Trainer Lance O'Sullivan had no obligation to tell stewards his top galloper Pentane had been treated for a skin condition prior to New Zealand's richest race, a judicial committee has found.

O'Sullivan was charged for failing to report a condition which may have affected the performance of a horse under his care after Pentane's surprise failure in the $1 million Kelt Capital Stakes at Hastings on October 7.

Reports two days later said Pentane had been treated for a skin condition the day before the race, leading stewards to charge O'Sullivan for not reporting it.

But the Judicial Control Authority (JCA), in a reserved decision released on Monday, said the condition and treatment was regarded as common and O'Sullivan had every reason to believe it would not have affected the horse's performance.

Pentane, who had been New Zealand's best backed runner for the Melbourne Cup and second favourite for the Kelt, ran well below his best at Hastings, finishing six lengths from the winner Legs.

Two days later, O'Sullivan was quoted in a newspaper report describing the October 6 treatment with Alamycin, a permitted antibiotic, and that Pentane was given anti-inflammatory treatment for discomfort where the back of the saddle sits two days after the race.

Senior stipendiary steward Cameron George said it was O'Sullivan's obligation to tell stewards of any such condition as it was in the best interests of racing.

He said stewards needed to know about any condition that might affect performance because they had to be able to ascertain whether Pentane was fit to race.

O'Sullivan's counsel, however, argued that the condition Pentane had was extremely common and was not regarded as likely to have affected his race performance.

Veterinary surgeon Dan Shaw told the JCA he treated Pentane four times for this condition in September and October, including before he won the listed Evans Mile at Paeroa on September 23.

He agreed with George that a painful skin irritation could affect performance, but all evidence suggested the horse was suffering no pain.

Shaw said the condition which Pentane had would "absolutely not" have affected his Kelt performance.

Shaw said Pentane raced poorly at his next start, the Geelong Cup in Australia, after which further diagnostic work found "a low grade respiratory condition that may be a more logical contribution to the horse's form".

The JCA committee decided the condition was one which those familiar to the horse would not have expected to affect his performance.

They also accepted that the treatment was as a precaution to kill bacteria and to prevent the common skin condition spreading.

As O'Sullivan and the stable team were open to conclude the condition and treatment would not be likely to affect Pentane's performance, they had no obligation to tell stewards, the committee ruled.

PIC - Sportpix.