how did gulliver's master react when he told him how houghnhnms who were called horse, where treated in his country?

From the text:

"My master, after some expressions of great indignation, wondered "how we dared to venture upon a Houyhnhnm's back; for he was sure, that the weakest servant in his house would be able to shake off the strongest Yahoo; or by lying down and rolling on his back, squeeze the brute to death." I answered "that our horses were trained up, from three or four years old, to the several uses we intended them for; that if any of them proved intolerably vicious, they were employed for carriages; that they were severely beaten, while they were young, for any mischievous tricks; that the males, designed for the common use of riding or draught, were generally castrated about two years after their birth, to take down their spirits, and make them more tame and gentle; that they were indeed sensible of rewards and punishments; but his honour would please to consider, that they had not the least tincture of reason, any more than the Yahoos in this country."