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  • Author or Editor: R. C. Waldron x
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Summary

Effects of the following treatments on abomasal and duodenal myoelectric activity in yearling cattle were studied: 2 ml of 0.9% sodium chloride solution (nacl); 0.07 mg of bethanechol (bet)/kg of body weight; 0.1 mg of metoclopramide (met)/kg; and 0.07 mg of bethanechol and 0.1 mg of metoclopramide (betmet)/kg. All treatments were administered SC during the early part of phase I of the migrating myoelectric complex. Myoelectric signals were recorded for 4 hours after administration of the treatments from 1 electrode in the antrum and 3 electrodes in the duodenum.

For the antral spike rate (asr), there was no significant difference among treatments during the first hour, but the asr was significantly (P < 0.05) greater during hours 2 to 4 after treatment with betmet, compared with asr. for met alone. The duodenal spike rate (dsr) was significantly (P < 0.05) greater during the first hour after administration of betmet than after the other treatments. After administration of BET, DSR was significantly (P < 0.05) greater than after met or nacl. There was no difference in dsr after met, compared with dsr after nacl. There was no significant difference in dsr among treatments during the second and third hours. The total antegrade propagating spike (tatp) count was greater after administration of betmet in all hours, compared with the other treatments. The ratio of taps to total spikes on the orad-most duodenal electrode was significantly (P < 0.05) greater after betmet during hours 1 and 2.

Free access
in American Journal of Veterinary Research

SUMMARY

The purpose of this study was to compare the thermodilution technique for estimation of cardiac output with the indocyanine green dye dilution technique at flows between 10 and 39 L/min in halothane-anesthetized horses. The estimation of area of dye dilution cardiac output curves was made by using the fore-’n-aft (fa) triangle method. This shorthand technique was compared with logarithmic exponential extrapolation and summation (extrapolated area), using 64 cardiac output curves. Then, 256 simultaneous thermodilution measurements were compared with dye dilution measurements calculated by use of the fa technique. Forty milliliters of iced 0.9% NaCl solution containing 15 mg of indocyanine green dye was used as the indicator. This was delivered in < 1 second to the right atrium, using a power injector. A thermistor positioned in the pulmonary artery detected the thermal indicator. Blood was withdrawn from the carotid artery through a densitometer cuvette to measure the dye concentration. The fa estimations of area were higher than those determined by use of extrapolated area. A multiplicative adjustment of 0.837 was estimated. On average, thermodilution estimates of cardiac output exceeded the adjusted fa determinations. Using a weighted linear regression, we determined the following calibration adjustment: thermal dilution cardiac output/1.048 = indocyanine green dye dilution cardiac output.

Free access
in American Journal of Veterinary Research

Summary

Electrodes were surgically implanted at 15-cm intervals in the jejunum and ileum of 4 healthy neonatal calves so that myoelectric activity could be recorded on 2 consecutive days. On the first day, each calf received a control treatment, and myoelectric activity was recorded for 340 minutes. Phase I was recorded for a mean of 175.8 ± 22.8 minutes (51.5%), phase II for 124 ± 27.4 minutes (36.5%), and phase III for 40.3 ± 6 minutes (11.9%). On the second day, each calf was treated with approximately 200 μg of heat-stable enterotoxin (STa) of Escherichia coli orally. All calves developed diarrhea after the administration of STa. Phase I was recorded for a mean of 92.5 ± 42.3 minutes (27.2%), phase II for 227.3 ± 52.5 minutes (66.9%), and phase III for 20.3 ± 11.4 minutes (6.0%). Increase in phase II and decrease in phases I and III after STa administration were significant (P < 0.05). Duration of the migrating myoelectric complex was longer after STa administration (median, 64 minutes), compared with the control treatment (median, 54 minutes). Minute rhythms, recorded on the day of toxin administration, ranged from 49 to 153 minutes. There was no difference between the number of migrating action potential complexes on the control days (range, 1 to 10), compared with those on treatment days (range, 1 to 14).

These findings are suggestive that enterotoxin-induced diarrhea of calves is accompanied by increased total spiking activity and minute rhythms in the distal portion of the jejunum and ileum.

Free access
in American Journal of Veterinary Research