Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your wee one’s situation, and wanted to help.
First, considering all you have told me, we do have a few concerns. With multiple goats affected, we would assume this is an infectious agent (ie bacterial, viral, protozoal, etc) or a shared contact (ie toxin, plant based, feed contamination, etc). Though I would just note that if the white cell count is in relation to this (not a red herring present in one goat), then infectious agents are more likely here. Furthermore, the signs you are reporting tell us that the trigger is targeting the brain.
Now your approach so far has been reasonable in trying to rule out some agents, but if we are seeing this spread through the herd, we need to be more aggressive in getting to the root cause here. One treatment you haven't noted that I do think is indicated here is a broad spectrum antibiotic. And since these signs are especially consistent with a the Clostridia spp. and Listeria; we'd want to be thinking about at least starting Penicillin +/- clostridial antitoxin.
Otherwise, in regard to other infectious issues that could trigger this, we'd have to be wary of bacterial or viral meningitis or a parasitic brain based situation (ie tapeworm cyst, Parelaphostrongylus tenuis, Sarcocystosis, toxoplasma, etc) though often we only will see one animal affected at a time. Still, the parasites can be treated or tested for to see if they are an issue or at least rule them out and get them off our differential list. At the same time, depending on your location, we may need to also test for viral agents and tick borne disease.
As well, another concern is that severe liver fluke loads can damage the liver to cause secondary brain signs like we are seeing. Though for that, we'd want to double check for yellowing of the gums and any blood work done for signs that the liver in tested animals have not been showing dysfunction or failure.
Furthermore, while this does sound like we likely are facing an infectious agent, I do want to note some toxicity concerns that could appear this way just in case there has been a possible exposure you haven't appreciated as significant. In regards ***** *****'d have to be wary of exposure to oleanders, astragalus, or ragwort. Some chemicals that could cause what you are reporting include organochlorine, antifreeze, sodium fluoroacetate, and some fertilizers. As well, arsenic, lead and selenium (in very high doses) could cause these signs.
So, these would be our remaining concerns based on the signs they are showing and their lack of treatment response to what has been tried so far. Therefore, we need to check for, rule out, and/or address the above concerns. Furthermore, if one has recently die, you can speak to the vet about having an autopsy done. They may be able to do this for you or you could have your local vet lab, vet school, or agriculture college do this for you. They can open the dead goat to narrow down causes based on the organ gross appearance. If they cannot find an obvious cause of death, they can collect samples to submit to the lab for the pathologists to evaluate. The pathologists will be able to examine the tissues under the microscope and determine the causative agent that lead to their death. As well, if bacterial or viral causes are suspected, these can be cultured to determine what is present and what treatments will effectively clear them. As well, heavy metals and mineral levels can be assessed at the same time. This will both give you an answer for losses, but also help you know what you are facing and what can be done to help your remaining goats.
Please take care,
If you have any other questions, please ask me – I’ll be happy to respond. *Please remember to rate my service afterwards, as this is the only way I receive credit for helping you today. Thank you! : )