Fears over bluetongue's impact on sheep fertility

Farmers with livestock affected by bluetongue face an anxious wait to measure the impact the virus has had on their animals' fertility.

Bluetongue is an insect-borne viral disease affecting sheep and cattle among other animals.

Jerry Sanders-Carr who runs livestock farm Exe Valley Lamb said the fertility of his flock had been affected with several of his rams failing initial tests, although passing them when retested weeks later.

He said "I've never had a ram fertility-tested in the past" and added "nobody really knows how rams will recover, as we are finding out".

Fertility testing involves inspecting ram semen under a microscope, assessing its viability by examining the number, mobility and morphology of the sperm.

Sanders-Carr said he bought rams from his neighbour to breed his ewes and sourced others from Yorkshire and Inverness in Scotland - ones that were "as far away as possible from bluetongue".

Government figures up to 5 October show Devon had the highest number of cases in this year's outbreak with 1,108 sites with bluetongue, and 316 locations in Cornwall with bluetongue.

Vet Ashley Rubens from the Moorgate Veterinary Group which has practices on the eastern side of Dartmoor has been monitoring the impact of bluetongue on fertility over two days of testing 150 rams.

He said the fertility of all the rams he tested which were vaccinated before this year's outbreak started was unaffected, with only half of those fertile which were vaccinated during the outbreak and none of those which had contracted the illness fertile.

"It will be at least a few months before they recover," he said and that would be too late for this year's tupping, or breeding season.

Rubens said cattle do not show the symptoms of bluetongue as "strongly" as sheep, but he noticed autumn pregnancy scanning "are definitely getting lower than expected numbers".

He expected a 90% pregnancy rate but was seeing 50% instead and added "longer term, we will be looking at a reduced fertility".

Sanders-Carr said for him: "The next crunch point will be when we do a pregnancy scan of the ewes in early December and we we will tell how many lambs we will have."

Midges which carry the virus have thrived in this year's hot weather and Rubens said: "We were hoping by now it would have cooled off."

He added: "What we really need is wet and windy weather."

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