Abstract: The recent development of potent and specifica lphar-adrenoceptoar gonistsa nd antagonists has enhanced their use in nondomestic animal immobilization and reversal. Medetomidine, a new potent alphar-agonist, in combination with the dissociative anesthetic ketamine, has been used to immobilize a variety of nondomestic mammals. Medetomidine alone induces sedation in a dose-dependent way, and complete immobilization has been achieved with high doses in semidomesticated reindeer (Rangifer tarandus) and blue foxes (Alopex lagopus). Howbver, we feel that ketamine should be added to the immobilization mixture to ensure complete immobilization and operator safety. In ketamine combinations, medetomidine doses are usually 60-100 pg/kg. The required ketamine doses are remarkably low:0.8-1.6 mglkg in most ruminants,2.5-3.0 mgUgin felids,u rsids,a nd canids,a nd 5.G-8.0m glkgi n primates,w olverines(Gulog ulo),ando therm uitelids. Clinically, the resulting immobilization is characterized by a smooth onset, good to excellent myorelaxation, and areflexia at higher doses. Determinations of hematologic, serum biochemicil, arterial blood gas,a nd acid-bases tatusp arametersi ndicate that the immobilization is physiologically sound. We have had no fatalities attributable to the immobilization mixture ( I ,240 immobilizations). The alphar-adrenoceptora ntagonist,a tipamezole,i s highly efective in reversingt he immobilization induced by medetomidine, medetomidine-ketamine combinations, or xylazine. In ruminants, the medetomidine-ketamine-induced immobilization can be rapidly and persistently reversed by administering 100-l 50 1rg/kg of alipamezole i.v. and the rest s.c., adjusting the total atipamezole dose to an atipamezole: medetomidine ratio of approximately 4-5 (w/w). Becauseth e required ketamine doses are relatively high in carnivores, we prefer to use a lower atipamezole dose (totil atipamezoie: medetomidine ratio approximately 2-3 w/w) and to administer it i.m. or s.c. Using thii regimen, reversals are calm and animals show minimal “residual ketamine effect.” Because atipamezole is a competitive antagonist, its dose should be reduced if it is administered late in the immobilization period when a large part of medetomidine has been endogenously metabolized. Xylazine-induced immobilization is rapidly reversed by I mg of atipamezole for every 8-12 mg of xylazine used.

Abstract: Nine small cats, including one bobcat (Felis rufus), one Pallas cat (F. manul), one Canada lynx (F. lynx canadensis), two fishing cats (F. viverrina), two margays (F. wiedii), and two sand cats (F. margarita), necropsied between June 1995 and March 1997 had large numbers of gastric spiral bacteria, whereas five large cats, including one African lion (Panthera leo), two snow leopards (P. uncia), one Siberian tiger (P. tigris altaica), and one jaguar (P. onca), necropsied during the same period had none. All of the spiral organisms from the nine small cats were histologically and ultrastructurally similar. Histologically, the spiral bacteria were 5-14 mum long with five to nine coils per organism and were located both extracellularly within gastric glands and surface mucus, and intracellularly in parietal cells. Spiral bacteria in gastric mucosal scrapings from the Canada lynx, one fishing cat, and the two sand cats were gram negative and had corkscrew-like to tumbling motility when viewed with phase contrast microscopy. The bacteria were 0.5-0.7 mum wide, with a periodicity of 0.65-1.1 mum in all cats. Bipolar sheathed flagella were occasionally observed, and no periplasmic fibrils were seen. The bacteria were extracellular in parietal cell canaliculi and intracellular within parietal cells. Culture of mucosal scrapings from the Canada lynx and sand cats was unsuccessful. Based on morphology, motility, and cellular tropism, the bacteria were probably Helicobacter-like organisms. Although the two margays had moderate lymphoplasmacytic gastritis, the other cats lacked or had only mild gastric lymphoid infiltrates, suggesting that these organisms are either commensals or opportunistic pathogens.