Last week we sent a group of lambs to the abattoir in mid Wales as we always do at this time of the year and when the kill sheets came back I was shocked with some of the results. It turned out that of the 87 lambs delivered the Food Standards Agency condemned 17 (nearly 20%) livers for something called Cysticercus tenuicollis. In total the weight loss was 11.7Kg, at £4.50/Kg which equates to £52.65 of lost income, but that's not really my point.
The disease stems from the dog adult tapeworm Taenia hydatigena and is transmitted to sheep when infected dogs shed eggs via their faeces onto the pasture. These eggs can survive on the pasture for up to 6 months. Another problem with dog faeces is very similar and is called Cystericercus ovis or sheep measles and is ingested almost identically. (Here's a cyst on a liver)
Once in the sheep the larvae develop and penetrate the sheep's intestine, spreading to various tissues including the omentum, mesentry, peritoneum and liver. As-side from liver condemnations heavy infestation can cause haemorrhages and peritonitis. Once the sheep has been exposed to tapeworm eggs, it is impossible to prevent the cysts developing so it really is out of our hands.
In order to reduce the risks we ensure that all of our farm dogs are wormed regularly, this is also covered as part of our Farm Assurance. We must insure that all visiting dogs are also wormed appropriately, using the correct wormer and using the right dose for weight of the dog. (Please see your vets about specific products)
With over 40Km of footpaths, bridleways and permissive paths on the farm, many of which run through our grazing pastures it is so important for you, the dog walking public, to make sure your dog doesn't contribute to this potential threat to the welfare of our sheep flock.
These two problems in 2009 cost the English sheep industry £7.5 million (EBLEX Lamb briefing 10/07).