Line Breeding

[ArmyDoc]

Hi,

I've been reading about Line Breeding. I understand the concept of breeding related animals to "set" a characteristic, essentially trying to increase the chance of obtaining a homozygous animal for certain traits so that it will breed true to type.

My question is, how much is too much? Obviously, the flip side of Line Breeding is in-breeding and the amplification of bad traits. So when does Line breeding become a problem and become inbreeding? I've read about inbreeding coefficients - is there a number that is too high, a cut-off if you will? Or is it more or less result driven. Line breeding is fine/good so long as the offspring are healthy and strong?

Also, what is "normal" breeding practice. I've seen two bull rotations and three bull rotations. Both of these will result in some inbreeding / line breeding - the first is grandfather to grand daughter and the second is great-grandfather to great-granddaughter, but not as close as father/daughter or sibling/sibling crosses. Would a cousin cross, for example, be considered Line breeding / in-breeding?

Thanks.

 

[OK Jeanne]

We have 3 or so cow families that we are trying to
emphasize their traits in our herd. But we never breed
animals that are more than 50% related to each other,
and will not breed father/daughter or son/mother. So
far it has worked out well and we have some really
dandy up-coming heifer replacements and good young
bulls also.

 

[Herefords.US]

The 50% rule is generally the rule most linebreeders follow.

However, I have mated a son back to his dam this year and I plan to do a couple of sire/daughter matings this fall.

The son may be the heir apparent to my current herd sire and become my "clean-up" bull going forward. He will also be a half-brother to a good portion of my cowherd.

I'm doing these matings in an effort to expose any problems that I'm unaware of - not because I think such closebreeding is a good breeding practice over time.

George

 

[backhoeboogie]

I will let a sire breed a daughter but that's it.

 

[ArmyDoc]

Several have posted a 50% rule... can anything be closer than 50%? Oh! Do you mean like a father/daughter offspring (50%) being rebred back to father again? I guess that would be 75%.

How far apart do they need to be to not be considered line breeding? Would cousins be considered line breeding? I've seen sites recommending 3 sire rotations. The offspring of sire one is mated to sire 2, that offspring is mated to Sire three, and those back to sire one. Is this considred far enough apart that it would be considered "normal", and not line breeding? What about 2 sire rotations?

Thanks.

 

[Dusty Roads]

Hey Doc,
J.D. here. I have been breeding quality cows, and dogs for some time now. In my opinion cousins is cross breeding. I have bread sire-daughter many times with no problems.
What you have to keep in mind is you may intinsify the good traits, but also the bad, so weigh the odds.
I do not cross breed brother-X-sister or line breed sire-X-grandaughter but I do know people that have with no probs.
Good luck,
J.D.

 

[ArmyDoc]

Hey Doc,
J.D. here. I have been breeding quality cows, and dogs for some time now. In my opinion cousins is cross breeding...
J.D.

Crossbreeding? I'm not sure what you mean. I've always heard crossbreeding as being between two breeds.

When I retire, I'm planning on running a small herd. Probably not more than a half a half dozen animals to start. As I learn, I think I will eventually get up to as many as 25 max, but I really don't expect to go higher than this given I don't think I can afford more than about 50 acres.

During the first several years, I was planning on avoiding line breeding. I suspect I won't have the experience necessary, and I don't want to risk having problems with inbreeding.

But in a herd so small, inbreeding could be a problem. AI is one option, but not until I learn enough about recognizing the signs of a cow in heat etc. Which means, I think, one bull for the first few years. I guess I could just sell or eat all the offspring, but I hope I end up with a calf or two worth keeping each year to slowly increase the size of the heard. (I may run a small operation, but I want to run it first class, and raise quality animals) I figure given my limited pasture resources, I can realistically only expect to keep one or two bulls. I planned on using AI down the line to keep things from getting too closely related

So, I am trying to get a handle on how soon I will need to start using AI, or get that second bull. Am I making a mountain out of a mole hill?

 

[Joy in Texas]

I wish Aero was here . He is good on this line breeding stuff.
Anyway, you could do a search on the boards that could tell you alot. This where I learned some things about line breeding.
Also someone suggested before of contacting Jim Lents about his book on line breeding. His email is [email protected].
Hope this helps.

 

[Bluestem]

I would consider using AI. Your future plans for max herd size doesn't justify having a bull around. You could start your linebreeding using AI. After a few generations you'll have to make some breeding decisions. Have you read "The basis of Linebreeding" by J.H. Lents, "Linebreeding" by Jay L. Lush ?

 

[jhambley]

You may want to consider purchasing "The Basis of Linebreeding" by Jim Lents. I have included a link to a thread discussing this book.

http://cattletoday.com/forum/viewtopic.php?t=37433&start=0&postdays=0&postorder=asc&highlight=lents

 

[ArmyDoc]

I've been mostly reading online sites so far, but I will be ordering his book.

My real question though, is how to avoid line breeding, as opposed to how to do it. When do you cross over the line between "normal" breeding practices and line breeding?

For example, a three bull rotation stabilizes with an in-breeding coefficient of 0.035 (3.5% related). Which is roughly 1/2 that of the inbreeding coefficient produced by breeding cousins (0.0625). Would this still be considered line breeding? I wouldn't think so, but it isn't the same as zero relatedness either.

Maybe there isn't a hard and fast rule, and I'm looking for a definition that doesn't exist. I don't know.

 

[backhoeboogie]

ArmyDoc, I may be totally off base here. The term linebreeding to me signifies someone is producing a "line" of cattle, and I have always associated it with breeding a bull back to his offspring. Same with horses and dogs. That is how it was explained to me in my youth. That is how folks with degrees in Ag (animal husbandry, vets etc) has explained it to me. I don't have a degree in Ag. In-breeding is something different which doesn't necessarily involve a sire back to his off-spring.

Again, I may be totally off-base, but ranchers have been breeding bulls back into their off-spring for hundreds of years. Most folks breeding range cattle change bulls after the second generation.

Your breeding reasoning needs to be understood before anyone can truly advise you. What are you trying to achieve specifically? Decide that, then weigh the risks, and determine if your willing to gamble. Then you can find all kinds of information that is credible.

 

[ArmyDoc]

Well, at first I just want to raise some quality beef for myself. I'm thinking a senepole/angus cross would be a good cross to try in Georgia because of the heat and humidity... and I like the look of the ones I've seen. So my first goal is simply not to do anything that will result in problems. My second goal to raise good looking, healthy cattle that do well off grass in my climate so that if I have an extra animal or two I can break even on raising the breeding stock and ones I eat.

If I can succede at doing that, then I might consider trying to establish a successfull line and expand into actually selling cattle to make a little extra.

At this point, it's a little more than a practical hobby for me. But I am a mildly Type A personality (my wife's not here, so I can say mildly ) So I want to learn as much as I can and do things right, so that I can be set up to succede in the future if I ever do get past the learning phase.

It sounds like I'm being overly cautious. It sounds like if I start with sound stock, and I happen to get a good looking bull, I could safely use him on a half sister or a niece or cousin without major concerns, so long as I used a different sire for the next generation.

 

[backhoeboogie]

If that is indeed the case, I believe I would swap bulls every two years. There is less risk and no worry.

 

[usernametaken]

Army Doc,

I haven't bred cows so take this with a grain of salt, but I figure a mammal is a mammal. I've bred dogs for about 15 years.

When is it linebreeding and when is it inbreeding ? The age old question. Some people believe it is all inbreeding. The phrase I hear most often is it's linebreeding when it works and inbreeding when it doesn't. Not too helpful I know.

A favored cross in Quarter Horses was grandsire to granddaughter. I don't think you'll see many ill effects from that one cross, unless you continue getting closer in subsequent generations. 1st cousins my veternarian actually thinks is a great idea. Uncles would be about the same degree.

I accidentally bred a sire/daughter litter. I was scared to death, but wow, what a nice litter. However, upon the advice of my vet, I sold them all on spay/nueter basis only. Not something I normally do. I sort of understand what my vet is saying but don't know if I can explain it - basically it goes like this - when you linebreed and stack the genes so closely together, you usually are ok that first generation. That is why that litter was ok. The danger is, according to my vet, in the next generation. If you take this close bred, actually inbred dog and outcross it to a totally different line, the chances of those genes pairing up with something negative is increased many times. Makes sense but doesn't make sense. Let's just say I totally trust and admire the knowledge of this particular vet.

I own a stud dog, not bred by me, but tightly linebred for 50 years of pedigree behind him. He is 7 years old and the picture of health and always has been. Even better, his offspring are predictable, no matter who you breed him to. But that old breeder where he came from had no problem with culling and he passes on desireable traits.

When have you linebred to much ? In dogs, you will see litter sizes begin to decrease. The vitality of the newborn will begin to diminish. You won't see them latching on and nursing within minutes of birth anymore.

AI is a great tool and can bring in great genetics that you otherwise wouldn't get. However, there are some things about it that worry me. 1. If you breed always and only AI you could be masking some problems with conception naturally in both the sire and/or dam. No one wants a dog who can ONLY be bred by AI anymore than they want pups that can ONLY be delivered by cesarian. 2. selection is often based purely on numbers and pictures. Seeing is believing.

Ideally I think if all animals, cows, dogs, whatever, were first bred the old fashioned way, and only using AI after that first successful calving the old fashioned way, then our stock would remain healthy in their reproductive capabilities.

 

[ArmyDoc]

Thanks for your help everyone. Maybe what I need to do is just lay out my plans, and see if anyone sees a problem with them. So here's what I was thinking.

I would like to start with a Senepole Cow and a Red Angus Cow with calves at their side, each already bred to the opposite breed. This would be my starting herd. I'm sure I can do this with the Senepol, as they also breed F1 Senepol/Red Angus cattle for sale. I'll have to see with the Red Angus, but I bet if I'm willing to pay for the AI, they'd be willing to do it.

This will get me started for the first year. During that year I can look for a bull. Ideally, I'd like to use one bull for the first two years so that I can learn to recognize standing heat etc, and take an AI course, identify a good tech etc.

Any offspring I keep from that first bull, I would then AI to a second bull, so I wouldn't have to actually own a second bull. I can then alternate bulls, or introduce a 3rd AI sire after 2 more years.

Does this sound reasonable?

Some have said I should just use AI alone, but I understand conception is only 70% that way, especially when you are learning. So a bull for clean-up seems reasonable. Oncel I am profficient, I could go either way.

 

[buhbuh]

breed the best to the best

 

[ArmyDoc]

Don’t know if anyone is interested, but I finally found a workable definition for distinguishing between line-breeding and in-breeding. Notice I say “A” and not “THE”. There are a lot of definitions out there, but few that are precise enough to draw a solid line between inbreeding and line breeding. Not everyone will agree with the line drawn using this definition, but at least it draws it in the same place every time!

It’s a little complicated, but really not that hard to understand.

The definition I found was that inbreeding is type of breeding that increases the percentage of genetic material for one ancestor beyond 50% in any one descendant. So, for example, a father daughter cross would be considered in-breeding because the offspring would be get 75% of its genetic material from the father, so this would be called inbreeding rather than line-breeding, using this definition.

A x B -> AB 50% A
A x AB -> AAAB 75% A

Full siblings crosses are also considered inbreeding.

AB x AB -> ABAB (100% AB, even though only 50% A and 50% B)

Line breeding tries to produce offspring that have a higher percentage of genetic material than would be expected, without exceeding the 50%. The expected percentage decreases by half every generation.

0 Sire
1 Child (50%)
2 Grandchild (25%)
3 great grandchild (12.5%)

So line breeding would be anything that causes the sires genetics to be present more than 25 percent in the grandchild, more than 12.5% in the great grandchild etc.

So, for example, half sibling crosses is a form of line breeding that does this.

Generation 1 A x B -> AB (50% A)
Generation 1 A x C -> AC (50% A)
Generation 2 AB x AC -> ABAC (50% A instead of the expected 25%)

The offspring of half sibling crosses can be bred to “unrelated” other half sibling crosses, which still retains the 50% concentration of that excellent animals genetics.

A x D -> AD
A x E -> AE
AD x AE -> ADAE (50% A)
ABAC x ADAE -> ABACADAE (50% A)

Any other breeding program that increases a single individuals genetics above what would be expected for unrelated breedings can also considered line breeding. How closely they are line-bred is determined by how close you get to 50% without exceeding it.

So, anyhow, that's the definition I'm going to use. It seems to be a safe definition, and one that at the very least is one I can wrap my brain around and use to evaluate a given match up to decide if it's too close or not.

 

[usernametaken]

Don’t know if anyone is interested, but I finally found a workable definition for distinguishing between line-breeding and in-breeding. Notice I say “A” and not “THE”. There are a lot of definitions out there, but few that are precise enough to draw a solid line between inbreeding and line breeding. Not everyone will agree with the line drawn using this definition, but at least it draws it in the same place every time!

It’s a little complicated, but really not that hard to understand.

The definition I found was that inbreeding is type of breeding that increases the percentage of genetic material for one ancestor beyond 50% in any one descendant. So, for example, a father daughter cross would be considered in-breeding because the offspring would be get 75% of its genetic material from the father, so this would be called inbreeding rather than line-breeding, using this definition.

A x B -> AB 50% A
A x AB -> AAAB 75% A

Full siblings crosses are also considered inbreeding.

AB x AB -> ABAB (100% AB, even though only 50% A and 50% B)

Line breeding tries to produce offspring that have a higher percentage of genetic material than would be expected, without exceeding the 50%. The expected percentage decreases by half every generation.

0 Sire
1 Child (50%)
2 Grandchild (25%)
3 great grandchild (12.5%)

So line breeding would be anything that causes the sires genetics to be present more than 25 percent in the grandchild, more than 12.5% in the great grandchild etc.

So, for example, half sibling crosses is a form of line breeding that does this.

Generation 1 A x B -> AB (50% A)
Generation 1 A x C -> AC (50% A)
Generation 2 AB x AC -> ABAC (50% A instead of the expected 25%)

The offspring of half sibling crosses can be bred to “unrelated” other half sibling crosses, which still retains the 50% concentration of that excellent animals genetics.

A x D -> AD
A x E -> AE
AD x AE -> ADAE (50% A)
ABAC x ADAE -> ABACADAE (50% A)

Any other breeding program that increases a single individuals genetics above what would be expected for unrelated breedings can also considered line breeding. How closely they are line-bred is determined by how close you get to 50% without exceeding it.

So, anyhow, that's the definition I'm going to use. It seems to be a safe definition, and one that at the very least is one I can wrap my brain around and use to evaluate a given match up to decide if it's too close or not.

The 50% rule sounds like a good, useful formula to keep in mind.
I like it! Thanks,
Untaken