Beef cattle genetics

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Source: University of Minnesota Extension, Joe Armstrong, DVM, Extension educator

Quick facts

  • There are several genetic evaluation tools that make interpreting beef genetics easier.
  • Sire selection is the fastest way to make improvements in herd genetics.
  • Crossbreeding and choosing the best breed of cattle for each farm is important.
  • Set goals and know what traits are most important for your farm to focus on.

Select cows for your system

Each beef operation is different and has different goals. Strive to have the best management practices possible and select cows that work in your unique system.

Not all genetics will work for every farm. Make selections, and culling decisions to find cows that work for you.

How are beef genetics measured?

Genetic indexes are effective tools in measuring beef genetics. Most indexes use a combination of traits to select animals that excel in a certain area that farmers want to focus on.

Consider the reliability of traits when reading a bull proof and selecting animals to mate.

Expected Progeny Differences (EPD’s) allows a comparison of two animals. EPD’s are estimates of an animal’s genetic value for a given trait that will be passed to offspring. Traits include calving ease, birth weight, weaning weight, yearling weight, marbling, rib eye area, maternal milk and many more.

Unlike predicted transmitting abilities (PTA’s) that are used for dairy animals, the average for every trait is NOT zero. Breed associations determine averages for each trait and index based on available data.

  • EPD’s are specific for each breed, meaning they cannot be used to directly compare two animals from different breeds without first converting to a common base.
  • Each EPD trait will have an accuracy number expressed as a decimal (i.e. 0.95).
    • The more information that is available the higher the accuracy.
    • The closer to 1.00 the number, the more accurate the reported value.

Many breeds have indexes that combine EPD traits using specific formulas for each segment of the industry or different farmer goals. The terminology for these indexes is not the same between breeds and farmers should read the definitions carefully.

Use these indexes in combination with your operation’s goals when making sire or dam selections rather than using single traits alone.

Angus Value Indexes as an example

  • Weaned Calf Value ($W): This index is designed for cow/calf farms that will keep replacements from their calf crop and sell cull females and male calves around the time of weaning. The index should identify differences in profitability pre-weaning.
  • Beef Value ($B): This index is designed to predict post-weaning feedlot performance and carcass traits. The index assumes retained ownership and grid-marketed animals.
  • Maternal Weaned Calf Value ($M): This index is designed for farms that raise their own replacements and includes traits to reflect profitability from conception to weaning. The index includes heifer fertility traits to help improve reproductive efficiency.

Does the bull or the cow make a bigger genetic difference?

The fastest genetic progress is made with sire selection. While cow families and pedigrees are incredibly important, sire selection usually makes up more than half of the equation in terms of genetic progress.

Breed choice

One of the biggest genetic decisions you can make is what breed or breeds to have on your farm. While production factors and economic decisions play a huge role in the decision, there are many other factors, tradition, what you have now, what breed the kids would like to show, etc.

Breeds will differ on the size of the animal, hide color, production and temperament. The decision for each farmer will be based on the market, personal preference, facilities and various other economic factors.

Crossbreeding

Crossbreeding is breeding an animal from one breed to an animal of a different breed. Often, this is done by using a bull of a different breed on the majority of the cowherd.

Crossbred animals can have increased fertility, increased longevity, and increased health, which all lead to increased profitability. The resulting increases of beneficial traits from crossbreeding are termed heterosis and are sometimes referred to as hybrid vigor.

Crossbreeding examples

Angus x Hereford

  • Crossing Angus and Hereford genetics usually results in a black calf with a white face.
  • Often these animals are referred to as “baldies.”

Angus x Brahman

  • This cross resulted in a breed now known as Brangus.
  • Brahman cattle are more heat tolerant, while Angus cattle are known for carcass quality.
  • The result is an animal that does very well in hot climates.

What traits to select for

Identify your overall genetic goals or preferences for your farm and select animals based on the specific needs of your system.

  • Avoid selecting sires or dams based on single traits.
  • Genetic indexes provide a data-driven method to select animals.
  • Genetic companies and seed-stock farmers usually have animals grouped according to different farm goals.

There are two main categories of bulls: terminal bulls and maternal bulls.

  • Terminal bulls are selected to make progeny that will NOT enter the reproductive system. Instead, their progeny excel in growth and carcass quality.
  • Maternal bulls are selected knowing their progeny have the potential to enter the reproductive system (become replacements).
  • There will always be a debate about which bull to use. The decision will depend on each operation’s goals, size, preference, breed, and more.

For a cow to maintain productivity, she needs to have a calf every year. Fertility is included in some genetic indexes and can be selected for to help achieve high pregnancy rates.

Improving weaning weights is important but does not compare to high pregnancy and weaning rates in terms of contribution to overall success.

One of the most important metrics of efficiency is pounds of calf weaned per cow exposed. This measurement takes into account reproduction, pre-weaning health, and pre-weaning growth. Farmers can use this measurement to track improvements.

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