Chocolate Cow2":1w5crr9n said:
http://www.beefproducer.com/breeding/you-cant-have-it-all
paragraph 2,3 & 4 of the above article
Today's big, energy-dependent cattle were specifically selected to "perform" under optimum conditions, such as in the feedlot, and under continuous stocking with plenty of options for what to eat, plus lots of inputs, including ample hay and feed supplements.
However, once you begin to pressure your stock with more competition, slightly older forage and requirements to eat things they normally do not, in addition to pulling out most or all their feed crutches, they will no longer perform like before.
In addition, you'll no longer be able to choose cattle like your paradigms tell you, nor to select for heavy milkers, nor cows that produced the heaviest calves, nor cows for which you paid a lot of dough. Instead, you'll begin putting enough pressure on your cattle that reproduction -- or the lack of it -- will become you primary sorting tool.
It's worth repeating, I've found this to be true.