PHA

[Minnie]

Hi Denise,

co-operation with breeders testing their OLDEST females aomngst themselves would be the way to go. But, as we have found in Oz, co-operation isnt easy to achieve! too many egos to be bruised

.

Too true!

In our group alone (which is not a lot of breeders) one PHA bull has 48 registered (not to think about unregistered) progeny, and many of us in the group have cattle from the source, but the 'oh it's not that much of a worry' is burying the heads in the sand.

Too many if they are tested positive won't have the herd book marked as they don't with chrondo either, but it's unhelpful down the track for the buyer and new to dexter breeder.

But Clive, different in the UK where my goodness you have sooo many issues that we don't have here, TB free Australia is so lucky.

And if you don't have cases of PHA yes you do have more important things to worry about that's certainly true!

Farming in the UK seems so hard compared to here, so I'm with Denise on wouldn't want to for quids.

Vicki

[Duncan MacIntyre]

The issue of PHA in the UK is at a delicate stage, and I speak here as an individual and not as a member of the Genetics sub-committee of the DCS.

We must establish for certain whether or not we have the condition in UK. It may be that it only arose abroad, or it may be that it was present some time ago in UK. If it was, it may still be, though it seems likely that if it is, it is in very small numbers of carriers. If we do have a small number and can identify them then it is important to eliminate it if at all possible. This does not mean slaughter of carriers, but through testing not registering any more carriers, and in time the carriers will go and through registration of clear progeney their blood lines will not be lost.

There are very important differences between PHA and chondrodysplasia - for a start chondrodysplasia is what creates the short legged Dexter, and a very substantial proportion of our breeders are not ready to give up breeding short legs. The presence of the chondrodysplasia gene is seen in a positive light by these breeders, and although I for one have decided to use only non carriers in my herd I cannot expect everyone else to agree. When it comes to selecting breeding animals those who wish short legs have already cut the numbers available by half, and if PHA is present and allowed to persist, then lines affected will have available animals for selection cut in half again, so selective breeding for other traits such as good udders, good legs etc etc becomes very much more difficult.

The danger of ignoring the possibility is that since the carriers are completely unaffected they are invisible, unlike the traditional short leg. So if we ignore it, then half of all their progeny will be carriers, so the longer we take to esablish the situation the more difficult it will be to eliminate.

Nothing would please me more than to establish that we do not have PHA in UK, but it will take some time to do that.

Duncan

[Rebecca]

Well, just for the record we have screened our entire herd for PHA. Being in Australia it was relatively easy.

We had previously screened the original herd members for Chrondo and as the DNA was held for even deceased animals we could then screen the orginal herd again. Some didn't need be done because they were free by inheritance due to other herd's screening. We have no carriers in our herd yet did have some that potentially could have been (from generations back). The cost is justified in that now we know that we will not have problems with PHA. Also, it becomes a selling point as we can guarantee the status of our animals both for Chrondo & PHA

We do have chrondo carriers and our policy is that we do not keep short bulls, they are all beefed. Any other calves (both suspected non-carrier stud bulls & all stud heifers) are tested to confirm status. Ideally we would eventually phase out the carrier animals but we have family members who like them. And our Chrondo carriers are all quality animals that produce quality non-carrier offspring, as well as the occassional carrier. :D

[Carol K]

Would it not be a good idea to start testing some herds or animals that were heavy on the Doesmead breeding just for peace of mind?

Carol K

[PorcPrunus NL]

I 've asked "Van Haeringen":
PHA test costs are 55 euro in Holland at the moment.
Not a lot of money.

I think its worth to test at least 5 bulls. But we like to know what the animals are wich have a "high risk" to carry PHA.
There are no watterbabies reported yet. But I think there are to many cows throwing their calves away at about 4 months wich never been found.
And aborted calves are often called bulldogs, while PHA is unknown in Holland (till now).

[marion]

We only assume Woodmagic Wheatear was a carrier. We can't know for sure because she hasn't been tested. If Wheatear was a carrier her dam could have been also, possibly. We presume the sire wasn't a carrier because there'd be more evidence if he was. We assume Wheatear's offspring were sired by the bulls documented on their pedigrees but there is no scientific parent verification to prove that they were.

A US breeder tested hair from a descendent of Woodmagic Wheatear and she was found to be a PHA carrier. WM Wheatear's son, Aldebaran Priapus, tested PHA carrier, was not in the pedigree. Trillium Cluny, tested PHA free, was verifed as the sire of Priapus. So, yes it is an 'assumption' that Wheatear was a PHA carrier, but all tested PHA carriers in North America do trace back to Wheatear..marion



Edited By marion on 1289447595

[PorcPrunus NL]

The cost from a test in the Netherlands are 55 Euro (van Haeringen) http://www.vhlgenetics.com/vhl/

'van haeringen' does not tell me how many carriers they have found. But they don't think this defect will cause a lot of problems.

[Minnie]

After writing yesterday approx 45 animals were on our herdbook as sired by a PHA positive bull, yesterday it went up to 51 and that's only the ones he directly sired and out of them on clicking quite a few, none were marked as tested.
We don't have to mark our animals as carriers as chrondo or PHA, something that I personally find an issue.
I have our carriers marked, so that no-one will make a mistake by ours and it may tip off others with the same bloodline to test.

Vicki

[Inger]

Using the information from the Australian website, I've worked out that one of the most well used semen in NZ is a bull with a carrier in his pedigree. So its highly possible that most of the herds in NZ could have carriers of PHA in them.

In our own herd, all 3 of our bulls have a carrier in their pedigree. But since we haven't had very many abortions in the 8 years of keeping Dexters (and no near full-term abnormal calves, I'm comfortable with waiting until there's an available test for the gene in NZ. We have around 30 Dexters in the herd, so I hope that the cost is reasonable, when it does become available.

[Minnie]

Hi Inger,

If you have a bull with the carrier in his line, is a bigger problem with the number of progeny.

To see anything you need two carriers which is why it took so long to surface.

Just watch with bull pedigrees until you have the test, or if you have a bull see if you can pull the tail hairs and send to Aus for the test.
:D
Vicki

[Duncan MacIntyre]

It matters not a jot whether an animal has PHA or Chondrodysplasia "in their line" if it has not been passed to that individual. Even assumining that BOTH PARENTS are carries, if the animal itself does not inherit the PHA or Chondro gene then it is free, and can never pass it on to its offspring. Recessive genes may appear to skip generations, but in reality if they are not there in an individual they are not there, full stop. But if they are there then they MAY be passed on. Even if carriers are found in your herd, you can still use them for breeding but be prepared to test offspring and only retain non carriers for future breeding and cull as beef any found to be carriers regardless of sex. Not perhaps an ideal position but it avoids parting with old friends.

Duncan

[Minnie]

It matters not a jot whether an animal has PHA or Chondrodysplasia "in their line" if it has not been passed to that individual. Even assumining that BOTH PARENTS are carries, if the animal itself does not inherit the PHA or Chondro gene then it is free, and can never pass it on to its offspring

Exactly Duncan, but the only way to know if it's come down the line is to test, if I had a bull and testing hadn't been done, before it put anymore calves on the ground I'd be testing. My PHA girls positive status came from their grandsire... and after posting a few days ago of 45 direct animals to him, I looked and we're now counting over 50 animals he's sired (not all carriers, although most not tested) on our Herd Book. Which is not all the generation and generation after.
I've marked my three in the herd book and have one heifer that's come back tested negative from a positive cow, and of course she'll never pass it on, because she doesn't have it.
It's not an issue for the UK but in my small group it's a big issue and too many people are putting their heads in the sand and not bothering to test. I know where a bull was sold on once it was known he was a carrier and he's still putting calves on the ground.
:D

Vicki

[PorcPrunus NL]

We have tested our stock bull, because there was born a calf at 7 months from him.
There were no sign's of watterbaby, but to be sure we've tested (at van Haeringen).
Yesterday the result came: He's not a carrier from PHA.

(cost 55 Euro excl. VAT)

I think it wise to test bulls wich are used on many cows.