A horse trained by Ciaron Maher and David Eustace has returned a positive swab to a prohibited substance after winning a race at Sale.

A blood sample taken from Piccatric after the filly won a maiden at Sale on February 28 showed the presence of Frusemide, a diuretic also marketed as Lasix.

Stewards told Maher and Eustace of the irregularity on March 31 ahead of confirmation of analysis of the B sample on Monday.

The trainers were fined $2000 on Saturday following an inquiry into the use of shockwave therapy given to Stardayz inside the seven-day cut-off period before she raced at Flemington in March.