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Hereford and Red Angus Heifers Recruited for Genomics Research

The University of Missouri is recruiting 2,500 Hereford heifers and 2,500 Red Angus heifers to participate in a heifer puberty and fertility genomic research project. Heifers should be registered Hereford, registered Red Angus, or commercial Hereford or Red Angus. Hereford x Red Angus crossbred heifers targeted for the Premium Red Baldy Program would also be a good fit for the research project. Producers must be willing to work with a trained veterinarian to collect the following data: ReproductiveTract Scores collected at a pre-breeding exam 30 to 45 days prior to the start of the breeding season. PelvicMeasurements (height and width) collected at the same pre-breeding exam 30 to 45 days prior to the start of the breeding season. Pregnancy Determination Using Ultrasound reporting fetal age in days. Ultrasound will need to occur no later than 90 days after the start of the breeding season. In addition, heifers must have known birth dates and have weights recorded eithe

BIF 2017: Genetics of reproduction project

Alison Van Eenennaam
UC-Davis

The grant dubbed the "heifer fertility project" is really looking for embryonic lethal variants. These are DNA variants that if an embryo inherits two copies of the variant, that embryo is aborted. The DNA variant breaks a gene. If an animal inherits two copies, it can't live.

The project sequenced the entire genome of hundreds of cattle. This is not genotyping thousands of DNA variants, it is looking at all 2.6 billion base pairs of the genome. From sequencing these bulls, the team identified millions of DNA variants. They selected 200,000 of these DNA variants that are predicted to affect proteins encoded by genes to build a new SNP chip. This chip is called the GGP-F250.

They then genotyped 17,000 cattle with the GGP-F250 chip. Taylor then looked for DNA variants for which there are not observed in two copies. If a DNA variant is at high frequency, but is never seen as two copies, then we have evidence that this is a lethal DNA variant. There appears to be hundreds of these lethal variants in Angus cattle.

Van Eenannaam is working on the producer applications from this grant. If there are lots of DNA variants responsible for embryonic loss, we will have to strategically manage them. If we don't use animals that carry embryonic lethal variants, we will basically be practicing single trait selection. If you haven't heard, single trait selection is bad!

What is important is to never mate a carrier to another carrier of the same lethal variant. Mate selection tools allow us to do this in a sophisticated way.

For more information, see http://beefreproduction.org/.


MateSel is a software program for mate selection. MateSel works to increase genetic merit while limiting inbreeding. Van Eenannaam's graduate student showed simulations using MateSel.
There is a trade-off between never using a carrier and economic genetic progress.

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