With the AGA Online Registry Service making herd data and EPD values easily accessible for producers to make genetic improvements within their herd, the AGA office often receives questions about the specifics of contemporary grouping, it's importance, and how they are formed. Below we break down the answers to those questions:

Contemporary groups are a group of animals that have experienced a similar environment with the expression of a trait, such as birth weight. Contemporaries are typically from the same location, are of the same sex, similar age, and have been managed alike. Grouping of animals for genetic evaluation is important because the heritability of traits can be increased by adjusting for known environmental effects and managing animals to minimize differences in performance influenced by the environment. It is not always possible for animals to be managed the same, particularly if you compare animals from different herds or even different areas of the country. Contemporary grouping makes it possible to fairly compare animals with different environmental influences.

Incorrect grouping of animals can distort genetic predictions for individual animals. Generally, this occurs when some animals receive preferential treatment in the herd but are contemporary grouped with animals that do not receive that special treatment. A common example of this situation would be show animals that are given extra feed and care apart from the herd. These animals typically grow faster than the rest of the herd because of the special management and feed, so they should be separated by the breeder into a different contemporary group. If all animals are grouped into one contemporary group, the potential for growth in the show animals may appear greater. While in reality, the relative performance of those animals is biased upward because of being compared to the rest of the herd that received no special treatment.

Additionally, it is important to report information on whole contemporary groups: the good, bad and indifferent. When only the good weights are reported, the weights that would be in the middle to the high end of the whole contemporary group would appear more towards the bottom when the less desirable weights aren't submitted. Reporting whole contemporary groups allows your good animals to look even better when compared to all contemporaries rather than just the good ones.