CEREBELLAR HYPOPLASIA OF GENETIC ORIGIN IN CALVES

Within 2 years, following the introduction of 2 Shorthorn bulls from the same stud into an Australian Illawarra Shorthorn (AIS) herd, 16 calves were born with cerebellar hypoplasia. All affected calves were the progeny of one bull mated to the daughters of the other. All other progeny of these bulls, most of which were from AIS dams, were normal. Affected calves exhibited severe ataxia, consistent head movement and abduction of the forelimbs. Microscopic changes in the cerebellum included sparsity of cells of the granular layer, loss of Purkinje cells and narrowing of the molecular layer. Observations on the frequencies of normal and abnormal calves are consistent with the hypothesis that the condition is caused by an autosomal recessive gene for which affected calves were homozygous and which was introduced into the herd in heterozygous condition by both of the Shorthorn bulls. Evidence is given for an unusually high frequency of the gene in the stud of origin of the Shorthorn bulls and a procedure for reducing its frequency is outlined. The possibility of a viral or toxic aetiology is discussed but is considered to be an unlikely explanation for the condition in this herd.     

Healing of Cortical Bone Grafts in the Dog The Role of Azathioprine

Sixteen unrelated beagles, randomly divided into groups of four, were used in evaluating the role of therapeutic immunosuppression in the healing of fresh cortical bone allografts over a 16-week period. The four groups included: nontreated allograft, treated allograft, nontreated autograft, and treated autograft. A 2.7-cm tibial cortical graft was fixed orthotopically using a dynamic compression plate. Healing was evaluated by radiography and by gross and histologic studies at 2, 4, 8, and 16 weeks after surgery. The treated dogs were immunosuppressed with azathioprine for eight weeks postsurgery. The conclusions were that: temporary immunosuppression did not significantly alter healing of fresh cortical bone autografts; healing of fresh cortical bone allografts in immunosuppressed dogs was similar to healing of fresh cortical bone autografts; slight differences were observed in the healing of bone grafts in all groups after eight weeks; and cellular reaction typical of graft rejection was found in nontreated allografts, but healing still occurred.     

A NEW TYPE OF RE-ENTRANT CANNULA DESIGNED FOR USE IN THE SMALL INTESTINE OF THE PIG

A new type of intestinal re-entrant cannula for the small intestine of pigs is described. It consisted of an intestinal tube joined to a stem bearing a flange and two perspex plugs ("maintenance plug" and "collection plug"). The cannula was inserted in the intestine through the incision on the antimesenteric side of the intestine and no transection of the intestine was required. No outside connection was present and the cannula extended only 1 to 2cm beyond the body. Cannulae were inserted in the duodenum and ileum of 5 pigs and these functioned satisfactorily for up to 3 months.