Genotype and Phenotype

[inyati13]

If you allow nature to eliminate problems then you will find that functional characteristics will multiply simply due to survival of the fittest (fit for their environment). However the temptation is always to modify that type to fit your own 'ideal', for example if you dislike more set to the hind legs than that which has emerged naturally over time then cattle with straighter hind legs get preferred over those with more set and for that there will be a consequence. An example of this is the dairy industry where classification of animals is done to a breed standard yet after fertility feet and legs remain a major reason to cull, I suspect that selection for environment ( in the case of dairy that would be concrete rather than pasture) has not been allowed to occur.

robert, the reason I said you were going into the science of Speciation is not because I thought you were unclear. On the contrary, your first sentence is a concept that you would spend a charpter on in any text book on Speciation. I took Speciation in about 1974, the text book was written by Ernst Mayr who at the time was the authority on how species are formed by the mechanisms of genetics, natural selection, and evolution. It occurred to me that Breeders are as close to Biologist as anything except maybe zoo keepers. Their fundamental materials are biological units. They are employing the sciences of genetics in their breeding to arrive at the phenotype they seek. It is interesting to me to see the diverse points of view on what a phenotype should be and how your arrive at it. But that is what you would expect. Despite the tools we use, man is pursuing a phenotype that is, "arbitrary and capricious". There is no word of God that gives us an absolute truth as to what a phenotype should be. In fact, what we generally accept as "the standard" might turn out to be a failure. I see it in everyone's comments. There are plenty of skeptics and I have even received PMs expressing them. I don't think anyone is right or wrong. I think the cattleman is doing his job and I applaud people who think their own thoughts and pursue them.

 

[regolith]

If you allow nature to eliminate problems then you will find that functional characteristics will multiply simply due to survival of the fittest (fit for their environment). However the temptation is always to modify that type to fit your own 'ideal', for example if you dislike more set to the hind legs than that which has emerged naturally over time then cattle with straighter hind legs get preferred over those with more set and for that there will be a consequence. An example of this is the dairy industry where classification of animals is done to a breed standard yet after fertility feet and legs remain a major reason to cull, I suspect that selection for environment ( in the case of dairy that would be concrete rather than pasture) has not been allowed to occur.

Robert: I think as cattle producers most of us are working with only 50% of the genetics. Unless you have a closed herd and are raising your own bulls the incoming genetics have not been tested under your *specific* environment.
Which is where this discussion starts, how to determine a way to select the genetics that will suit your wants/needs/environment/cattle.
Now my observation thus far is that survival of the fittest is a nice theory but doesn't work in practise as well as you would expect. I don't know if that is because my observations are of herds that can only select 50% (the female line) that way or if the environment is changing over time or some other factor.
One of the key traits is fertility. In the NZ dairy industry we have seasonal calving cows with daughters usually only retained from cows mated to AI in the first three - four weeks of the calving season. Yet fertility is getting worse over time. The local semen sales rep says farmers aren't feeding them enough to get pregnant - yet cow feeding has improved in that time, and every farmer who's been in the business long enough will tell you that thirty years ago cows got in-calf far better than they do now. That is true also in herds that cull all the opens and don't use cidrs or favour the younger/skinnier/slower cycling cows to help them get back in calf.

 

[robert]

Right, you can have as much 'performance' as you care to support / feed, whether that is lbs of gain to weaning or yearling or if it is lbs of milk yield per cow/lactation. It is human nature to want more, there's no bragging rights for a 500lb weaned calf yet that may well be the optimal level to create the 1200lb mature cow. Most genetic evaluation systems reward the outcross, and conversely punish the within herd, potentially linebred herd where optimal levels of production and sustainability have been achieved within the environmental constraints and the goal is to perpetuate the herd with consistent production matched to resources.

 

[cow pollinater]

BUT, There ARE still cattle out there that are doing BOTH. I agree wholeheartedly that we should select for cattle that work in our environments but when I see a cow that is outmilking everything else in the herd and still breeds back on time, I WANT MORE LIKE HER. :lol: The hard part is making a son out of her that is prepotent enough so that every daughter can handle that level of production and still breed back. The female side of the equation is the limiting factor there.

 

[cow pollinater]

It's likely I wasn't clear, I was more pointing out that when we refuse to accept the form that evolves under the pressure of environment / management because it doesn't meet our minds eye vision of perfection and end up distorting true functional selection in favor of idyllic phenotypic expression. Regarding Dairy type I wonder if the judging team ideal of hind leg set / foot angle / heel depth / pastern strength is in reality unsuited for life on concrete and is an obstruction to actual improvement?

You're dead on.
We've proven over and over again that a more moderate, feminine dairy cow holds up longer but the big money still goes to big strong framey cows that "look" like they're sturdy enough to last... "Gotta have that dairy strength!"
Most guys that I sell to are completely ignorant to foot and leg traits. They'll glance at a feet and leg composite and want to see "at least a point" or look at a bar graph and want to see everything way over to the right but they don't know what that really means. I've been in a few herds where the cows were stood up so strait that when they were locked up they're stand there and rock back and forth to take the pressure off their legs and the guy was still paying top dollar for bulls with "everything way over to the right" on the little bar graph. :frowns:
Try to sell them something that will help and see where it gets you. ;-)