At least 541 sheep from a flock of 700 to 750  belonging to Relbia farmer Darryl Edward Johnson were euthanised because of their extremely poor condition.

The Launceston Magistrates Court previously heard that one beef cow, from a herd of 35 to 40, was ‘‘skin and bones’’.

Johnson, 59, claimed he was ‘‘a victim of the RSPCA’’, meaning a high-profile case to prosecute.

He contested all animal cruelty charges and represented himself at a hearing.

On Wednesday  magistrate Sharon Cure found Johnson guilty of two counts of poor animal management, one count of animal cruelty and two counts of aggravated cruelty.

Ms Cure found Johnson not guilty of two counts of having failed to comply with an instruction and dismissed those charges.

Johnson’s offences related to sheep and cattle at his property in Relbia Road between May 9 and 22 in 2013.

Various RSPCA inspections uncovered new and old sheep carcasses, sheep unable to rise, parasite-infested sheep, eight sheep stuck in a creek, 11 sheep among prickly plants in a vineyard, an ulcerated and infected pony with a tumour, an emaciated cow, insufficient feed and a lack of appropriate treatment.

Johnson had given evidence that he had 25 years’ experience with the Department of Primary Industries as an agronomist and left in 2006.

He had also argued that the condition of his sheep was ‘‘not as bad’’ as the RSPCA had described.

Ms Cure asked Johnson if he wished to say anything after her decision.

‘‘I don’t know what to do, your honour,’’ he said.

Ms Cure said Johnson had had a number of items repossessed and had said he was having financial difficulties.

Johnson said it was ‘‘a difficult period’’.

Prosecutor Glenn Carey said the case had cost the RSPCA more than $86,000, which was mainly the care of about 30 cattle that had been seized from Johnson.

Ms Cure adjourned Johnson’s plea in mitigation and sentence to January 14 at 11.30am.