DNA Testing for Scrapie Resistence

dna_sampleI decided I wanted to test two of our rams for the scrapie resistance gene. Rams that are “RR” at codon 171 are valuable in that all of their offspring with either be “RR” or “QR,” both of which are considered resistant to scrapie. Hershey is our older ram, I am interested in his status. I did not castrate #900, who was born in January, thinking I may want to keep and breed him. He was sired by Jessica’s ram, #650, so is unrelated to all the sheep I have (except his mother, of course). And, #650 is “RR” and also is a very nice ram, so capturing his genetics may be desirable. So, I’m testing those two rams before deciding on my breeding plans for this fall.

The other two ram lambs born this year I castrated- they were born late enough that they’ll probably still be around when the ewes start going back into heat around August/September. I don’t want any accidental breedings, or the necessity of having to separate them; so they’ll be dedicated as butcher lambs. I figure that if I decide not to keep #900 for breeding, I’ll either sell or butcher him before that time frame, so it was safe to keep him intact. He is a lunker, a chubby boy, his mama is feeding him well!

I shopped around a bit on the web for DNA testing companies. I found three, but sadly, one appears to have gone out of business in the last week, I assume as a result of the tough economy. Of the remaining two, Biogenetic Services, offers customers the option of using blood “cards” instead of collecting blood in a vial/tube. I didn’t want to have to call a vet out, or haul the sheep to a vet just to collect a tiny bit of blood. I figured I could probably figure out how to draw blood on my own, but would still have to get a hold of the “purple top tubes” necessary to send blood in vial form. And then you have to pay for faster shipping, to keep the blood fresh.

By comparison, collecting a few drops of blood to put on a paper card is much easier to collect, and mail. Biogenetic Services sells the cards in batches of 15, for a dollar each, plus a few bucks S&H. I purchased a small box of lancets intended for diabetic use, so that I could be sure that each blood sample was clean. The instructions say you can also use the same piercing instrument and clean it with alcohol between animals, but there is risk of contamination. We are talking about such small quantities of blood here, that if you just get the tiniest bit of somebody else’s blood mixed in, it will invalidate the sample.

I spoke with the veterinarian on staff at Biogenetics, and he warned that even animals housed together in close quarters (like a feedlot) can often have each other’s blood on them. He recommended collecting from the ear, which I did. I found that piercing the tip of the ear produced the best blood drop, which I carefully squeezed from lower on the ear, to keep my hands away from the sample. I tried to make sure that I handled the card from the edges, and that the only thing that touched the target area of the card was the blood drop.

Then all that was left to do was label the cards, and send them off in the mail in a regular envelope! I’m anxious to learn the results!

4 thoughts on “DNA Testing for Scrapie Resistence

  1. Laura says:

    Hi, I’m looking for a Katahdin ram lamb to put across my two blackbelly ewes this fall. Might you have one available, for sale or for rent? (I’m especially partial to colored ones!) Thanks!

    • workingcollies says:

      Hi Laura, I tried to send you an email with more info & photos of my rams, not sure if you got it. Let me know if you want to try to make plans to use one of them this fall!

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