Frequently Asked Questions

Here’s a brief description of the American Simmental Association (ASA) FAQ section:

​

American Simmental Association

Frequently Asked Questions (FAQs)

The American Simmental Association (ASA) is committed to supporting Simmental breeders with the resources and information they need. Our FAQ section is designed to answer common questions about membership, breed registration, genetic testing, and more. Whether you're a new breeder or an experienced professional, the ASA FAQ section provides clear and concise answers to help you navigate the association's services and make informed decisions for your operation.

​

What does EPD stand for?

Expected Progeny Differences - A measure of the genetic potential of an animal as a parent. These represent the difference in the average performance of the progeny in units of a trait.

​

How do I use EPD when making selection decisions?

An EPD should be used in making comparisons of potential parent animals. If you are selecting for improved weaning weight and sire A has a WW EPD of 40 and sire B has a WW EPD of 70, then you should expect progeny of sire B to average 30 pounds heavier at weaning than the progeny of sire A.

​

How do I know if an EPD is good for my breeding program?

One way to benchmark the genetic merit of one individual to the entire population is by using an EPD or $Index percentile rank. Animals that rank above the 50th percentile are considered to be above the breed average for a trait. Note: it's important to know which animals are included in the population used for the percentile ranking. ASA has four different populations established for the percentile rankings: Purebred Simmental, Fullblood, Simbrah, and Hybrid. The percentile ranking of a Purebred Simmental would compare that animal to all other Purebred Simmentals in ASA’s database. It would NOT compare it to SimAngus, for instance.

​

What traits or EPD should I be selecting for in my breeding program?

Traits that are economically relevant to your production system are the EPD you should be selecting for. If a vast majority of your customers sell calves at weaning and keep replacement females, the All Purpose Index ($API) combines all economically relevant traits into a weighted index to provide a balanced selection for your customers.

​

Why don’t I have an adjusted weight for an animal?

Weight measurements that are reported outside of the required age or weight ranges will not be accepted and thus no adjusted weight will be calculated. 

Birth Ranges:

• Weight must be between 30 and 160 pounds.

Weaning Ranges:

• Weight must be between 200 and 1200 pounds.

• Age must be between 160 and 250 days of age.

Yearling Ranges:

• Weight must be between 350 and 2,000 pounds.

• Age must be between 330 and 440 days.

• Weight must be reported at least 60 days after weaning.

​

Why is my calf’s adjusted weight lower than the actual weight?

Adjusted weights standardize weight records taken on animals to a fixed age. For weaning weight, that age is 205 days of age. Weaning records taken on older calves (age >205) tend to have lower adjusted values than their actual weight.

​

Why are my Embryo Transfer calves ratioed separately?

Calves born as a result of Embryo Transfer are treated as a single animal contemporary group and will not be included in the larger calf crop contemporary group. This means that they will ratio differently since a ratio is a measure of an individual’s performance compared to the contemporary group average.

​

Why is carcass EPD accuracy not increasing with more carcass ultrasound data?

Carcass ultrasound data are an appropriate substitute for actual harvest records, but since they are a correlated trait in the model, the improvement in carcass EPD accuracy can only go as high as the genetic correlation between carcass ultrasound and actual carcass. This is why the collection of actual harvest data is encouraged in tandem with carcass ultrasound.

​

What is the difference between GE-EPD and standard EPD?

Genomically enhanced EPD (GE-EPD) are significantly more accurate on young animals than standard EPD. The reason is because the genetic evaluation now has a new source of information to make genetic predictions: the animal’s own genome. The genome is host to a large number of known gene locations that are associated with a quantifiable effect for performance traits. We use these data to inform the genetic evaluation for improved prediction.

​

How should breeders factor in breed composition when using selection indexes?

ASA’s Quick Reference Guide to EPDs and Indexes, which is published in many bull sales catalogs, states the proper approach well: Important disclaimer: DO NOT compare index values of purebreds of different breeds, hybrids of different breed composition or purebreds with hybrids — our system was not developed to make valid comparison among these groups. Therefore, you must first determine the breed and breed composition appropriate for your herd and use index values to compare animals within that population.

​

Is growth treated differently between the All-Purpose ($API) and Terminal ($TI) Indexes?

It is easy to see that there is a strong tendency for high-growth animals to be at the top of the heap for $TI, while it is not unusual to see low-growth animals rank highly for $API. Because of that, it may be logical to conclude that growth is treated differently between $API and $TI. What may be a surprise to many, however, is that growth is treated identically between the indexes. The economic value of growth in beef cattle production is realized through weight at weaning and harvest in cattle not retained for breeding. Since both indexes predict differences in profit in an integrated production system, the economic value of growth in slaughter cattle is factored into both $TI and $API. Further, since the same pricing grids are used, the value for a unit increase in growth in a sire’s slaughter offspring is the same for both indexes.

So, why does it appear that growth is treated differently between the indexes? Why does growth seem so important in $TI, while appearing to not be as important in $API? The reason lies in the fact $TI assumes that all of a sire’s offspring go to slaughter, while $API is predicated on retaining replacement females, i.e., only steers and cull heifers go to slaughter. This means that, though an increase in growth for a single slaughter calf has the identical impact between indexes, since all of a sire’s offspring go to slaughter under the $TI scenario, the collective impact of growth is magnified in $TI. Furthermore, since $API also factors in economic differences in cow herd traits, which tend to have more economic impact on the production system than growth (particularly stayability and cow herd intake), superiority in this area can easily make up for shortcomings in growth.

​

Why is selecting on ASA's indexes not the same as single-trait selection?

The assertion that index selection is akin to single trait selection is only true if the trait being referred to is profit. Unlike single-trait selection for biological traits, selection on $API and $TI simultaneously applies selection pressure to all traits that impact each phase of beef cattle production — cow calf, feedlot and packing plant. Because ASA’s indexes weight these traits in a mathematically optimal manner, selection on them maximizes genetic progress in the trait we all should be practicing single trait selection on — profit! A major distinction that sets ASA’s indexes apart from those published by some organizations is that they simultaneously account for all segments of beef cattle production. Our industry has been inundated with what I call “segmented” indexes — indexes geared toward specific and limited segments of the production cycle, e.g., weaning, feedlot, and grid. Though indexes of this nature may have utility for users who are interested in single phases of beef production, e.g., a feeder sourcing calves or a packer buying fat cattle, they should not be used to provide direction for a population. In fact, if used widely, “segmented” indexes can have unintended and undesirable consequences for a population.

​

Because ASA’s indexes consider all traits a sire will impact across the entire production system, they are “balanced” — this balance prevents selection on the indexes from taking our population down unintended and undesirable paths. It ensures that we will make optimal genetic progress in all traits that have an economic impact on beef cattle production.