Nevada County Picayune and Gurdon Times Newspaper Archive

Farm and Home

SUGGESTED BEEF CATTLE MANAGEMENT

As we approach the spring breeding season, many beef cattle producers are considering a new bull to use in the cow herd. Many producers will simply look at bulls to make selection decisions. Visual or physical evaluations of bulls are still an important part of the selection process.

What type of additional information can we use to evaluate bulls? Birth, weaning and yearling weights are normally used to evaluate breeding animals. Actual or adjusted weights may help in making comparisons between bulls in the same contemporary group (a group of animals fro the same herd, year and season, raised together under the same conditions). Since environmental factors like feed and weather affect weights, actual or adjusted weight can be misleading if bulls come from different contemporary groups. A ratio of 100 means a bull's weight is average in his contemporary group. A ratio of 110 means a bull's weight is 10% heavier than average. Ratios can also be misleading if bulls come from different herds. Expected Progeny Differences (EPDs), on the other hand, are calculated across herds. A bull's EPD for a trait is a more accurate estimate of his genetic worth than his weight, adjusted weight or ratio. EPDs not only account for contemporary group and herd differences, they also include information on a bull's relatives as well as his individual performance.

Most major breed associations have National Cattle Evaluation programs. Breeders involved in their breed's performance program should have birth, weaning and yearling weight EPDs available on yearling bulls. In all of these breeds, EPDs are expressed in pounds of calf. For example, if bull A has a weaning weight EPD of +15 and bull B has a weaning weight EPD of +5, the calves produced by Bull A are expected to weigh, on the average, 10 pounds more at weaning than those of bull B, assuming the bulls are bred to comparable cows.

Rapid growth rate of calves is of obvious importance in a commercial herd. But there are genetic correlations between birth, weaning, yearling and mature weight. Selection for high weaning and yearling EPDs without regard for other traits will result in increased calving problems and larger cows that require more feed for maintenance.

Potential calving ease can be best evaluated with birth weight and calving ease EPDs. Birth weights account for the major share of variation in calving difficulty in cows of the same age and size. Because birth weight is influenced by age of dam and nutrition, actual birth weights can be misleading. Birth weight EPDs are much more accurate for across herd comparisons. Selecting bulls with low birth weight EPDs is most important when they are used on small cows or first calf heifers. Since weights at all points in the life of cattle are positively correlated, some sacrifices in growth may have to be made to stay within a workable range of calving ease or birth weight for a particular herd.

Advances in National Cattle Evaluation have made estimating a bull's genetic worth more accurate than ever before. EPDs allow valid comparisons of all bulls of the same breed, but they do not allow you to compare bulls from different breeds. Since breeds have different average performance, base years and evaluation procedures, direct comparisons of EPDs from different breeds can be extremely misleading. It should also be noted that a bull with an EPD of zero is rarely average. In most breeds zero is the average of some base group of animals. Since weaning and yearling weight EPDs that are several pounds below the average of all yearling bulls in that breed. Current breed averages and information on how to use EPDs are included in breed association sire summaries. Sire summaries are available at no charge from most major breed associations.