Cornwall farmer David Evans has been de-selected by UKIP after admitting six charges relating to animal welfare.
He was announced last week as the party's candidate for Camborne and Redruth, a key target seat for UKIP at the next general election.
On Monday, at Bodmin Magistrates' Court, Evans confessed to causing unnecessary suffering to six sheep by failing to address their emaciation and to nine sheep by failing to address lameness.
Animal welfare officers and police were shocked to find 119 dead animal carcasses strewn across Evans' farm.
Another 141 sheep were found living in such poor conditions that they had to be put down.
A UKIP spokesman said: "There is no way he would've been selected if we had known. We rely on people's good faith and straightforwardness and we expect people to tell us these things."
The 71-year-old farmer told the BBC he was "disappointed" and was not given the chance to give his side of the story before being de-selected by the party.
Kingsley Keate, prosecuting, said the sheep had been "left out to their own devices to survive a very wet winter".
Evans returns for sentencing on November 20, when he could face jail over the offences.