Sentence:  Each pony had his <WSD>sais</WSD>, his groom, who lived and ate and slept with the animal, and had betted a good deal more than he could afford on the result of the game. There was no chance of anything going wrong, but to make sure, each <WSD>sais</WSD> was shampooing the legs of his pony to the last minute. Behind the <WSD>saises</WSD> sat as many of the Skidars' regiment as had leave to attend the match ... 
Meaning of the word marked with <WSD> tags:  A groom, or servant with responsibility for the horses.