Pig producers have blamed the government for failing to understand the 'severity of the situation' if the sector's ability to trade with the EU collapses.
With the end of the transition period less than two months away, industry leaders say they are still seeking answers to a 'long list of critical questions' relating to Brexit and trade.
The UK pig sector faces the prospect of being unable to continue the trade in breeding stock to the EU, further aggravated by the disruption caused by Covid-19.
According to the National Pig Association (NPA), there is a 'lack of understanding' within Defra and wider government on the 'urgency' of the situation.
The body's chief executive Dr Zoe Davies said: “While we are making progress in some areas, time is now running short and we need more engagement from government before it is simply too late."
She said the pig sector faced severe delays, added costs and reduced market access for UK pork exports: "The impact could be devastating."
Dr Davies pointed out that in many cases, the issues would affect the industry whether or not the UK had a deal in place with the EU on 1 January 2021.
The main areas of concern include the inability to export any breeding stock due to a lack of necessary Border Control Posts (BCPs) at key EU seaports. Imports could also be affected from July.
At ports, delays after January and lack of prioritisation for fresh food could jeopardise short shelf life product exports.
A lack of veterinary resources to carry out all the additional checks required on animal and meat exports is also an industry concern, as is the lack of clarity over new requirements and authorisations needed for hauliers transporting breeding pigs.
Dr Davies said the situation was 'extremely frustrating': "We always try to be prepared and remain optimistic, and still believe there is time to resolve at least some of these issues and minimise the negative impacts the new trading arrangements will create.
“We will continue to strive to get solutions, but we need better engagement and answers from across government and fast.
"Our message is that we are facing a very real threat to the viability of the UK pig sector and we must do all we can, collectively, to avoid serious disruption.”