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SUMMARY
The effect of bethanechol, neostigmine, metoclopramide, and propranolol on myoelectric activity of the ileum, cecum, and proximal loop of the ascending colon was determined in 6 healthy Jersey cows implanted with 8 pairs of bipolar electrodes. Assigned at random, each cow received each of 5 treatments in 3-day intervals. The treatments included bethanechol (0.07 mg/kg of body weight, sc), neostigmine (0.02 mg/kg, sc), metoclopramide (0.15 mg/kg, im), dl-propranolol (0.2 mg/kg, im), and 0.9% sodium chloride (NaCl) solution (20 ml, sc). All drugs were administered during early phase I of the migrating myoelectric complex in the ileum. Myoelectric activity was recorded for 4 hours after treatment, and data were analyzed for each hour separately.
Bethanechol and neostigmine significantly (P < 0.05) increased the number of cecocolic spikes per minute per electrode, duration of cecocolic spike activity (%), and number of cecocolic propagated spike sequences per 10 minutes, relative to NaCl, during 1 or more hours of the recording period. The effect of bethanechol was more pronounced on duration of spike activity and number of propagated spike sequences, whereas neostigmine mainly increased the number of (uncoordinated) spikes. Metoclopramide and propranolol had no significant effect on cecocolic myoelectric activity, relative to NaCl.
It was concluded that bethanechol and, less likely, neostigmine at the dosage used in this study may be suitable for medical treatment of cecal dilatation in cattle in which hypomotility of the cecum and proximal loop of the ascending colon has to be reversed. The potential advantage of bethanechol vs neostigmine for medical treatment of cecal dilatation is worth further evaluation.
SUMMARY
The effect of xylazine, cisapride, and naloxone on myoelectric activity of the ileum, cecum, and proximal loop of the ascending colon (plac) was determined in 4 healthy Jersey cows implanted with 8 pairs of bipolar electrodes. A 4 × 4 Latin square design was used. The treatments included xylazine (0.04 mg/kg of body weight), cisapride (0.08 mg/kg), naloxone (0.05 mg/kg), and 0.9% sodium chloride solution (20 ml). All treatments were administered IV during early phase I of the migrating myoelectric complex in the ileum. Myoelectric activity was recorded for 4 hours after treatment, and data were analyzed for each hour separately.
Xylazine significantly (P < 0.05) increased the duration of phase I of the first migrating myoelectric complex in the ileum to 220.72 ± 26.89 minutes, compared with 30.91 ± 10.11 minutes after administration of 0.9% sodium chloride solution. The number of cecocolic spikes per minute per electrode and the duration of cecocolic spike activity (percentage of recording time) were significantly (P < 0.05) decreased for the first 3 hours, and the number of propagated spike sequences in the cecum and PLAC was significantly (P < 0.05) decreased for the first 2 hours after administration of xylazine. Significant difference was not found between control and either cisapride or naloxone treatment of healthy cows. However, during hour 1 after treatment with cisapride, number of spikes per minute, duration of spike activity, and number of propagated spike sequences were highest, compared with the other treatments.
It was concluded that naloxone at the dosage used in this study was not suitable for medical treatment of cecal dilatation in cattle, when hypomotility of the cecum and PLAC must be reversed. Xylazine should not be used for relief of signs of pain in cases of cecal dilatation, because it significantly reduced myo electric activity of the cecum and PLAC for at least 2 hours after treatment. Furthermore, results of this study indicated a trend (P > 0.05) toward increase of cecocolic myoelectric activity after administration of cisapride. It is the authors’ opinion that the potential benefit of cisapride for medical treatment of cecal dilatation in cattle needs further evaluation.
Abstract
Objective—To evaluate the effect of an indwelling nasogastric tube on gastric emptying of liquids in horses.
Animals—9 healthy adult horses.
Procedure—A randomized block crossover design was used. For treatment group horses, a nasogastric tube was placed and 18 hours later, acetaminophen was administered; the nasogastric tube remained in place until the experiment was complete. For control group horses, a nasogastric tube was passed into the stomach, acetaminophen was administered, and the nasogastric tube was removed immediately. Serial blood samples were collected 15 minutes before and after administration of acetaminophen. Serum concentration of acetaminophen was determined by use of fluorescence polarization immunoassay. The variables, time to maximum acetaminophen concentration (Tmax) and the appearance constant for acetaminophen (Kapp), were determined. The values for Kapp and Tmax in horses with and without prolonged nasogastric tube placement were compared.
Results—No significant difference was found in Kapp between horses with and without prolonged nasogastric tube placement; the median difference in Kapp was 0.01 min–1 (range, –0.48 to 0.80 min–1). No significant difference was found in Tmax between horses with and without prolonged nasogastric tube placement; the median difference in Tmax was 5 minutes (range, –30 to 50 minutes). Reanalysis of data following the removal of possible outlier values from 1 horse resulted in a significant difference in Tmax between horses with and without prolonged nasogastric tube placement.
Conclusions and Clinical Relevance—Although no clinically important impact of 18 hours of nasogastric intubation was found on gastric emptying in healthy horses, considerable variability in Kapp and Tmax was found among horses. (Am J Vet Res 2005;66:642–645)
Abstract
Objective—To assess signalment, history, results of clinical and laboratory testing, and outcome for beef cattle with a left displaced abomasum (LDA), right displaced abomasum (RDA), or abomasal volvulus (AV).
Design—Retrospective study.
Animals—19 beef cattle with an AV, LDA, or RDA.
Procedure—Signalment; history; results of physical examination, diagnostic testing, and surgical exploration; and condition of the animal at discharge were obtained from medical records.
Results—Fourteen cattle had an AV, 4 had an RDA, and 1 had an LDA. Duration of clinical signs ranged from 1 to 21 days. Eighteen cattle had an AV or RDA; 7 were Brahmans, 12 were males, and median age was 10 months. Abdominal distention was observed in 11 cattle, heart rate of ≥ 100 beats/minute was detected in 14, and the abomasum was palpable per rectum in all cattle in which per rectal examination was performed. Leukocytosis, neutrophilia, hyperglycemia, azotemia, hypochloremia, and hypokalemia were common laboratory findings. At surgery, 3 cattle with an AV or RDA had a ruptured abomasum. Of the remaining 15 cattle, 12 survived.
Conclusions—Clinical course in beef cattle with an AV or RDA was more protracted than that typically associated with these conditions in dairy cattle, but survival rate in beef cattle that did not have rupture of the abomasum was sim ilar to that of dairy cattle.
Clinical Relevance—Abomasal displacement should be considered for beef cattle with abdominal distention. Prognostic indicators recommended for use in dairy cattle may not be useful for beef cattle. (J Am Vet Med Assoc 2000;216:730–733)
Objective
To evaluate the use of auricular vein catheters (AVC) in cattle in a clinical setting.
Design
Case series.
Animals
57 cattle.
Procedure
68 AVC were placed in cattle for the administration of drugs or rehydration fluids. Catheter size, quantity of fluids administered, duration of administration, drugs administered, duration of catheter maintenance, and problems were recorded.
Results
The AVC ranged in size from 20 to 14 gauge, with the latter being the predominate size. A maximum flow rate of 7.7 L/h was achieved, and the flow rate was satisfactory in all but 1 case. The maximum duration of maintenance was > 96 hours. Problems occurred in 29 of 68 (43%) catheterizations; the most frequent problem was occlusion of the catheter, which occurred 16 times (24%). No serious complications occurred.
Clinical Implications
Auricular vein catheters were a convenient, safe, and low-cost alternative to jugular vein catheters. (J Am Vet Med Assoc 1996;208:905–907)
Summary
Six Jersey cows were implanted with 8 pairs of bipolar electrodes: 1 in the jejunum, 1 in the ileum, 3 in the cecum, and 3 in the proximal loop of the ascending colon (plac). Myoelectric activity was recorded at 2- to 3-day intervals, 3 times for 8 hours or 4 times for 6 hours, using a computer-based oscillograph and data-acquisition program.
Mean (± sd) duration of the migrating myoelectric complex (mmc) in the ileum was 84.52 ± 4.87 minutes. Phases I and II of the mmc lasted significantly (P < 0.05) longer than phase III. Two types (A and B) of cyclic activity were found in the cecum and plac. Cyclic activity type A was observed predominantly in the cecum, and type B was observed exclusively in the plac. Phase III of the mmc in the ileum was accompanied by hyperactivity type A at the level of the ileocecocolic junction in 60.90 ± 12.65% of the mmc. Twenty-seven types of orally and aborally propagated spike sequences, involving the cecum and plac, were found. They were most frequent when an mmc phase III was observed in the ileum, and least frequent when an mmc phase I was observed in the ileum (P < 0.05). All electrode sites of the cecum and plac served as pacemaker areas. Propagated and nonpropagated spikes were found at all electrode sites of the cecum and plac. Although propagated spikes lasted significantly (P < 0.05) longer than nonpropagated spikes, a clear distinction on the basis of duration could not be defined between the 2 spike types because broad overlapping of duration existed. Duration of cecocolic spiking activity per electrode (expressed as percentage of time) was significantly (P < 0.05) greater during mmc phase III in the ileum than during mmc phase I.
It can be concluded that myoelectric activity of the cecum is well coordinated with the ileum and the plac. Phases of reduced and increased myoelectric activity in the cecum and plac are simultaneous with phases I and III of the mmc in the ileum.
Abstract
Objective—To develop a better system for classification of herd infection status for paratuberculosis (Johne's disease [JD]) in US cattle herds on the basis of the risk of potential transmission of Mycobacterium avium subsp paratubeculosis.
Sample—Simulated data for herd size and within-herd prevalence; sensitivity and specificity for test methods obtained from consensus-based estimates.
Procedures—Interrelationships among variables influencing interpretation and classification of herd infection status for JD were evaluated by use of simulated data for various herd sizes, true within-herd prevalences, and sampling and testing methods. The probability of finding ≥ 1 infected animal in herds was estimated for various testing methods and sample sizes by use of hypergeometric random sampling.
Results—2 main components were required for the new herd JD classification system: the probability of detection of infection determined on the basis of test results from a sample of animals and the maximum detected number of animals with positive test results. Tables were constructed of the estimated probability of detection of infection, and the maximum number of cattle with positive test results or fecal pools with positive culture results with 95% confidence for classification of herd JD infection status were plotted. Herd risk for JD was categorized on the basis of 95% confidence that the true within-herd prevalence was ≤ 15%, ≤ 10%, ≤ 5%, or ≤ 2%.
Conclusions and Clinical Relevance—Analysis of the findings indicated that a scientifically rigorous and transparent herd classification system for JD in cattle is feasible.
