Fledgling country trainer Nicholas Dixon has had a mixed day on his first visit to Randwick, with stewards opening an inquiry into alleged race day treatment breaches.

The Dixon-trained Depth That Varies, his only runner so far in his two-month career, finished third in Saturday's Highway Handicap.

Shortly after, the Tamworth trainer was called before stewards to answer questions relating to race day treatment.

Dixon said he was ignorant of the rules when he told stewards Depth That Varies was given a feed additive and an ulcer paste in the early hours of Saturday morning at Randwick where he was temporarily stabled.

The trainer told stewards he had administered the oral treatment daily on his vet's advice and admitted he had done the same before the horse's three previous runs for him.

He also told stewards a syringe filled with green paste found in his float contained phenylbutazone which he planned to give Depth That Varies to help with his recovery on the trip home.

Stewards adjourned the inquiry after ordering blood tests from Depth That Varies.

Chief steward Marc Van Gestel advised Dixon to read the rule book before the inquiry resumed.