It is strongly recommended that all breeding stock be tested, at minimum, for SCID and Cerebella Abiotrophy (CA) heritability. Information and testing are available through UC Davis/VetGen:

SCID
www.vetgen.com/equine-scid-service.html

Cerebellar Abiotrophy
www.vgl.ucdavis.edu/genomic/cerebellar/

Lavender Foal Syndrom
www.vetgen.com/equine-LFS-service.html