Chondrodysplasia in Australian Dexter cattle.
OBJECTIVE
To describe the occurrence of chondrodysplasia in Australian Dexter cattle.


METHODS
A pathological and genetic case report.


METHODS
Congenital lethal chondrodysplasia was studied in two female Dexter foetuses aborted mid to late gestation. Clinicopathological findings including histological changes in limb bones, and analysis of pedigree information were evaluated.


RESULTS
Characteristic features of congenital lethal chondrodysplasia (Dexter bulldog) include abortion, disproportionate dwarfism, a short vertebral column, marked micromelia, a relatively large head with retruded muzzle, cleft palate and protruding tongue and a large abdominal hernia. Histological changes in limb bones are consistent with failure of endochondral ossification. Dexter chondrodysplasia is considered to be inherited in an incompletely dominant manner with the homozygous form producing the congenital lethal condition. A preliminary minimum estimate of heterozygote frequency is 19% within the registered Australian Dexter herd, based on analysis of the contribution of three obligate heterozygotes whose semen has been widely used by artificial insemination in Australia.


CONCLUSIONS
Dexter chondrodysplasia is present in Australian cattle and further cases of the homozygous form, congenital lethal chondrodysplasia, are likely to occur.


CONCLUSIONS
It is requested that spleen and liver tissue from bulldog foetuses and blood from their parents be collected to assist research into Dexter chondrodysplasia.
Harper
P A
PA
NSW Agriculture, Grafton Agricultural Research & Advisory Station.
Latter
M R
MR
Nicholas
F W
FW
Cook
R W
RW
Gill
P A
PA
D000034:Abortion, Veterinary / Q000473:pathology*; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000235:genetics / Q000473:pathology*; D018902:Chondrodysplasia Punctata, Rhizomelic / Q000235:genetics / Q000473:pathology / Q000662:veterinary*; D005260:Female; D005333:Fetus / Q000473:pathology*; D008297:Male; D010375:Pedigree; D011247:Pregnancy