But he also argued that shechita would probably not be outlawed under their proposal because of the high standards that exist: "[If] shechita does not cause any undue suffering for the animal then it would fall within the requirements that Ukip has in mind."
Mr Nuttall said that he, party leader Nigel Farage and agriculture spokesman Stuart Agnew, are all on record supporting the right of Jews to continue practising shechita.
Ukip's Jewish candidates reacted with anger to the policy change.
Jeremy Zeid, who is due to stand in Hendon - the constituency with the highest proportion of Jewish voters in Britain - threatened to resign unless the ban was reversed.
Mr Zeid, a member of Kenton United Synagogue, described the proposal as a "monumental mistake".
He said: "If there was a ban on shechita, I would resign immediately. I support shechita, it is moral and probably the most ethical method of slaughter. If I don't stand up for fellow Jews, who else is going to?"
Keith Fraser, candidate in Hackney North and Stoke Newington, who keeps kosher, said: "I'll do my best to lobby for its reversal. It's something I care about and am upset about."
The JC understands that the policy change emerged after a member of the party's National Executive Committee - described by a Ukip source as a "bunny-hugger" - pushed it through without fellow NEC members grasping the implications of the change.
A press release announcing the policy was then sent out before either Mr Farage or Mr Agnew had been consulted.
Ukip treasurer Andrew Reid, who owns the Belmont Children's Farm in Mill Hill, north-west London, defended the policy. He said: "Speaking as a farmer, we are backing a ban on non-stun slaughter, not a ban on religious slaughter.
"We are defending ritual slaughter if the animal is stunned first. We have modern standards today, modern developments. There's a lot in the Bible that we wouldn't do today." He added: "As a farmer I would prefer that my animals were slaughtered in the least cruel way."
In its statement announcing the policy, Ukip said: "Animal and veterinary science has long concluded that cutting the throats of animals whilst they are fully conscious can cause significant distress and pain.
"We see no reason why religious groups should not take into account the concerns of animal welfare when carrying out slaughter.
"We find the government response to this issue is weak, lazy and bordering on spineless. It says it would 'prefer' animals to be stunned before slaughter but that it must 'respect the rights of Jewish and Muslim communities to eat meat in accordance with their beliefs'.
"It's about time someone stood up for the rights of the silent majority in the ethical treatment of animals instead of bowing down to those who shout the loudest."
Speaking to the JC in 2013, Mr Farage stressed his support for shechita: "Even if 71 per cent of Ukip supporters are not comfortable with religious slaughter - perhaps because they come from a different background and it's not their thing - that's different to saying to your community 'you can't do it'."
Food Standards Agency statistics indicate that kosher and halal abattoirs cut the throats of 2.4 million sheep and goats without stunning them first. Animals killed by the shechita method accounted for 1 per cent of the total.
