NEWS RELEASE

September 28, 2001

COMPLEX VERTEBRAL MALFORMATION (CVM)

The Board of Directors of the Holstein Association USA has officially recognized CVM as an undesirable genetic recessive. Procedures for handling affected calves, testing potential carriers, and labeling known carriers have been developed. Animals determined to be carriers will be identified with the code "CV" on all pedigrees and similar lineage statements, and those determined not to be carriers will be identified with the code "TV". These codes are expected to be standardized internationally. Members of Holstein Association USA are required to report CVM test results, to report affected calves and to label known carriers in all published material.

Holstein Association USA took this action after extensive consultation with the National Association of Animal Breeders (NAAB), and numerous scientists and pathologists. This action follows a recent announcement by NRS, in The Netherlands, that their research provides strong evidence that CVM is caused by a single recessive gene. Subsequently, Danish scientists announced that they had identified the gene causing the malformation, such that carriers and non-carriers can now be identified using a simple genetic test. Specific details about the gene and the mechanism underlying this malformation have not been released to the general public, but communication with Danish scientists regarding the details of this condition is ongoing.

Holstein Association USA and NAAB recently initiated a breeding trial to confirm the mode of inheritance of the CVM defect. However, after careful evaluation of the Dutch and Danish research results, this project was discontinued.

CVM is a genetic defect that causes aborted fetuses and stillborn calves. Affected calves are often stillborn, typically 1-2 weeks prior to the expected calving date, however, many fetuses are also aborted earlier in the gestation period. The most noticeable defects are malformed legs with flexed and rigid pasterns. A shortened neck may also be noticed. Because the physical defects are so subtle, many affected calves and fetuses go unrecognized. Definitive diagnosis of CVM usually requires a necropsy or autopsy to detect abnormal curvature of the spine, fused vertebrae and fused or missing ribs. Vertebral anomalies vary from severe to subtle and may require radiographic studies or careful dissection of the spine to be distinguished. All calves aborted with flexed and rigid fetlocks need coordinated veterinary examination to determine CVM status.

A DNA test for CVM is available at the Van Haeringen Laboratory in The Netherlands. Testing kits can be requested from Holstein Association USA, Inc. Hair or semen samples are preferred for this test.

In addition to recording test results, the Holstein Association will record results of pathological examinations of malformed fetuses and calves. The primary pathologist for the examination and diagnosis is Dr. David Steffen, Director, Veterinary Diagnostic Center, University of Nebraska-Lincoln. (Telephone number 402-472-1434 or dsteffen1@unl.edu. ) Dairy producers are urged to report the birth or abortion of a malformed fetus or calf to Dr. Steffen, the Holstein Association or to their AI representative.

CVM is inherited through a single recessive gene. CVM-affected calves can only result when a carrier cow is mated to a carrier bull. When two carrier animals are mated, 75% of the calves will be normal, and 25% will be affected with CVM. Calves that have one defective gene will appear physically normal, and their performance will be unaffected, but they will be CVM carriers. Test results to date have revealed that about 15% of AI sires are CVM carriers. If we assume that the frequency of CVM carriers is similar in the cow population, a 200-cow herd that is randomly bred to AI sires would have about one CVM-affected calf each year.