Technology for a better breed

Opinion
Aug 23, 2013
by WLJ

In the 92 years of publishing the Western Livestock Journal, many advancements in technology ,have been reported on and as we move forward, many more innovations will be discussed through this publication. Last week, the WLJ published the annual Commercial Cattle Issue. In this magazine, practical uses and technology involving DNA was a central theme. Ironically, in the same week, a new genetic condition involving Angus genetics was announced by the American Angus Association.

 

Every breed of every species contains genetic abnormalities. Each breed of cattle contains them, but because Angus has the largest population, they have had the most attention from corporate DNA labs and academic institutions as they have the quickest means to validating DNA technology.

Five years ago, the first major genetic defect in over a couple decades was announced in Angus genetics. Mass panic ensued as this simple recessive defect incriminated over 30 percent of the registered Angus population as possible carriers. All the other breeds that allow Angus genetics into their population as a means to composite bred cattle were also incriminated with the discovery of the defect. The use of DNA testing resulted a very quick response in identifying the carrier animals of the Arthrogryposis Multiplex (AM or curly calf syndrome) defect with AAA taking a strict stance to not allow this defect to continue to enter commercial herds.

I have applauded this stance from day one and think this position should remain standard. This defect was the first strong example of how DNA technology could be used to eradicate the defect from the breed by testing known potential carriers, identifying the carriers from this list based on the results of the DNA test, and allowing non-carriers to remain in the registered population and carry on those genetics. The days of mass culling based on pedigree alone are gone. The population will now be able to move forward and keep the gene pool more diverse. Without this ability, the gene pool would be condensed, creating a stronger opportunity for more genetic abnormalities in the future.

Once AM became public knowledge, a paradigm shift happened for every dead calf that was born to an Angus or Angus-based cow. Before, the thinking was the dead calf was a result of a toxicity or a mere freak incident in nature. Afterwards, thoughts shifted to the possibility that genetics may have played a role in the deformity. This shift resulted in a vast increase in tissue and blood samples being sent to DNA labs and breed associations. At that point, each sample was then identified as genetics or nature. Because of this increase in submitted samples, these labs have been able to identify nearly every genetic abnormality in the population, and a DNA cleansing has ensued.

The new condition, known as Developmental Duplication (DD), stems back to bulls bred over 35 years ago and the defect was discovered recently in Australia. Bulls bred today that have genetic mutations will not be discovered for several generations, making it extremely difficult for the conditions to present themselves phenotypically. I’m not saying the situation isn’t serious and in no means downplaying a genetic condition. I’m saying breeders have the tools to quickly eradicate this condition, and provide a clean product to commercial cattlemen.

The initial release of the new condition is estimated to implicate 10 percent of the Angus population. When comparing this condition to other conditions in the population, studies have found that a larger percentage of affected embryos and fetuses were absorbed or aborted in early gestation. If proper management ensued, most likely those cows were removed from the herd because of a perceived fertility issue and many carrier cows exited the population before ever knowing there was a genetic concern behind her reproductive performance. Nonetheless, a small percentage of the population is identified as a potential carrier and major testing is underway.

 

In conclusion, this defect will be short-lived in the population and as the DNA samples of potential carriers are tested, the list will diminish very quickly. Because the defect has affected so few cattle in the past, the breed will move forward. All we can do as cattle breeders is continue to make ethical breeding decisions and when these issues arise, test the cattle as quickly as possible and move forward. The commercial cattleman is the key to success in this business and that should never become unclear to a registered breeder. — LOGAN IPSEN

 

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