HERDA, HYPP & OLWS

Effective 1st August 2016

  1. GENETIC DISORDERS 
    1. Scientific Testing: The Association may require, at its sole discretion, scientific testing to determine the incidence of genetic disorders. 
    2. Results: Test results for all genetic disorders will only be accepted from testing facilities deemed appropriate by the Association.
    3. HYPP: Hyperkalaemic Periodic Paralysis.  
      1. HYPP is an Autosomal Dominant Genetic Disorder, being a muscular disease caused by a hereditary genetic disorder that leads to uncontrolled muscle twitching or profound muscle weakness and in severe cases may lead to collapse and/or death. According to research this condition exists in certain descendants of the stallion “Impressive” AmQHA #0767248;
      2. Horses applying for registration that have lineage to “Impressive” will be tested for HYPP, except where both parents have been tested for HYPP with a negative result on file with the Association, then the horse applying for registration will not be required to be tested for HYPP;
      3. Horses that return a positive (homozygous/afflicted) result to HYPP will not be accepted for registration or recording; 
      4. Horses that return a positive (heterozygous/carrier) result to HYPP will be considered for registration with the Association if gelded or spayed;
        Note: Chemical alternatives to surgical spaying will not be accepted by the Association;
      5. Horses that return a negative result to HYPP will be considered for registration; 
      6. Any horse applying for registration, whose pedigree does not contain the ‘Impressive” lineage will not be required to be tested for HYPP;
      7. Any registered horse may be required to be tested for HYPP using the official procedure at the Association’s discretion;
      8. Horses tested for HYPP will have their registration papers marked with the test result.
    4. HERDA/OLWS 
      1. HERDA (Hereditary Equine Regional Dermal Asthenia) is an Autosomal Recessive Genetic Disorder.
        HERDA is a devastating disease that causes the skin to lift and peel away. The condition, which renders a horse unable to wear a saddle or harness, is known by two names: Hyperelastosis Cutis and Hereditary Equine Regional Dermal Asthenia. The reported age of onset ranges from birth to four (4) years old. According to research this condition exists in certain descendants of the mare “Miss Taylor” AmQHA #0002636 and stallion Poco Bueno” AmQHA #0003044;
      2. OLWS: Overo Lethal White Syndrome is an Autosomal Recessive Genetic Disorder in which the caecum, colon and sometimes the rectum undergo a large dilation and fill with faecal mass. Associated with homozygosis of the Overo Lethal White gene it results in incomplete migration of nerve cells to the large intestine during embryonic development. Affected foals may die within seventy-two (72) hours of birth;
    5. Autosomal Recessive Genetic Disorders:
      1. Horses applying for registration that have lineage to Poco Bueno/Miss Taylor must be tested for HERDA; 
      2. Where both parents have been tested for HERDA/ OLWS and both parents have a negative result on file for that genetic disorder, the horse applying for registration is not required to be tested for that particular genetic disorder;
      3. Horses applying for registration that display excessive white markings beyond the limits described in Rule 11.4, unless the horse applying for registration is out of two (2) negative parents, must be tested for OLWS;
        Exception: Horses applying for Foundation Recording that display excessive white markings beyond the limits described in Rule 11.4 will not be accepted for Foundation Recording;
      4. Any horse that does not carry lineage for HERDA will not be required to be tested for that disease;
      5. Horses that return a positive (Homozygous/Afflicted) result to HERDA/OLWS will not be accepted for registration;
      6. Horses that return a positive (Heterozygous/Carrier) result to HERDA/OLWS will be considered for registration;
      7. Horses that return a negative result to HERDA/OLWS will be considered for registration;
      8. Geldings that display excessive white markings are not required to be OLWS tested if parent validated to two (2) registered Quarter Horses;
      9. Geldings who are by or out of a HERDA carrier are not required to be HERDA tested;
      10. Geldings whose parents are both HERDA carriers will be required to be tested, and if they return an Hr/Hr result will not be eligible for registration;
      11. All horses tested for HERDA/OLWS will have their  papers marked with the test result. 
    6. Foundation Recorded Horses Genetic Testing
      1. ​​​​​​​All ASB registered horses to be considered for Foundation Recording must return a negative result to HERDA and OLWS;
      2. All ASHS registered horses to be considered for Foundation Recording must return a negative result to HYPP, HERDA and OLWS.
    7. Stallions and Mares
      1. ​​​​​​​All breeding stallions and mares with lineage to Poco Bueno/Miss Taylor and no HERDA results on file with the Association will be suspended and no paperwork will be processed for the stallion or mare; 
      2. All breeding mares who cannot prove that they do not have lineage to Poco Bueno/Miss Taylor and do not have their HERDA results on file will be suspended and no paperwork will be processed for that mare;
      3. Once a negative or carrier HERDA result has been received, all rights and privileges for the stallion/mare will be reinstated.
    8. Other Genetic Disorders
      1. ​​​​​​​At the direction of the Association any horse may be required to be tested for any genetic disorder at any time;
      2. On notification from the Association, a registered Veterinarian will, using an official testing kit, be required to take the specified sample and forward it to the place of testing directed by the Association;
      3. The horse’s registration papers must be forwarded to the Association where they will be marked with the official result.