Fawn Calf Syndrome

Congenital Contractural Arachnodactyly

History

  • ™Congenital Contractural Arachnodactyly (CA)
  • ™Commonly known as Fawn Calf Syndrome
  • ™First identified in Victoria, Australia in 1998
  • –Now identified in several countries
  • ™Affected calves traced back to Freestate Barbara 871 of Kaf
  • ™Freestate Barbara was an Indiana born Angus bull from which semen was imported into Australia

DIAGNOSIS IN NEWBORNS

  • –Unusually long legs resulting in unusually large frame scores
  • –Loose jointed-ness in distal limb joints
  • –Poor muscling
  • –“Knock knees”
  • –Significant post-natal improvement in the above symptoms as the calf matures
Fawn calf syndrome in angus calves

CA AGE PROGRESSION

FCS AGE PROGRESSION

FCS AGE PROGRESSION

GENETIC TRANSMISSION

  • ™Autosomal recessive in the Angus and Angus-influenced breeds
  • –Not sex linked
  • –Caused by the deletion of 38,000 base pairs
  • ™CA free cattle have both copies (CAF)
  • ™CA carrier cattle have one copy (CAC)
  • ™CA affected cattle lack the sequence (CAA)
  • –Researched by Dr. Jon Beever at the University of Illinois
  • ™Discovered the base pair deletions
  • ™Formulated a commercial test for CA

GENOTYPES

™As the illustration shows:
™

Mating a homozygous dominant (CA free) bull with a heterozygous carrier cow yields:

  • –50% chance of homozygous dominant (CA free) offspring
  • –50% chance of heterozygous carrier offspring
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Mating two heterozygous carrier parents yields:

  • –25% chance of homozygous dominant (CA free) offspring
  • –50% chance of heterozygous carrier offspring
  • –25% chance of homozygous recessive (CA affected) offspring

KNOWN ANGUS BULL CA CARRIERS

  1. ™Rambo 465T of JRS – US bred
  2. ™Te Mania Kelp K207 – Australian bred
  3. ™Bon View Bando 598 – US bred
  4. ™SAF 598 Bando 5175 – US bred
  5. ™Boyd on Target 1083 – US bred

DIAGNOSIS PROBLEMS WITH CA

™As the phenotype is subtle, newborn calves may not be detected to have CA. As the calf grows, the symptoms are less observable or completely void.
™

DNA testing is the only way to determine genotypes:

  • –Whole blood samples
  • –FTA blood cards
  • –Semen samples
  • –Hair follices
Big image

PRODUCTION PROBLEMS

  • ™Calves born with CA are less muscular
  • ™Calves born with CA have a much larger frame score
  • ™Calves born with CA do not have as much vigor for suckling or standing (reducing survival rate) and requiring human intervention
  • ™Carrier bulls cannot be registered with the Angus Association

ERADICATION METHODS

™Carrier bulls are not allowed to be registered
™Angus Association education website
™DNA testing for possible carriers
  • –$88 per test per animal
  • –Pays for itself
  • –Market purebred cattle as registered certified CA free

ERADICATION BARRIERS

  1. ™Ability to register carrier heifers
  2. ™CA calves will outgrow the symptoms
  3. ™No specific abnormalities or definitive phenotypic features at adulthood
  4. ™The degree of severity can vary between calves

OPINION

™The American Angus Association should educate purebred breeders and require all cattle that are to be registered DNA tested if they do not come from DNA tested and CA free pedigrees. Similarly, purebred breeders should educate bull and heifer buyers about CA and be able to market all of their reproducing cattle as CA free. We suggest that CA positive cattle should only be used for slaughter and CA carrier cattle should only be bred to tested CA free cattle or crossed with non-Angus breeds.

REFERENCES

™1. Denholm, Laurence. "Congenital Contractural Arachnodactyly (‘fawn Calf Syndrome’) in Angus Cattle." www.dpi.nsw.gov.au. NSW Government, May 2010. Web. 23 Oct. 2012. http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0011/336944/Congenital-contractural-arachnodactyly-in-Angus-cattle.pdf.

2. ™Fawn Calf Syndrome in Angus Calves. Dir. Laurence Denholm. Youtube.com. N.p., 20 July 2008. Web. 23 Oct. 2012.

™3. Pfizer. "Testing for Contractural Arachnodactyly in Your Herd." www.animalhealth.pfitzer.com. Pfizer Animal Health, Animal Welfare, 2012. Web. 30 Oct. 2012.<https://animalhealth.pfizer.com/sites/pahweb/US/EN/Products/PublishingImages/CA%20Info%20Sheet%2010-5-10.pdf>.

4. Whitlock, Brian K. "HERITABLE BIRTH DEFECTS IN CATTLE."Appliedreprostrategies.com. The University of Tennessee, Aug. 2010. Web. 23 Oct. 2012. <http://www.appliedreprostrategies.com/2010/August/pdfs/3-1_Whitlock.pdf>.