Gastrointestinal ultrasonography in normal adult ponies

The objective of this study was to determine the characteristics based on ultrasonographic examination of the stomach, duodenum, jejunum, cecum, and peritoneal fluid in normal adult ponies. Abdominal ultrasonographic examination was performed in nine unsedated standing ponies. The duodenum was examined at three sites and the jejunum in 12 regions. Wall thickness, contractility, distention, and luminal contents were recorded. Stomach wall thickness and location, cecal wall thickness, and peritoneal fluid location and character were recorded. Statistical analysis was performed. Wall thicknesses (in cm) were 0.431 +/- 0.069 for the stomach, 0.188 +/- 0.033 for the duodenum (at all sites), 0.195 +/- 0.031 for the jejunum (at all regions), and 0.179 +/- 0.031 for the cecum. Duodenal contractions per minute were 3.78 +/- 1.10. The stomach spanned 5.14 +/- 0.9 intercostal spaces, with the 8th intercostal space being the most cranial and the 15th intercostal space being the most caudal space through which the stomach was identified. It was possible to identify the jejunum in all ponies dorsal to the left dorsal colon and from the ventral abdominal wall. Peritoneal fluid was identified in six ponies. Peritoneal fluid was usually seen transiently and most commonly in the ventral aspect of the abdominal cavity or around the duodenum. Overall, the ponie's abdominal ultrasonographic examinations revealed wall thicknesses that were less than the published normal ranges for horses. It appears that ponies may have increased duodenal contractility than horses and that the conformation of ponies may change the locations for imaging the stomach.     

Effect of a Histamine H2 Type Receptor Antagonist (WY 45, 727) on the Healing of Gastric Ulcers in Ponies

Using video gastroscopy, the efficacy of a Histamine-H2 type receptor antagonist (WY 45, 727) was investigated in young ponies with spontaneous and experimentally induced gastric ulcers. Oral administration of WY 45, 727 at 2 mg/kg and 10 mg/kg of body weight every 12 hours for 14 days resulted in complete healing of spontaneous gastric ulcers in the non-glandular portion of the stomach in 2/5 (40%) and 3/4 (75%) of the ponies, respectively, compared (P < 0.05) to 0/5 (0%) placebo-treated ponies. After intramuscular administration of flunixin meglumine at 1.5 mg/kg body weight every 8 hours for 6 days, 9/18 ponies had ulcers in the non-glandular portion of the stomach. Oral administration of WY 45, 727 at 10 mg/kg body weight every 12 hours for 14 days resulted in complete healing of the non-glandular gastric ulcers in 3/4 (75%) compared with (P < 0.05) 1/5 (20%) placebo-treated ponies. This study indicates that 1) the occurrence of subclinical ulcers may be common in young ponies; 2) flunixin meglumine at 1.5 mg/kg intramuscularly every 8 hours for 6 days may result in ulcers of the non-glandular stomach in ponies; and 3) WY 45, 727, a histaminergic H2 type receptor antagonist could be of value in the therapeutic management of ulcers in the non-glandular stomach of foals and adult horses.     

SERIAL GASTROINTESTINAL ULTRASONOGRAPHY FOLLOWING EXPLORATORY CELIOTOMY IN NORMAL ADULT PONIES

The objective was to characterize ultrasonographic changes in bowel wall thickness, contractility, degree of distension, luminal contents, and peritoneal fluid associated with exploratory celiotomy in normal ponies. Gastrointestinal ultrasonographic examination was performed in 14 ponies on days 1, 3, 5, and 7 after an exploratory celiotomy. Wall thickness, contractility, degree of distension, and luminal contents were recorded for the duodenum and jejunum. Stomach wall thickness and location, cecal wall thickness, and peritoneal fluid location and character were recorded. Peritoneal fluid was identified most frequently on day 1 (P=0.0005). Duodenal wall thickness was significantly decreased on day 7 compared with days 1, 3, and 5 suggesting inflammatory thickening postoperatively (P=0.005). Stomach wall thickness was decreased on day 1 compared with days 3, 5, and 7 (P=0.03). All measurements, however, were within normal limits. Hypocontractile segments of jejunum were most frequently identified on day 1 (P=0.02) and hypoechoic contents were identified most frequently in the jejunum on day 1 and the duodenum on day 3, suggesting mild functional ileus or enteritis in the early postoperative period. Our findings support that bowel handling during abdominal exploration causes minimal changes in bowel wall thickness, contractility, degree of distension, luminal contents, and peritoneal fluid. This study was performed in ponies without gastrointestinal disease and further studies are necessary in patients.     

Effect of fibre content in the diet on the mean retention time in different segments of the digestive tract in growing pigs

Development of mechanistic models of digestion is a means to account for interactions between different nutrients, and between nutrients and the animal. Although some digestion models for pigs have been proposed, quantitative information concerning the underlying processes is extremely limiting. The aim of this study was to determine the effect of dietary fibre on the transit of the solid and liquid phases of digesta in different segments of the gastro-intestinal tract (GIT) in growing pigs. Six barrows (initial BW 30 kg and fitted with two simple T-cannulas at the proximal duodenum and distal ileum) were used in a double 3 × 3 Latin square design. Pigs were offered diets differing in total dietary fibre content (17, 22 and 27%) at 4 h intervals. A single meal marked with YbO₂ and Cr-EDTA was used to determine the passage kinetics of respectively the solid and liquid phases of digesta in different segments of the GIT.

The mean retention time (MRT) averaged 1 h from the mouth to the proximal duodenum (stomach), 4 h from the proximal duodenum to the distal ileum (small intestine), and 35 h from the distal ileum to the faecal excretion (large intestine). Increase in dietary fibre content had no effect on MRT in the stomach, tended to decrease MRT of solid phase in the small intestine (P = 0.07), and decreased MRT of both phases in the large intestine (43 to 29 h, P = 0.06). For all diets, transit of the liquid phase in the large intestine was 4–8 h less than transit of the solid phase.     

Effect of Concentrate form on blood and gastric fluid variables in ponies

Eight ponies were used in a two-period, crossover design experiment to determine if the physical form of a concentrate feed affected selected gastric fluid and blood variables. Each pony had been surgically fitted with a gastric cannula 2 years prior to the study. In each 29-day period, four ponies received hay and a pelleted concentrate and four ponies received hay and a textured (sweet feed) concentrate. The concentrate portions of the diets were identical except for physical form and contained 57.5% corn, 25% oat, 8.5% soybean meal, 7% molasses and 2% minerals and vitamins. On day 15 of each period, the ponies received a concentrate meal (.4% of body weight) and blood and gastric fluid samples were obtained for 9 h after feeding.Feeding a concentrate meal resulted in increased plasma glucose, serum insulin, gastric fluid glucose and gastric fluid L-lactate concentrations. The pH of gastric fluids before feeding ranged from 1.4 to 8.36, but gastric fluid pH was at least 5.0 within 30 min of eating in all ponies. Few effects of concentrate form were observed, but plasma glucose concentrations at 150 and 180 min after feeding were higher (P < .05) when the ponies received the pelleted feed than when they received the textured feed. One objective of the study was to evaluate rate of gastric emptying by making total gastric collections at 2, 4, 6 and 8 h after feeding on days 22 and 29 of each period. Unfortunately, the gastric cannulae did not prove suitable for making total gastric collections, thus no con- clusions regarding the effect of concentrate form on rate of digesta passage from the stomach could be made.     

Pneumoperitoneum secondary to a perforated gastric ulcer in a cat

A 7-year-old domestic cat was examined because of a history of weight loss, intermittent diarrhea, and anorexia of 6 months' duration. Results of physical examination were normal except for marked abdominal tension. Results of a CBC and serum biochemistry profile were unremarkable. Severe pneumoperitoneum was noted radiographically, and abdominocentesis yielded 640 mL of air. Abdominal distension recurred 1 day after abdominocentesis. Exploratory laparotomy was performed 3 days after recurrence of abdominal distension and revealed a gastric perforation along the greater curvature of the stomach with omental and pancreatic adhesions at the site of perforation. Mild local peritoneal inflammation was also noted. A partial gastrectomy was performed to resect the lesion, and histologic examination confirmed a severe perforating ulcer. The gastric wall adjacent to the ulcer was histologically normal. Aerobic and anaerobic bacteriologic cultures of abdominal swab specimens were negative for bacterial growth. The cat was discharged 4 days after surgery and clinically normal at suture removal.     

Use of bacitracin in the prevention and treatment of experimentally-induced idiopathic colitis in horses.

Ten healthy ponies from a single herd were found by repeated fecal culture to be free of Salmonella species and Clostridium cadaveris. In a preliminary study, four ponies administered a single oral dose of 10 mg/kg lincomycin did not develop idiopathic colitis when the drug was administered alone. Four other ponies were administered 10 mg/kg lincomycin by stomach tube together with 0.45 L of colonic content from a horse with idiopathic colitis induced earlier by lincomycin alone. Two of the four ponies were treated with 25 g oral zinc bacitracin premix (110 g/kg active ingredient) 24 h later. Forty-two hours after inoculation the two untreated ponies had severe signs of idiopathic colitis and were euthanized. Postmortem findings were typical of idiopathic colitis. The two treated ponies had milder illness but the more severely affected was also euthanized; the other was retreated at 42 h with bacitracin pre-mix and again 12 h later. Its illness and diarrhea resolved over the next 24 h. Clostridium cadaveris was isolated in large numbers from the cecum of the euthanized ponies and their cecal content contained mouse lethal and guinea pig dermonecrotic, but not cytotoxic, activity. Enterotoxins of Clostridium perfringens and Clostridium difficile could not be demonstrated. No toxin could be demonstrated in culture supernatants of C. cadaveris or in supernatants of cecal contents treated with ethanol prior to culturing in anaerobically incubated broth. No Salmonella spp. were isolated. A further two ponies were administered 10 mg/kg lincomycin orally with 0.45 L colonic content from a horse with idiopathic colitis, as described.(ABSTRACT TRUNCATED AT 250 WORDS)     

Phenylbutazone induces equine glandular gastric disease without decreasing prostaglandin E2 concentrations

In equids, phenylbutazone at high doses induces gastric disease, primarily in the glandular portion of the stomach. However, the mechanism of nonsteroidal anti‐inflammatory drug (NSAID)‐induced gastric disease in horses has yet to be determined. While phenylbutazone‐associated ulceration is often attributed to a decrease in basal gastric prostaglandins, this has not been demonstrated in the horse. Twelve horses were randomly assigned to treatment (n  = 6; 4.4 mg/kg phenylbutazone PO in 20 ml molasses q 12 hr for 7 days) or placebo (n  = 6; 20 ml molasses PO q 12 hr for 7 days) groups. Before treatment and 3 and 7 days after initiation of treatment, gastroscopy was performed and glandular gastric biopsies were collected and frozen at ?80°C. Glandular disease was assessed on a scale of 0–4. Prostaglandin E₂ concentrations in biopsies were measured using a commercially available enzyme‐linked immunosorbent assay. All phenylbutazone‐treated horses developed grade ≥2 glandular disease. Prostaglandin concentrations increased over time (p  = .0017), but there was no effect of treatment (p  = .49). These findings indicate that despite induction of glandular disease grade ≥2, phenylbutazone did not decrease basal glandular gastric prostaglandin E₂ concentration.     

Ultrasonography of the gastrointestinal tract of toco toucans (Ramphastos toco)

Baseline data for wall thickness in healthy toucans can be used to diagnose disease in sick individuals. This study aimed to evaluate the use of ultrasonography for the examination of the gastrointestinal tract of healthy toco toucans (Ramphastos toco). Ten non-anaesthetized healthy adult toco toucans were evaluated. Food was withheld for 3 h prior to the ultrasound examination. Longitudinal and transverse images of the gastrointestinal tract were obtained using ventromedian cranial and ventromedian caudal approaches to evaluate the morphology and stratification. The wall thickness of the sections was measured: proventriculus and ventriculus, duodenum, jejunum/ileum, and cloaca. Additionally, the thickness of the mucosal layer of the duodenum and jejunum/ileum was also measured. Subsequently, the ratios of the duodenal wall thickness to the duodenal mucosa layer and the total wall thickness of the jejunum/ileum to the jejunum/ileum layer mucosa were stablished. The wall thickness of the proventriculus was significantly higher than the wall thickness of ventriculus. The wall thickness of the duodenum was significantly higher than the wall thickness of jejunum/ileum. The mean ratios of the duodenal wall thickness to the duodenal mucosa layer and the wall thickness of the jejunum/ileum to the jejunum/ileum layer were 83.15% and 80.07%, respectively. In conclusion, it was possible to assess the stomach and intestines using ultrasound examination in healthy toco toucans, due to their medium body size and no interference by surrounding air sacs.     

Evaluation of a wireless ambulatory capsule (SmartPill®) to measure gastrointestinal tract pH, luminal pressure and temperature, and transit time in ponies

Reasons for performing study: This study investigated the use of a wireless ambulatory capsule (WAC; SmartPill^® pH.p GI Monitoring System) to determine WAC‐gastric emptying time (GET) in ponies. Objectives: To measure WAC‐GET and compare it to those findings with GET assessed by nuclear scintigraphy (S‐GET). Hypothesis: WAC‐GET will be slower than S‐GET, but will be significantly correlated. Methods: Seven healthy adult mixed‐breed pony mares were used in this study. Feed was withheld for 12 h prior to the WAC administration. After administration, a complete‐feed diet was fed to allow the WAC to pass into the stomach. Luminal pH, temperature and pressure were collected by a modified receiver secured to the pony. Once the pH reached a value of ≥8.0, it was determined that gastric emptying had occurred, and ponies were fed grass hay. After 5 days, data were downloaded and analysed using proprietary software. During the second period of the study, after at least 2 weeks, 4 of the ponies underwent a standard S‐GET test. Results: The WAC was successfully administered, and data were collected from all ponies. The mean percentage of data packets collected by the receiver was 84.9 ± 3.51% (range 66.8–95.1%). Mean WAC‐GET was 7.38 h (range 0.15–46.65 h). Mean gastric pH was 4.75 (range 2.07–6.99). Mean small intestinal transit time was 4.6 h. The mean pH for the small intestine was 8.0. The mean S‐GET time (in hours) when 10% of the radioactive feed is present in the stomach (T‐90%) was 2.3 h. The S‐GET did not correlate significantly with the WAC‐GET. Conclusions and potential relevance: The WAC was safely administered to ponies, and data were collected using a modified receiver. The WAC‐GET varied considerably between ponies, but was ≤3 h in 5 of the 6 ponies. The WAC used in this study provided a noninvasive technique that produced novel information about the pony gastrointestinal tract, but owing to the substantial variability in GET values and long transit time it may not be a reliable clinical tool at this time.     

Small intestinal segmental volvulus in horses after gastroscopy: Four cases (2011–2012)

Gastroscopy is the most common technique used in veterinary medicine to evaluate the stomach in horses and to date, no complications have been described associated with the procedure. This paper reports 4 cases developing a nonstrangulating segmental volvulus of the small intestine after gastroscopy at 3 referral institutions over a 2 year period. After performing diagnostic gastroscopy, all horses developed acute and severe clinical signs of colic unresponsive to medical management. Time range between gastroscopy and onset of colic signs varied from 10 min to 3 h. An exploratory laparotomy revealed a nonstrangulating segmental volvulus of the small intestine that was manually corrected without need for resection in all horses. In all cases, affected small intestine was severely gas distended. Three of those horses survived to discharge and were alive at follow‐up. One horse was subjected to euthanasia 2 days after surgery due to diffuse intestinal lymphoma.     

Efficacy of moxidectin equine oral gel against endoscopically-confirmed Gasterophilus nasalis and Gasterophilus intestinalis (Diptera: Oestridae) infections in horses

A 3 m, video gastroscope was used to screen 47 horses suspected of being naturally infected with equine bot larvae. 17 of 47 (36.2%) candidate horses harbored Gasterophilus nasalis larvae in the proximal duodenum and 46 of 47 (97.9%) had G. intestinalis larvae in the stomach. All horses infected with G. nasalis had concurrent infections with G. intestinalis. 14 horses with dual infections were allocated randomly to two treatment groups. Seven horses in Group 1 received 2% moxidectin oral gel once at a dosage of 0.4 mg/kg bodyweight (BW), and seven horses in Group 2 were untreated controls. 14 days after treatment, all horses were necropsied and the stomach and proximal duodenum harvested from each. Bot larvae were recovered, identified to species and instar, and counted. At the label dosage, moxidectin oral gel was 100 and 97.6% effective (P < 0.05) against third-instar G. nasalis and G. intestinalis, respectively. In addition to demonstrating the boticidal efficacy of moxidectin, this trial illustrated that gastroscopy/duodenoscopy is a feasible method for confirming infections with different species of bot larvae in the horse.     

Acute hemolytic anemia after oral administration of L-tryptophan in ponies

The hematologic and pathologic effects of orally administered L-tryptophan and indoleactic acid and of L-tryptophan administered IV were studied in ponies. Sixteen adult Shetland ponies were allotted into 4 experimental groups. Group 1 consisted of 5 ponies (1-5) given 0.6 g of tryptophan/kg of body weight in a water slurry via stomach tube. Group 2 included 4 ponies (6-9) given 0.35 g of tryptophan/kg orally. Group-3 ponies (10-13) were given 0.35 g of indoleacetic acid/kg orally. Group 4 consisted of 3 ponies (14-16) given a single 4-hour IV infusion of 0.1 g of tryptophan/kg. Restlessness, increased respiratory rate, hemolysis, and hemoglobinuria were detected in 4 of the 5 group-1 ponies. Only pony 7 in group 2 developed hemolysis, hemoglobinuria, and a significant increase in respiratory rate. Renal pathologic lesions, consistent with hemoglobinuric nephrosis, were seen in ponies 2, 4, 5, and 7. Bronchiolar degeneration was evident in 4 of 9 ponies given tryptophan orally. The importance of these respiratory lesions was unknown. Clinical or pathologic abnormalities were not noticed in the ponies of groups 3 and 4. Mean plasma tryptophan values increased significantly in groups 1 and 2 at 6 hours after dosing. A second peak of tryptophan was detected in both groups at 12 hours. Values returned to predose values by 48 hours. Plasma indole and 3-methylindole concentrations were detectable in only 2 ponies (4 and 7). In vitro incubations of cecal fluid from ponies 6, 8, and 9 yielded a percentage conversion of tryptophan to indole of 16.75%, 5.84%, and 7.96%, respectively. 3-Methylindole was not produced. These results suggested that indole was the major metabolite of orally administered tryptophan in these ponies.     

Endoscopic evaluation of the esophagus and stomach in three loggerhead sea turtles (Caretta caretta) and a Malaysian giant turtle (Orlitia borneensis).

Three loggerhead sea turtles (Caretta caretta) and a Malaysian giant turtle (Orlitia borneensis) were presented with suspected or confirmed esophageal foreign bodies. Esophagoscopy was performed on all turtles, and gastroscopy was performed on three turtles. In all cases, endoscopy was easy to perform, and allowed visualization of most upper gastrointestinal features. The papillated esophagus was easy to navigate, but mucosal papillae in the loggerhead sea turtles prevented examination of the underlying mucosa. The stomach was easily entered and examined in both species, but the working endoscope length (100 cm) prevented inspection of the pyloric antrum and the duodenum in all turtles. The turtles in this report may serve as references for future endoscopic examinations of these species.     

Efficacy of misoprostol in prevention of gastric hemorrhage in dogs treated with high doses of methylprednisolone sodium succinate.

OBJECTIVE: To determine whether administration of misoprostol prevents gastric hemorrhage in healthy dogs treated with high doses of methylprednisolone sodium succinate (MPSS). ANIMALS: 18 healthy hound-type dogs of both sexes. PROCEDURE: All dogs were given high doses of MPSS (30 mg/kg of body weight, initially, then 15 mg/kg 2 and 6 hours later, and, subsequently, q 6 h for a total of 48 hours) IV. Dogs were assigned randomly to receive concurrent treatment with misoprostol (4 to 6 microg/kg, PO, q 8 h; n = 9) or an empty gelatin capsule (9). Gastroduodenoscopy was performed before and after treatment. Hemorrhage was graded from none (0) to severe (3) for each cardia, fundus, antrum, and duodenum. A total stomach score was calculated as the sum of the regional stomach scores. Food retention was recorded, and pH of gastric fluid was determined. Gastric and fecal occult blood was measured. RESULTS: Gastric hemorrhage was evident in all dogs after MPSS administration, and its severity was similar in both groups. Median total stomach score was 6 for misoprostol-treated dogs and 5.5 for dogs given the gelatin capsule. Difference in gastric acidity, frequency of food retention, and incidence of occult blood in gastric fluid and feces was not apparent between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of misoprostol (4 to 6 microg/kg, PO, q 8 h) does not prevent gastric hemorrhage caused by high doses of MPSS. Alternative prophylactic treatment should be considered.     

Use of a wireless system to measure invasive arterial blood pressure in ponies – preliminary study

Objective  To evaluate the feasibility and functionality of intra-carotid wireless device implantation in ponies, and to investigate its short-term complications.
Study design  Prospective preliminary study.
Animals  Five mixed breed, adult, intact male ponies weighing 104 ± 28.8 kg (mean ± SD) underwent surgery. Arterial blood pressure data were continuously collected from four animals.
Methods  General anesthesia was induced on two consecutive days. On the first day, an intra-arterial wireless device was implanted in the right carotid artery. On the next day, a transcutaneous intra-arterial catheter was placed in the left facial artery. Data from both sources were collected. Post-mortem examination was performed.
Results  Surgical time was 27.1 ± 11.85 minutes. All catheters remained in place with some extra vascular migration. Complications included mild seroma and hematoma.
Conclusion  The wireless system allowed continuous monitoring in ponies throughout anesthesia and at rest and may allow for the recording of arterial blood pressure and heart rate when it would be difficult to achieve with a conventional system (e.g. during recovery from anesthesia).
Clinical relevance  The wireless invasive blood pressure monitor may allow continuous measurements when only intermittent measurements would be feasible with a wired system.     

Equine thyroid function tests: a preliminary investigation.

A similar and significant (P less than 0.001) increase in plasma thyroxine (T4) concentration was seen in seven clinically normal thoroughbred horses 2 h after the intravenous administration of either 2.5 iu or 5 iu of thyroid stimulating hormone (TSH) with a peak response around 4 h after administration. The intravenous administration of 0.2, 0.5 or 1 mg thyrotrophin releasing hormone (TRH) resulted in a significant (P less than 0.01) increase in T4 concentration in three groups of animals; six thoroughbreds in full work, five thoroughbreds at rest and four ponies at rest. The peak response was recorded at 3 or 4 h after administration. A significant difference between the groups in the degree of response to TRH was only found between the thoroughbreds in work and those at rest with 1 mg TRH (P less than 0.05). When two additional ponies were investigated in a similar way, a reduced response to TRH was observed: a pregnant mare had a similar response to 5 iu TSH as the thoroughbreds; the other pony also showed a lowered response to TSH. In a group of 2- or 3-year-old thoroughbreds in training no difference in the T4 response 4 h after intravenous administration of 0.5 mg TRH could be determined, according to the month, age, sex or work intensity. Although resting T4 concentrations did not differ significantly between animals believed to be suffering from the equine rhabdomyolysis syndrome (ERS) and those suffering from a variety of other conditions, some ERS sufferers may have a lowered response to TRH.     

Inter-relationship between Gasterophilus larvae and the horse's gastric and duodenal wall with special reference to penetration.

The degree of penetration into the stomach and duodenum of the horse by bot fly larvae, Gasterophilus intestinalis (De Geer) and G. nasalis (Linnaeus) (Diptera : Gasterophilidae) was evaluated. Evidence of larval perforation of the stomach or duodenum was not found on gross inspection. Palpation of the intact stomach and duodenum was not effective in establishing the existence of Gasterophilus larvae within the organs. Findings suggest that larvae of both species produce an ulcer of similar depth within the gastrointestinal wall. The ulcer depth produced by larvae did not correlate with the normal, unaffected thickness of the particular stomach or duodenum. Tissue proliferation beneath ulcers of the stomach and duodenum was not correlated with the depth of the ulcer. Proliferation of the tissue beneath the ulcers of the stomach generally exceeded that found under duodenal ulcers. Gastric wall beneath the G. intestinalis ulcer frequently attained a thickness equal to or greater than the normal stomach wall. Histopathological examinations below the ulcer revealed intense fibrosis. Duodenal thickness below the G. nasalis ulcer was typically less than normal and resulted in an attenuated wall. Histopathological analysis of the affected duodenum revealed severe loss of submucosal glands in a sharply demarcated area below and surrounding the lesion. Fibrosis of the underlying lamina propria mucosae and tunica submucosa was appreciable but failed to restore the original thickness of the duodenal wall. Host tissue response and moderation of the parasite' s behavior reduce the chances of direct perforation of the gastrointestinal tissue.     

Effect of treatment with oxytetracycline during the acute stages of experimentally induced equine ehrlichial colitis in ponies.

Eighteen ponies were inoculated IV with Ehrlichia risticii-infected P388D1 mouse monocyte cells. Twenty-four hours after onset of fever (rectal temperature > 38.8 C), 9 ponies were treated with oxytetracycline (6.6 mg/kg of body weight, IV, q 24 h) for 5 days. The remaining 9 ponies served as infected nontreated controls. Mean scores of the following variables were not significantly different between groups on the day treatment was begun: rectal temperature, diarrhea, borborygmal sounds, feed intake, mental attitude, and evidence of a hyperresonant area in the abdomen. All ponies were observed for progression of clinical signs typical of ehrlichial colitis. Within 12 hours of initiation of treatment, only 1 treated pony had a rectal temperature > 38.8 C and most rectal temperatures were < 38.3 C. In contrast, only 2 control ponies had rectal temperatures < 38.8 C (mean rectal temperature values were significantly, P = 0.01, different between groups). In the treatment group, 4 ponies had no signs of depression after the first day of treatment, and only 1 had signs of depression after the second day of treatment (mean scores between groups were significantly different, P = 0.01). Feed intake remained normal in 4 treated ponies and improved in 4 of the remaining 5 after treatment began. Most of the control ponies had a progressive decrease in their feed intake during the observation period (mean scores between groups were significantly, P = 0.01, different). Three ponies in the control group and 2 ponies in the treatment group developed diarrhea before the treatment observation period began.(ABSTRACT TRUNCATED AT 250 WORDS)     

A comparison of enterotomies through the antimesenteric band and the sacculation of the small (descending) colon of ponies

Three pairs of longitudinal enterotomies were performed in the small colon of 10 ponies. Each pair consisted of one enterotomy through the antimesenteric band and one through the sacculation. The ponies were destroyed 96 h after surgery. The enterotomies in the two sites were compared for: speed of surgery, adhesions, bursting wall tension, neovascularisation by micro-angiography, and histological reaction. Enterotomies made through the antimesenteric band were superior because they were quicker to perform, stronger, more accurately apposed, and had less inflammation than those made through the sacculation.