Condrodisplasia hereditária em ovinos da Raça Cabugi.

Abstract

This paper reports a new form of chodrodysplasia in sheep from Brazilian hair sheep of the Cabugi breed, also known as “cara curta” (short head). This breed is characterized by short head and sometimes the animals are slighter smaller and more compact that animals from similar breeds. Dwarf lambs that died in 2-6 months after birth are frequent in this breed. In a flock of 68 ewes and 3 rams of the Cabugi breed, 39 lambs were born. From these 5 (12,8%) had marked dwarfism and died or were euthanized. From the other 34 lambs 10 (25,6%) had a normal face, and 24 (60%) had the short face characteristic of the Cabugi breed. Dwarf lambs were much smaller than normal, with short legs, a domed head with retruded muzzle and slightly protruded mandible, sternal deformities and exoftalmic eyes situated more lateral in the face than normal. Four dwarf lambs were euthanized and necropsied and one was necropsied after the spontaneous death. Histologic examination of the long bones of the limbs, basocranial bones and vertebrae showed mild disorganization of the growth plates with increased resting cartilage and shorter and disorganized proliferative and hypertrophic cartilage. Smaller amount of bone were observed in the primary and secondary spongiosa, and metaphysis when compared with a control lamb of the same age. It is suggested that the disease, is a hereditary chondrodysplasia caused by a recessive gene; homozigotes have marked lethal dwarfirm, but the disease is also partially expressed in all animals with the characteristic short face of the Cabugi breed, which are in heterozygotes.