Syndrome of arachnomelia in Simmental cattle

The first pathologically confirmed arachnomelia syndrome-cases in the current Simmental population appeared in the year 2005. By 2007, an additional 140 calves with the arachnomelia syndrome were identified. The major pathological findings were malformed bones affecting the head, long bones of the legs and the vertebral column. It could be shown that, with the exception of two cases that were considered as phenocopies, all of the paternal and about two-third of the maternal pedigrees of the affected calves could be traced back to one common founder. Together with the data from experimental matings, the pedigree data support an autosomal recessive mutation being the etiology of the arachnomelia syndrome. The frequency of the mutation in the current population was estimated to be 3.32%.We describe the repeated occurrence of the arachnomelia syndrome in Simmental calves. It resembles completely the same defect occurring in the Brown Swiss breed. The mutation became relatively widespread amongst the current population. Therefore, a control system has to be established and it is highly desirable to map the disease and develop a genetic test system.In the year 2006 a syndrome was described in the German and Austrian Simmental (Fleckvieh, as it is locally called, is the main dual-purpose breed in Germany, in short called Simmental in the further text) population, that was pathologically similar to the arachnomelia syndrome in Brown Swiss cattle [1]. The congenital arachnomelia syndrome (AS, OMIA Phene ID 139, Group 000059) is mainly a malformation of the skeletal system in cattle that was initially described by Rieck and Schade [2] in Holstein Friesian, Red Holstein and Simmental.The main pathological changes are skeletal malformations of the legs, the spinal column and the skull. The legs are thinner and appear longer than normal (dolichostenomelia, arachnomelia) since the diameter of the diaphyses is reduced. These long bones are more fragile and, in combination with sti