There are several schools of thought about the scrapie situation in the USA. Some say that since there are fewer and fewer cases every year, it is inevitable that, over time, scrapie will become a non-issue. Others say that having a certified scrapie free flock is enough. Yet others test for genetic scrapie resistance. It could be said that everyone is right. A combination of these positions can offer the absolute best security for a shepherd’s flock and add value for a potential buyer. Every shepherd must judge for themselves what makes sense for their geographic location, market, and risk.
The United States Department of Agriculture (USDA) Animal Plant Health Inspection Service (APHIS) scrapie eradication program determines how animals, farms, and entire flocks are handled when scrapie is discovered.
A surveillance program managed with cooperation between the federal government, each state, and industry, monitors scrapie through testing at slaughter, on farms, and through the Scrapie Free Flock Certification Program. When an animal tests positive it is tracked back to the source (if possible) with the potential for any sheep having contact with the diseased animal to be euthanized (genetic testing aside). Heartbreaking, but tracing the disease back to the point of infection eliminates the source, thus making future positive scrapie from that flock unlikely. With this stance, the scrapie incidences will be reduced to a point of almost being a non-issue. Eventually, the goal being to eradicate scrapies from the USA.
Having a certified scrapie free flock takes time and adherence to the Scrapie Flock Certification Program Standards. Check the link for further information. https://www.aphis.usda.gov/animal_health/animal_diseases/scrapie/downloads/standards_current.pdf
The caveat is that while the animal from a flock certified free of scrapies is indeed a safer alternative than a non-certified flock, the animal brings limited value to the new flock unless the genetic resistance of that animal is known. There is the peace of mind that certification brings to a flock owner and to buyers of those animals, especially buyers that already have certified flocks. To maintain the certification (there are two categories with three statuses) any additions to the flock must be the same level or higher certified. Co-mingling reduces all certifications to the lowest level animal in the flock.
Genetically testing sheep for Codon 171 can help determine which sheep carry lower susceptibility for scrapies. QQ sheep are at the lowest end of the scale and are most susceptible to scrapie infection. QR sheep are much less susceptible and RR sheep stand at the top with genetic resistance to scrapie. With the new regulations from United States Department of Agriculture (USDA) Animal Plant Health Inspection Service (APHIS), having tested valuable members of the flock can add a level of security especially if those sheep come in contact with other animals (such as shows or fairs). And in marketing lambs with genetic resistance a buyer is assured that those lambs will bring added value in the form of genes that will be passed on to their offspring.
By taking the steps of certification and genetic testing, scrapies incidences are decreasing every year. Protecting our flocks by adopting best practice biosecurity protocols can help but the long incubation time necessitates a multi-pronged approach. Genetic testing is a valuable tool in the ongoing fight to eradicate scrapies from the USA.