Inbreeding coefficient

[Lonesome Pine]

Hi All, looking for some advice on how closely our cattle should be to each other in our breeding program. Is a half sibling a problem, especially if the half they don't share are different breeds? How about grandparents or uncle?
Appreciate any advice as the data out there referencing inbreeding coefficients is scant and doesn't seem to consider the above breeding an issue.
Many thanks, Mary

 

[wbvs58]

Hi All, looking for some advice on how closely our cattle should be to each other in our breeding program. Is a half sibling a problem, especially if the half they don't share are different breeds? How about grandparents or uncle?
Appreciate any advice as the data out there referencing inbreeding coefficients is scant and doesn't seem to consider the above breeding an issue.
Many thanks, Mary

Mary, I personally don't stress about the occaisional bit of inbreeding. The bulls I use after AI I breed myself so there will sometimes be a bit of breeding back to their mother, 1/2 sister or other relation. For the most part these will be terminal calves but I sometimes retain a heifer from a close breeding of a very good cow and like to follow the result.
What is the situation in your case, what are your goals for the close breeding?

Ken

 

[Mountaintown Creek Ranch]

COI of 15 is our limit.
In Japan they breed the Jap Blk up to 28.

 

[SBMF 2015]

A guy I consult for used to run a reg. Hereford bull. The bulls pedigree Said his sire and dam were full siblings. That’s a little close for my comfort but he did throw some really nice calves when crossed on pure bred angus cows.

 

[Mark Reynolds]

Inbreeding probably has an unnecessarily bad reputation for what it is. You need to have a good understanding of it before you start labeling it. All inbreeding does, on the short term anyway, is dramatically increase the likelihood of creating homozygous pairs of chromosomes in the resulting individual. When you are trying to create a homozygous trait that is particularly desired but very rare, inbreeding can be a great thing. On the other hand, most all individual organisms (you and me as well) carry a few, rare, recessive genes that if they get paired in a resulting offspring, the results are less than desired or even disastrous.

Inbreeding creates a high stakes risk/reward scenario that most commercial operations do not/should not approach. Now on the other hand, if you are running an operation trying to create highly desirable breeding stock to improve the breed as a whole, the risk/reward very well could be worth it.

For the commercial operator, hybrid vigor is the route I would recommend, with a three-way cross. That doesn't mean that's the way you want to go or what is best for you.

 

[ClinchValley86]

how's about a 4 way cross?

 

[Lonesome Pine]

Mary, I personally don't stress about the occaisional bit of inbreeding. The bulls I use after AI I breed myself so there will sometimes be a bit of breeding back to their mother, 1/2 sister or other relation. For the most part these will be terminal calves but I sometimes retain a heifer from a close breeding of a very good cow and like to follow the result.
What is the situation in your case, what are your goals for the close breeding?

Ken

Thanks Ken and everyone who has replied. I really appreciate the advice. We are a small operation, less than 20 head and our bull has thrown consistently good calves who zero birthing issues. Now we just had one of our best cows throw a beautiful little bull from him too. Would luke to breed this new bull to his half siblings in the future. Thanks again, Mary

 

[Travlr]

Hi All, looking for some advice on how closely our cattle should be to each other in our breeding program. Is a half sibling a problem, especially if the half they don't share are different breeds? How about grandparents or uncle?
Appreciate any advice as the data out there referencing inbreeding coefficients is scant and doesn't seem to consider the above breeding an issue.
Many thanks, Mary

I think the question you might want to consider is... Why am I considering inbreeding when there are other options with less risk?

I read your last post which indicates that you like your bull. Is your attachment to your bull worth the admittedly low risks? Risks are only low when they don't result in bad outcomes.

I know of a couple who married as first cousins. They had five children. All of their kids are deaf. One of the five has developed a kidney disease requiring a transplant.

Golden retrievers and dalmatians have genetically linked potential for psychosis due to inbreeding.

Gar Precision 1680 was a powerfully popular bull several years ago, and when he was bred to his descendants the lethal genetic condition of curly calf syndrome resulted in dead calves. The anomaly was traced back to him and his genetic contribution threatened to spread through the black Angus breed. A concerted effort by registered Angus breeders doing genetic testing resulted in a lot of otherwise superior animals being culled.

How much do you like your bull?

 

[4hfarms]

It may be an issue with a breed back to mom but the others are not a concern for terminal stock.
I do believe from my understanding, once the related animal is crossed with an unrelated animal, the offspring will not have issues if bred back.

We also have a small heard and have to watch the way we pair them up.
We also change out bulls every couple years to make sure we don't "castrate" ourselves in the process.

 

[Travlr]

I do believe from my understanding, once the related animal is crossed with an unrelated animal, the offspring will not have issues if bred back.

A lot of it depends on how many alleles are involved in any one trait and how each is triggered by a protein. Once a detrimental mutation gets into the population it can concentrate or be diluted over generations.

 

[Mark Reynolds]

how's about a 4 way cross?

You'd still get the hybrid vigor, but there isn't going to be a real noticeable increase going from a 3 way to a four way. I'm not saying it's a bad idea, but not a lot to be gained. For whatever reason, you get a substantial increase in vigor when you add a third breed to a hybrid between two different breeds. There is no significant increase in vigor when a 4th is added to a 3 way. I would think though that you may get an increase in vigor in the progeny if you were to cross a 2-breed bull with a 2-breed cow of different breeds over the parents.

IF I were to have a herd myself. I would utilize 1 or 2 purebred bulls and have cows that were crosses between 2 breeds that were different from the breed of the bull. I could/would retain heifers, but I would breed them back to a bull of either of the breeds the heifer's cow was. Should I retain a heifer from that cross, that heifer would be matched with a bull from the other breed the original cow was composed of. I hope that makes sense.

 

[Rancher]

You'd still get the hybrid vigor, but there isn't going to be a real noticeable increase going from a 3 way to a four way. I'm not saying it's a bad idea, but not a lot to be gained. For whatever reason, you get a substantial increase in vigor when you add a third breed to a hybrid between two different breeds. There is no significant increase in vigor when a 4th is added to a 3 way. I would think though that you may get an increase in vigor in the progeny if you were to cross a 2-breed bull with a 2-breed cow of different breeds over the parents.

IF I were to have a herd myself. I would utilize 1 or 2 purebred bulls and have cows that were crosses between 2 breeds that were different from the breed of the bull. I could/would retain heifers, but I would breed them back to a bull of either of the breeds the heifer's cow was. Should I retain a heifer from that cross, that heifer would be matched with a bull from the other breed the original cow was composed of. I hope that makes sense.

Clear as mud...kidding

 

[wbvs58]

Thanks Ken and everyone who has replied. I really appreciate the advice. We are a small operation, less than 20 head and our bull has thrown consistently good calves who zero birthing issues. Now we just had one of our best cows throw a beautiful little bull from him too. Would luke to breed this new bull to his half siblings in the future. Thanks again, Mary

Mary, I would probably consider it for an interim situation but shoot for another bull for the longterm.

Ken

 

[StrojanHerefords]

The larger issue that I see is using just one bull. If your bull goes bad then you will have no calves.

 

[Mountaintown Creek Ranch]

how's about a 4 way cross?

Cattle orgy

 

[Lucky_P]

Needs & requirements may be somewhat different for registered seedstock producers and commercial producers.
For a small commercial producer, I've always felt that maximizing use of a good bull that throws the kind of calves you want, could and would include using him over his own daughters, and in the vast majority of cases, you'll get by just fine - and buyers don't know or care that they have some inbreeding/linebreeding. With small cow numbers, I found it hard to justify selling a really good bull after two years, just because he'd be breeding a daughter here or there.
That said, in order to maximize productivity, switching to a second or third breed bull will maximize hybrid vigor and probably return sufficient $$ to justify swapping out bulls every 3 years or so.

That said, in the event that there are recessive genetic defects in the woodpile, you can have problems. The GAR Precision 1680 bull was mentioned earlier... he inherited the Arthrogryposis Multiplex (curly calf) gene from his maternal grandsire, Rito 9J9, but the Neuropathic Hydrocephalus defect originated in 1680, so he was a 'double-carrier'. No one knew that these defects were sliding along undetected. 1680 was used widely and heavily, and when his sons/daughters/grandsons/granddaughters started being bred to one another (or back to 1680), carriers of one or both defects had the opportunity to be mated and defective calves began to arrive.

We experienced our very own Angus genetic defect, courtesy of a bull we purchased in 2007. Used him across the entire herd for two years, and his daughters were fabulous, steers were good. We started doing AI on 90% of the herd, and kept the walking bull for 'cleanup' behind AI. So... for about 5-6 years, there were several instances of him breeding a daughter, or even a granddaughter. Most calves were fine, but over a 6 year period, we had about 9 defective calves born, which were determined to have Sodium Channel Neuropathy. Genetic testing revealed that a high percentage of my cows, which were daughters/granddaughters of the original bull were carriers. Testing of all ancestors of the bull with DNA profiles on file revealed that none of them were SCN carriers, so it was determined that our bull was the 'founder' of the SCN defect, just like the NH defect arose in Precision 1680. We sold him at 10, but had retained a SimAngus son to use on heifers... which turned out to be a SCN carrier, and sired 2 or 3 defective calves himself. Confined to our herd, with both affected sires sent to slaughter, SCN is essentially relegated to the dustbin of history.

 

[Travlr]

We experienced our very own Angus genetic defect, courtesy of a bull we purchased... SimAngus son to use on heifers... which turned out to be a SCN carrier, and sired 2 or 3 defective calves himself. Confined to our herd, with both affected sires sent to slaughter, SCN is essentially relegated to the dustbin of history.

So you are saying that the females are a terminal nexus for the anomaly? Was the defect on the Y chromosome? How are the female "carriers" not passing the defect down the line?

And was the original bull the result of close breeding? Inbred or line bred?