Two newly reported genetic disorders have prompted the Canadian Maine Anjou Association to strengthen its policy on reporting anomalies.
Genetic diseases appear from time to time in most livestock breeds and modern testing procedures can identify most carriers.
The most recent conditions, pulmonary hypoplasia with anasarca, or PHA, and tibial heminmelia, or TH, appeared in Maine Anjou and Shorthorns in the United States. Associations in both countries have released policies on testing and handling the diseases.
“If they have it, it wouldn’t be a surprise if we did too,” said Heather Hartmann, general manager of the Canadian association, which is maintaining a list of verified carriers of several genetic disorders.
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Producers can submit DNA samples by collecting a tail hair from the calf and its parents. If the calf is dead, cut a one inch square notch from its ear, freeze and submit it for DNA testing.
Producers should take photographs of the calf and write a detailed description of its appearance.
The association will conduct a pedigree search for common ancestors and the sire and dam will be identified as suspect carriers after two abnormal calves are born.
If an animal is named a carrier, producers are advised to remove it from the breeding population.
The diseases are the result of two abnormal genes and American Maine Anjou website reports cattle with TH trace to Shorthorn breeding while those with PHA trace to Maine Anjou breeding. There is a genetic test for TH but not for PHA. However, it is known that parents of an affected calf are carriers of this recessive condition.
TH presents multiple congenital defects. Calves are often born dead. There may be head deformities, an absence of bone in the legs and a large abdominal hernia. The coat may be shaggy.
PHA has been seen in Maines, Shorthorns, Chianina and some crossbreeds. Calves may be born dead and have deformed lungs, as well as other anomalies.
Other breeds have faced similar problems. The Canadian Charolais Association has dealt with arthrogryposis, which leads to leg deformities, a cleft palette and the 1:29 Robertsonian translocation, which is a fusion of a chromosome 1 with chromosome 29 and results in fertility problems. This translocation has been shown to occur in most beef breeds from the European continent and has likely existed for a long time.
A chromosome test called karyotyping can determine if a problem exists.
The Charolais policy states any bull going for semen collection must be tested for the translocation and a positive result must be reported.
“We haven’t had anything on that front for four or five years,” said association manager Neil Gillies.
“If somebody has a bull that is positive, they don’t draw semen,” he said.
If translocation does appear, it is traced to see if it is a genetic or environmental condition. Breeders tend to be proactive when genetic anomalies are detected and get rid of them.
Gordon Stephenson, manager of the Canadian Hereford Association, said genetic policy is being updated along with the American association. There are certain conditions they watch for such as rat tail, hairless calves and a diluter gene causing grey calves when Herefords and Angus are mated.
Producers who find anomalies complete a form, submit the information for analysis and if necessary, report to the breed improvement committee. The bulls are not necessarily removed.
Genetic anomalies hurt not only the animals but can damage breeders’ reputations.
“If it is misinterpreted or misconstrued or used improperly, it can destroy a purebred unit,” Stephenson said.
Sean McGrath, breed improvement co-ordinator for a number of beef associations, said these conditions are unlikely to occur within the commercial industry where there is considerable cross breeding.
“In the purebred industry it is extremely rare,” he said.
Some diseases have an environmental cause and are hard to separate from a genetic defect without testing.
For example, certain toxic plants found in pastures cause calf deformities if consumed at the wrong stage of pregnancy.
“It gets tough because usually you have such a small sample size. If you have two calves affected out of the same bull in a year, you may not see anything for five years.”
Tracing pedigrees for common denominators is difficult and time consuming. Sometimes no genetic test exists.
The problems are often traced to a bloodline or single animal.
“Breeders run far and fast from those bloodlines even under rumour,” McGrath said.
“In some cases it is the right approach and some cases it is over reaction.”
