Genomic Testing is one method to ensure the Dutch Spotted Sheep, recorded and registered in the DSSSUS, conform with breed standards. It is today’s gold standard to detect potential disease carriers, susceptibility, and resistance. It is also the method to determine that genes associated with desired traits are present in the genes of purebred sheep.

Since the Dutch Spotted Sheep Society US is presently allowing a Grading Up Program, it is important that detrimental recessive genes are not found in registered sheep. Genomic testing confirms those recessive traits do not become a problem in the purebred population in the years to come. When we start with solid animals, the future population is inevitably stronger. 

The gene responsible for the nice muscling seen on Dutch Spotted Sheep is the myostatin gene mutation. Myostatin is a muscle growth regulator. The myostatin gene mutation inhibits myostatin production resulting in the nicely muscled phenotype of not only Dutch Spotted Sheep but can be seen in Texel Sheep as well as a few other breeds. This genetic trait is most commonly depicted as M (present) or – (not present) on lab test results. Several allowable foundation ewes used in the Grading Up Program do not carry the myostatin gene mutation. Since each parent contributes exactly half of the genes in an offspring, the best result in a Grade 5 (50% DSS or 1st generation) is one myostatin gene mutation M/-. Through the generations of Grading Up it is a high probability that by Grade 0 (not less than 96.875% DSS or 5th generation) the double myostatin mutation will be present. To ensure that all Dutch Spotted Sheep registered with the DSSSUS carry the M/M gene marker, testing by a certified lab is necessary for all initial sheep registered. Once a sire and dam are both confirmed as having the M/M designation, ALL subsequent offspring will carry the M/M gene marker and do not need testing for registration.

To ensure that detrimental recessive genes do not enter the initial Dutch Spotted Sheep registry, testing for Callipyge and Spider Lamb is also required. A negative result on both is required.

Genomic testing is already the vanguard in several countries around the world.  In keeping with the goal to utilize best practices to build solid, high quality, desirable, registered stock, The Dutch Spotted Sheep Society US will adopt practices that ensure the health and longevity of the Dutch Spotted Sheep registered with the US Society.