Some common genetic defects that can occur

By Gary Sliworsky
OMAFRA Rep.

This week’s article is part 2 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 are often 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 has been identified in the Polled Hereford breed. At the time of birth, alopecia anaemia may be mistaken for hairlessness. Affected calves are often 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.
Translocations. 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. 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.
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, most being of very low frequency.
When you suspect that 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 work 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. Practice no inbreeding within the herd. Crossbreeding to a different breed is another alternative.
Genetic abnormalities are not common. When they do occur, they cause economic losses. 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.

Dates to Remember
Jan.26 - Nor-West Animal Clinic Meeting “General On-Farm Procedures Owners can Often Do”, 7:00 pm, Stratton Millenium Hall.
Jan.27 – Grower Pesticide Safety Course. Call 1-800-652-8573 to register.