Why Linebreed?

[dun]

Linebreeders like to claim that their stock will have less variation in measurable production traits than standard outcross stock of the same breed when used in a commercial crossbreeding situation; but somebody would have to show me actual scientific research showing that to be true for me to accept that as anything but conjecture. I am not disagreeing with the theory; just am not convinced that it is valid.

http://digitalcommons.unl.edu/cgi/viewc ... eefcowsymp

The first thing I noticed is that the data is from 1997 and the second is that the breed averages have changed (for Red Angus anyway) significantly

 

[novatech]

http://digitalcommons.unl.edu/cgi/viewc ... eefcowsymp

The first thing I noticed is that the data is from 1997 and the second is that the breed averages have changed (for Red Angus anyway) significantly[/quote]

The math they are using is way beyond me. The guy wanted something scientific and I gave it to him. He can enter numbers from linebred bulls currently on the market today and still show the results.
What is most important to those interested, is the very last paragraph. Seems as though it agrees with Brandon 22.

 

[Brandonm22]

http://digitalcommons.unl.edu/cgi/viewc ... eefcowsymp

Very interesting link; but it did not answer my question. Certainly you will have less variation in a calf crop if you used 6 Angus bulls who were full sibs as the bull battery versus 6 unrelated Angus bulls; but I would expect that of full sibs whether they were outcross or linebred. Heck that would be true even if they were composites. Now that using only sires that were half brothers (all sired by Scotch Cap) showed just as much variation as if I had used unrelated Angus is not really shocking either; but nobody would really call that linebreeding either.

 

[alexfarms]

Scientifically, linebreeding does one main thing.....it increases homozygosity of the gene pairs. If you select and cull as you linebreed, you should then be improving your seedstock in both performance and genetic homozygosity. More homozygous seedstock should sire more consistency. It is all about genetic improvement. You should be able to make more improvement in seedstock by linebreeding and selecting and culling as you go than by outcrossing because you are increasing homozygosity of desirable gene pairs (traits) and eliminating negative genes pairs (traits). In outcross stock you are creating heterozygosity, which may give you more growth in the most heterozygous offspring, but very difficult to consistantly replicate those more heterzygous, high achieving, individuals.

 

[ANAZAZI]

Scientifically, linebreeding does one main thing.....it increases homozygosity of the gene pairs. If you select and cull as you linebreed, you should then be improving your seedstock in both performance and genetic homozygosity. More homozygous seedstock should sire more consistency. It is all about genetic improvement. You should be able to make more improvement in seedstock by linebreeding and selecting and culling as you go than by outcrossing because you are increasing homozygosity of desirable gene pairs (traits) and eliminating negative genes pairs (traits). In outcross stock you are creating heterozygosity, which may give you more growth in the most heterozygous offspring, but very difficult to consistantly replicate those more heterzygous, high achieving, individuals.

The more linebred the less genetic info to choose from. Basically, it it is possible to fix the good traits of the population and to eliminate the bad traits. However; they must be high quality to start with, as nothing new will appear to take them to the next level.

 

[Brandonm22]

Scientifically, linebreeding does one main thing.....it increases homozygosity of the gene pairs. If you select and cull as you linebreed, you should then be improving your seedstock in both performance and genetic homozygosity. More homozygous seedstock should sire more consistency. It is all about genetic improvement. You should be able to make more improvement in seedstock by linebreeding and selecting and culling as you go than by outcrossing because you are increasing homozygosity of desirable gene pairs (traits) and eliminating negative genes pairs (traits). In outcross stock you are creating heterozygosity, which may give you more growth in the most heterozygous offspring, but very difficult to consistantly replicate those more heterzygous, high achieving, individuals.

That IS the theory anyway.

 

[alexfarms]

Scientifically, linebreeding does one main thing.....it increases homozygosity of the gene pairs. If you select and cull as you linebreed, you should then be improving your seedstock in both performance and genetic homozygosity. More homozygous seedstock should sire more consistency. It is all about genetic improvement. You should be able to make more improvement in seedstock by linebreeding and selecting and culling as you go than by outcrossing because you are increasing homozygosity of desirable gene pairs (traits) and eliminating negative genes pairs (traits). In outcross stock you are creating heterozygosity, which may give you more growth in the most heterozygous offspring, but very difficult to consistantly replicate those more heterzygous, high achieving, individuals.

The more linebred the less genetic info to choose from. Basically, it it is possible to fix the good traits of the population and to eliminate the bad traits. However; they must be high quality to start with, as nothing new will appear to take them to the next level.

The options will always exist to outcross your linebred stock or to bring in some outside stock to add to the line and then reclose off the line and linebreed again.

 

[Brandonm22]

The options will always exist to outcross your linebred stock or to bring in some outside stock to add to the line and then reclose off the line and linebreed again.

I don't disagree; BUT if you are breeding something like linebred Anxiety the Fourths and then decide that an outside bull (lets say Feltons Legend 242 just to throw out a currently popular name) would add something to your closed breeding experiment so you breed the outside bull to half of your cows, then cross those half Legend cows to the remaining Anxiety the Fourth cow families to produce a whole cowherd that is 25% Legend and THEN decide to linebreed again by crossing those 1/4 Legend lines to each other from that point on, what do you call those cattle? Is it "honest" to claim that they are still linebred Anxiety the Fourths? Or are you now really selling linebred Feltons Legend 242 since every calf traces back to Legend four or more ways after two generations?

 

[alexfarms]

The options will always exist to outcross your linebred stock or to bring in some outside stock to add to the line and then reclose off the line and linebreed again.

I don't disagree; BUT if you are breeding something like linebred Anxiety the Fourths and then decide that an outside bull (lets say Feltons Legend 242 just to throw out a currently popular name) would add something to your closed breeding experiment so you breed the outside bull to half of your cows, then cross those half Legend cows to the remaining Anxiety the Fourth cow families to produce a whole cowherd that is 25% Legend and THEN decide to linebreed again by crossing those 1/4 Legend lines to each other from that point on, what do you call those cattle? Is it "honest" to claim that they are still linebred Anxiety the Fourths? Or are you now really selling linebred Feltons Legend 242 since every calf traces back to Legend four or more ways after two generations?

I think it would be misleading to call them straight Anxiety 4th or straight Feltons. If it was up to me, I would give the new line a new name. A historical example in Herefords would be at Miles City they had 12 lines and discontinued all but the Line 1 and mixed all the other lines together along with some Line 1's and they called that new line "MIXER DOMINO" on the paternal side and "MISSY DOMINA" on the maternal side. I have had a few people tell me those MIXER DOMINOS were the best cattle to come out of the station. But why wouldn't they be, they were the result of "unwrapping" several tightly wound up linebred lines. The Feltons cattle themselves were the result of Frank Felton taking his linebred cows and adding Prospector 0716 to them and linebreeding from there. Mr Felton didn't call them just "PROSPECTOR". It has been done alot through the years and done very successfully. The Remital cattle were linebred Enforcer and Enforcer 107h was a WSF PRL JUSTA BANNER son out of a Remitall cow....so he represented the addition of JUSTA BANNER to the Remital line.

 

[Red Bull Breeder]

When you outcrossed and then started line breeding agin you could call the your own. Then you would be a breeder instead of a copy producer. Unless it is a train wreck.