I say, and with God's success: Its saliva is pure and there is no doubt about it, nor is there any dislike; because the original ruling regarding animals is to associate them with their mother, and the saliva of the horse is pure, unlike the mule whose mother is a female donkey, as the saliva of the domestic donkey is questionable in its purification from ritual impurity. Refer to: Al-Talweeh on Al-Tawdeeh 2: 210, Maraqi Al-Falah p. 28, Nafi' Al-Mufti and the Questioner p. 26, and Kanz Al-Daqaiq p. 5, and God knows best.