Evaluation of halothane as an anaesthetic in camels (Camelus dromedarius).

Halothane as an anaesthetic was evaluated in 12 adult camels, thiopentone being used as an induction agent. In six camels, clinical signs and haematological and blood biochemical changes were investigated while in other six haemodynamic, acid base and blood gas changes were monitored. The dose of thiopentone required to ensure intubation for halothane anaesthesia was 7.25 +/- 0.33 mg/kg. A modified technique of tracheal intubation was found to be safe and quick. During halothane administration all anaesthetic effects were predictable. Complete recovery occurred in 39.5 +/- 9.8 min after discontinuation of halothane administration. Halothane moderated the thiopentone-induced tachycardia. The mean arterial pressure decreased significantly. There was an increase in the arterial carbon dioxide and venous oxygen tension during halothane anaesthesia and development of hypoxaemia after its discontinuation. The alanine aminotransferase values increased during recovery, while plasma sodium, potassium and calcium decreased. Halothane appears to be safe for camels. However, to avoid hypoxaemia in the immediate post-anaesthetic period, oxygen administration should be continued.

Evaluation of triflupromazine as a sedative in camels (Camelus dromedarius).

Effects of administration of triflupromazine were evaluated in 11 adult domesticated camels (Camelus dromedarius) weighing 403 +/- 29.5 kg (Mean +/- SE). Six camels were used to evaluate sedative properties of the drug and its effects on haematological and blood biochemical parameters. In the remaining 5 camels, effects on haemodynamics, acid base status and blood gases were studied. In all the animals triflupromazine was administered intramuscularly in the gluteal region at the rate of 2 mg/kg. Camels voluntarily sat down 48.9 +/- 5.4 min after administration of the drug but stood up again if disturbed. Drowsiness, drooping of lower lip and salivation were evident. The animals stood on their own and started walking with ataxia after 159 +/- 7 min and recovered completely from the effect of drug within 259 +/- 23 min. The drug caused a significant tachycardia and a moderate hypotension. The decrease in central venous pressure was also significant. Rectal temperature, respiratory rate, acid base status, blood gases, haemoglobin concentration, packed cell volume, total erythrocyte count, total leucocyte count, differential leukocyte count, blood urea nitrogen, plasma alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase, blood glucose and plasma concentrations of sodium, potassium, chloride and inorganic phosphate were not significantly affected by triflupromazine.

Studies on intravenous regional analgesia of the hind limb in the bovine.

Twenty-five buffalo calves (age: 14 +/- 1.9 months; body weight: 102 +/- 9.4 kg) were subjected to intravenous regional analgesia (IRA) of the hind limb with 2% lignocaine HCl (4 mg/kg b.w.), infused through the dorsal digital vein. In control animals 15 ml of normal saline was infused. The effect of tourniquet release after 35 (8 calves) and 65 min (7 calves) on EEG, ECG, arterial and venous pressures, blood gases and pH, respiration and temperature were studied. A detectable concentration of lignocaine occurred before the release of tourniquet. The lignocaine concentration recorded in the systemic circulation did not produce any significant nervous or cardiovascular changes before or after release of tourniquet. Transient EEG and ECG changes were seen in six (tourniquet release after 35 min) and three (tourniquet release after 65 min) IRA animals, respectively. No significant changes were seen in heart rate, respiratory rate and rectal temperature, systolic, diastolic, mean arterial and central venous pressures. Arterial blood pH, PCO2 and HCO3- concentration showed no significant differences. Animals receiving IRA did not show hypoxaemia typical to postural changes.

Sedative effect of detomidine in infant calves.

Detomidine administered intramuscularly at a dose of 10, 20 or 40 micrograms/kg body mass was evaluated for its sedative effects in 15 unfasted infant calves (age: 15-20 days; body mass: 18-33 kg). The drug produced dose-dependent sedation. At a dose of 10 micrograms/kg detomidine produced effective sedation for 30 to 45 min without any observable analgesia. At doses of 20 or 40 micrograms/kg it caused deep sedation, sternal recumbency, and moderate analgesia of the trunk. Hyperglycaemia was recorded at all dose levels. The changes in respiratory rate, rectal temperature, haemoglobin, packed cell volume, total erythrocyte count and plasma concentration of total protein were not significant.

Evaluation of detomidine as a sedative in goats.

Intramuscular (i.m.) and intravenous (i.v.) administration of detomidine at doses of 10, 20 and 40 micrograms/kg body mass was evaluated for its sedative and analgesic properties in 15 goats (Capra hircus). The drug produced dose- and route-dependent sedation. The 10 micrograms/kg dose was effective only when administered i.v. There was no observable analgesia at this dose. Higher doses produced effective sedation and moderate analgesia of the body with either route of administration. Severe ataxia and sternal recumbency were seen in all the animals after the dose of 40 micrograms/kg. Other effects of detomidine in these goats included mild to moderate salivation, depressed respiratory rate, decreased rectal temperature, bradycardia and hyperglycaemia. Plasma concentrations of total protein, sodium, potassium and chloride were not affected.

Haemodynamic and blood gas changes in buffaloes (Bubalus bubalis) in the supine position following thiopentone anaesthesia with premedication.

Studies were undertaken on seven adult female buffaloes (Bubalus bubalis) premedicated with triflupromazine hydrochloride (0.3 mg/kg) and chloral hydrate (30 mg/kg). Anaesthesia was induced with thiopentone sodium (10 mg/kg) and animals were kept under intermittent positive pressure ventilation. Measurements were made for 30 min in the lateral position, for 20 min in the supine position and subsequently for 40 min again in the lateral position. Regurgitation during anaesthesia was avoided by evacuation of the rumen by rumenotomy two days prior to the experiment. When animals were in the lateral position there were minimal changes in arterial pressure and heart rate but central venous pressure rose. These changes were related to intermittent positive pressure ventilation. In the supine position, increase in heart rate (28%) was associated with profound hypotension (56%) and decrease in central venous pressure (171%) in these animals. There was a fall in venous oxygen tension and a marked increase (91%) in oxygen extraction ratio. Restoration to the lateral position ameliorated all these changes rapidly. It was suggested that a 'low pressure-low flow' circulatory state exists in anaesthetised adult buffaloes in the supine position.

Haemodynamics, blood gas and metabolic changes after anaesthesia with chloral hydrate and magnesium sulphate in camels (Camelus dromedarius).

The effects of chloral hydrate and magnesium sulphate (1:1, 10 per cent solution) were evaluated in six healthy adult camels. A dose of 1 ml kg-1 was used. These agents produced satisfactory anaesthesia with good muscle relaxation. The changes in the electroencephalogram showed that the anaesthetic effect lasted for 45 to 60 minutes. Tachycardia and hypotension were moderate and within safe limits. Electrocardiogram studies showed ST segment elevation and primary T wave changes. The acid-base status, blood gas tensions, haemoglobin concentration, blood glucose level and the plasma concentration of total protein, sodium, potassium and chloride were not altered.

Studies on the effects of total nephrectomy in sheep.

Effects of total nephrectomy were studied in six sheep. There was no marked deterioration in the clinical condition of the animals except anorexia and reduced water intake. Three sheep survived the period of observation of 120 hours when they were euthanized. One animal suddenly died at each of 76, 80 and 100 hours. Progressive increase of blood urea nitrogen concentration was accompanied by severe metabolic acidosis in the later stages. Plasma creatinine rose significantly but the change was not marked. Plasma inorganic phosphorous and calcium decreased significantly. Unaffected plasma sodium levels were accompanied by hyperkalemia and hypochloremia. Plasma total proteins and albumin decreased significantly in the later stages. Results showed markedly different responses to total nephrectomy in sheep as compared to changes reported in cattle and nonruminants.

Effects of limb tourniquet ischemia on local and systemic acid-base and blood gases of cattle.

Effects of forelimb tourniquet ischemia of 90 minute duration were investigated in six bulls aged two to three years. Studies were also conducted up to 150 minutes after release of the tourniquet. Parameters investigated were pH, PCO2, PO2, oxygen saturation and HCO3. In systemic circulation no variations in different parameters were observed during 90 minutes of ischemia. However, significant increase in arterial and venous pH were observed after 30 and 45 minutes of the release of tourniquet, respectively. These increases were accompanied by an increase in HCO3. In the affected limb, ischemia resulted in severe acidosis with a significant increase in PCO2 and a nonsignificant decrease of HCO3. There was a significant fall in PO2 and oxygen saturation. After release of the tourniquet, limb venous pH increased significantly due to a significant fall in PCO2 and a nonsignificant increase in HCO3. A significant increase in the limb venous PO2 and oxygen saturation post tourniquet was observed up to the end of the experiments. There was evidence of very poor oxygen exchange and utilization up to 150 minutes after release of the tourniquet. These results demonstrated that tourniquet ischemia of 90 minutes duration of the limb of cattle may not be safe.

Anesthetic and hemodynamic effects of ketamine hydrochloride in buffalo calves (Bubalus bubalis).

Ketamine HCl was evaluated as a general anesthetic alone and in combination with chlorpromazine HCl on the basis of sedative and cardiovascular effects in 40 buffalo calves (Bubalus bubalis). Calves were rapidly immobilized after IV administration of ketamine HCl (2 mg/kg of body weight). Preanesthetic treatment of calves with chlorpromazine increased the duration of analgesia, standing and recovery times, and the degree of muscle relaxation. The duration and degree of analgesia obtained were adequate for short-term surgical procedures. All animals survived the anesthetic trials, and recovery was smooth and rapid. Hemodynamic studies revealed increases in heart rate, mean blood pressure, cardiac output, and peripheral vascular resistance during maximal depth of anesthesia. The venous pressure decreased initially and then increased progressively. Increases and decreases in these measurements were transient, and the measurements returned to base-line values within 30 minutes after ketamine administration. Definite trends were not seen on ECG tracings, except for elevations and depressions of ST segment, T-wave changes, and wandering pacemaker in a few animals, and sinus tachycardia in all animals.