Hello and welcome, I am Dr. B and would like to help you today.
Now I am concerned to hear that she hasn't responded to this antibiotic course. It suggests that this is being caused by a resistant bacteria, viruses, parasites, or potentially an individual issue ( ie choke, aspiration pneumonia, etc). With this in mind, we'd be best to have her vet come out and listen to her chest. Otherwise, you'd want to make sure she is isolated from others to avoid any risk of spread, make sure she is treated for lungworm, consider changing antibiotics ( ie Draxin, Nuflor, Penicillin, etc), and adding in a cattle safe decongestant ( ie Bisolvin) and potentially an anti-inflammatory ( ie Flunixin). That way we are treating symptomatically but also covering as many bases as possible without testing ( the next step if this persists).
Please take care,
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