A previously undocumented hypokalaemic condition with a cyclical nature, comprising acute bouts of polymyopathy followed by spontaneous recoveries, is described in the cat. Cats being fed a high protein vegetarian diet developed recurrent episodes of polymyopathy, characterised by ventroflexion of the head and neck, stiff forelimb gait, lateral head-resting and generalised muscle weakness. Plasma potassium concentrations (mean +/- standard deviation) were reduced from 3.28 +/- 0.33 mmol/l at the beginning of the experiment to 2.45 +/- 0.24 mmol/l during bouts of myopathy. This hypokalaemia was associated with increased creatine kinase activities indicative of muscle damage, and decreased urinary potassium concentrations, and was caused by insufficient dietary potassium. Cats that received the same diet supplemented with potassium did not develop hypokalaemic polymyopathy. Spontaneous recoveries of affected cats were not associated consistently with increases in plasma potassium concentrations. Plasma taurine concentrations decreased and glutamic acid increased markedly in all cats fed the experimental diet. There was no evidence of thiamin deficiency associated with the high glutamic acid intake. Veterinarians should be aware that hypokalaemic cats, and in particular those on potassium-deficient diets, may show cyclical disease with episodes of polymyopathy recurring after periods of spontaneous clinical recovery. This condition in cats may be a useful animal model for familial hypokalaemic periodic paralysis in humans.

A surgical technique for catheter implantation for sequential blood sampling in the pig is described. This methodology minimizes stress to the animal and chances of catheter dislodgement, both of which are detrimental to accurate long-term metabolic assessment of the animal model. The technique involves implantation of a vinyl catheter via the external jugular vein into the vena cava. To ensure catheter retention, the method uses a silicone plug fitted to the catheter and located cranial to its entry to the vein, double ligation at the venous insertion, subsequent passage of the catheter to exit 10 cm cranial to the scapula on the dorsal midline, and a denim vest fitted to the thorax. With this technique seven out of nine catheters have functioned more than 50 days, two functioned for approximately 100 days, and one for over 150 days.