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 Frame and Muscle
USDA Feeder Calf Grades are based on frame and muscle scores. Frame and muscle are highly heritable, and they both have a major effect on feeder calf prices. Frame and muscle in the bull should be matched with that of the cow herd to produce calves that will be acceptable in the marketplace and replacements that will perform in the herd's environment.

     Frame size provides an estimate of rate of maturity, mature size and carcass cutability at a given live weight. Frame size is generally appraised visually by bull buyers or measured in terms of hip height adjusted to a standard age. Some breeders provide adjusted hip heights or frame scores on their sale bulls. Larger framed steers gain more efficiently and are leaner than smaller framed steers at a given weight. Packing plants discriminate against carcasses that are too light or too heavy. For these reasons, feeder calves that are at the upper end of USDA Medium or the lower side of USDA Large generally bring the best prices. While larger framed market animals may be preferred, larger framed females in the herd may reach sexual maturity later and require more feed for maintenance. Increasing frame size in the cow herd without increasing the level of nutrition will generally result in a decline in reproductive efficiency.

     Adequate muscling is usually determined by visual appraisal. Feeder calves that are not thick enough to grade USDA Number 1 muscle are generally discounted heavily. While light?muscled bulls can affect the marketability of calves and carcass cutability, extreme heavy muscling may be associated with structural and reproduction problems. Evaluate the cow herd and determine the amount of muscling required before selecting a bull.

     Some breeds are developing carcass EPDs. However, these are not generally available on most yearling and two year old bulls. As more carcass data are collected, these EPDs will become more available.

Structural Soundness
Any consideration of a bull's potential genetic contribution to a herd is meaningless if he is not structurally sound and physically fit to seek out cows in heat and service them. Structural soundness is not an all-or-none trait. It usually occurs in various degrees. Bad feet, pigeon toes, straight hocks and loose sheaths are examples of some of the more common structural problems. It is especially important to critically evaluate young bulls since these problems tend to get worse as bulls get older and heavier. Structural soundness in bulls is best evaluated from the ground up. Inspect the bull's feet, toes, heels, pasterns, knees, hocks, sheath and testicles and study his movement carefully to see that he moves freely and strikes the ground evenly with each hoof.

     Many structural problems are heritable and should be particularly discriminated against in bulls whose daughters will be kept for replacements. Minor structural problems can be tolerated in a terminal sire, as long as they do not affect his longevity or ability to service cows. The tolerance level for structural problems should be determined beforehand, not while looking at prospective herd bulls.

     Visually evaluating a bull for structural soundness also affords an excellent opportunity to evaluate disposition or temperament. Disposition is heritable. A bull with a poor disposition not only causes problems himself, he also produces daughters that can make the cow herd more difficult to work.

A good prediction of bull fertility can be made by a complete breeding soundness exam that includes a semen test, scrotal measurement, and a physical examination of the reproductive tract. Commercial bull buyers should not hesitate to ask seedstock breeders for a breeding soundness examination on all prospective herd bulls.

     Although the importance of producing viable semen in ample quantities is obvious, semen evaluation of yearling bulls (12 to 15 months of age) can be misinterpreted. Certainly the production of live sperm cells is meaningful, but failure to produce good semen at the first collection of a yearling bull is not conclusive. Young bulls should be rechecked after a few days rest (or weeks if they are less than 13 months old). Often they will produce acceptable semen when rechecked. Normal extension of the penis (free of adhesions) and absence of pus in the ejaculate are positive, meaningful observations, which by themselves are sufficient reasons to semen check young bulls.

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