I have no idea!
How much would you give orally?How do you know it's fowl cholera? Did you have testing done to confirm it? I'm only asking because a lot of diseases can have those same respiratory symptoms, and testing is the only way to tell them apart. And each disease has antibiotics that are more effective against it than others.
What are the symptoms you are seeing?
If you haven't had testing done, I would start by getting it done. If you have a dead bird, you can send it off for a necropsy. If not, you can take a swab from a bird showing symptoms and send it to Zoologix Labs and have them run their Poultry Respiratory Panel on it to see which disease it is. The cost is $98, which is far less than what testing through most vets will cost you.
While Cholera and m. synoviae aren't included in this test, if you suspect m. synoviae they can test for that too. Fowl cholera they don't have a test for, but if you got the test and it didn't come back positive for anything else, that would basically rule everything else out for you, at least.
Just to do the math for you, if you're giving 50 mg/kg, that would mean you need to give .55 mls per pound of body weight.
However, the normal dosage I've seen for oxytetracycline in birds is 5 mg/kg 1-2 times a day. If you were following that rule, then you'd give .055 ml per pound of body weight twice a day. That is quite the difference, and I don't know if there's a reason this particular medication might need to be given at such a high dose more spread out. I'll tag @casportpony to see what she recommends
Luckily, this is one of the kinds of medicine that can be given orally. Because of the possibility of injection site necrosis, I'd give this orally, instead of as an injection.
