Calf is Unable to Stand

“hi - have a two month old calf down and he can't stand. first noticed it looked like he just has sprained right front knee (swollen) and wasn't able to bear weight. two days later, he is now unable to stand. i've been standing him up and holding him (weight off front leg, thinking his back legs are asleep due to extended laying down) flexing and massaging the legs. legs will flex pretty readily - including the swollen one. lays with his head and neck down, except periods when he arches his head and neck above his shoulder. (could be looking for momma) good appetite, wet nose, no mucus, no diarrhea.”  -Question

  I get asked the above question in some form or other all the time about a calf unable to stand. I chose this question because it is textbook example of the illness causing a calf that was doing great and then almost over night the calf cannot stand.
  What makes it such a good example it contains two important symptoms. First, you can help the calf to stand but it flops right back down unable to support it own weight. Second, it has one swollen joint. But what is good appetite, wet nose, no mucus, and no diarrhea is important also.
  The key is the calf was fine and now cannot stand. It could have one or more swollen joints or possibly none. The calf could or could not have mucus from the nose. Either way the illness is the same. It normally effects calf between the ages of three days old to a little over two months old, but can affect adult cattle of any age.
Mycoplasma pneumonia. In people, we commonly call it “walking pneumonia.” In cattle, we commonly refer to the illness as “silent pneumonia.” The reason why is the calf can walk around without coughing or showing any signs of illness like mucus until it is unable to stand.  The illness goes unnoticed and the calf still takes milk and/or eating until swelling around the brain causes a loss a motor skills. The bacteria causing the swelling around the brain will also settle in the joints causing them to swell as well.
  Mb bacteria are everywhere that causes mycoplasma pneumonia in calves. Each calf has some of the bacteria in them and it is around in the air and carried on containers or other supplies around the farm. It only becomes a problem with the calf’s immune system is weak. The calves own defenses are unable to fend off the illness. That is way it occurs more often in calves under two months old. In the first two months calves immune system are at their weakest and any other illness like scours or dehydration can start the growth of the bacteria causing mycoplasma pneumonia.
  Silent pneumonia’s bacteria grows rapidly and spreads quickly once it gets a foot hold it is hard to cure. It is a very common illness for calves. Antibiotics have a hard time killing the bacteria. That is what makes this illness so dangerous. It is everywhere, you don’t see any signs until it is almost too late, and hard to treat. 
  But there are treatments and cures available from veterinarians. They are powerful drugs and injections and can only be gotten from a veterinarian. But when you got a calf unable to stand holding up it’s own weight, it does have a chance to recover.  The following is from:
Virginia Cooperative Extension
John Currin, D.V.M. Veterinary Extension Cattle Specialist

“Mycoplasma is very difficult to treat in calves as well. Several of the commonly used antibiotics do not work well for Mycoplasma. Penicillin, Polyflex®, Naxcel®, Excenel®, and Excede® kill bacteria by destroying their cell walls. Since Mycoplasma does not have a normal cell wall, these antibiotics are ineffective in treating the organism. Micotil® shows little or no activity against Mycoplasma as well.
Oxytetracycline has produced mixed results in treating Mycoplasma in calves. Tulathromycin (Draxxin®) is the only drug approved for Mycoplasma and in one study, was the drug most likely to work (Butler et al., 2000). Draxxin® provides the most convenient treatment of mycoplasmosis because one dose provides 7 to 14 days of therapeutic blood levels. Draxxin® cannot be used in female dairy cattle 20 months of age or older. Other drugs that show good results are Nuflor® and Adspec®.
The two most important factors in the successful treatment of Mycoplasma infected calves are early recognition and prolonged treatment. Calves that are treated early in the course of the disease respond fairly well, but need to be treated for 10 to 14 days or 50 percent to 70 percent will relapse and require treatment again. Each time a calf relapses it will have more lung damage and be less likely to recover.”