The American Hereford Association (AHA), in partnership with the University of Nebraska-Lincoln, led by Dr. David Steffen and Dr. Jessica Petersen, has identified a novel defect in Hereford cattle known as delayed blindness (DB).
This autosomal recessive genetic anomaly manifests in calves with carrier parents, initially exhibiting no apparent vision issues but experiencing vision loss around nine to 12 months. Afflicted cattle struggle with navigation and exhibit limited response to light stimuli.
The association noted the condition is not associated with the amount of pigment around the eyes. Pedigree analysis revealed a shared sire on both sides of the pedigree of affected animals, indicating a potential deleterious recessive genetic variant might be the cause for the blindness. Whole-genome sequencing identified a consistent mutation.
Breeders can use the “potential carrier” search tool in MyHerd, located under the DNA tab on the platform, to determine which animals to test. Breeders can access real-time search capabilities for their active registered animals and dams. AHA recommends periodic searches over the next few months as more animals are tested.
If you suspect a calf may be affected by DB, please alert the AHA or Steffen at the Nebraska Veterinary Diagnostic Center.
