Ulcerative colitis and protein losing enteropathy associated with intestinal salmonellosis and histoplasmosis in a horse.

Ulcerative colitis, protein losing enteropathy and intestinal histoplasmosis-salmonellosis were diagnosed in a six-year-old Quarterhorse stallion. For six months before examination, the horse experienced a slow continual loss of weight. During the 17 day period of hospitalisation the horse developed progressive generalised oedema. On the 12th day of hospitalisation a severe profuse watery diarrhoea began; the horse was killed five days later.

Pulmonary artery and aortic pressure changes during high intensity treadmill exercise in the horse: effect of frusemide and phentolamine.

Intravenous frusemide (1.0 mg/kg bwt) or phentolamine (0.33 mg/kg bwt) was given to 7 horses 1 h before exercise and their effects on pulmonary artery and aortic pressure changes during strenuous exercise were examined. Short-term near-maximal treadmill exercise (10 m/sec, 3 degrees incline) produced increases in heart rate, mean pulmonary artery pressure (PAP), mean aortic pressure (AP), and packed cell volume (PCV). Frusemide did not affect heart rate, PAP or PCV during exercise. Frusemide significantly decreased mean AP by 10 to 15 mmHg during exercise. Phentolamine produced an increase in heart rate relative to control only early in exercise but not during later, more strenuous, exercise. Phentolamine had no statistically significant effect on AP, PAP, or PCV, but a significant reduction was observed between 180 and 230 sec of exercise when PAP and AP were standardised against heart rate. Frusemide did not prevent horses from haemorrhaging during exercise in this study. Treatment with phentolamine did not sufficiently reduce the PAP and AP to test our hypothesis that a reduction in PAP and AP would eliminate EIPH.

Haematological changes during development of acute laminitis hypertension.

Experimental carbohydrate overload of 15 horses resulted in consistent haematological changes during development of laminitis hypertension. Significant alterations in packed cell volume, leucocyte differential count, serum glucose levels and protein values occurred before onset of Obel grade 3 lameness and hyperkinetic circulatory state. Blood platelets were significantly decreased 8 h after the onset of severe lameness. Findings in this study were indicative of haemoconcentration due to compartmental fluid shifts and leucocytic stress response consistent with increased circulating adrenoglucocorticoids and/or catecholamines.

Equine laminitis of alimentary origin: an experimental model.

Acute alimentary form of laminitis was uniformly induced in 11 of 12 horses by administration of a starch and wood flour gruel and could be graded by previously established (Obel) and presently defined criteria. The experimentally induced laminitis was similar to naturally occurring laminitis, as determined on the basis of lameness severity and vital signs. Packed cell volume, leukocyte count, and total protein were significantly increased (P smaller than 0.05) at 24 and 40 hours after administration of gruel. Arterial systolic and diastolic pressures increased, central venous pressure decreased, heart rate increased, and rectal temperature increased consistently within the 56-hour experimental period. Of the 11 affected horses, 7 horses had Obel grade 3 lameness (horse moved most reluctantly and vigorously resisted attempts to lift a forefoot) at 40 hours after gruel was placed in the alimentary tract, 2 horses had Obel grade 3 lameness at 32 hours, and 2 horses had Obel grade 3 lameness at 48 hours.

Cardiac output, left ventricular ejection rate, plasma volume, and heart rate changes in equine laminitis-hypertension.

Acute laminitis-hypertension was produced experimentally by carbohydrate overloading of the gastrointestinal tract in 8 horses, and the resulting hemodynamic changes were measured. Statistically significant (P less than 0.01) increases in cardiac output, left ventricular ejection rate, heart rate, and arterial pressure were related to statistically nonsignificant changes in peripheral resistance and a delayed (Obel grade 3 plus 24 hours) decrease in plasma volume. When compared with control values, the doubling of cardiac output and left ventricular ejection rate simultaneous with little or no change in either peripheral resistance or plasma volume (16 hours after the occurrence of Obel grade 3 lameness) was suggestive of an increase in myocardial contractility. Because these pathophysiologic phenomena have important time relationships to the onset of Obel grade 3 lameness in acute laminitis, the results of this investigation are discussed in light of their relationship to clinical signs, serum electrolyte changes, plasma L-lactate alterations, and histologic deterioration of the digit.

Angiographic appearance of the normal equine foot and alterations in chronic laminitis.

The angiographic appearance of the normal equine foot was compared with the appearance of equine feet affected with chronic laminitis. The normal foot was characterized by complete filling of the terminal arch, 8 to 10 main branches between 0.1 and 0.2 cm in diameter, a symmetrical netlike vascular pattern in the corium of the hoof, and numerous fine vessels in the corium of the coronary band. The feet affected with chronic laminitis were characterized by poor filling of the terminal arch, larger and less numerous primary branches, an irregular vascular pattern in the corium of the hoof, areas of the corium of the hoof that were apparently avascular, and irregular, tortuous vessels in the corium of the coronary band.

Epidural melanoma causing posterior paresis in a horse.

An aged gray stallion was examined because of fullminating posterior paresis, bladder paralysis, and perineal anesthesia. Lower motor neuron dysfunction was detected at the lumbosacral level of the spinal cord, and cerebrospinal fluid was yellow. After brief supportive treatment, the horse died. Necropsy revealed a single epidural melanoma at L5-6. The absence of cutaneous melanotic growth, absence of organ involvement, and extensive vertebral remodeling indicated the neoplasm to have been primary and to have been present for an extended period. Neurologic dysfunction was acute and progressive, as a result of spinal cord compression by the neoplasm.

Orgotein in equine navicular disease: a double blind study.

Fourteen horses (7 treated with orgotein and 7 treated with a placebo) with navicular disease were studied on a double blind basis. All 14 horses had clinical and radiographic evidence of navicular disease. Orgotein and the placebo were administered by juxtabursal injection. Of the 7 orgotein-treated horses, 3 responded but none of the 7 placebo-treated horses responded. The difference was statistically significant (P less than 0.05).

Neutropenia and salmonellosis in hospitalized horses.

Colitis due to salmonellae was diagnosed in 9 horses following hospitalization for various reasons at the University of Missouri Veterinary Teaching Hospital, from May, 1971, to April, 1972. Diarrhea, fever, and either a neutrophil count of less than or equal to 3,600/cmm or a rapid decline in neutrophil numbers were specific for salmonellosis. The value of hematologic survelillance in hospitalized Equidae was demonstrated in another group of 9 horses with neutropenia, each of which was promptly treated and did not develop colitis. Bacteriologic culturing of fecal samples from 28 clinically normal horses yielded only 2 salmonella isolations, S manhattan in each case. The serotyped salmonellae isolated from the patients with colitis were all S typhimurium, with similar antibiotic resistance patterns.

Monitoring and evaluating the physiological changes in the horse with acute abdominal disease.

Initial examination and therapy, and the avoidance of maltreatment are emphasized. Gastric decompression is of prime importance, after which no compound should be administered via stomach tube. Where large amounts of high starch grains are fed, primary acute gastric dilatation must be differentiated from that secondary to small bowel dilatation, by immediate gastric intubation and irrigation of the cardia with lidocaine. If cessation of pain and improvement of peristalsis and general attitude follow, the former state may be assumed. If pain persists and peristalsis does not improve markedly, one should assume small bowel displacement. Rectal examination is helpful in initial evaluation: impactions, inguinal herniation and ileocaecal intussusception may be diagnosed and small bowel displacement suspected. Palpation of one or more distended loops of bowel in the ventral middle third of the abdomen indicates small bowel displacement or ileus and flaccid distension. Distinction by rectal palpation alone is difficult. Palpation of the gas-distended apex of the caecum in the middle third of the abdomen is virtually pathognomonic for 180 degrees rotation of the large bowel. Abdominal paracentesis yielding true sanguineous effusion indicates a necrotizing segment of the bowel. If negative, such a segment is absent, or there is an infarcted segment, not yet damaged to the point of leaching whole blood, or the necrotizing segment is outside the peritoneal cavity, i.e., in the thorax, intussuscepted into the caecum, or herniated into the inguinal canal. Recurrent colics frequently may be due to verminous arteritis but the relationship to diet should be investigated. Recurrent colics after grain ingestion with occult blood in the faeces may be due to ulcers; such cases respond well to grain withdrawal. The advantages and disadvantages of phenothiazine-derived tranquillizers are discussed. They are contra-indicated if there is any evidence of circulating volume insufficiency but are benefical in many instances through improved peripheral perfusion of organs provided circulating volume is adequate, i.e., early in acute abdominal disease prior to development of circulatory insufficiency. They should not be administered if immediate surgery is contemplated because of hypotensive effects. The administration of oral antibiotics (Neomycin) early in the course of the disease is encouraged. This is contra-indicated if the horse is already toxic, when it should receive parenteral antibiotics, preferably chloromycetin. Tetracyclines may predispose to the later development of salmonella diarrhoea. Absolute analgesia should be provided; our preference is the magnesium sulphate-chloral hydrate solutions. Administration of mineral oil is desirable in initiation of peristalsis, depression of Gram-negative overgrowth and softening of impactioning obstructions but nothing should be administered per os if the stomach has required decompression.