It would appear that you are referring to bloodletting and other Melachos permitted for an animal. Bloodletting is considered a Davar ha'Aved in a sick animal (Me'iri), and the other Melachos described in the Gemara did not require special expertise and are defined as Ma'aseh Hedyot.

However, Rabeinu Yehonasan of Lunil in his commentary adds that scraping the skin of the horse is permitted because it gives the horse pleasure and adds to its sale value. This, too, is viewed as Davar ha'Aved since not scraping causes the horse to suffer and depreciate.

Yoel Domb