possible to control Mycoplasma in dairy herds. Let us know what’s worked for you in your (or your clients’) herds!

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