ArmyDoc -(and ANAZAZI)-
Your comments regarding the factor of "Bone Size" in seedstock bulls brings to the discussion some interesting analysis appraisals. When judging, analysing, and determining seedstock selections, in preparation for acquiring satisfactory and "improved" genetics to realize a PROFIT from our efforts in beef production, factors OTHER than Phenotype and Genotype come into play - primary among them being the physical traits we refer to as "Functional" traits. These physical or 'type' traits have not been focused upon sufficiently as yet to be described with EPDs. Functional characteristics may be understood and clarified as those which work, or perform, or allow other factors to work for the longevity of the herd and to the benefit of the producer. Skeletal structure (sound feet and legs) which encompasses adequate bone substance and capacity, quantification, and value, is critical - not necessarily size, thickness or bigness.
Other Functional Traits include masculinity, femininity, mammary structure and teat size (again - not too big or too little), shoulders, spine, (top line), disposition -- and others as well. But, we are concerned in this discussion with Bone structure (fine, or heavy [ "big boned"]), and the relativity of such to seedstock selection.
When we consider the activities (functions) of a breeding bull, one may easily understand that a fine-boned herd sire could be inadequate in attempting to settle 25-60 females in heat over a large paddock or pasture - for a period of several YEARS, and continue to maintain his physical capabilities as a successful breeder. With inadequate bone development he could become stifled (broken down in his "Knees"), pasterns, sickle-hocked, cow-hocked, and splay-footed. His inability to function as a herd sire would be in sharp jeopardy, both for himself as a breeder and for his produced progeny as future seedstock or terminal feedlot performers. In much the same way, if a buyer is seeking thick, muscular bulls for a Terminal program and you as a seedstock provider have only light-boned, frail, funnel-butted sires, one is not going to make many seedstock sales.
It is a matter of balance within the breeding business. Finding that "narrow window" of selection traits which incorporates all of the Genotype, Phenotype AND adequate "Functional" traits which are necessary for PROFIT to yourself AND your customers is the operative selection criteria which is necessary for success. :nod:
Whether the skeletal structure (bone) of seedstock is too much or too little depends upon the particular breed, and the selection standards one determines is necessary for his own particular operation and beef production protocols. This is another example of the inadvisability of using "single trait selection" practices in seedstock selection.
As a final thought for this thread, as a bull matures, his leg bone thickness reveals itself through the endrocrine action of testosterone which stimulates Nitrogen retention resulting in medium legs as the result of male hormones stopping the growth of long bones. This is another justification for early castration of feedlot steers so as to not allow them to become "staggy", and demonstrating male sex characteristics.
Successful, PROFITABLE, Beef Cattle Production is a little more complicated than breeding A bull to A cow with a single trait selection Agenda. It's NOT easy!
DON'T GET ME STARTED!
DOC HARRIS