Treeing Papillon

Chimera ran out the door as my parents were visiting. I figured he'd do a lap and then come back, but then I heard his "I've cornered a cat" bark. I went out with a flashlight and sure enough, he had treed a cat in the orchard. As I approached, the cat jumped down and and they both took off again. The cat went up another tree way down the property. I found them thanks to Cai's barking as he treed it again.  I stopped a few feet away, squatted, and called Cai. No acknowledgement. It took some calling for him to finally give up and return to me. His legs and belly are covered in burrs.