Scrapie surveillance | Officials hope to better understand disease
Don’t tell the postal and courier services, but certain people are hoping more goat heads are shipped through the system as producers provide samples for scrapie testing.
Sample collection is part of the National TSE Eradication Plan, and goat producers have until March 31 to voluntarily provide heads from animals at least 12 months old that have died on farms or have been slaughtered.
Prevalence of scrapie in Canadian goats is unknown. One case was found in 1975 and another in the early 2000s, but that is not necessarily an indicator of disease levels.
“There haven’t been a lot of cases found in Canada, but that may be a function of the fact that not as much testing has gone on in the goat industry,” said national scrapie co-ordinator Corlina Patterson.
Until 2011, it was commonly thought that goats contracted scrapie only from infected sheep.
However, a U.S. Department of Agriculture report found that half of the country’s scrapie cases involved goats and among those, none had commingled with sheep within the previous five years.
Tests conducted on goat brains will help researchers determine prevalence, but only if enough samples are collected to be statistically significant, said Patterson.
However, the lack of a mandatory registry or traceability program in Canada means the size of the country’s goat herd is unknown. As a result, the goal is to get as many samples as possible in hopes it will be statistically significant relative to the size of the domestic herd.
“It’s important to the success of the prevalence study to get enough samples,” said Patterson.
“Really all we can do is request that we get as many samples as possible.”
Producers will be reimbursed $50 for each sample provided.
Sample collection of 15,000 sheep brains was completed in December, said Patterson. The process was simpler than it is for goats because Canadian Food Inspection Agency personnel were contracted to collect the brain samples at slaughter.
As well, Statistics Canada collects domestic sheep numbers, which meant the number of required samples was easy to calculate.
No such data or system is in place for goats, many of which are raised for milk and fibre as well as for meat.
Scrapie is a reportable disease, which Patterson said adds another element of reluctance to test goats.
“If you find a positive case of scrapie in a goat that you can’t identify and trace to its farm of origin, you have a big problem on your hands.”
She speculated that some goat producers are reluctant to submit samples for fear scrapie will be found and their herd destroyed.
“I understand the economic loss that comes with it, not to mention the emotional loss and loss of the genetics that you lose as part of an investigation, but having the disease risk infecting other herds … the idea is to get rid of the disease so we don’t have to worry about it.”
Darlyne Hoberg, a goat producer near Edenwold, Sask., said she agrees with the need to discover more about scrapie in goats.
“Anything that dies on my farm is sampled for scrapie,” she said.
“The reason I do it is because I believe that hiding your head in the sand and saying that we don’t have any scrapie in goats is counterproductive. We just don’t know. It’s very uncommon in goats, but unless we check, we’re not going to find out if it is here.”
Hoberg said it appears goats can get scrapie from sheep, but little is known about spontaneous cases in goats and it is dangerous to assume keeping goats away from sheep will prevent the disease.
It is fairly common for producers to have both types of livestock, she added.
“That has to do with the meat market. A lot of the people who really like goat also like lamb.”
Canada has a three-part plan to eradicate scrapie in sheep and goats. Sample collection, testing and identifying control methods make up the first part.
The second step is developing a strategic plan and third is a flock certification program that guarantees Canadian stock is free of the disease.
Patterson said Canada already has a voluntary scrapie flock certification program, in which producers test stock, keep records and are endorsed by the CFIA to have scrapie-free animals.
Details on the scrapie program and sample submission forms can be found at www.scrapiecanada.ca.