A Contemporary Group - a group of the same breed, born within the same 90-day period, raised at the same location or in the same herd, of the same sex and managed alike from birth until the time of measurement. If some members of a group are treated differently in any way, these members must be separated from the group.   For example, a group of animals that was managed alike at birth must be regrouped separately at weaning if half of the group was creep-fed and the other half was not.

Phenotype - how an animal looks and performs - is a combination of the animal's genetics and the environment to which it is exposed. Both genetics and environment contribute to an animal's performance and cannot be measured separately.

Both factors are measured together in the form of weights, scrotal circumference or other performance measurements. Both genetics and environment affect actual measurements like milk production or weight.

For example, environmental factors like age and nutrition can affect the amount of milk a dam produces. Milk production will, in turn, have an effect on a calf's performance through weaning -regardless of the genetics that calf possesses for weaning weight.

Similarly, physiological differences between bull and heifer calves allow bull calves to gain weight quicker and more efficiently than heifers, regardless of genetics.

These are examples of environmental factors; they do not have anything to do with the genetics an animal may have inherited, but they do alter that animal's performance.

EPDs, expected progeny differences, were developed to measure an animal's genetic value after environmental effects have been removed.

To separate genetics from environment, we need to accurately identify an animal's environment, and the effects that environment may have on performance. Contemporary groups define an animal's environment, so that genetic and environmental effects can be separated correctly.

If animals within a contemporary group are similar in terms of their management and environment, then differences in the performance of the animals can probably be attributed to genetics. Thus, proper contemporary grouping is important, even essential, to obtain accurate and predictable EPDs.

By definition, a contemporary group consists of at least two calves of the same sex. Ideally, contemporary groups should be ten animals or larger to provide accurate comparisons. However, smaller breeders may not be able to form contemporary groups of that size.

Each individual producer is ultimately responsible for the accurate contemporary grouping of their animals. The American Gelbvieh Association (AGA) helps producers by placing animals in the correct contemporary group-according to percent Gelbvieh and sex-when information arrives in the office. But producers must carefully group animals according to other factors, like health and feed.

In most cases, calves born within a 90-day period on the same farm can be grouped together. However, consideration should always be given to the way the calves are managed and to their nutrition. A group of cows and calves grazing on improved bluegrass pasture should not be compared to a group of cow/calf pairs grazing on infected fescue pasture. The management and nutrition of these two groups are different.

Similarly, if illness caused poor performance in some calves, they should not be compared with other, healthy calves. Any variation in management practices that may change-either by benefiting or adversely affecting-an animal's performance requires that those animals be put into different contemporary groups.

For a contemporary group to be useful in comparing sires, at least two sires must be represented in a contemporary group and at least one of those sires should be a reference sire-a sire that has previous progeny records reported. Contemporary groups that represent several sires allow for comparison of different sire's progeny in a similar environment.

At the academic level, contemporary grouping is easy. But in real life it can create many difficult decisions. Should calves from favorite cows that were run for two months in the small pasture behind the house be separated when forming birth-weight groups? The possibilities are endless.

A GUIDE TO CONTEMPORARY GROUPING

• Use group codes on the AGA registration application forms to put calves into contemporary groups according to how they were managed prior to weaning. Also, use the group code to put a sick calf in a single-animal contemporary group if performance is affected.
• Don't worry about grouping by sex, percent Gelbvieh or ET since the AGA performance program handles those items automatically.
• Take weaning weights and measurements on all calves in a group on the same day (when a majority of the calves are between 160 and 250 days of age). Try to get as many calves as possible in one contemporary group.
• Weigh and measure all animals before separating them. If possible, weigh and measure all bulls before castrating. Try to weigh and measure before separating off show calves and bulls for test stations.
• Have more than one sire represented in a contemporary group when possible.
• Choose a day to take yearling weights and measurements when all animals are between 320 and 410 days of age.
• If an age spread is greater than 90 days, select two different weigh dates. Use the least number of weigh dates possible.
• Try to take scrotal circumference, pelvic area and hip height on the same day as yearling weights.
• Do not weigh each calf individually as it reaches 205 days of age.
• Do not include calves receiving special treatment (show, bull test or sale) in the same group with those who were not receiving special treatment.

The Gelbvieh breed is well-known for its commitment to performance records. Accurate, reliable information from AGA members - including proper contemporary grouping - allows AGA staff to continue to provide accurate reliable information to them. If you have any questions about how to form contemporary groups, please contact the AGA office.