DANTAS, F. P. M.; http://lattes.cnpq.br/5215256704216932; DANTAS, Francelicia Pereira Marques.
Resumen:
The chondrodysplasias are diseases of the skeleton of different animal species. Affected
animals are generally characterized by dwarfism and short heads. The disease is
commonly hereditary, caused by a defect on the ephyphiseal cartilages that prevent
normal bone growth. This dissertation is formed by two papers. The first is a review on
osteochondrosis in domestic animals, mainly livestock. The second paper reports a new
form of chodrodysplasia in sheep affecting 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 three rams of the Cabugi breed, 134 lambs were born during four
years. From these 14 (10.4%) had marked dwarfism and died or were euthanized, 43
(32%) had a normal face, and 77 (57.5%) 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 exophthalmic
eyes situated more lateral in the face than normal. Four dwarf lambs were euthanized
and necropsied and one was necropsied after the spontaneous death. Histological
examination of the long bones of the limbs, bones of the skull base, and vertebrae
showed no histological lesions. Four dwarf lambs and a control lamb were macerated
for bone measurements. The biometric data showed that affected lambs have a
disproportionate dwarfism with marked shortening of the skull and limbs ranging from
24% to 75% of the normal size (control lamb). 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.