Oh boy...navel ill...yes I know that one. :shock:
I picked up a freebie in late August/early September of last year.
I wondered the same thing as you; stepped on? broken? dislocated? nuh-uh. Joint infection; vet ran a culture and it was e-coli that entered through the navel and localized in the stifle joint.
Calf is now approximately 5 months, 350lbs and still...well, let's say I wish I could go back to when I first got her with the knowledge I have now. One, knowing how she looks
now, I wouldn't hesitate like I did about putting her on the illegal drugs. Two, I would have treated it much more aggressively.
What I did do - she had one injection in the joint of sulfa. Then the infected area flushed with saline water and gentamycin (illegal drug). Then had her on SMZs for a few days (I didn't like the results/reaction and do keep in mind it can cause liver/kidney damage). Then she was on an every-other-day dose of Nuflor for a month. And Banamine. And Sodium Iodide IVs. And Micotil. And Gentamycin. And Nitrofurazone-DMSO (another illegal one). And there might have been more that I can't remember right now. Run a quick search on the boards; I believe I had three separate topics about that calf.
So........if I could go back, I would have started with draining the area, cleaning it well, and putting her on Nuflor. Vicky tells me that one only causes damage to the intestinal flora with long-term use (can be fixed with probiotic), as opposed to other drugs that tend to cause kidney damage. Would have also run Sodium Iodide IVs to start with - that targets bacteria in the bone, which is really what you're dealing with. No withdrawal; all it is, is putting a heavy concentration of iodine in the bloodstream that kills bacteria. Also, I've recently decided to put a little more effort/money into my calf, and I went and had two iodine IVs done a week apart, and now, over this past week, I've been aggressively using a NFZ-DMSO mix (liquid) that I spray on the area, and I'm liking the results. (Might give you guys another update on her soon.)
DMSO penetrates the tissue (taking the NFZ with it-antibacterial stuff) and also increases blood flow to the area. Might give that a try - DMSO at the very least. It isn't approved for food-producing animals, but 1) when the calf has a 50-50 chance anyways... and 2) it isn't going to have a very long withdrawal time. My vet was telling me today I could use it on lactating dairy cows, and it's metabolized and eliminated quickly - suggested a 48hr withdrawal.
I've seen the way my calf is --- she's not used to putting any weight on one leg, and the other leg is having to support all her weight, so...not good. She'd had it for about 2 weeks before I acquired her, and the longer they go the harder they are to treat. I've decided if I ever deal with it again, it needs to be brought under control as quickly as possible.
Which antibiotics are you using?