"I am determined that we should be able to continue our lawful trade and that means live exports," he said, addressing nearly 1,000 farmers at the Royal Lancaster Hotel.
Calling for a calm and reasoned debate on the issue, Sir David said farmers cared passionately about animal welfare. "For farmers animal welfare is a way of life. Farmers care about welfare, they care night and day. For farmers animal welfare is not a fad or trend, it's a 365 days a year job."
He condemned the "tiny sinister minority of boot boys in balaclavas" who believe animals can be helped by terrorising people.
Security at the conference was tight with Compassion In World Farming handing out leaflets to delegates and around 20 animal rights protesters picketing the hotel's entrance.
Sir David said that he had met the leaders of CIWF a few days ago to discuss the issue of live animal exports and was prepared to continue talking to animal welfare groups.
"At the same time I have made it quite clear that we are determined that a trade, within the law, must be able to continue. We won't be deviated from our goal - to preserve a competitive farming industry in the UK."
Sir David reiterated his call for CIWF to withdraw their encouragement for the picketing of farms. He strongly contested claims that he had, in an earlier statement, insinuated that CIWF had issued a rallying call for a violent minority to picket and possibly target for attack farmers, business and families.
"We are extremely concerned that even the encouragement of peaceful picketing of farms could be hijacked and misused by a violent minority whose selfish actions are aimed at causing maximum disruption."
The NFU, he added, had taken the lead in seeking an end to the veal crate rearing system in Europe. He wanted this issue and the question of transporting live animals to be resolved urgently at European Union level in Brussels.
The NFU's position on the export of livestock is that it is a legitimate trade which, when conducted properly within the law, is not cruel to animals.
The NFU admits that in a small number of cases some hauliers and exporters have put their own desire for profit before the welfare of animals. It condemns their actions and supports prosecution and severe penalties for those who fail to treat animals with respect.
The union points out that Britain cannot unilaterally impose a ban on live exports because it would contravene European law. The NFU believes the UK's humane standards of veal calf rearing - veal crates were banned in the UK in 1990 - should be adopted throughout Europe as soon as possible.
Earlier Paul Tyler, Liberal Democrat MP for Cornwall North, told a meeting of Welsh farmers that "at best protesters are ill-informed, at worst hypocrites." They were not doing anything to improve the conditions of calves in Holland, he said.
n Meat processors and distributors in three west German states have decided to boycott British beef because they fear it could be contaminated with "mad cow disease", the state governments said yesterday, Reuter reports. The move comes in response to a decision by the federal government in Bonn allowing imports of British beef to resume from Monday after a ban imposed last summer over outbreaks of bovine spongiform encephalopathy (BSE), as the cattle brain disease is formally known.Reuse content