line breeding-inbreeding

[Anonymous]

just got around to checking out this board and found a subject from a few weeks ago. line breeding is used and is still being used quite extensivly in many species of critters. It just shows results much faster in animals that have quick turn arounds, rabbits, hogs ect. The USDA still has one or two experimental herds that are closed and have been since the 1920,s. I toured the Line One herd in Mont. several years ago. No outcrosses for 80 years! The speaker stated that they were just now sure enough on a few selected traits that they could guarentee the effects of selected outcrosses. There was some line-breeding suppression but the herdjust looked normal, no 7 frame animals, and they all had the right number of legs! The good part was that they could also just about guarentee no throw backs, and a 20% (I think the number is right, but it is coming from my memory) bump in selected traits thru hybird vigor in outcrosses. I think that the problem with a lot of seed stock producers is that they dont cull hard enough to make a line-breeding program stand out and pay off.

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[Anonymous]

Not many cattle seedstock operations have been in business as long as you're talking about. And even fewer of them were supported by taxpayers while they made the mistakes and figured out what worked and what didn't. With so many breeds having EPDs that identify important economic traits, why would you want to linebreed?

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[Anonymous]

> With
> so many breeds having EPDs that
> identify important economic
> traits, why would you want to
> linebreed?

EPDs tell you what an animal will do on average. Linebred animals will throw calves much close to what their EPDs predict. Others will throw a scatter that will average out to what the EPD says. If you breed to a bull that should throw 65 - 70 pound calves on heifers, you don't want to be getting 50 to 85 pound calves.

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