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The Beefmaster Pay Weight
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Purpose of an Index
by Lance Bauer, Beefmaster Breeders United Expected Progeny Differences (EPDs) are the best tool available for making genetic improvements in a herd. When looking at EPDs it can sometimes be difficult to avoid single trait selection because a producer may become too focused on one trait, such as birth weight. To help producers avoid this many breeds including Beefmaster have implemented one or more indices that weight EPDs appropriately for different production systems. The use of index selection has been around since the 1940s, in 1943 Hazel noted that selecting using an index that was properly weighted was more efficient than single trait selection or culling based on several traits with an individual culling level for each trait. In the summer of 2016 BBU released two indices, $M and $T, to help producers
select animals that fit their production systems and in 2021 BBU released $FE. $M is the maternal index and should be used when females are being retained in the herd, $T is the terminal index for BBU and should be used in a terminal production system and $FE is the feed efficiency EPD that is focused on feed efficiency and growth. $M is the maternal index, and it is designed to balance weaning weight with cow maintenance and fertility. The index includes the EPDs for BW, WW, Milk, YW and SC. It was developed for the profit per cow exposed, due to the weaning weight of her calf and accounting for cow maintenance. $M is helpful in evaluating how a bull’s daughters will contribute to the advancement of a herd. When looking at Beefmaster
cattle $M seems like a smaller number than $T does, however the effects of $M are cumulative because of retaining females in the herd. A bull that consistently produces high quality females that are kept in the herd is continually increasing in value to the producer in terms of $M. For example, if a producer is looking to use a bull that will produce quality females that
will wean a good calf every year and is choosing between bull A and bull B $M is a good tool. If bull A has a $M of $24.50 and bull B has a $M of $14.50, then it would be expected that bull A’s daughters would return approximately $10 more per head per year. This may seem to be a small amount, but if we assume that both bulls are bred to 20 cows and 10 heifers are
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