New Heterosis Question

[lakading]

I took the following statemets from the story at this link: http://www.oznet.ksu.edu/news/sty/2000/heterosis.htm

"Heterosis is particularly important to the commercial producer because the greatest rewards from cross-breeding are in traits that are not highly heritable," Moser said.

Fertility, milk production and growth improve slowly through selection, Moser added, but are quickly affected by heterosis.




Now my question...Am I wrong in interpreting the above to mean that a purebred herd that has been in existence for many many years and practiced continual selection pressure for the mentioned traits would be able to attain the same results as someone using a cross breeding system to benefit from heterosis???

 

[Jeanne - Simme Valley]

Not sure if this is what you're asking but:
Yes, PB breeders can improve Fertility, milk production and growth - through EPD's & selection - BUT, you can achieve improvements quicker through controlled crossbreeding - picking breeds that compliment each other.
PB breeders can improve traits quicker (but not quicker than crossbreeding) by using unrelated bulls/cows within a breed. That is why it is so important to choose a breed that has a LARGE genetic base. If you pick a novelty breed, most available bulls are closely related.

 

[mtnman]

Yes and no.

Registered herds could get there.

Crossbred vigor will still improve them after they get there.

You could never select enough that crossbred vigor quits working.

mtnman

 

[lakading]

Fair enough, mtman.

Also, to maintain the highest level of heterosis, would it be necessesary to purchase replacements rather than hold some back yourself?

 

[mtnman]

Well, according to my old college notes, yes.

It says if you want the highest crossbred vigor, you need some sort of a cross bred cow, then mate her to another breed bull that isn't in the cow.

The diagrams show that to max out vigor, you can't keep the daughters in your own herd.

It says too that maxing out crossbred vigor isn't the best thing to do, unless the calves are going to feedlot.

It says that going for maximum is too much labor, too many pastures, and that the cows can be too many different "biological types", whatever that means.

mtnman

 

[DiamondSCattleCo]

You could never select enough that crossbred vigor quits working.

I think eventually we're going to get to the point where the species just isn't able to do anymore and crossbreeding will net minimal benefits. But we're not close to that point yet.

It says that going for maximum is too much labor.

I'm not sure I understand this point. You can buy a bunch of PB cows, say 40 or so, and breed them to another PB of another breed. Keep the best daughters as your commercial cows and breed them to another breed of PB bull. You've now got maximum hybrid vigor in your second herd.

Rod

 

[Brandonm2]

It says that going for maximum is too much labor, too many pastures, and that the cows can be too many different "biological types", whatever that means.

mtnman

I disagree with your proffessor. To maximize heterosis you would only need a pasture of
1) purebred Breed As, usually bred to breed B
a second larger pasture of
2) Breed A x Breed Bs being bred to breed C
and
3)a third pasture of AxB heifers except in that 1 out of 5 years where you replenish your purebred herd of breed A (though AIing your top 10 cows every year would probably be simpler).


we are only talking one more pasture of cows than your standard cattle farm with just two groups (cows and heifers) so I don't really see the too much labor and too many pastures argument. The farm would only sell a handful of pure breed A steers, a bigger group of AxB steers, and then a much bigger group of AxBxC steers and heifers so I don't really buy the "too many biological types" argument either.

 

[Brandonm2]

I think eventually we're going to get to the point where the species just isn't able to do anymore and crossbreeding will net minimal benefits. But we're not close to that point yet.

I don't think there IS a genetic limit. We know from the fossil record that 8 foot tall hogs, 10 foot tall apes, giant flightless birds, and cow sized oppossums have existed in significant numbers in ages past. Look how much range exists in the cat family (from 5lb house cats to lions). The wild ancestor of modern cattle, the aurochs, is bigger than almost all domesticated cattle. By multiplying the genetics on the outer fringe of the bell curve and creating a new bell curve with an even more extreme outer fringe we should be able to continue increasing performance for almost any trait genetically. The problem is not the lack of genetic diversity; but rather the real world point of diminishing returns. While 1000 pound weaning wts are achievable genetically, most of us do not have the quality of forage to achieve that even IF we had the genetics in our herd to do so and most of us can't easily manage the big heavy milking mama cows that are needed to do that routinely. There are a few Dairy cows who have produced over 80,000 lbs of milk in a lactation; but we as beef producers run into real management problems keeping cows in condition and breeding back when milk gets too high (and nowhere near that high). That is a classic example of the genetic potential being FAR greater than what we as producers can use in a practical environment. I think we will hit forage, environment, and management limits to production LOONNNG before we ever max out the potential in the genome.

 

[dun]

It says that going for maximum is too much labor, too many pastures, and that the cows can be too many different "biological types", whatever that means.

mtnman

I disagree with your proffessor. To maximize heterosis you would only need a pasture of
1) purebred Breed As, usually bred to breed B
a second larger pasture of
2) Breed A x Breed Bs being bred to breed C
and
3)a third pasture of AxB heifers except in that 1 out of 5 years where you replenish your purebred herd of breed A (though AIing your top 10 cows every year would probably be simpler).


we are only talking one more pasture of cows than your standard cattle farm with just two groups (cows and heifers) so I don't really see the too much labor and too many pastures argument. The farm would only sell a handful of pure breed A steers, a bigger group of AxB steers, and then a much bigger group of AxBxC steers and heifers so I don't really buy the "too many biological types" argument either.

From all of the reading I've done on heterosis, the maximum heterosis is achieved with a 7 breed composition. That definitely takes a lot of pastures. I don;t know where you would find 7 breeds of beef cattle that had enough comlimentary traits that are different enough to make a difference. It seems that after about 5 breeds mixed in you really start getting a mongrel herd and any pure breed you introduce would have more of a tendency to stamp it's mark on the offspring. But I ain;t educated enough to understand all the scientific stuff anyway.

dun

 

[DiamondSCattleCo]

From all of the reading I've done on heterosis, the maximum heterosis is achieved with a 7 breed composition.

Dun, would be able to provide me with a link to an article about 7 breed compositions? Most articles I've ever read state that maximum heterosis is obtained on the 3rd cross, and I'd like to read some conflicting articles. You never know when you'll pick up a gem

Rod

 

[dun]

From all of the reading I've done on heterosis, the maximum heterosis is achieved with a 7 breed composition.

Dun, would be able to provide me with a link to an article about 7 breed compositions? Most articles I've ever read state that maximum heterosis is obtained on the 3rd cross, and I'd like to read some conflicting articles. You never know when you'll pick up a gem

Rod

I'll search around and see if I can find them. Lost all of that stuff in the big disk crash of "04".

dun

 

[Brandonm2]

From all of the reading I've done on heterosis, the maximum heterosis is achieved with a 7 breed composition. That definitely takes a lot of pastures. I don;t know where you would find 7 breeds of beef cattle that had enough comlimentary traits that are different enough to make a difference. It seems that after about 5 breeds mixed in you really start getting a mongrel herd and any pure breed you introduce would have more of a tendency to stamp it's mark on the offspring. But I ain;t educated enough to understand all the scientific stuff anyway.

dun

I have never seen a crossbreeding system utilizing 7 breeds, though I am sure it is doable. Now in a recent comparison of a 4 breed system involving crossing F1 composite cows with F1 composite bulls (of a different 2 breeds) AxB X CxD they did not quite equal the heterosis of the classic 3 breed roto terminal system AxB X C; but it is logical that 7 would really maximize it though what are we talking about there? 2% gain by stacking on breeds? IF you are going to get that complex what stop at 7? You might as well kick it to 8 breeds......
Cow AxB X CxD bred to composite bull ExF X GxH. I wonder what 7 or 8 breeds you would use???

A Hereford x Angus X Brahman x Simmental cow crossed to a
Limousin x Shorthorn X Gelbvieh x Maine Anjou bull????

I wonder if those calves will qualify for CAB???

 

[Jovid]

I wonder if those calves will qualify for CAB???

If it had a black hide it could :nod: :lol2:

 

[dun]

The site that I searched originally (http://www.adobe.com/search/main.html) no longer has links to anything that I can find. It was 4-5 years ago that I searched it but apparently it isn;t around anymore. I'll keep looking.

dun

 

[MikeC]

I wonder if those calves will qualify for CAB???

If it had a black hide it could :nod: :lol2:

Funny thing about this is.....................................

only 18% of angus calves qualify for CAB.

 

[Frankie]

I wonder if those calves will qualify for CAB???

If it had a black hide it could :nod: :lol2:

Funny thing about this is.....................................

only 18% of angus calves qualify for CAB.

Who says?

 

[lakading]

I wonder if those calves will qualify for CAB???

If it had a black hide it could :nod: :lol2:

Funny thing about this is.....................................

only 18% of angus calves qualify for CAB.

Who says?

IMO, if you are only getting 18% CAB with angus, you have absolutely no idea about how to feed cattle.

 

[MikeC]

I wonder if those calves will qualify for CAB???

If it had a black hide it could :nod: :lol2:

Funny thing about this is.....................................

only 18% of angus calves qualify for CAB.

Who says?

Eileen Keller at Certified Angus Beef LLC, says. In fact, a couple of tests I read a few years back had it less than that.

 

[mitchwi]

I believe the remark was more along the lines of....

...1 in 5 angus influenced animals will pass C.A.B. precise guidlines to earn the CAB brand


there is a whole lot of room between angus and angus influence

 

[MikeC]

I believe the remark was more along the lines of....

...1 in 5 angus influenced animals will pass C.A.B. precise guidlines to earn the CAB brand


there is a whole lot of room between angus and angus influence

That's a silly argument given the context of the article.

NOT ALL ANGUS BEEF IS EQUAL

In fact it goes on to say say:

"Angus" refers only to a breed of cattle. Angus beef does not refer to a specific percentage of genetic purity. The majority of cattle marketed in the U.S. are crossbred. Angus cattle grade USDA Prime, Choice or Select-all the way down to Utility.