Some common congenital defects in cattle

By Gary Sliworsky, Ag rep, Emo

This week’s article is part two on congenital defects in cattle.
Here are some of the more common genetic defects that can occur.
•Hypotrichosis (hairlessness)
Hairlessness occurs in several breeds of beef cattle. It expresses itself as complete or partial loss of hair.
Calves often are born with no hair but will grow a short curly coat of hair with age.
Affected individuals are prone to environmental stress (cold and wet) and skin infections are more prevalent.
A recessive gene causes hairlessness.
•Alopecia Anemia
This syndrome recently has been identified in the Polled Hereford breed. At the time of birth, alopecia anaemia may be mistaken for hairlessness.
Affected calves often are small at birth, have a dirty-faced appearance, and have protruding tongue and eyes. Hair is wiry, tightly curled, or absent while wrinkled skin gives the appearance of advanced aging.
Calves are lethargic, cannot tolerate stress, and are very prone to disease. Few survive past six months of age.
Malfunction of the skeletal structure results in reduced red blood cell production (anaemia).
Alopecia anaemia occurs in families but the exact mode of transmission is unknown.
A translocation occurs when part of a chromosome breaks off and attaches to another chromosome.
The 1/29 translocation has been identified in the Simmental, Charolais, and Blonde D’Aquitaine breeds while the 14/20 translocation occurs in most Continental breeds.
Translocations affect fertility but no other production traits. Carriers of translocations have reduced conception rates and increased abortion rates.
Blood analysis allows easy identification of carriers.
•Beta-mannosidosis (Beta-man)
The Beta-man disorder is due to a recessive gene that produces a defective enzyme. The result is the birth of calves that never get up and eventually die.
The syndrome occurs in the Salers breed, and a blood test is available for identifying carriers.
•Syndactyly (Mulefoot)
Syndactyly refers to the fusion of the two toes of the foot. Caused by a recessive gene, mulefoot most often affects the front feet.
This condition occurs in the Aberdeen Angus breed.
Other genetic defects exist, with most being of very low frequency.
When you suspect you have a problem calf, consult your veterinarian. Investigate all symptoms and possible causes before concluding the problem is genetic or environmental.
When the cause is genetic, contact the breed association and give them a full report of the findings. Progressive breed associations are working to reduce the frequency of genetic abnormalities within their breed.
To avoid further abnormalities in your herd without culling female carriers, use non-carrier bulls unrelated to your herd. As well, practice no in-breeding within the herd.
Cross-breeding to a different breed is another alternative.
Genetic abnormalities are not common. When they do occur, they cause economic losses.
Both genetic and environmental factors cause abnormalities. Environmental causes are quickly corrected while genetic causes require longer-term solutions.
If an abnormality occurs on your farm, take immediate action.

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