A new undesirable genetic factor, known as Jersey Neuropathy with Splayed Forelimbs (JNS), has been identified in the Jersey breed, according to the American Jersey Cattle Assn. (AJCA). The AJCA board of directors was made aware and discussed the results of the investigation at the November board meetings in Louisville, Ky.
Calves affected with JNS are unable to stand on splayed forelimbs that exhibit significant extensor rigidity and/or excessive lateral abduction at birth, AJCA said. Affected calves are generally bright at birth but exhibit neurologic symptoms, including spasticity of head and neck and convulsive behavior. Other symptoms reported include dislocated shoulders, congenital craniofacial anomalies and degenerative myelopathy.
According to AJCA, JNS is attributable to a specific haplotype on Bos taurus autosome 6 (BTA6) of genotyped Jerseys, and fewer than 6% of the genotyped Jersey population are carriers of the haplotype, meaning 94% of the genotyped population is free of the JNS haplotype.
The official JNS haplotype status was reported to AJCA by the Council on Dairy Cattle Breeding (CDCB), which will incorporate the JNS haplotype status into its standard data formats provided to industry cooperators after Jan. 1, 2021.
On Nov. 20, AJCA updated the animal database with the carriers identified by CDCB through genotyping. As required by AJCA policy, breeders, owners and lessees will receive notification of designated carriers of JNS. AJCA staff has started the process of contacting individuals affected by the animals identified with the JNS haplotype. A complete list of carrier bulls, with corresponding NAAB codes, will be included in the Green Book as soon as feasible.
The association added that JNS carriers will be identified as JNSC and that tested free individuals will be identified as JNSF on the "Official Performance Pedigree & Performance & Progeny Report."
In addition to identifying the new haplotype, the board voted to amend the "Policy Regarding Undesirable Genetic Factors" to include the "Statement of Designation Procedures for Jersey Neuropathy with Splayed Forelimbs (JNS).
AJCA, organized in 1868, compiles and maintains animal identification and performance data on Jersey cattle and provides services that support genetic improvement and greater profitability through increasing the value of and demand for registered Jersey cattle and genetics and Jersey milk and milk products.