This spring, alongside the routine annual update of economic assumptions and genomic scores, significant enhancements were implemented in the Sire Evaluation Report and National Cattle Evaluation. These updates, effective May 24, 2024, aimed to refine the accuracy and performance of genetic evaluations within the Angus breed. 

Phenotypic trait updates  

Since 2021, phenotypic traits submitted to Angus Herd Improvement Records (AHIR®) were listed in a variety of places, including the performance registration certificate and EPD (expected progeny differences)/Pedigree Lookup on www.angus.org. By adding these traits, it provided visibility to members submitting phenotypes on animals and continued to fuel the genetic evaluation.

Taking it one step further, starting May 24, some phenotypes were bolded in the list, while others were not. This differentiated what phenotypes were included in the genetic evaluation and which traits were not. The phenotypes included in the genetic evaluation helped to inform the predictions for EPDs.

For more detailed information on the bolding of phenotypes listed, refer to the May 2024 Angus Journal “Data Dive” article.

Heifer pregnancy contemporary groups 

Contemporary groups play a significant role in any genetic evaluation, accounting for non-genetic sources of variation that affect an animal’s phenotype. Updates made to the heifer pregnancy contemporary groups aimed to better characterize weather and environmental conditions that could affect heifer pregnancy outcomes. This update led to a more accurate and less biased heifer pregnancy genetic evaluation. 

More details about this update can be found in the “By The Numbers” column of the April 2024 Angus Journal.

Carcass weight, ribeye area and fat 

On May 24, updates to the carcass model and its genetic parameters, including heritability estimates and genetic correlations, took place.This carcass model update involved the modeling of the ultrasound fat thickness and ultrasound ribeye area records in the evaluation. Previously records for animals of different sexes (bulls, cows and steers) were modeled as separate traits. However, our research indicated accounting for the sex within the contemporary group, rather than modeling it as different traits, yielded the same prediction accuracy while reducing model complexity. Reducing model complexity without sacrificing prediction accuracy was important as it allowed for more accurate estimation of genetic parameters (heritability and genetic correlations) and optimized computations. This allowed a significant reduction in the weekly evaluation computing time.

In addition to this model update, updating genetic parameters in genetic evaluations is a routine procedure. This was necessary because over time, the population evolved due to selection, and as more phenotypes were collected, the variances, heritability estimates and genetic correlations changed. 

By updating genetic parameters regularly, we could accurately estimate the genetic variation in the population and the relationships between traits. In multiple-trait models, as is the case with the carcass evaluation, accurately estimating the genetic correlations between traits was crucial to take advantage of the accuracy that correlated phenotypes brought, particularly ultrasound records. 

Continuous research and the implementation of regular updates ensured accurate and unbiased genetic evaluations were delivered on time. These updated estimates can be seen online and in the 2023 Fall Sire Evaluation Report.

Core update

The core update related to the computation of the genomic relationship matrix’s inverse, which played an important role in genetic evaluations with many genotyped animals. This was not a new update, and the most recent one was done in May 2021. 

Since then, more than half a million animals had added genotypes to the weekly evaluation. With the addition of Australian genotypes to the World Angus Evaluation, that number increased by more than 800,000 for a total of more than 1.8 million genotyped animals. 

With all genotypes being used in the evaluation, this update ensured a good representation of the current population and provided optimized convergence for the models and computing time efficiencies, allowing us to maintain a timely delivery of weekly genetic evaluations.

More details about the core update could be found in the May 2024 Angus Journal article, “A Good Problem to Have,” and in the “By The Numbers” column of the May 2021 Angus Journal.

Economic assumption update

The bio-economic model driving the Association’s dollar value indexes ($Values) undergoes annual updates, utilizing data from CattleFax. Economic assumptions are averaged from the past seven years to reflect stability, with the 2024 assumptions based on data from 2017 to 2023. This long-term perspective mitigates market volatility, aligning with the average cattle cycle.

Weaned calf sale prices and ration costs rose again this year. In May 2023, the average weaned calf price was $167 per hundredweight (cwt.) for steer calves and $152 per cwt. for heifer calves. The May 2024 update increased the average calf price, reaching $182 per cwt. for steer calves and $164 per cwt. for heifer calves. Ration costs in the feedlot also increased from $199 to $225 per ton, affecting feed costs in the cow-calf sector. These changes influenced the outcome of the maternal weaned calf value ($M), where calf price relative to cow cost became the major revenue driver.

The price per hundredweight for a fed steer delivered and dressed increased from $192 per cwt. to $206 per cwt. from 2023-2024. This shift redirected economic weight in beef value ($B) towards weight traits like carcass weight and postweaning gain, away from grid premiums, which only saw a slight increase. 

Despite the significant increase in fed cattle prices and minimal changes in quality premiums, overall changes in $B were minimal. However, producers may notice a slight reranking favoring cattle excelling in feedlot value ($F) over those at the top of the $B ranks to their grid value ($G).

Overall, updates didn’t substantially alter individual $Values, with economic assumption updates resulting in correlations above 0.99. Some individual animals experienced changes, with the largest decreases in $M, $B and combined value ($C) across the 4,146 current sires being -$4, -$6, and -$9, respectively. Changes in $Values were less likely due to economic assumption updates and more due to changes in individual EPDs from other evaluation updates.

Annual genomic scores update

Genomic scores are updated annually. This process involves updating SNP effects for each trait based on additional phenotypes and genotypes from the previous year. 

With an increased number of genotyped animals, the reference population grows, leading to reranking. Genomic scores are a byproduct of genetic evaluation, updated alongside EPDs. It’s preferable to use genomic-enhanced EPDs (GE-EPDs) for selection decisions, with genomic score updates not affecting GE-EPDs themselves.