A new undesirable genetic factor, known as Jersey Neuropathy with Splayed Forelimbs (JNS), has been identified in the Jersey breed. The American Jersey Cattle Association (AJCA) board of directors were 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. 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. JNS is attributable to a specific haplotype on Bos taurus autosome 6 (BTA6) of genotyped Jerseys.
Less 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 is reported to AJCA by the Council on Dairy Cattle Breeding (CDCB). The CDCB will incorporate the JNS haplotype status into their standard data formats that are provided to industry cooperators after January 1, 2021.
On November 20, the 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 impacted 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.
Carriers of Jersey Neuropathy with Splayed Forelimbs (JNS) will be identified as JNSC and tested Free individuals will be identified as JNSF on the Official Performance Pedigree and Performance and 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). The Description of Condition (above), Determination of JNS Status and marketing statement follow .