Our (roughly) 16 year old Quarter horse has always had problems with keeping weight and staying healthy - he's a rescue. He has repeatedly had thrush in his front hooves, even though we are vigilent about cleaning his hooves, etc. Then, about 3 - 4 months ago, he was diagnosed with having a tapeworm (we think from some cattle that had been in the area that his pen is now). We wormed him with the Zymectrin Gold, then again a little while later after he continued to lose weight, after consulting our vet. He seemed his normal self but super, super skinny up until about 2 days ago (we've been tailoring his food to give him some extra oomph to help him gain weight back).
Now, he is really lethargic and doesn't want to walk anywhere. He eats but not every last bit of his food (and that's very much not like him). He's drinking okay. He's pooping and peeing fine. He is sweating under his mane, but that could just be me overreacting - we do live in Arizona and it's still HOT here! We don't have a way to take a temp. He doesn't appear to have a runny nose or cough.
Basically, it's just those three things - the lethargy, sweating and not eating everything. Does anyone have any similar experiences that might lead us to the problem? I feel so badly for him at this point that I'm afraid we might need to put him to sleep. But, of course, I want to know my options before it comes to that.
If you have anything, that'd be great. Thanks!