A sheep farmer who has lost five pregnant ewes to bluetongue has welcomed emergency authorisation of some vaccines - but fears he will face big costs as a result of the outbreak.

Tim Pratt, of Wantisden Hall Farms at Woodbridge,  said it was "good news" that the BTV 3 vaccines - which are likely to lessen the severity of the virus in animals rather than preventing the disease - have been given the green light.

"For any farmers they don't want any animal to suffer. We want to make sure our animals are in the best of health. Anything that minimises the severity that's good news," he said.

But sheep farmers are under increasing financial strain, he warned. "We have already had a financial cost of lambs dying," he said. "It is what it is but it's just another expense I suppose."

It was unclear yet how quickly the vaccines would be available, how much they would cost and how long the protection would last, he said.

A bluetongue movement restriction zone has been declared across Suffolk, Norfolk and Essex - which means they can't take their animals out of the zone except under licence.

Autumn is a key period for sheep farmers who often take their breeding sheep to markets outside of East Anglia.

Four sheep in Mr Pratt's flock tested positive for the virus - which can be severe or deadly to infected sheep and cattle - on Saturday.

Around three or four of his pregnant ewes aborted their lambs in addition to five ewes died with lambs in utero.

He has four or five sheep confined to a pen after showing some milder symptoms, and another ewe appears to have tender feet - a symptom of the disease - while her lamb is wobbly on its hind legs, suggesting they may have contracted the virus, he said. All of these animals appear to be recovering.

"I know some people locally have got it more inland - I think it's sheep mainly. I think within cows they get it but at the moment they are just a bit poorly but they are OK," he said.

If it proves practical, he would be looking at vaccinating sheep not in lamb first and pregnant ewes later to avoid adding to their stress, he said. The farm is currently involved in its main lambing season.

For him, the ongoing uncertainty is a strain - with no clear idea of when the restrictions might be lifted.

Environment secretary Steve Reed has given the go-ahead for the use of three bluetongue serotype 3 (BTV-3) vaccines in the UK subject to licence.

Government officials are advising farmers to contact their private vets if they want to use the vaccines.

The latest bluetongue virus cases are thought to have come from midges carried across the Channel from continental Europe where the disease has taken hold.

Available licences for the vaccines will either be geographically targeted general licences or specific licences which can be applied for through the Animal and Plant Health Agency (APHA). General licensing will be subject to risk assessment.

Unlike other BTV vaccines, the currently available BTV-3 vaccines are suppressive not preventative - meaning they should reduce some of the symptoms of the disease.

National Farmers' Union (NFU) president Tom Bradshaw - an arable farmer based at Fordham, Colchester - said the announcement of an emergency authorisation for the BTV3 vaccines is "great news".

"We must now ensure that there is enough availability for livestock farmers in the high-risk area to use if they wish," he said.

"The BTV3 vaccines make no claim to reduce infectivity, but they do appear to reduce mortality and the severity of clinical signs – they will suppress the virus, not prevent it.

"So, while they won’t stop animals from becoming infected, they could reduce the impact of the disease on individual animals and therefore provide an animal welfare benefit.

"The use of these vaccines will therefore not ease the movement controls and licences that farmers are dealing with in the Restricted Zone.

“We continue to urge all livestock keepers to remain vigilant for any signs of clinical disease and to report any concerns quickly to their vet or APHA. 

"We also encourage all livestock keepers to comply with any APHA testing requests. The NFU is continuing to work closely with Defra and APHA to ensure that licences to permit movements within the Restricted Zone are available to farmers.”