The phenotype measured is influenced by the environment and genetics. Within a herd, there can be visible differences in weight, for example, among groups of calves that are exposed to varying feed resources. How do we separate the effects of the environment and management from what is genetic potential? The answer is contemporary groups.

What are contemporary groups?

Well-designed contemporary groups are the cornerstone of genetic evaluation. They allow separation of the environmental effects from genetic effects on phenotypes. A contemporary group is a set of animals that have had equal opportunity to perform and are the same sex, managed alike, and exposed to the same environmental conditions and feed resources. 

When animals are exposed to different management or environment, it is impossible to know if differences in performance are because of the environment or their genetics. To attribute differences in performance to genetics, the animals within a contemporary group must have been exposed to the same management and environment. 

In many cases, one contemporary group per sex for an operation is sufficient. However, there are circumstances that require the establishment of multiple contemporary groups within a herd. 

How are groups formed?

Members submitting data are responsible for creating proper contemporary groups for management reasons within their herd. For growth-related contemporary groups (birth, weaning, and yearling), there are a few factors that will separate calves. 

Calves will be grouped by sex, birth dates within a 90-day window, management codes, group codes, weaning date (no more than three days apart), location codes, registered vs. commercial dams, natural calves [including natural service and artificial insemination (AI)] vs. embryo transfer (ET) calves vs. in vitro fertilization (IVF) ET calves, and registered Angus recipients vs. nonregistered recipients. How and when data process can also separate groups of calves. 

Codes

Group codes should be used to distinguish calves that should be grouped together. Most group codes are optional to use, but are required at weaning. Birth group codes are used to distinguish calves whose dams were managed differently than other dams while gestating. The most common use of the birth group code is if first-calf heifers are fed a different ration than the mature cows. Note that unless there is a management reason, calves do not need to be separated in groups based on dam age. The age of the dam is accounted for when weights are adjusted at birth and weaning.

Weaning group codes are required and are used to separate calves that need to be in different groups. For example, calves that are orphaned or extremely sick between birth and weaning should receive a code to separate them as they did not have the same opportunity to perform as the other calves. 

Management codes are used to designate if animals receive additional feed while nursing through supplemental or creep feed. 

Location codes designate animals raised in a different location. If an operation has multiple locations, this code can be used to separate groups.

When do groups start?

Since 2017, contemporary groups for traits like growth start with birth weights. Starting with a good foundation from the start will set groups up for success. If an animal is in a single-animal contemporary group at birth, it will remain that way through weaning and yearling. 

There are circumstances where a calf should be in a single-animal contemporary group, covered later in the article, but in most cases, calves will be grouped with other contemporaries. 

The birth group is the largest group the calf will be in, and the group may get smaller as calves are sold or culled from the herd. 
How does data submission affect groups?

One of the most common reasons for unnecessary contemporary groups is because of data submission dates. When records arrive at the Association, unless otherwise indicated, records in that file are processed and it closes the contemporary groups. Whether data is submitted through paper forms or spreadsheets [i.e., Angus Information Management Software (AIMS) files or a spreadsheet downloaded from AAA Login], it will close groups. 

This makes it especially important to submit complete records at one time for proper grouping.

The exception is birth weights that are checked out through AAA Login. When there are birth weights in the cart, there is a question at check out, “Are these birth weights the last calves to be reported for the birth contemporary group?” 

Answering “yes” will process all birth weights that have been submitted to the Association that have not yet been processed and close the contemporary group. Answering “no” will allow additional calves to be included in the same contemporary group at later submissions.

What closes the birth contemporary group?

1. Answering “yes” to the question at checkout in AAA Login. 
2. The submission of weaning weights. If there are unprocessed birth weights and there are weaning weights submitted, it will close the birth contemporary groups. All weaning weights should be submitted at one time for groups of animals. Weights can be left in the cart for multiple days until ready for submission. 
3. If no weaning information has been processed within 205 days of birth information submission, the group will close.

Reviewing contemporary groups

Contemporary groups allow for expected progeny differences (EPDs) to be predicted from the genetic evaluation. They are critically important for genetic evaluation, predicting EPDs, and calculating ratios. After data are submitted and processed, you can review Angus Herd Improvement Records (AHIR^®) reports in your AAA Login account the next business day under Reports > AHIR Reports > AHIR Work History/Reports.