Post by Shawn on Nov 7, 2008 11:46:09 GMT -5
I'm going to post this, it's copied with permission, from Patti Adams' email to me. She's on this board, but doesn't post often because of her connection problems. Patti has mostly Dexter cattle and 8 head of Kerry cattle.
If anyone has further questions regarding this subject I'll let her know as she is very knowledge about the procedures.
After people have had a chance to see this a bit, I'd like to put it in the TOK.
Thanks, Shawn
"I'm glad that the you and your vet were able to discuss Belle's health concerns and arrange for the additional testing. I shared our BLV testing problem with other Kerry breeders, mainly because of what we learned firsthand when we started doing the testing on Kelmscott's Seamus while he was being collected for export and domestic use at the Kansas Artificial Breeding Service Unit (KABSU) at Kansas State University. His false positive result on BLV with the ELISA test resulted in us finding out that other Kerrys also had given false positive results with the same test. Since all of the Kerry cattle in the United States are very closely related, we thought that there might be a genetic component involved that made their immune response "different". Then we found out that false positive (and false negative) results have occurred within other breeds as well.
Most people don't realize that there are several tests available for each of the diseases that they ask their vet to test for. Some are "screening" tests that are used to inexpensively identify "potential" carriers, then if it's a valuable animal, other more expensive tests are used to confirm their disease-status - such as the PCR which looks for actual viral DNA in the test sample. Seamus had a positive BLV test using the ELISA (a screening test), then he had a negative AGID for BLV and a negative PCR for BLV. A blood serum sample was then sent to VMRD, the manufacturer of the ELISA test used on Seamus, and their lab came back and reported that the test result with their ELISA test was invalid -- it was a false positive.
When only a screening test is used to determine if an animal stays in the breeding herd or goes to slaughter, most of the time the disease-carriers are properly identified and culled. But some of the time, the screening test can give false positive results and you won't know the result is wrong unless a follow-up test using a different method is used. It is important to use a different test method to verify test results because whatever is causing the false positive in the screening test may repeat itself if the same screening test is repeated. Conversely, there are times when an animal gets a false negative result, and it is a disease-carrier and because of the false negative, it stays in the herd and continues to be a source of the disease. Same deal, additional testing is needed to verify actual disease-status of an animal, particularly one (like an AI-bull) that can have a major impact on a number of different herds.
Here are some good weblinks on BVD and IBR, two very common diseases in cattle that can affect their reproductive performance and longevity. These diseases can take on different symptoms in different animals, can be present at the same time in an animal, and can also be confused with each other:
BVD
IBR
You are welcome to share this information with others.
Best Always,
Patti"
MODIFIED TO ADD:
Here is the website of the vet school in College Station TX that will do the testing for you:
College Station TX
link(s) verified: 9.30.10
If anyone has further questions regarding this subject I'll let her know as she is very knowledge about the procedures.
After people have had a chance to see this a bit, I'd like to put it in the TOK.
Thanks, Shawn
"I'm glad that the you and your vet were able to discuss Belle's health concerns and arrange for the additional testing. I shared our BLV testing problem with other Kerry breeders, mainly because of what we learned firsthand when we started doing the testing on Kelmscott's Seamus while he was being collected for export and domestic use at the Kansas Artificial Breeding Service Unit (KABSU) at Kansas State University. His false positive result on BLV with the ELISA test resulted in us finding out that other Kerrys also had given false positive results with the same test. Since all of the Kerry cattle in the United States are very closely related, we thought that there might be a genetic component involved that made their immune response "different". Then we found out that false positive (and false negative) results have occurred within other breeds as well.
Most people don't realize that there are several tests available for each of the diseases that they ask their vet to test for. Some are "screening" tests that are used to inexpensively identify "potential" carriers, then if it's a valuable animal, other more expensive tests are used to confirm their disease-status - such as the PCR which looks for actual viral DNA in the test sample. Seamus had a positive BLV test using the ELISA (a screening test), then he had a negative AGID for BLV and a negative PCR for BLV. A blood serum sample was then sent to VMRD, the manufacturer of the ELISA test used on Seamus, and their lab came back and reported that the test result with their ELISA test was invalid -- it was a false positive.
When only a screening test is used to determine if an animal stays in the breeding herd or goes to slaughter, most of the time the disease-carriers are properly identified and culled. But some of the time, the screening test can give false positive results and you won't know the result is wrong unless a follow-up test using a different method is used. It is important to use a different test method to verify test results because whatever is causing the false positive in the screening test may repeat itself if the same screening test is repeated. Conversely, there are times when an animal gets a false negative result, and it is a disease-carrier and because of the false negative, it stays in the herd and continues to be a source of the disease. Same deal, additional testing is needed to verify actual disease-status of an animal, particularly one (like an AI-bull) that can have a major impact on a number of different herds.
Here are some good weblinks on BVD and IBR, two very common diseases in cattle that can affect their reproductive performance and longevity. These diseases can take on different symptoms in different animals, can be present at the same time in an animal, and can also be confused with each other:
BVD
IBR
You are welcome to share this information with others.
Best Always,
Patti"
MODIFIED TO ADD:
Here is the website of the vet school in College Station TX that will do the testing for you:
College Station TX
link(s) verified: 9.30.10