Reynoldsburg, Ohio – 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 .
Determination of JNS Status
The Board of Directors will not designate an animal
either a carrier or free of JNS haplotype if the Board considers that there is
a reasonable doubt that the animal is a carrier. The determination as to
reasonable doubt depends upon the quality and amount of available evidence
which will vary in each case.
Official JNS status is obtained (1) by direct observation
of the UCLH1 missense variant on BTA6 in the genotype of an animal, or (2) by
direct observation of the haplotype including the UCLH1 missense variant on
BTA6 in the genotype of an animal, or (3) by use of genomic test results of the
individual and family members to determine through imputation if the variant is
contained in the JNS haplotype of other genotyped animals, and reassessed as
additional information is obtained from genomic analyses.
With respect to all sales sponsored by the Association, a
bull shall not be accepted unless designated Free of Jersey Neuropathy with
Splayed Forelimbs (JNS).
Information to identify the undesirable genetic factor
was determined from a study of 11 affected calves reported by Jersey breeders
across the country. The AJCA worked with the breeders, their veterinarians, and
scientists of USDA-ARS-AGIL to document the new factor.
CLICK HERE FOR MORE INFORMATION ON USJERSEY WEBSITE.
The Importance of Reporting
There are three important factors involved in controlling
genetic abnormalities: reporting abnormal animals; labeling the carriers; and
making this information available to people making breeding decisions.
Whether or not the AJCA’s abnormality reporting program is
effective depends almost entirely upon complete reporting. The question often
arises, “What do you report?” The answer is, “If it’s out of the ordinary in
your experience, report it to the Association.” Report forms are available upon request from the
Executive Secretary or from www.USJersey.com.