Research PAP EPD launched by Angus Genetics Inc.

Kate Ryan
Angus Communications

A research expected progeny difference (EPD) for pulmonary arterial pressure (PAP) was launched by Angus Genetics Inc. (AGI) on Feb. 1. This research EPD stems from collaborative efforts between Colorado State University (CSU), the American Angus Association and AGI, combining datasets collected at CSU, the Association and by Dr. Tim Holt. This latest EPD from AGI is a first of its kind for any breed association and will help producers identify cattle less susceptible to high altitude disease (HAD).

HAD is caused by lack of oxygen, which adds stress to the heart, changes the way blood flows and results in right heart failure. Symptoms like lethargy, shortness of breath and brisket edema begin to show when cattle are exposed to an elevation of 5,000 feet or higher. Though the goal of the EPD is to identify low-risk genetics to be used as parents for the next generation, Kelli Retallick, AGI director of genetic service, cautions that the EPD will not replace individual PAP tests for animals living at altitude.

“If we send a calf that does not PAP well up to high altitude, it could now be a life or death situation,” Retallick said. “This is probably one of the most important traits that we need to think about from a phenotypic standpoint. Relate it to something like scrotal size and scrotal EPD for instance. In this case, an animal can have the genetics to produce larger scrotal sizes as indicated by the EPD, but the scrotal EPD does not replace breeding soundness exams.”

This research EPD intends to prompt discussion among high altitude breeders to gather feedback from the industry before a weekly production PAP EPD would be released later this year. With this initial release, only A.I. sires with accuracy values of greater than 0.40 are published in the research report. EPDs in this report were predicted with the use of the Association’s Single Step genomic evaluation; therefore, genotypes were readily used for the PAP evaluation to more precisely define relationships among pedigrees.

Association members who have sent in data to the Association will receive research PAP EPDs on individual animals in their herds who have PAP scores submitted and on herd sires who have enough progeny scores recorded. If members have PAP data they would like to send into the Association to be used for future analysis, members are asked to log into their AAA Login to submit these scores. The collection of more PAP data will allow for more research on the topic and, ultimately, more definitive answers about HAD susceptibility.

“PAP testing is phenotypic data that validates the genomic data,” Retallick said. “We cannot find information SNP (single nucleotide polymorphism) markers without the physical data. Geneticists have identified some markers possibly linked to the disease, but they have not been validated yet.”

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