Sending live animals abroad for slaughter and fattening will be banned in England and Wales under new plans.
Environment Secretary George Eustice said the ban could be in force by the end of 2021 in a post-Brexit break from EU trade rules.
The RSPCA welcomed the move, saying it would be "a landmark achievement for animal welfare".
But the National Farmers Union is calling for improvements to export rules, rather than an outright ban.
The government is launching an eight-week consultation on the plan - which includes measures to cut the amount of time animals spend in trucks within the UK.
A package of reforms is then expected to come to Parliament next summer.
Current EU trading rules allow for animals to be transported abroad for slaughter.
One local authority in Kent tried to ban the exports in 2012 after a lorry full of lame sheep was found at the local port and the animals had to be put down.
But the High Court overturned the ban, saying it was a breach of EU free trade rules.
Only a few thousand of the millions of animals bred for meat in the UK end up being shipped to Europe for slaughter.
But the government said now the UK has left the EU - and will stop following its rules after the post-Brexit transition period ends on 31 December - a ban can be introduced.
Its consultation will also look at further elements of animal welfare in transport, such as reducing maximum journey times, giving animals more space and headroom during transport, and stricter rules on transporting animals in extreme temperatures or by sea.
After months of taking a battering on issues like food standards in future trade deals - chlorinated chicken and the like - here is a strong push from the government on animal welfare issues.
An outright ban of this kind on live animal exports is stronger than some animal welfare experts had expected the government to propose - although one MP who's campaigned on this issue for years (and was delighted) told me he didn't care how the practice ended, just that it did.
Announcing the measure just weeks before the transition period ends sends a strong signal.
The government has long maintained that exporting live animals was a practice which could be ended as a result of Brexit - a good example of where leaving the EU would bring benefits.
No surprise then that it is keen to deliver on it fully.
But included in this consultation are some measures which will limit how far animals can travel within the UK, and it could well be that those measures prove a bumpier ride for the government.
The Conservative Party made the pledge to ban live animal exports in its election manifesto.
There had been fears a ban may not be possible under global trade rules, but ministers are confident its plans are inline with them.
Mr Eustice said the government had "struck the right balance" with its plan, saying it would "remove the trade that most people are concerned about - predominantly the export of lambs for slaughter to continental Europe - but would enable high value breeding stock still to be traded, as they are usually transported in very good conditions".
The basics on Brexit
- Brexit happened but rules didn't change at once: The UK left the European Union on 31 January 2020, but leaders needed time to negotiate a deal for life afterwards - they got 11 months.
- Talks are happening: The UK and the EU have until 31 December 2020 to agree a trade deal as well as other things, such as fishing rights.
- If there is no deal: Border checks and taxes will be introduced for goods travelling between the UK and the EU. But deal or no deal, we will still see changes.
The move has the support of the RSPCA, which has campaigned on the issue for more than 50 years.
The charity's chief executive officer, Chris Sherwood, said: "There is absolutely no reasonable justification to subject an animal to an unnecessarily stressful journey abroad simply for them to be fattened for slaughter.
"Ending live exports for slaughter and further fattening would be a landmark achievement for animal welfare."
But the NFU is instead calling for improvements to export regulations.
The union's livestock board chairman, Richard Findlay, said: "The NFU has developed a solution to raise the standards for live exports for slaughter.
"We believe that an assurance scheme which goes beyond the current regulation would be best to ensure all animals travel in the best possible conditions and that they arrive at the approved and final destination in the best possible health."
He added: "Significant regulatory changes could potentially have a massive impact on the UK food supply chain."
However, the chief policy adviser for campaign group Compassion in World Farming, Peter Stevenson, urged farmers not to oppose the plans.
Instead he called on the industry to "recognise that this is an important part of moving forward to a high welfare future".