Spider Lamb Syndrome

Ovine Hereditary Chondrodysplasia


  • Scientific Name - Ovine Hereditary Chondrodysplasia
  • Commonly known as Spider Lamb Syndrome (SLS)
  • Also referred to as Hereditary Chondrodysplasia
  • First Identified in the Late 1960's and became a major problem in the 1980's
  • 1986 the "Spider Syndrome" Symposium was held in Sedalia, Missouri
  • Now identified in many countries
  • Predominantly found in black faced lambs
  • Approximately 75% are of Suffolk breed
  • Approximately 25% are of Hampshire breed


  • Autosomal homozygous recessive genetic disorder
  • Lambs appear normal at birth
  • Causes skeletel deformaties
  • Commonly causes abnormally long and bent limbs, twisted or humped spines, shallow bodies, flattened rib cages, roman nose, and long necks
  • Causes an inactivation of normal fibroblast
  • Abnormal transformation of cartilage to bone
  • Lambs appear to be twisted

Why Is This A Problem?

  • Lambs may appear normal at birth but can develop this over the next 6 weeks
  • Causes lambs to be too weak to suckle
  • Breeders loose profit
  • Animals suffer
  • Individual cannot be kept as seed stock
  • Individual does not normally survive to breeding age
Meet Gitta: Spider Lamb Syndrome

Genetic Transmission

  • Happens along the distal end of ovine chromosome 6
  • Requires lamb in inherit two SS genes at the 136 locus
  • Sheep can have N and S genes at locus 136
  • NN sheep are spider free
  • NS sheep are carriers but are not affected
  • SS sheep develop into spider lambs.
  • It is best to always use a NN ram for breeding


There are two main ways to diagnose this problem.

  1. Wait for it to visually manifest
  2. Test breeding stock for SLS
  • Testing is done by blood or semen
  • Most breeder test individuals with relations exhibiting SLS to see if they posses the mutation, if so many are culled
  • Large concern with breeding males as they will have more babies than females

Eradication Methods

  • The best way to eradicate SLS would be genetic testing (expensive)
  • The next best method is to test all rams for SLS and only keep NN status for breeding (less expensive)
  • Knowing that both parents have to attribute this gene you could cull by production (less costly up front, potentially more expensive in the long run)
  • If ewes are with multiple rams and field bred the presents of any SLS lambs would denote you have at least one ram that is not NN and they should all be tested.


Testing may be expensive for a farmer in the short run but every lamb that comes out unhealthy cost time and money. I believe this is one of those diseases that if you do not want to test your whole herd you should at least test your breeding rams. This is particularly important if you raise Suffolk, Hampshire, or and cross including these two. I personally do not believe that people should nurse them along and per long their suffering. They are never going to get better it is inevitable they will need put down before they are of good meat production size or breeding age. When symptoms become apparent the owner has already done an injustice to the lamb by not testing and should do the humane thing.


  • Beever, J. E., Smit, M. A., Meyers, S. N., Hadfield, T. S., Bottema, C., Albretsen, J. and Cockett, N. E. (2006), A single-base change in the tyrosine kinase II domain of ovine FGFR3 causes hereditary chondrodysplasia in sheep. Animal Genetics, 37: 66–71. doi: 10.1111/j.1365-2052.2005.01398.x
  • Drögemüller, C., Wöhlke, A. and Distl, O. (2005), Spider Lamb Syndrome (SLS) mutation frequency in German Suffolk sheep. Animal Genetics, 36: 539–540. doi: 10.1111/j.1365-2052.2005.01384.x
  • Oberbauer, A.m., N.e. East, R. Pool, J.d. Rowe, and R.h. BonDurant. "Developmental Progression of the Spider Lamb Syndrome." Small Ruminant Research 18.2 (1995): 179-84. Print.
  • West, D.m., H.m. Burbidge, J.j. Vermunt, and D.g. Arthur. "Hereditary Chondrodysplasia (“spider Syndrome”) in a New Zealand Suffolk Lamb of American Origin." New Zealand Veterinary Journal 43.3 (1995): 118-22. Print.
  • Nakano, T., B. Walker, and B.A. Young. "Analysis of Tissues from Normal Lambs and Those with Spider Syndrome." Canadian Journal of Animal Science 74.3 (1994): 583-85. Print.
  • Fox, Dawn, Laurie Soliday, and Kyle Barnard. "Spider Lamb Syndrome." Spider. N.p., n.d. Web. 25 Apr. 2013. <http://ag.ansc.purdue.edu/sheep/ansc442/semprojs/spider/spider.html>.
  • Scholz, Leah. "Spider Lamb Syndrome." Spider Lamb Syndrome. N.p., n.d. Web. 25 Apr. 2013. <http://ag.ansc.purdue.edu/sheep/ansc442/Semprojs/2003/spiderlamb/history.htm>