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Post by Cascade Meadows Farm - Kirk on Feb 17, 2015 19:39:17 GMT -5
I understand the theory from the cattleman's perspective; but I don't agree as a scientist. Genetics is much more than what you see and the implications on future generations cannot be adequately predicted or controlled, especially if the first generation from a sire/daughter cross is allowed to breed. This is NOT a typical cattlemen's perspective (most cattle-folk would stay away from inbreeding because they lack scientific understanding of inbreeding and they often have a cultural aversion to it ). There is NOTHING in science that says what you are saying about inbreeding. Inbreeding simply allows more genes to double up into homozygous pairs. If you have good genes, then you double up on good genes. If you have bad genes, then you double up on bad ones. There are only two types of breeding 1. In-breeding = breeding two animals that are more closely related than the average two animals in the breed 2. Out-breeding (outcrossing) = breeding animals that are less closely related than the average two animals in the breed. Inbreeding doubles up on existing genes (double good, or double bad) and allows you to eliminate the bad. Outcrossing introduces new genes and helps hide any recessive bad genes (but helps pass those bad genes to future generations) Both have their advantages and disadvantages You've heard of inbreeding depression (where there are too few allele choices to correct bad situations)... Well, there is also outcrossing depression (where too many new alleles come flooding in and mess up some well-tuned animals) Animals tend to tune their genetics to a given local environment over time. It takes a good degree of inbreeding to accomplish this tuning... If too many outside animals keep coming into a local population, those outside genes mess up the tuning of the local animals. Sire/Daughter matings simply double up on the sire's genetics in the grandchildren. With the assistance of DNA testing, scientists can actually study these results and dispel the myths about inbreeding. There are some experimental breeds that have been so highly inbred that they are practically clones of each other and they are doing very well. But that requires expert selection and culling and starting with all the right alleles. If you paint yourself into a corner via un-careful or unlucky inbreeding, it's an easy fix to simply bring in an outcross to help you hit the reset button. Inbreeding can NOT create lasting problems, but poor selection or unlucky selection might make you lose some important alleles that you'll have to get from elsewhere to correct your problems.
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Post by J & M Chambers on Feb 17, 2015 19:57:12 GMT -5
Hmm Kirk, and where is this typical cattleman located, the Northwest? To whom are you referring to as most cattle-folk? "Cattleman with a lack of scientific understanding..." - you might be in a time warp on this one or maybe things are a lot different way up yonder. I think this entire characterization is with far too wide of brush.
Jeff
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Post by cddexter on Feb 18, 2015 11:45:27 GMT -5
Hmmm, Jeff, but do you disagree with his analysis of what to start with, localization, and results?
Carol
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Post by Cascade Meadows Farm - Kirk on Feb 18, 2015 14:51:38 GMT -5
Go to the Cattletoday.com discussion board and do a search on "inbreeding" and you'll see 9 out of every 10 comments are negative toward inbreeding and they contain WRONG myths about inbreeding "Causing Defects"... so they just use out-breeding to hide the defective genes, rather than working to eliminate those genes.
Most cattle people are producers, NOT breeders. They aren't working toward improving a breed, they're just producing pounds of beef. Many just buy a new somewhat random bull each year for production. But there certainly are a lot of excellent skilled breeders with amazing skills who are developing amazing lines of cattle and using inbreeding appropriately to develop those lines.
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Post by J & M Chambers on Feb 18, 2015 15:47:40 GMT -5
Hi Carol and Kirk, Kirk, I do not, as shocking as it may sound, base my knowledge of the world from what I read on the internet! So regardless of the discussion on cattletoday.com your comments about not being a typical cattleman's viewpoint because of lack of scientific understanding and cultural aversion I still call bogus. I agree completely if you mean by 'typcial cattleman' those that are most numerous and who are interested in heterosis and hybrid vigor to produce. But the reasons they prefer an outcross system of breeding is not because they do not understand or adverse because of cultural aversions to inbreeding. That is incorrect. You did not ascribe the 'typcial' cattlemans has an aversion to inbreeding systems for those reasons. You called them uninformed and anthropomorphic moral prudes. You are wrong on that account. It is because they have a different purpose. Carol, do I disagree with there being two basic systems of breeding inbreeding and outcrossing? Nope. Do I disagree that seed stock producers should wisely utilize inbreeding systems? Nope. Do I disagree that inbreeding schemes are effective modes of identifying recessive undesirable traits? Nope. Do I disagree that inbreeding systems have potential to develop excellent high quality homozygous stock to be used in breed multiplier operations? Nope. I and other "typical" cattleman have understood these things for quite some time. In fact, even my typical cattleman grandfathers understood these basic breeding concepts and were reading about them in basic livestock breeding textbooks since at least the 40s! What I disagree with is suggesting that typical cattleman avoid inbreeding systems because they are stupid. Next. Jeff
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Post by cddexter on Feb 19, 2015 11:03:57 GMT -5
Hi Jeff: got it. I still think it would be great if you added Vancouver Island to your list of stops when you come west this year. cheers, c.
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Post by Dahdo on Feb 19, 2015 17:19:26 GMT -5
Hold out for lamb and homemade biscuits Jeff...
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Post by J & M Chambers on Feb 19, 2015 21:50:54 GMT -5
Carol, thanks and I would love to do so. Hello Dave, I have heard I should drop by and take a look at your dexters if I am out that way as well.
I did not intend to derail or stop this discussion as I think Kirk is providing excellent information we all can use and certainly hope it continues. I only wanted to correct an egregious mischaracterization.
Perhaps it is another thread, but one I think feeds out of and into this discussion and might be enlightening, is a discussion around the different roles of breeders and various levels and kinds of owners of minor breeds of livestock.
I've for many years pondered the inverted pyramid structure of the dexter breed in which producers - those that mass produce the terminal products of our cattle (beef and dairy) are by far the smallest number of us, while those that are mass producing livestock for producers use are virtually non-existant (what I referred in in previous post as breed multipliers), and what should be the tip of the pyramids is our base - everyone with animals is a breeder and producing.
The producer segment of our breed does/should include the homesteaders who use dexters as home beef and dairy supply. But otherwise our breed structure is topsy-turvey. Probably always has been but as the breed has boomed over the last 20 years at some point that structure will need to adapt.
Most livestock breeds have in some fashion a typical pyramid structure with a small segment that use the techniques which Kirk was discussing to produce 'seed stock' from which the progeny will be very predictable. This stock because of the very rigorous and lengthy process required in which to achieve the predictable, desirable results is the least common of stock, purchased by multipliers which use this "seed" stock to multiply the breed in sheer numbers from which bulls are generated for the producer segment of the market and so on...
To tie this longer than anticipated post back to Kirk's assertion that typical cattle producers are "just buy a new somewhat random bull each year for production" may appear to be the case when not examining or understanding the entire structure of the breed framework. These producers can just buy a new somewhat random bull each year because they know who to go to buy that bull - those folks that have used the premium seed stock to produce on a mass scale large numbers of bulls that will provide the producer exactly what they need without having to do the investigative work in selecting a bull in a breed in which there is not a breeding structure from seed stock, multipliers to producers exist. That selection is not random. It is most assuredly not - what it is typically is a purchase with little to no uncertainty as to the end results regardless of the particular animal brought home.
Jeff
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Post by Dahdo on Mar 3, 2015 12:03:40 GMT -5
Jeff, I hope you will come by when you are in the area. We don't have any lamb, but we have a freezer full of some tasty Dexter beef.
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Post by cddexter on Mar 3, 2015 20:23:56 GMT -5
oh oh, hope it wasn't named calum c.
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Post by Dahdo on Mar 4, 2015 9:38:47 GMT -5
LOL! No, but that would be a good way to get YOU to come visit...to kill me.
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Post by cddexter on Mar 4, 2015 10:23:38 GMT -5
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Post by J & M Chambers on Mar 6, 2015 15:49:18 GMT -5
Thank you for the invite Dave.
Looks like the effort not to stop this thread was a failure.
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