Contractural Arachnodactyly (CA)

Return to Genetic Defects

American Angus Association Update on Fawn Calf Syndrome (Contractural Arachnodactyly)

July 26, 2010

This link provides information about research done on CA.

This is a non-lethal condition wherein calves are normally born alive and most can walk, suckle and survive. The birth weight of affected calves is normal. The phenotype is subtle and hence CA may not initially be recognized as an inherited defect. Affected calves at birth assume an abnormal crouched posture resembling an elk or deer fawn. In their first days of life, affected calves are also flat down on their pasterns. Although there is a reduced range of movement in the upper limb joints, particularly the hip, stifle and hock, there is an increased extensibility of the lower limb joints, particularly the pasterns. CA affected calves are reported as taller and more slender than their unaffected siblings.

Australian researchers assert that the inability to passively extend the hip, stifle and hock joints to the normal extent by pulling downwards on the foot of a newborn calf—while it is held on its side on the ground—is a valuable diagnostic sign in CA cases.

Affected calves can show significant recovery and usually appear relatively normal by 4 to 6 months of age. As weanlings and yearlings, CA affected calves appear lighter framed and lighter muscled, particularly in the hindquarters. Most perform poorly and remain tall, slender animals with poor foot conformation. The more normal appearance of CA cases as mature adults makes early evaluation of the phenotype essential. Australian researchers have also reported the early onset of degenerative arthritis in cows that were CA-affected as calves, particularly in the stifle joints.

– Dr. David Steffen, University of Nebraska

CA Carrier animals

CA Tested Free Animals

Lists last updated August 30, 2011

Click here to request a CA test

Test commercially available as of 2010