Body Temperature In Dogs Research Articles

Daily rhythmicity of body temperature in the dog.

Research over the past 50 years has demonstrated the existence of circadian or daily rhythmicity in the body core temperature of a large number of mammalian species. However, previous studies have failed to identify daily rhythmicity of body temperature in dogs. We report here the successful recording of daily rhythms of rectal temperature in female Beagle dogs. The low robustness of the rhythms (41% of maximal robustness) and the small range of excursion (0.5 degrees C) are probably responsible for previous failures in detecting rhythmicity in dogs.

Use of infrared thermometry and effect of otitis externa on external ear canal temperature in dogs

Objective To compare infrared thermometry with rectal thermometry as a method of assessing core body temperature in dogs and to assess the effect of otitis externa on external ear canal temperature (EECT). Design Prospective study. Animals 650 dogs without history or clinical signs of otitis externa and 85 dogs with recurrent or chronic otitis externa. Procedure Rectal temperature was measured, using a mercury thermometer. External ear canal temperature was measured, using an infrared tympanic thermometer. Results Measurements of body temperature at the 2 sites did not agree. Sensitivity and specificity of infrared thermometry in detecting fever, as determined by rectal thermometry, were 69.7 and 84.6%, respectively. Use of methods to predict rectal temperature from EECT did not improve the accuracy of infrared thermometry. Otitis externa significantly influenced EECT. Clinical Implications Use of infrared thermometry as a replacement for rectal thermometry in assessing core body temperature in dogs was unsatisfactory. The 2 methods for measuring body temperature were not interchangeable in dogs. (J Am Vet Med Assoc 1998;213:76-79)

The effect of intraventricular thyroxine administration on body temperature in dogs at rest and during physical exercise

Infusion of 1 μg thyroxine into the left cerebral ventricle of the dog did not change body temperature at rest, but it caused significantly higher increases in Tre during physical exercise.

Effect on body temperature in dogs of perfusion of cerebral ventricles with artificiaL CSF deficient in calcium or containing excess of sodium or calcium.

In anaesthetized dogs at room temperatures of 28-33 degrees C, the cerebral ventricles were perfused with artificial CSF from the left lateral ventricular to the aqueductal cannulae. The animals' temperatures were recorded from the rectum. Addition of Ca(++) in excess to the artificial CSF perfusing the ventricles produced hyperthermia and addition of Na+ in excess produced hypothermia. Perfusion with medium deficient in Ca(++) and containing sodium edetate produced hypothermia. The temperature effects of Na(+) or Ca(++) in excess were mutually antagonistic.

CAROTID SINUS DEPRESSOR REFLEXES DURING HYPOTHERMIA.

Reducing body temperature in dogs to 24 C caused a small reduction in the size of the carotid sinus depressor response. Along with this reduction the response also became more gradual at the lower body temperatures. Systematic studies demonstrated that the more gradual nature of the response appeared to result from changes in the vascular smooth muscle. Depression of the nervous elements of the baroreceptor reflex arc during hypothermia was not evident. The response to carotid sinus stimulation in the warm, perfused hindlimb was essentially unchanged by cooling the body to 24 C. Local cooling of the perfused hindleg did not reduce the size but did result in a more gradual response.

Recovery of conditioned reflexes in dogs after induction of hypothermia by means of head packs

Following the restoration of the body temperature in dogs, overcooled by head packs to the rectal temperature of 28°C, the secretory food and defensive respiratory conditioned reflexes are also completely restored. The process of restoration of the cerebral cortical function is 2–3 times slower than after external overcooling of the whole body. The restoration of defensive respiratory reflexes begins on the day after over cooling and is completed on the sixth day. The restoration of secretory food conditioned reflexes begins only on the third day after hypothermis and is completed on the 8th day.

Life without breathing oxygen—II

If the body temperature of dogs is reduced to 25–27°C., it is possible to give all the oxygen required by the animal by the intravenous route so that they need not breathe oxygen from outside.

Pharmacology of fluphenazine (prolixin)

Ten phenothiazine derivatives, substituted in the 2- and 10-positions, were tested as inhibitors of a conditioned avoidance response in rats. The intraperitoneal activities, in decreasing order were: fluphenazine = SQ 10,037 > SQ 4924 = SQ 10,036 > perphenazine > trifluoperazine > thipropazate > triflupromazine > prochlorperazine > chlorpromazine. A CF 3 group in position 2 in place of Cl increased activity, and incorporating the N of the side chain in a piperazine ring increased activity still more. A direct comparative study in conditioned rats showed fluphenazine and acetyl-fluphenazine (SQ 4924) to be equally potent and 7 to 9 times as active as triflupromazine. When duration of action was included in the evaluation of activity, fluphenazine and acetylfluphenazine were 25 times as active as triflupromazine. In operant behavior studies in rats, fluphenazine was somewhat slower acting than triflupromazine but was more potent and longer acting. Fluphenazine was 6.5 times as potent as triflupromazine as a “tranquilizer” in hostile rhesus monkeys. The effects of fluphenazine and triflupromazine on behavior and body temperature of dogs were not significantly different. Both drugs reduced spontaneous motor activity, caused sedation and ataxia, and decreased rectal temperature. Cumulative, intravenous doses of fluphenazine or triflupromazine caused slight to moderate hypotension in anesthetized and unanesthetized dogs. Cumulative, intravenous administration of large doses of fluphenazine or triflupromazine to cats caused progressive bradycardia, marked transient hypotension and cardiac arrest. No changes in EEG were noted. At the peak of action, fluphenazine was approximately 4.5 times as potent as triflupromazine as an inhibitor of an elicited head-twitch response in mice. Fluphenazine and triflupromazine caused motor deficits in mice and were equally toxic. In general, fluphenazine (or its acetyl ester) appears to be a more potent and longer-acting tranquilizing agent than any other compound tested and this activity is unattended by corresponding increases in toxic or undesirable autonomic side actions.

Effects of intravenous administration of fat emulsion on formed blood elements and body temperature in dogs.

Intravenous administration of a 10% olive oil emulsion or lymph to healthy dogs anesthetized with Nembutal produced marked thrombocytopenia, leucopenia, neutropenia, eosinopenia, lymphopenia, increase in mechanical fragility of erythrocytes, and increase in hematocrit. The increase in mechanical fragility of erythrocytes correlated directly with the degree of lipemia. Heparin administration accelerated the removal of the injected fat from the circulation and hastened the return to normal of the formed blood elements. The changes in the formed blood elements were more marked and persisted longer in the dogs receiving piromen. The changes in the formed blood elements following oral ingestion of olive oil were either mild or insignificant except for the moderate eosinophilia. Elevation of rectal temperature and persistent lymphopenia were observed only in the animals receiving emulsion and piromen. It is concluded that the changes in formed blood elements, including the increase in mechanical fragility of erythrocytes following intravenous administration of fat emulsion, did not seem to correlate with the rise of body temperature.