VetGen - The leader in veterinary genetic disease research and genetic disease detection services for purebred animals

Breeding Strategies

VetGen's DNA test findings can be extremely valuable when developing and implementing your breeding plans.

Interpreting Your SCID/CA/GBED/LFS/OAAM DNA Test Results

There are three possible test results: Clear, Carrier, and Affected. Below is a description of what each result means to you as a breeder.


This finding indicates that the gene is not present in your Horse. Therefore, when used for breeding, a Clear animal will not pass on the disease gene.


This finding indicates that one copy of the disease gene is present in your Horse, but that it will not exhibit disease symptoms. Carriers will not have medical problems as a result. Horses with Carrier status can be enjoyed without the fear of developing medical problems but will pass on the disease gene 50% of the time.


This finding indicates that two copies of the disease gene are present in the Horse. Unfortunately, the Horse will be medically affected by the disease. Appropriate treatment should be pursued by consulting a veterinarian.

Helpful Equine Breeding Chart

The chart provided below outlines the implications of various breeding pair combinations. Remember, it is always best to breed "Clear to Clear". If followed by all breeders, these strategies will ensure a significant reduction in the frequency of the targeted disease gene in future generations of Horses. However, to maintain a large enough pool of good breeding stock, it may be necessary for some breedersto breed "Clear" to "Carriers" (see below).

Breeding Pair Combinations CLEAR Stallion CARRIER Stallion
CLEAR Mare 100% Clear 50/50 Carrier/Clear
CARRIER Mare 50/50 Carrier/Clear 25/50/25 Clr./Carr./Affctd.

Ideal Breeding Pair - Foals will not have the disease gene

Breeding Is Safe - No Affected foals will be produced. However, some or all foals will be Carriers. Accordingly, it is recommended that Carrier Horses which are desirable for breeding be bred with Clear Horses in the future, which will produce 50% carrier and 50% clear animals,to further reduce the disease gene frequency. These offspring should be tested by VetGen's test for this defective gene, and if possible, only the clear animals in this generation should be used.

High Risk Breeding - Some foals are likely to be Carriers and some foals are likely to be Affected. Even though it is possible that there will be some clear foals when breeding "Carrier to Carrier", in general, breeding this pair is not recommended.

Equine: SCID Patent
US Patent No. 5,976,803
Canadian Patent No. CA 2272850
United Kingdom Patent No. GB 2335984
Licensed Exclusively by The Board of Regents of the
University of Texas System to VetGen LLC

Equine: LFS Patent
US Patent No. 13/093,173
Licensed by Cornell University to VetGen LLC

Equine: GBED Patent
US Patent No. 7,129,049
Licensed by The University of Minnesota to VetGen LLC