Expected progeny differences (EPD) for Dry Matter Intake (DMI) and $Gain (an economic subindex) have been released by the International Genetic Solutions (IGS) science team in a research release format. The purpose of these traits is to help breeders better characterize terminal performance by evaluating genetic differences for feed intake and the profitability potential associated with growth relative to intake. 

The IGS science team is committed to the development of genetic tools that aid breeders in making commercially relevant selection decisions. Being able to identify animals with genetics for more efficient growth relative to feed intake is an industry-wide concern. Feed intake records submitted to IGS partner breed organizations and the existing growth records database were used to develop the DMI EPD and $Gain, which is an economic subindex that weighs an animal’s growth potential with respect to its intake to provide a snapshot of that animal’s profitability potential in the feedlot growing phase (growth relative to intake). An extensive validation process was performed to ensure DMI and $Gain were reflective of the existing growth and feed intake records. 

DMI EPD:

The DMI EPD is expressed as the difference in pounds of daily dry matter intake. A lower EPD is more desirable, as this is representative of the genetic potential for progeny to consume less feed. For example:

Bull A = 1.00 DMI EPD

Bull B = 0.00 DMI EPD

You would expect progeny from Bull B to eat 1 pound less daily dry matter of feed compared to progeny from Bull A. 

$Gain:

$Gain is a prediction designed to identify animals that are more profitable in the feedlot by converting feed into weight. $Gain is a combination of Dry Matter Intake EPD (DMI) and Average Daily Gain EPD (ADG), where ADG is weighted by the value of a pound of gain, and DMI is negatively weighted by the cost of a pound of dry matter. $Gain is expressed as the dollar difference per head per day during the post-weaning period, and a higher value is more desirable.

For example:

Bull A = $0.10 subindex value

Bull B = $0.00 subindex value

You would expect progeny from Bull A to be $0.10 more profitable per day than progeny from Bull B due to a combination of feed requirements and growth potential. 

As research EPD, these will be released monthly to incorporate new data as it is received by IGS. It is important to acknowledge that development of both metrics into a weekly genetic evaluation is still under development and may take some time. 

Data Collection

The IGS science team encourages producers to submit feed intake records on their animals to their breed association staff, which can then be uploaded to the IGS multi-breed database. Reporting feed intake data will greatly help bolster the genetic evaluation, improve prediction accuracy, and help to accelerate the launch of DMI into a weekly genetic evaluation. Members are encouraged to follow these guidelines for feed intake data collection. For more information, members should visit the Beef Improvement Federation guidelines available at guidelines.beefimprovement.org.

Individual feed intake records are often taken post-weaning or around yearling age.

Warm-up period: Depends on the background of the cattle and the type of feed intake system. If calves are already accustomed to eating out of bunks, a seven-day warm-up period with the feed intake system is likely adequate. For cattle that have not yet been bunk-broke, they could need up to a 21-day warm-up period. 

Feed Intake Test: Recommend a 42-day minimum, which allows for missed days due to weighing or problems with the intake measurement. Records should be submitted as a measure of dry matter intake. No as-fed data should be reported.

Producers are encouraged to evaluate DMI and $Gain predictions and compare with their expectations. Producers that have any questions, or those who have submitted feed intake data and would like a full download of EPD on their animals, should contact IGS at IGS@InternationalGeneticSolutions.com.

by ASA Staff

Continuing to improve genetic predictions is one of the main goals of the International Genetic Solutions (IGS) genetic evaluation. Over the last year, several updates to models used in the weekly genetic evaluation have been investigated to be incorporated into the weekly genetic evaluation. As the IGS genetic evaluation has grown and expanded from historical partners, as well as the addition of new partners, the ability to run genetic evaluations within a week’s time frame has become difficult. One of the main goals of these updates was to increase the efficiency of evaluations; however, these upgrades are also to maintain or improve the accuracy of prediction of each evaluation. To account for these challenges, three evaluations recently underwent updates, which are detailed below. 

Growth Evaluation: The growth evaluation produces EPD for Birth Weight, Weaning Weight, Yearling Weight, Average Daily Gain, Milk, and Maternal Weaning Weight. We updated the way that breed and years are incorporated into the genetic evaluation, and the method used to incorporate information from other genetic evaluations. Previously, breeds and years were incorporated by fitting interactions of these effects for each animal; with the updates, these effects are separated. For the incorporation of information from outside genetic evaluations, IGS will now use a new method that allows for better tracking of the changes that occur to EPD when this information is added to the evaluation.

Carcass Weight and Ribeye Genetic Evaluation: The CW/REA updates now include the updates described above for the growth evaluation, as well as updated across-breed adjustments from the US Meat Animal Research Center (USMARC) Germplasm Evaluation (GPE) program. This program helps to determine breed differences and is an important part of the carcass evaluations at IGS. 

Marbling and Backfat Genetic Evaluations: These updated breed differences will also be applied in the Marbling and Backfat genetic evaluations, which is the third evaluation. The updated across-breed adjustments from USMARC is the only change to the Marbling and Backfat evaluation.

Results of the Updates to Genetic Evaluation
When implementing updates to genetic evaluation, the IGS team undergoes a strict validation procedure to evaluate how potential changes will influence the predictive ability of the updated EPD. One of the most common ways this is done is by excluding a portion of the phenotypes, running an evaluation, and correlating the EPD from this run with the excluded phenotypes. For each of the evaluations, all animals that were born after 1/1/2020 were removed from the evaluation and used to test the predictive ability. The results for these comparisons are included in the table below. 

The results in the table above show that the implemented updates had the same or higher correlations than the previously implemented models. This would correspond — in most cases — to more accurate EPD for each of the traits. With the updates, some breeders may notice that the resulting EPD for animals may change, but the percentile rank for the trait may be similar. This is due to differences in estimated breed effects as part of the evaluation. While most traits will have strong EPD correlations between the previous and current evaluation, some animals may have been re-ranked because of these updates.  

For current EPD and percentile ranking of animals please visit Herdbook.org. For information, or if you have questions about these updates, please contact Lane Giess, ASA Geneticist, at lgiess@simmgene.com. 

by Randie Culbertson, PhD
Carcass records on terminal cattle remain rare and highly sought-after phenotypes for National Cattle Evaluation. As the number of carcass phenotypes are limited in the National Cattle Evaluation, IGS uses breed effects from the USDA Meat Animal Research Center to adjust genetic predictions for various breeds. Programs like the Carcass Merit Program and Carcass Expansion Program are adding valuable terminal records and genomic information to the genetic evaluation.

As with any trait under selection, breed effects will change over time. As a result, US-MARC updates their breed effects annually and the IGS Multi-breed Genetic Evaluation recently updated the breed effects in the published EPDs (as of 12/20/21). The implementation of these updated breed effects caused some changes in carcass EPDs. The adjustments are set to an Angus base and are applied depending on the breed percent of the animal. When comparing the rank of bulls with a high percent of a breed, breeders may see a shift in the EPD value but the bulls still have the same rank among other bulls with the same breed percentage. However, reranking occured when comparing one breed to another as well as different percentage composites.

An ongoing challenge of estimating carcass EPDs is the lack of carcass phenotypes. This lack of phenotypes creates a real challenge for the genetic evaluation to appropriately account for breed differences. With traits that have limited records and breed comparisons within contemporary groups, using field data (i.e. IGS data) can lead to unreliable estimation of breed effects. In those cases, breed effects from scientific literature are often used. The advantage of using breed effects from literature is that the effects are derived from “clean” data and often from herds with breeding systems designed specifically to obtain these breed effects. In the case of carcass trait breed differences, the IGS Multi-breed Genetic Evaluation uses the breed effects derived from US-MARC.