Commentary for Moed Katan 20:16

[We discuss cures for animals that entail Melachah] A cure that does not entail Isur Melachah, Chachamim just decreed against Refu'ah lest one grind spices, some permit even on Shabbos [for animals]; The Halachah follows the opinion that permits, like it says in Shabbos (53b). Rava expounded that the Halachah follows R. Yoshiyah, who does not decree lest one grind spices, regarding Refu'ah of animals. Rashi's opinion: "Lisrukei Susya" is rubbing and cleaning a horse with a comb. Rebuttal: We hold that both Kirod and Kirtzof (combing with a fine or coarse comb) are permitted (Beitzah 23a), according to R. Shimon, who permits Davar she'Eino Miskaven (a fine comb makes a wound), and the Halachah follows him! Conclusion: Rather, it is another matter.