False Test Results

[yuppiecowboy]

I wanted everyone to see this and not have it buried in the 602 Cunia thread.

I talked to a breeder today who had a bull tested for TH when the test first came available. Tested clean. It was ,what? 2 years and the PHA demon came about? Bull is dead so they sent in semen to test for PHA. They tested for both. Bull came back POSITIVE for TH and PHA. He has sold a boatload of heifers and represented them as clean by pedigree. Same guy had a PHA calf this year out of clean by pedigree cow and a bull that tested positive after the fact. When he gets sued, who does he sue?

How infallable is this testing?

People have their torches lit and pitchforks sharpened, ready to head to South Dakota, but who regulates the regulator?

Maybe Show Heifer should get on her broom and head to Illinois.

 

[OH Breeder]

When the test came out  I brought up the error rate(on another board), _.....what were the number of false positives and what were the number of false negatives. I was told I was crazy the test wouldn't give false positives or negatives. So go figure. I didn't and don't know enough about these types of test to dispute what was being said. Most of the test I deal with are lateral flow.

I tihnk it is always important to get both sides of the story before burning down the house. Nothing is perfect unfortunately and there is a margin of error with everything in life - If there wasn't there would be less population running around today. 

 

[knabe]

with TH, there are two mutations.  the lab usually keeps samples.  did they have them retested? 

if you wanted to investigate this, you could have the two samples tested for other markers, and or dna typed.

it would be a bother, but it can be done.  it would take some time to track down the samples.  over time, inventory systems change, but it should be trackable.  what i would do is make contact with no accusatorial verbage with agrigenomics.

 

[Show Heifer]

Did whoever pull the blood use a clean syringe and needle for each animal they pulled? How many animals was pulled that day? Was all blood removed from the hands of whoever handled the samples? Was the samples labeled correctly?  Cross contamination is a bigger problem on the farm than it is in the lab.  Most of the time the cattleman wants to save time and money and "rinse" the syringe between animals (if they even do THAT) and do not switch syringes and needles. Then the answer would be "He would sue himself."

 

[Jill]

I can understand how reusing a needle could give you a false positive, I don't really understand how it could give you a false negative, you are either negative or your not, cross contamination shouldn't turn a positive anything but positive.
There is a margin of error with ANY test, like it or not that's just a fact of life, to say that there isn't is burying you head in the sand.

 

[linnettejane]

i have told my story before i think, so sorry for repeating...i sent a few samples in for testing back when it first started...called to check on results and got great news everything was clean...in my conversation with someone at the testing lab i mentioned that i must have gotten lucky using a carrier bull, outcast...they then said oh wait a minute...they had run my samples against the double vision line, they would have to rerun using the other, something about there were two strands of th...when they ran my samples back on the outcast they came back positive..............but at least i found out at the beginning...not several years later...


*NOTE*  this was at the beginning of the testing "era"...there is now only one test!!! 

 

[frostback]

They should be looking for both then, because I never saw a box to check for one or the other TH mutation.

 

[justintime]

I think the test itself is probably 100% correct, but where there is problems is when you throw human error into the mix.  I also had a situation where I sold a bull on the basis that he had tested TH free. The bull was sold to a small breeder with 12 cows, one of which was a TH carrier. As luck would have it, the second calf born was a TH calf, and it was out of the carrier female. There was a fair bit of excitement after that point in time. I called the lab and asked them to retest the bull. The owner of the bull collected some more blood samples. I did not know it at the time, but he sent a new blood sample in using the bulls name and tattoo for identification, and he sent two other samples in using fake ID information. This time, all the blood tests came back as TH positive.

AgriGenomics owned up to someone making an error ( after a little persuasion) and made a settlement with the bull owner. This was a bad deal all around, but just think of the mess that would have occurred if it had been a larger herd, or if the carrier female had produced a normal calf. If this calf had tested TH Carrier, he would have assumed that the was a carrier because the dam was a carrier. He probably would not have tested his other calves, as the rest of his cows were TH free, and the bull had tested TH free as well. In the end, it was fortunate that this mistake surfaced at the beginning of this bulls use. The sad part was that this was a very good bull, and his calves were outstanding. The owner slaughtered the bull immediately.

This has always been one of my concerns as we all know that the lab is always under pressure from us breeders, to get the results done as soon as possible. With this much pressure to push the test results out the door, we have probably helped set up a situation where mistakes can be made... by humans, and not by the test itself.

 

[yuppiecowboy]

Show heifer it was one animal tested. People that actually own cattle rarely run entire herds through the chute to pull blood.

How the sample was handled isnt the issue. Varying test results is the issue.

 

[knabe]

I talked to a breeder today who had a bull tested for TH when the test first came available. Tested clean. It was ,what? 2 years and the PHA demon came about? Bull is dead so they sent in semen to test for PHA. They tested for both. Bull came back POSITIVE for TH and PHA. He has sold a boatload of heifers and represented them as clean by pedigree. Same guy had a PHA calf this year out of clean by pedigree cow and a bull that tested positive after the fact. When he gets sued, who does he sue.

just want to clarify, there was never a negative PHA test right, only a negative TH test?

what's the reg of the clean by pedigree cow.  does it state that on the registration?

for some people, clean by pedigree could mean a variety of things.

 

[justintime]

Knabe, you are exactly right, in saying " clean by pedigree" can be mean a variety of things to different people.  I had a TH calf from a female that I had purchased as being clean by pedigree. I knew she was bred to carrier bull, and I knew the calf would have to be tested. The service sire was found to be a THC bull, after this female had been bred.  I did a pedigree search on the female, and found Deerpark Improver, 9 generations back in the pedigree, so there obviously had been several generations of carrier females from that one infusion of Improver. This is another of my main concerns about TH and managing it in your herd. It is manageable in a herd that is established maybe, but I am continually amazed at how little many newer breeders know about these defects, even after all the articles and talk about them.  I am afraid that 20 years down the road, everyone may be wishing these defects had been handled in a completely different way.

In regards to using the same needle and syringe in collecting samples, I do think this is a major concern. I do know of people who think using the same syringe and needle is OK if they are cleaned. This is absolutely not correct. Yuppiecowboy, there are lots of herds who run large groups of cattle through a chute to collect blood samples. I rarely ever send in samples of less than 15 or 20 at a time, and usually it is more like 30 - 40 samples. I try to test most everything that is going to be used as breeding stock, and while it is a big extra expense that I do not need, it is an additional piece of information rather than selling animals as clean by pedigree. I know of many other herds that do the same. Personally, I use 3 cc syringes and they are discarded after every sample is drawn. I also use surgical gloves, and if I happen to get a drop of blood on them, I change them immediately as well. I have witnessed some pretty scary ways of collecting samples, so there could definitely be human error at the producer end as well.

 

[yuppiecowboy]

JIT thank you for pointing out that broad statements have exceptions. I should have said Non Canadians. Fact is I stick by what I said. I doubt there are 20 shorthorn herds in the midwest with over a hundred cows. It is a breed made up of small producers, many who have other breeds. ALMOST nobody who has cattle in the midwest does large scale testing. It is USUALLY done on a need-to basis. Its expensive and a pain in the rear.

I would imagine the percentage of procedure error being attributal to the producer around a billion to one, however a sample is a sample. When you have discrepancies in test results it makes you question the test.

 

[Jill]

While there may be many interpretation of "clean by pedigree" IMO it should only mean 1 thing, there is absolutely no chance in this calf's pedigree that there could be a carrier and if that isn't what they are stating then they need to stop putting that statement on the registration papers because when I see that statement I assume that is exactly what it means.

 

[brandisshortys]

The clean by pedigree statement could very well be null and void in a case like this.  Very unfortunate.  Makes one uneasy about buying breeding stock.

 

[knabe]

clean by pedigree according to the Maine association means that both parents have been tested clean.  from that convergence point in the pedigree, and assuming all converging points are the same, 15 generations later, clean by pedigree would be valid.

if, on the other hand, there is even one exception anywhere in the pedigre that doesn't converge between two tested parents, then it is not clean.

 

[Jill]

I don't think that is exactly correct, there are a couple of breeds that they state are clean even though they haven't been tested, Angus being one of them.

 

[brandisshortys]

I agree with Jill.  Some breeds do have different wording/determination of this phrase.

 

[knabe]

clean by pedigree according to the Maine association means that both parents have been tested clean.  from that convergence point in the pedigree, and assuming all converging points are the same, 15 generations later, clean by pedigree would be valid.

if, on the other hand, there is even one exception anywhere in the pedigre that doesn't converge between two tested parents, then it is not clean.

"I don't think that is exactly correct, there are a couple of breeds that they state are clean even though they haven't been tested, Angus being one of them."

for maine's, that is the case i think.  can there be a base cow not tested in maine's. yes, so i guess we are both wrong.  technically, for me at least, if even one animal isn't out of two parents tested clean, there is a chance of dirt.

 

[TMJ Show Cattle]

When I read "clean by pedigree"on any sale animal I automatically assume the worse and test them myself.It's a pain,and I'm glad we are a much smaller operation than what I used to be.Every calf is tested befor he or she leaves this place.I have carrier cows and try and use non carrier bulls,so to have peace of mind we test the calves.

 

[Jill]

clean by pedigree according to the Maine association means that both parents have been tested clean.  from that convergence point in the pedigree, and assuming all converging points are the same, 15 generations later, clean by pedigree would be valid.

if, on the other hand, there is even one exception anywhere in the pedigre that doesn't converge between two tested parents, then it is not clean.

"I don't think that is exactly correct, there are a couple of breeds that they state are clean even though they haven't been tested, Angus being one of them."

for maine's, that is the case i think.  can there be a base cow not tested in maine's. yes, so i guess we are both wrong.  technically, for me at least, if even one animal isn't out of two parents tested clean, there is a chance of dirt.

I have Mainetainer papers on a heifer stating F/P on both TH and PHA and as far as I know OCC Anchor has not been tested for either.