Go to
http://www.fabric.com and put into the search box "horse panel" and "wolf panel". You should get a selection. This would work for other online stores also. Or did you mean you want a panel that has both a horse and a wolf in it??? If it's more extreme like that, you can Google "horse wolf panel", click on "images", and see what comes up that way.
Edit: If you find something on fabric.com that you like but it's "not currently available", check eBay and Etsy. You can often find out-of-print fabric that way if you have the manufacturer's name, fabric line, fabric name, etc.
Here are just a couple of options I found by Googling:
https://www.4my3boyz.com/pine-ridge-...c#.VBX6QvmwLYg
http://www.nancysfabrics.com/product...n-fabric-panel