What is in this article?:
• A bone disorder that affects humans, cattle, and other animals, osteopetrosis is characterized by overly dense yet brittle bones that shatter easily.
• Calves that suffer from the mutation have deformed skulls, receding lower jaws, and protruding tongues. They usually are stillborn or die within 24 hours of birth.
• Breeders now have a test they can use to manage the defect, identify cattle that may be carriers, and make decisions on whether the animal’s other traits make it valuable enough to continue using it for breeding.
What once took years to accomplish was done within a matter of months with fewer samples.
Scientists were able to develop a PCR (polymerase chain reaction) test and have it available to breeders in less than a year. They also determined that the popular bull was not a carrier, to the relief of the industry.
“The mutation had crept into the pedigree of the offspring of the bull by his mating with a carrier heifer,” Smith says.
Scientists looked at the genetic makeup of more than 450 normal Red Angus to see how common the mutation might be in the breed. No healthy animals were found to be homozygous for the mutation, consistent with the prediction that all animals with two copies of the mutation should be affected.
More than 570 Black Angus bulls were also tested and found to be negative for the osteopetrosis-causing mutation.
Breeders now have a test they can use to manage the defect, identify cattle that may be carriers, and make decisions on whether the animal’s other traits make it valuable enough to continue using for breeding, Smith says.
This way, the bone disease can be eliminated from the herd without sacrificing other genetic progress made during development of the breed.
“What’s really important is that with the rapid response time with which we can now put a test like this into the hands of producers, they don’t have to be as afraid of genetic defects anymore,” Smith says.
“We can create tests relatively fast now and prevent these kinds of diseases from spreading throughout the herd.”
The newly developed PCR test — provided through RAAA — has been widely used and is required for registration of most Red Angus.
“If it had not been for the research team, we would not have this tool to provide to our customers in their ongoing quest to develop those reliable genetics,” Keenan says.
“The Red Angus Association is grateful for that.”
This research is part of Food Animal Production (#101), an ARS national program described at http://www.nps.ars.usda.gov.
"New Test Detects Bone Disease in Red Angus" was published in the September 2011 issue of Agricultural Research magazine at http://www.ars.usda.gov/is/AR/archive/sep11/angus0911.htm.