pha status of cowans ali

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DL

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Ali is PHA free and TH free.

There was some concern early in the hunt for the PHA gene (and as we were getting a better understanding of the disease itself)  that ALi was a PHA carrier because there were so many reports "from the field" that he had sired a PHA calf. These reports were never verified by DNA testing. Similar reports of PHA calves were received from AI Angus sired calves. These were not verified by DNA either. What this told us is that many PHA calves are born "early" to the AI date when in fact they are sired by the herd bull.
 

JbarL

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dragon lady said:
Ali is PHA free and TH free.

There was some concern early in the hunt for the PHA gene (and as we were getting a better understanding of the disease itself)  that ALi was a PHA carrier because there were so many reports "from the field" that he had sired a PHA calf. These reports were never verified by DNA testing. Similar reports of PHA calves were received from AI Angus sired calves. These were not verified by DNA either. What this told us is that many PHA calves are born "early" to the AI date when in fact they are sired by the herd bull.
dl ....thanks...i got hooked up[ with a gent in utah last week that has some interest in touching his angus with a bit  of cowmans ali....and  wasnt sure of his status  hope he took my advice and got on the site.....thanks jbarl
 

xxcc

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this is strictly tailgate talk that was handed down to me, but what are the possibilities of detecting a PHAC by DNA testing blood, but missing the same animal by testing semen.  e.g. John's Whiskey son is blood tested PHAC, but when a sample of semen is sent in, Mr. Whiskey son tests PHAF?  I thought DNA was DNA?
 

DL

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xxcc - given human nature (and the fact that people have send in the same sample multiple times under different names trying to get a free result) IMHO the chance of getting PHAC on blood and PHAF on semen is about as close to zero as one can get. As you say, DNA is pretty much DNA (nuclear DNA is DNA residdeing in the nucleus) - so my guess with John's Whiskey is that he was drinking too much and his samples are not from the same animal!
 

knabe

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what's good about the PHA test, as well as the TH test, is that you see a marker for each status of the animal.  since the amplified DNA is digested with a specific enzymye for a specific sequence, the one that has one form will be digested into two pieces, the other will be undigested.  this is why the enzyme used are "restriction" digests.  they were called this early in the genomics game, because digestion was restricted to a specific sequence, rather than just randomly digesting dna.  in PHA, the digest occurs on the actual SNP i believe which is great, as opposed to around a defect, which could allow alternative allele sequences without knowing it, unless sequenced everytime.  the odds of that are low though.  what is nice about having a positive result for a negative, is that the absence of a band for a negative wouldn't tell you if the reaction worked or not.  that's why in this case, something else has to be wrong, unless the digestion enzyme wasn't added to that well, which is highly unlikely, and can be repeated easily on the same sample if there is a question, which, is why they carefully archive all their samples.
 

Barrel Racer

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There was a rumor going around that a bull had tested PHAC by blood and then semen was sent by distribution company and it came back PHAF.  We were alerted to this rumor and we found that a semen sample had never been sent on this particular bull.  If there is another bull in question, please PM me and I will see what I can find out about this problem.  DNA is DNA whether it comes from semen or blood.  The only problems we have had are dealing with twins and DNA needs to come from hair in those cases.  Dr. B has always stated the tests are accurate barring human error, so if there is a problem he needs to know.  We go back to the original tube or semen sample, reisolate the DNA and redo all tests to confirm results.  Just did a PHA calf that was "by a clean bull", redid all the samples, they all came back the same, paternity showed calf wasn't by that bull, but another proven carrier bull. 

knabe - just an FYI for you... we have a digestion control in the test, so the enzyme cuts in both normal and carrier animals, just one extra time in the carriers so we know if the digestion was done/complete or not. 
 
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