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Should Beef Producers Implement Genotyping Technologies/DNA Testing Into Their S

Should Beef Producers Implement Genotyping Technologies/DNA Testing Into Their Selection Strategies?
What are genotyping technologies? The genotyping technologies that are currently being marketed to beef producers are based off of genetic markers that have been identified to be associated with economically important traits. A producer can have DNA extracted from an animal’s sample of hair, tissue or blood for future genomic testing. Specifically, these genomic tests evaluate genetic markers that are inherited by animals that are either high producers for a trait or low producers for a trait. Typically, these markers are located on a single gene or in a specific place in the bovine genome. The goal in using these technologies is to increase the accuracy of selection from traits ranging from growth, efficiency, carcass quality, fertility and disease resistance. The genotyping technologies are used to try to identify the underlying genetic predisposition for important traits so that producers can select for their superior animals early in the production process. This is prior to having to maintain an animal to a specific production point to visualize if that animal is indeed superior. These technologies, if developed further, could provide a method for producers to more rapidly improve lowly heritable traits such as fertility or disease resistance.
How can genotyping technologies have limitations if we are looking at the genetic makeup of an animal? The idea that producers could make selection decisions much earlier in the production process led to the commercialization of many genotyping tests. Initially, this type of testing seemed like a good method to try to improve traits that were highly desirable or might be hard to measure in a live animal. However, producers must really understand that the concept of selecting animals based on their genetic makeup is still in the early development stages for a couple of reasons. First, there are an estimated 30,000 genes and three billion individual nucleotides in the bovine genome. Researchers are still attempting to understand where exactly these genes are and what tissues of the body those genes influence. Second, many of the traits that producers are interested in, such as disease resistance and fertility, are lowly heritable and most likely influenced by multiple genes. As such, relationships among genes and mutations on these genes need to be evaluated prior to marker assisted selection (MAS) becoming an accurate method of selection. Selecting for single markers affecting a single trait may not be the most accurate method of selection as that particular marker may not account for a large amount of variation for that trait. Thus, if producers begin selecting for single markers for single traits, it may in fact result in little if any significant improvement for that trait.
Should a producer use genotyping technologies? There are questions producers should ask themselves prior to implementing this technology into their selection. They are: 1. What traits am I trying to improve? 2. Are these traits highly or lowly heritable? 3. How much improvement in one generation or multiple generations can I expect to see by implementing this tool as part of my selection strategy? 4. Will I be able to cover the cost of testing (tissue collection, shipment, DNA extraction and cost of the DNA test) with the increased performance of my animals?
As previously stated, this technology has been around for many years but is still in the early development stages. While this technology may prove to be beneficial for some producers, it may not be cost effective for others. It is always important to know as much as you can about these technologies prior to implementation so that a decision can be made as to whether it is going to bring an added benefit to your operation. While genomic tests are still relatively new, they are getting more accurate and will continue to improve. As such, this technology, if developed correctly, will provide producers a new selection tool in the future to make them more profitable and sustainable. —Source: LSU AgCenter, Pasture to Market, Dr. Matthew Garcia, LSU School of Animal Sciences; LSU SAS Animal Industry News Update—September 2015