8 September 1995

Enzootic abortion costs flock dear

By Rebecca Austin

A FLOCK infected with enzootic abortion will cost £10 to £12 a ewe in lost income, says Dr Karl Linklater, director of veterinary services at the Scottish Agricultural College.

He advises buying in breeding ewes from abortion-accredited flocks to help cut this cost.

"In the 70s and 80s the national flock expanded and farmers wanted a warranty that they were not buying-in abortion," says Dr Linklater.

Enzootic abortion is introduced into clean flocks by infected animals. And as the stratification system ensures most replacements come off the hills into lowland flocks, buyers must be sure of the health status of that stock.

When the enzootic abortion scheme was introduced by the SAC seven years ago lowland flockmasters had to pay a premium for accredited ewes and ewe lambs. Now, even though the premium is no longer visible, it is still producers with unaccredited flocks who feel the pinch, in some cases up to £15 to £20 a ewe.

Dealers view

But the differential in value between an accredited and non-accredited ewe is not all down to the health scheme, explains Wilts-based Peter Walker. He is a dealer who brings about 5000 breeding ewes south for clients each season.

"I have been going to the big Mule sales at Castle Douglas every year for about 20 years now. I tend to know those farmers with the better breeding stock which I buy," says Mr Walker. "It is those producers who have taken up the scheme and the wise buyers have gone with them. Many of my clients have, therefore, built up an enzootic abortion-free flock without even realising it."

This year at Castle Douglas, where nearly 17,000 breeding Mules were sold, only about five consignments were not accredited. It was the reverse 10 years ago.

"The number of accredited flocks has built up gradually over the years," he says. "In the past four or five years more and more people are becoming accredited."

The cost of becoming accredited depends on flock size, explains Dr Linklater, as a larger flock needs a relatively smaller sample of ewes blood tested. Producers with up to 30 ewes are charged £31.30 by the SAC, whereas those with 5000 ewes plus pay £630.

So far, a third of ewes in Scotland – one million – are in the scheme. The rules and guidelines outlined (see box) also govern the Highlands and Islands Sheep Health Scheme. Accredited ewes and ewe lambs are sold with a certificate signed by the farmer, his vet and the local SAC veterinary services vet, which states the consignment comes from an enzootic abortion accredited flock.

Prices at Castle Douglas last month were about £2 a head up on last year at £50 a head. Mr Walker puts this increase down to producers who have leased their quota out for the past two years needing to buy-in stock to ensure they retain their units.

"Those producers must start buying-in accredited stock, otherwise the chance of their ewes aborting in their first year increases," warns Mr Walker. "The easiest way back in is through accredited breeding ewes and lambs.

Leave yourself open

"Over the years the scheme has proven its point. Unless you buy lambs every year from the same Scottish boys, you leave yourself open to abortion attacks because the sheep are not covered for any vaccinations. They might be accredited free but they might not have any resistance."

For farmers already struggling with enzootic abortion at lambing time Dr Linklater advises they either just live with the disease and vaccinate against it, or get rid of the breeding flock and repopulate with accredited stock. "It would be foolish not to vaccinate an infected flock," he says.

&#8226 Bob Moffatt, who runs 850 Grey Face ewes on 283ha (700 acres) at Wooplaw, Galashiels, buys in about 200 accredited ewe lambs each year from Castle Douglas. This reassures him that the lambs are free from enzootic abortion.

"Eight years ago the farm was clean. Then I bought 150 gimmers, some of which aborted," he says. "Since then I have bought ewe lambs and, even though theyre accredited, I vaccinate against enzootic and toxoplasmosis."

He is concerned his system is getting too costly at £6 a head. But with many of the farms in the region still suffering from enzootic abortion, he believes it is best to take every precaution. "You must buy in clean sheep and then vaccinate them to be sure," he says.

&#8226 Farmers apply to their local veterinary centre via their own vet to join the scheme.

&#8226 Most join the scheme in early spring so that any abortions can be submitted to the local Scottish Agricultural College (SAC) vet centre for examination.

&#8226 Any ewes which have aborted, or are barren, are blood tested.

&#8226 Three months post lambing, usually at shearing, blood samples are taken by the farms vet. The sample will cover all age groups within the flock.

&#8226 If all tests are positive in the first year, the flock gains supervised status.

&#8226 After the second year of being provisionally accredited (two years of negative tests) the flock becomes fully accredited.

&#8226 Annual retest – except in areas of low risk. For example, an island or a discreet area where all flocks are tested. These designated areas are retested every two years.

Enzootic abortion – cut the cost.