The following information is taken from the website of UC Davis Veterinary Medicine / Veterinary Genetics Lab
Congenital myotonia, characteristic of Fainting Goats, is a heritable neuromuscular disorder characterized by a slow relaxation of skeletal muscles following voluntary contraction. The sudden muscle stiffness often causes the animal to fall over briefly.
Phenotype: Affected goats become stiff and immobile, and often fall over briefly, following sudden forceful movements or when startled.
Mode of Inheritance: Autosomal recessive
Alleles: N = Normal, CM = Myotonia Congenita
Breeds appropriate for testing: Myotonic or Tennessee Fainting Goat and their crosses, Nigerian Dwarf Goat
Explanation of results:
• Goats with N/N genotype will not have this inherited form of neuromuscular disorder and cannot transmit this allele to their offspring.
• Goats with N/CM genotype will not be affected by this inherited form of neuromuscular disorder but are carriers . They may transmit this allele to 50% of their offspring. Matings between two carriers are predicted to produce 25% of affected goats.
• Goats with CM/CM genotype are expected to develop this form of neuromuscular disorder and will transmit this allele to all of their offspring.
Congenital myotonia, characteristic of Fainting Goats, is a heritable neuromuscular disorder characterized by a slow relaxation of skeletal muscles following voluntary contraction. The sudden muscle stiffness often causes the animal to fall over briefly.
Phenotype: Affected goats become stiff and immobile, and often fall over briefly, following sudden forceful movements or when startled.
Mode of Inheritance: Autosomal recessive
Alleles: N = Normal, CM = Myotonia Congenita
Breeds appropriate for testing: Myotonic or Tennessee Fainting Goat and their crosses, Nigerian Dwarf Goat
Explanation of results:
• Goats with N/N genotype will not have this inherited form of neuromuscular disorder and cannot transmit this allele to their offspring.
• Goats with N/CM genotype will not be affected by this inherited form of neuromuscular disorder but are carriers . They may transmit this allele to 50% of their offspring. Matings between two carriers are predicted to produce 25% of affected goats.
• Goats with CM/CM genotype are expected to develop this form of neuromuscular disorder and will transmit this allele to all of their offspring.
While we have not seen any symptoms of congenital myotonia in our herd, this inherited disorder has been discovered in some Nigerian Dwarf goats, and in November 2025, this became a hot topic and new concern for Nigerian Dwarf breeders.
There has been speculation by some breeders about particular goats being carriers. These goats go way back and are, therefore, present in the pedigrees of a huge number of today's Nigerian Dwarf goats. Because one of the bucks we built our herd on (Proctor Hill Farm Atlantis) is related to one of the "mentioned" animals, we decided to have him tested.
Proctor Hill Farm Atlantis is N/N
As we test additional animals in our herd, you will find their test results here.
There has been speculation by some breeders about particular goats being carriers. These goats go way back and are, therefore, present in the pedigrees of a huge number of today's Nigerian Dwarf goats. Because one of the bucks we built our herd on (Proctor Hill Farm Atlantis) is related to one of the "mentioned" animals, we decided to have him tested.
Proctor Hill Farm Atlantis is N/N
As we test additional animals in our herd, you will find their test results here.
