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Heifer Selection and Genomics

Originally written by Taylor Grussing, former SDSU Extension Cow/Calf Field Specialist.

Weaning is done and calves are hopefully getting settled into backgrounding yards. Now is the time to select replacement heifers and start them on a development plan that aligns with female management and breeding goals. While the feeder cattle counterparts need to optimize on performance and feed efficiency, replacement heifer targets are based on mature size and breeding benchmarks.

Heifer Selection should always start with selecting heifers that will meet herd goals. Usually this begins with analyzing age of heifers as the older heifers are more likely to get bred earlier in their first breeding season. In addition, phenotype and structural integrity need to be considered in order to plan for longevity in the mature cow herd. However, with current genomic technology at our fingertips, we can also get an inside look at replacement heifer genetic potential which can assist producers in selecting replacement candidates.

What are Genomics?

Genomic information is an analysis of an animals’ DNA based on the genes it inherited from both is dam and sire. Not all full siblings receive the same genes, which is why they usually perform differently when put into production. Genomic data can be used to enhance EPD’s and provide insight to heifer performance and maternal genetics before any progeny are on the ground.

Genomics data is generated using DNA and genomic equations which starts with collecting a blood sample, hair sample or tissue sample. Make sure the collection area is clean before collecting any sample to avoid cross contamination and new tools are used for each animal. Blood samples can be collected from the tail vein or ear vein and carefully applied to a blood card for submission to the laboratory. Hair samples should be taken from the tail, as a good hair follicle or root bulb is needed for adequate DNA extraction. Using a pliers to pull 20 – 25 tail hairs out and place directly on the plastic collection card to preserve the root bulbs. Tissue samples are commonly taken from the tip of the ear by an ear notch or special collection tools are now available too. Collection cards are available from several breed organizations or genetics company representatives.

Where can Producers Learn About Genomics?

Genomic data can be used by both seedstock and commercial cattle producers. However, the tests will need to be applied differently to achieve the most impact on individual operations. Also, the use of genomics has even more potential to increase genetic change and decrease the generation interval when utilized on bull selection. If you are interested in learning more about genomic testing and how it can be used on purebred and commercial heifers, plan to attend the heifer development conference in Aberdeen on December 6th.

Contact Taylor Grussing for more information or with any questions regarding the conference.