Effects of xylazine/ketamine on cardiac function and serum ionised calcium in horses

Haemodynamic variables, with emphasis on right ventricular (RV) contractility, were measured in horses prior to, during and following anaesthesia with xylazine/ketamine. In an attempt to elicit mechanisms of anaesthetic-induced alteration of myocardial function, serum ionised and total calcium concentrations were also measured. Xylazine caused decreased cardiac function, including RV contractility, that was not reversed immediately by ketamine but was insignificant from pre-anaesthetic baseline by recovery (45 min following induction). Serum ionised and total calcium concentrations did not change.     

Hemodynamic Effects of Calcium Gluconate Administered to Conscious Horses

Calcium gluconate was administered to conscious horses at 3 different rates (0.1, 0.2, and 0.4 mg/kg/min for 15 minutes each). Serum calcium concentrations and parameters of cardiovascular function were evaluated. All 3 calcium administration rates caused marked increases in both ionized and total calcium concentrations, cardiac index, stroke index, and cardiac contractility (dP/dt_max). Mean arterial pressure and right atrial pressure were unchanged; heart rate de creased markedly during calcium administration. Ionized calcium concentration remained between 54% and 57% of total calcium concentration throughout the study. We conclude that calcium gluconate can safely be administered to conscious horses at 0.1 to 0.4 mg/kg/min and that administration will result in improved cardiac function.     

Comparison of six different regimens for the control of atrophic rhinitis in swine

Effectiveness of six different programs of atrophic rhinitis (AR) control was evaluated under field conditions. Efficacy of treatments was recognized on the basis of--comparative evaluation of the average daily gain (ADG), morphometric examination of turbinate bones and computer conchal morphometry (TPR). Usefulness of the evaluated regimes differed significantly. TPR appeared to be the most objective method for AR evaluation. Correlation between severity of turbinate atrophy and ADG was only partial.     

Comparison of the efficacy of ivermectin, oxibendazole, and pyrantel pamoate against 28-day Parascaris equorum larvae in the intestine of pony foals

Sixteen helminth-free pony foals were inoculated with a mean (+/- SD) 2,000 (+/- 545.5) infective Parascaris equorum eggs (day 0). Foals were allocated to replicates of 4, and treatments within each replicate were assigned at random. Treatment administered on postinoculation day (PID) 28 included no treatment (control), 0.2 mg of ivermectin/kg of body weight, 10 mg of oxibendazole/kg, or 6.6 mg of pyrantel base (pamoate)/kg. Paste formulations of the anthelmintics were administered orally. The foals were euthanatized 14 days after treatment (PID 42) and examined for P equorum larvae in the small intestine. The mean +/- SD (and range) numbers of fourth-stage P equorum larvae recovered from nontreated foals and those treated with ivermectin, pyrantel, or oxibendazole were 1,603.8 +/- 1,026.8 (305 to 2,480), 29.3 +/- 55.8 (0 to 113), 413.0 +/- 568.1 (0 to 1,204), or 889.5 +/- 1,123.1 (1 to 2,345), respectively. Compared with the value for control (nontreated) foals, treatment with ivermectin, pyrantel, and oxibendazole was 98.2, 74.2, and 44.5% effective, respectively, when administered 28 days after experimentally induced infection with P equorum. Adverse reactions attributable to treatment were not observed.     

Pulmonary hypertension as a cause of atrial fibrillation in young horses: four cases (1980-1989)

Four young horses of various breeds and suffering from atrial fibrillation died of heart failure. All had markedly high pulmonary arterial pressure, right-sided cardiomegaly, and lack of histologic lesions in the right atrium or pulmonary parenchyma. Three horses had hypertrophy and/or necrosis of the tunica media of the pulmonary vasculature. Clinical signs of disease, physiologic data, and pathologic findings indicated that these horses had primary pulmonary hypertension with secondary right-sided cardiac ventricular hypertrophy and dilatation, atrial fibrillation, and heart failure.     

Ubiquity of biological ice nucleators in snowfall

Despite the integral role of ice nucleators (IN) in atmospheric processes leading to precipitation, their sources and distributions have not been well established. We examined IN in snowfall from mid- and high-latitude locations and found that the most active were biological in origin. Of the IN larger than 0.2 micrometer that were active at temperatures warmer than -7 degrees C, 69 to 100% were biological, and a substantial fraction were bacteria. Our results indicate that the biosphere is a source of highly active IN and suggest that these biological particles may affect the precipitation cycle and/or their own precipitation during atmospheric transport.