Using Selection Indexes in Breeding Decisions

by Ryan Boldt, Director of Breed Improvement The beef cattle selection process is a complicated one. There are many aspects and traits that are economically important to consider when making these decisions.

Strictly looking at an EPD profile, it is often difficult to weigh tradeoffs and identify animals that will make a more positive economic impact. A proven strategy in solving this problem is utilizing economic selection indexes.

The advantage of economic selection indexes is that they help simplify the selection process when evaluating EPD information. Each trait’s relative economic emphasis is accounted for in the index. This information is then summed to produce one overall index value that allows for an easier metric to compare EPD profiles. This value can be used to summarize an animal’s EPD profile. Thus, a producer can more easily compare animals to determine which genetic combinations are more profitable for a given segment of the beef supply chain.

Another big advantage to using indexes is that they allow for an easy mechanism for multiple trait selection. Generally, when animals show up with increased index values, they have genetic advantages for multiple traits within their EPD profile.

The RAAA currently publishes three indexes. The HerdBuilder index is a maternal index that covers traits from conception through weaning, the GridMaster index is a post-weaning terminal index that covers traits after weaning through harvest and the Profitability and Sustainability index is an all-purpose index that combines the HerdBuilder and GridMaster indexes, so it contains traits from conception through harvest. Each of these indexes is expressed on a dollar-per-head basis.

To better understand the emphasis that is being put on different traits in each of the selection indexes, the following charts were generated.

As illustrated in the charts, each of the indexes contains multiple traits and puts varying levels of emphasis on each of the traits. When looking at the ProS index figure, there are many traits that receive measurable emphasis in the index. This clearly shows that this tool is very useful for use in multiple trait selection that can benefit all sectors of the beef industry. //

Profitability and Sustainability Importance Graph

HerdBuilder Importance Graph

GridMaster Importance Graph