THE BIRTHING of a live, healthy calf every 12 months with a minimum of labor and attention is the single most important factor effecting the economy of beef production. Therefore, calving difficulty is an important consideration.

Unfortunately, the industry has tended to over-simplify the solution to calving trouble by a never-ending search for "heifer bulls." Such bulls are defined as small in size, light-muscled and with small birth weights. Each of these three traits is in conflict with efficient beef production.

Why search for bulls that sire calves that any cow can have without difficulty, knowing the calves will be of little value? It is more appropriate to use bulls whose daughters can have a big, strong calf that will grow rapidly and produce a desirable carcass.

There are many factors involved in determining whether or not a cow calves successfully without assistance. Therefore, selection for any single trait involved in calving ease will not solve the problem. The important measure is simply whether or not a female produces the right kind of calf without assistance.

Currently, only the Angus and Simmental breed associations have meaningful data banks on calving ease. The Angus association's performance pedigree lists individual birth weight, birth weight EPD, and calving ease score. Also, this pedigree includes a bull's progeny and the progeny of both paternal and maternal grandsire as follows.

(A.) Number of herds represented.

(B.) Total number of progeny.

(C.) Average calving ease score (1 to 5).

The cores are: (1 ) No assistance.

(2) Some assistance.

(3) Mechanical assistance.

(4) Caesarian section.

(5) Abnormal presentation.

The Simmental association also furnishes the individual records plus EPD's on a bull's daughter's first calving ease as well as maternal calving ease EPD'S.

The Polled Hereford Association has recently initiated a similar system, and every breed association should do so.

Another factor that can cause calving problems is simply lack of compatibility when crossing different strains or breeds of cattle. A typical example can be found in the introduction of the Charolais breed into the United States in the 1950s.

At that time, the commercial cow herds of this country were primarily Angus and Hereford, both of which were smaller at maturity than they should have been. The Charolais cattle were larger at mature weights than they needed to be, and so calving trouble resulted. This calving trouble unfairly branded WP bulls as "cow killers."

Charolais cattle still suffer from this "hard calving" reputation even though they have much to offer in both growth rate and carcass desirability.

Summarizing the calving difficulty problem, purebred breeders should treat cattle uniformly and under a nutritional and management program typical of the commercial herds in their respective areas. Seedstock producers should ask replacement heifers, when bred to herd mates, to calve as two-year-olds without assistance.

The steer calves resulting should have the genetic potential to weigh 1,200 pounds at 13 or 14 months of age and produce a USDA Choice, Yield Grade 2.0 carcass. Cattle not meeting these standards should be culled.

The very best of the cattle that meet these requirements should be retained for herd improvement and the rest offered for sale along with complete performance records.