My wiew on inbreeding

EddieM wrote:

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About the two ugly rams; to test animals with inbreeding, and use them in crossbreeding if they are good, is in line with my thinking. What will the outcross tell you about them?

The outcross will let me know if they are truly duds or just exhibiting a high level of inbreeding depression. If they are duds I do not want them as anything.


When I was talking paternal/maternal I was more speaking of baseing lines on particular rams or particular ewes. I probably misused the terms. One other potential line got culled in the first effort due to a lack of resistance to internal parasites.

Now that puts the sheep lines in a different light.
Is it likely that if you have three rams, that are "more than brothers"; two of them suffer greatly from inbreeding depression but not the third?
I would think the two shows up homozygous for something more detrimental; thus they are duds. And what I call inbreeding deperession is a slow process, kind of creeps up, no leaps or bounds.

EddieM wrote:

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I would handle the yearly culling of the line far better than to guess which animals that should be in the start group!

Use the life hands you lemons, make lemonade approach to start. Yearly culling has been one of the big questions that we have all asked here at KC.

That is a good way to describe it.

MKeeney wrote:

Chopping this afternoon as I have the last few days, actually gives me time to think before I post And I thought today how all this inbreeding discussion seems repetitous; already well covered in the Reflections from LL thread...it may be repetitious, but each time we "do it again", we find new gems...and each time , as proven by Kent above, and by Dylan earlier , we learn how to articulate the concepts more clearly...that alone makes these discussions with newcomers so worthwhile to us all...for once, I more thoughts than time to type, so more later...

It truly helps a thinker sorting his thoughts to have to explain them to someone, be it to a child or to a philosopher.

Keystone wrote:

What I am trying to say is that an individual that is registered is not holy; the fact that it is seedstock does not alter the obvious. It must be culled on the very same principles that that apply for commercial cattle, although not necessarily only for weaning or yearling weight, but real world characteristics none the less. Linebreeding do tend to lead to regression; for growth, vitality, fertility. And quality seedstock is supposed to posess higher quality for these traits. Would it not be the hallmark of an inbred cow to perform like any good cow, so that her quality masks the fact that she suffers from regression?
Are there important capabilities that seedstock need to have, that production stock can do without?

Registered does not mean seedstock. Seedstock do not need to be culled on the same principles that apply to commercial cattle. Commercial cattle are the production. The producers. The end. Seedstock are bred to be the parents. The source of vigor in a package designed to pass on their traits with regularity and if crossed provide that shot of vigor one time. Seedstock are percieved to NEED higher levels of those traits, because when from the mainstream system they breed down. Regression of the heterozygote. Superior individuals who do not have the ability to pass it on with any regularity. [/quote]

Registered does not mean seedstock. Point taken. Henceforth I will use the term seedstock. This terminology will also put my project side by side with other seedstock operators, because I have no registry for my cattle.

Since TULIP is new and all of these nicknames befuddle me like Chief SweetBeet, FungusFescueFace, the BridgeBrave and his squaw SaladShooter, Ol' ShoeSole and who knows who else, I'll let TULIP see what indicators you can use when you need to back off on the linebreeding efforts. I sure don't need another sheep around who can eat two times as much as the rest of them.

EddieM wrote:

Since TULIP is new and all of these nicknames befuddle me like Chief SweetBeet, FungusFescueFace, the BridgeBrave and his squaw SaladShooter, Ol' ShoeSole and who knows who else, I'll let TULIP see what indicators you can use when you need to back off on the linebreeding efforts. I sure don't need another sheep around who can eat two times as much as the rest of them.

for goodness sakes Eddie, put more lamb chops in, or three legs of lamb...don`t bother to attempt 4 udders, that`s already been accomplished in cows; so nothing new there...

I call him Larry and Mike. I kind-a wish he had 3 heads and then I could call him Larry, Mike and my other ram, Mike. Couldn't stand anymore legs of lamb per lamb as I have a devil of a time catching the 4 legged day old lambs now not that I'm old and slow, now mind you. I'll think about adding a couple of more loins but that might make them look too different like the cow with 4 uuuuddddddddeeeerrrrssss like you mentioned. One good thing about having the 4 ears, he sure can hear good and you can use all kinds of ear tags and such.

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...the performance of this line was below that of other lines already in the herd
...the line was discontinued in 1964 due to the occurrence of dwarfism
...line was terminated in 1953 to provide room for the expansion of more superior lines
...the line was eliminated in 1955 due to below average performance
...line was discontinued in 1954 due to below average productivity as well as the high incidence of dwarf calves
...line was discontinued in 1977 to make room for the more superior lines
...line was discontinued due to poor productivity

No inbred matings were made on the station; thus, an inbred Rover line was never initiated.

...line prior to being discontinued because of poor productivity

Two spastic calves that became completely rigid when handled were observed in one
line. Crossed eyes were observed in another inbred line. Hypoplasia of testes was observed in
another line. Striking abnormalities were not common, however, in the lines.

Death loss in the linecross herds was only 6% in 1200 calvings over the years. In 900 inbred calvings, losses were about 13%, more than
double that of the linecrosses; whereas in the controls, losses were about 12%. This remarkably low death loss in the linecrosses could be one of the most economically important genetic
advantages we encountered.

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Three out of 23 lines are left. None had to be discarded. The environment didn't have much to do with the project. A project with more than one master will likely fail. Somewhere Stonaker wrote that no line had to be discarded. When you find the problem, it is no longer a problem. The solution is known.

There seemed to be reasons to discard some lines. Maybe not from the angle of publically funded research, but more from the practical side of "it ain't worth the trouble"! The solution to some problems is to stop, like the deal of if you are getting deeper, quit digging.