Banamine is not going to do them any good for pneumonia... unless the breathing is extremely painful.... by then it is likely you will not save them....
Couple things... feeding the bottles... How high are you holding the bottle??? Too high and a calf will aspire some fluid into lungs.. some do it because they drink too fast... nipple end made too big for milk to go through it? Yeah, we all do that... Hold bottle lower it should not be much above their shoulder height when small ... For a visual... calf's neck should make a bit of a "u" shape when drinking... it causes the windpipe to close with the actual throat/"food pipe" (esophageal groove) to let the milk go into the abomasum.
Do not do any IV on calves unless they are severely dehydrated and need fluid... that is the only way to get into their system... Personally I do not give IV's... I am not good at it and if they get that weak, they need a vet.
Since you don't know what the vet gave them, yes, it is probably long acting... BUT... if it was excede that is not my drug of choice... works good in some specific situations but not as broad based.
Use LA 300, age/size appropriate dose... and make sure to follow with repeat doses... I don't have a bottle in front of me, but thinking that it is a "repeat in 2 or 3 days" ? Oxytets all are gram positive and gram negative so should hit most of the stuff. I find Draxxin is better for things like pinkeye, some pneumonia things... but usually a one shot deal and if disease is not kept at bay, so theraputic levels get high to stop the disease from replicating, for it to work before it fully does the job, a 2nd dose is needed. Besides it is way more expensive. It is good for some things but we try to go a different route to start. Draxxin works very good in a dart gun when we have to treat on pastures where there are no catch facilities.
If the calf seems satisfied with 80% of the bottle and acts okay otherwise, do not try to get them to take the rest... Calves should always "be a little hungry" when bottle fed. Encourages them to get started on grain sooner too.
Honestly, I will hit anything here sick with a shot of penicillin and a shot of oxytet... same time, different sides of the neck SQ.... and then follow up with another oxytet shot in 2-3 days.
This will do nothing for scours...
