New Undesirable Recessive - Brachyspina
Select Sires has always taken a position of open disclosure and aggressive testing when genetic recessives are discovered by various sources from around the globe. The newest of these genetic lethals is called Bovine Brachyspina Syndrome or BY as its abbreviation. Only found in the Holstein breed to date, BY was first discovered in Denmark in 2006 (Journal of Vet Diagn Invest 18:418-422). The name of this defect comes from the Latin term meaning very short spine. Like many other genetic recessives, both parents must transmit a copy of the BY allele to produce an affected offspring. Most pregnancies affected by BY are aborted within the first 40 days of gestation, which is the key difference from CVM. However, a few calves have been born after a prolonged gestation, with reduced body weight, short body and neck length, a defined hump between the shoulder blades, and a deformed lower jaw. Some say the calves look more like a baby moose than a normal bovine.
The common ancestor to which BY traces is Sweet Haven Tradition, and his sons Bis-May Tradition Cleitus and Rothrock Tradition Leadman. The most prevalent carrier sires in more current breeding programs are Ramos and Bolton. Knowing about this potential development, Select Sires has been aggressively testing suspect pedigrees over the last several months to provide genetic decision tools and build our database of test results so we'd be prepared once the recessive trait was declared a genetic defect by the Holstein Association. Only two European labs today offer the BY test. The current test uses a panel of genetic markers to identify the condition. This means the current test has a confidence rating of 95% accuracy. Many claim with the use of the genomic tools available now, a gene test will soon become available to provide a very precise answer to those pedigrees carrying this genetic lethal.
As with any genetic recessive, Select Sires is already armed with a mating tool to avoid doubling up carrier pedigrees with the Select Mating Service® (SMS®) program. SMS allows breeders the opportunity to still use a few carrier sires that also transmit breed-leading profitable traits. Currently there are some carrier bulls that are just too good to completely ignore. SMS provides the means to make wise use of carrier bulls to take advantage of their good traits while avoiding the BY condition. At the recent Select Sires Board of Directors meeting, the decision was made to allow sampling of a few very elite BY carriers, provided proper labeling was developed. In this manner, we provide you with our current lineup of bulls that have been tested to date.
|Code No.||Code Name||Brachy|
|Code No.||Code Name||Brachy|
The Holstein Association has issued a public announcement as follows:
Brachyspina Confirmed as Undesirable Recessive Trait by Holstein Association USA
At their recent meeting, the Holstein Association USA board of directors voted to declare Brachyspina as an undesirable recessive trait in the Holstein breed, and approved the recording of testing results on Holstein Association USA pedigrees and other performance products. Brachyspina is expressed when an animal is homozygous for the undesirable allele, meaning that two carrier animals have been mated. Holsteins that are known carriers will be labeled with the code BY, and tested non-carriers will be labeled TY.
"It's our belief that labeling the carriers of Brachyspina will give breeders the information they need to dramatically reduce the frequency of the undesirable recessive allele in the Holstein breed. In the interim, top genetic animals, identified with BY, can still be used with some attention given to the pedigree of the potential mate" said Dr. Tom Lawlor, Holstein Association USA Director of Research and Development. It is estimated that approximately 6 percent of Holstein cattle carry the gene for Brachyspina, which can cause embryonic death, stillbirth or other physical deformities. In a random mating population, it's estimated that 1 out of 1,000 matings would result in early embryonic death and an increase in days open.
Since this announcement was just made it was impossible to get full labeling of tested animals in place for the April evaluations. We can expect for the August evaluations that BY will receive official labeling status on all Holstein pedigrees and sire summary publications. Select Sires will include this new condition in the list of other genetic recessives that our breeding leading sire program monitors. Your sire development team is taking a strong approach to minimize this genetic recessive though selection of future TY sires which will greatly reduce the gene frequency of this lethal trait for the future.® Select Mating Service, SMS are registered trademarks of Select Sires Inc.
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