Ds-what percentages when breeding 2 carriers?

[mark tenenbaum]

I know alot of DS cattle have been bred to each other-either unknowingly or otherwise. Proud Jazz has been linebred alot;and Ihavent heard of many trainwrecks.-I guess my question is what are the numbers Re getting a messd up calf  when you breed a carrier to a carrier?-It just doesnt seem to show up as often like TH or some of the others. O0

 

[shortybreeder]

Statistically, it should be 25% homozygous, 50% carriers, 25% free. The reason we don't hear about it as often is because DS cattle exhibit varying levels of symptoms, and not all homozygous cattle will be "train wrecks." Compared to TH where homozygosity usually results in a dead cow and dead calf. People are more likely to complain about a lost pair than a calf born with twisted toes that can still be sold for something.

 

[idalee]

I know a shorthorn breeder who used a DS carrier bull on up to five generations of his own daughters,  grand-daughters,  etc.  and never produced a calf which he identified as having DS.    Now,  there are about three possible conclusions that can be drawn from this.  First,  maybe the test result was erroneous and the bull really was not a DS carrier.  Second,  transmission of DS may not act like a simple recessive.  We know that it seems to be enhanced by PHA,  even to the extent that PHF offspring from PHA background seem to express DS more readily.    Finally,  maybe this breeder doesn't know what a DS calf looks like!

 

[sue]

I know alot of DS cattle have been bred to each other-either unknowingly or otherwise. Proud Jazz has been linebred alot;and Ihavent heard of many trainwrecks.-I guess my question is what are the numbers Re getting a messd up calf  when you breed a carrier to a carrier?-It just doesnt seem to show up as often like TH or some of the others. O0

Mark, my sister has a cow base of DSC and has used DSC bulls through AI. The calves have not shown any signs. I think this year she has a couple DSC X DSC  bred back to DSC. The gizmo lines ( linebred) apparently have not shown train wrecks either? 

 

[mark tenenbaum]

Thats what Ive heard alot. Matt Bigelow linebred Jazz alot and so did the people with the Ohlde cattle.-I flushed a cow that we havent gotten DNA back on that could possibly be-but shes had a proud jazz, and 2 Lucky Ralphs (whos pha) and all were fine. It may be shes clean-but I am not just going to leave the embryos in the tank. If she and the bull were PHA or TH-I wouldnt use them O0 O0

 

[j3cattleco]

This calf tested DSH. We tested him as we had considered leaving him a bull.  My bull Hidden Treasure also tested DSH and I challenge anyone to find a sounder more ideally designed mature bull structurally than him.  The DS thing to us will need to be managed but not the end of the world that some have made it out to be

Joshua

 

[justintime]

I got a big surprise last summer when I DS tested the rest of my donor cows that had not been done yet. One of the oldest cows, who has a non appendix pedigree, came back as being a DS carrier. She had been in our herd for many years and I had never had an issue with any of her progeny and she herself, is as sound made as you can find. I had 7 daughters in our herd , and so far I have tested 5 of them and all are DS free. I tested the donor a second time and she came back as a carrier the second time as well. When going back in her pedigree to try and see where this defect is coming from, I did find Deerpark Improver however, he is 9 generations back in her pedigree.

I would think there are lots of other breeders who have DS carrier females in their herds and don't even know it. IMO, the hoopla over the DS defect has been overblown considerably. To me, TH is a more destructive defect but lots of breeders actually try in include a TH carrier in their breeding program.

 

[mbigelow]

As long as you don't have PHA in the pedigree the DS is not much of an issue.  I have bred up to five times with jazz with no issue however,  I have had two calves that had expressed the turned in pasterns.  Both straighten out and weaned off at near 700 lbs with no signs by weaning.  I don't think DSH cattle should be propagated.  An interesting side note, one that Sue and I have discussed is that DSC cattle seem to have increased longevity.  At least in her and my herds.  My current goal is finding strains that remove DS.  As JIT pointed out in some cases this trait continues on for multiple generations despite being bred to free animal's. I think DS would be a non issue if PHA carriers were eradicated from the breed.

 

[aj]

I would concur. If the breed hadn't of had pha carriers in their germ plasma, I would argue that DS would have never been tracked down or figured out.