Determination of the acid-base status in 50 horses admitted with colic between December 1998 and May 1999.

The purpose of the present study was to investigate the acid-base status and the concentration of organic acids in horses with colic caused by various disorders. Blood samples were collected from 50 horses with colic and from 20 controls. No intravenous fluids had been given prior to sample collection. Identified causes of colic included gastric ulceration, small intestinal volvulus, cecal intussusception, cecal rupture, colonic impaction, left dorsal colon displacement, right dorsal colon displacement, colonic volvulus, colitis, peritonitis, and uterine torsion. Thirty-seven horses recovered from treatment of colic, 8 horses were euthanized, and 5 died. Most cases were not in severe metabolic acidosis. In previous studies, most horses presented for diagnosis and treatment of colic were in metabolic acidosis and in shock.

Both L- and D-lactate contribute to metabolic acidosis in diarrheic calves.

Diarrhea in neonates is often complicated by metabolic acidosis. We used blood gas analysis and HPLC to determine whether bacterial fermentation might contribute to acidosis in diarrheic calves. Diarrheic calves (n = 21) had significantly lower pH, PCO(2), HCO(3)(-) and a higher anion gap than healthy calves (n = 21). Serum concentrations (mean +/- SD, mmol/L) of DL-, L- and D-lactate were also significantly higher in diarrheic (8.9 +/- 5.1, 4.1 +/- 3.4 and 5.2 +/- 5.7) than in healthy calves (1.7 +/- 1.2, 2.0 +/- 1.1 and too low to quantify). D- and L-lactate accounted for 64% anion gap increase in diarrheic calves. Fecal D- and L-lactate concentrations were also significantly higher in diarrheic calves (9.4 +/- 3.0 and 11.9 +/- 2.7 mmol/L) than healthy calves (1.1 +/- 0.1 and 1.6 +/- 0.1 mmol/L). The elevated concentrations of serum and fecal D-lactate suggest gut bacterial fermentation contributes to the development of acidosis in diarrhea.

A comparison of pH determination methods in food animal practice.

The accuracy of a portable pH meter in measuring blood pH in neonatal calves, urine pH, and ruminal fluid pH in cows has been assessed. Thirty-five diarrheic and 15 healthy beef calves were used for blood gas analysis; 57 healthy dairy cows provided voided urine samples; and ruminal fluid samples were obtained from 10 dairy cows with ruminal fistulas on 4 separate days. Measurements of blood pH were obtained from an automated blood gas analyzer and the portable pH meter. Measurements of urine and ruminal fluid pH were determined with the benchtop pH meter, urinalysis strips, narrow range pH paper, and the portable pH meter. The portable pH meter was more accurate in measuring urine pH and ruminal fluid pH in cows than blood pH in neonatal calves. The urinalysis strips and the narrow range pH paper were found adequate to evaluate urine and ruminal pH.

Comparison of abomasal emptying in neonatal calves with a nuclear scintigraphic procedure.

The purpose of the present study was to demonstrate that nuclear medicine technology allows observation of the effect that milk clotting has on abomasal emptying in the living neonatal calf. Scintigraphic evaluation of abomasal emptying was carried out in 6 healthy male Holstein calves. The calves were fed 10% of their body weight daily as whole cow's milk that was divided equally and consumed as 2 feedings via a nipple bottle. One day before the nuclear scintigraphic procedure, the calves were randomly fed whole cow's milk, or an oral rehydration solution (ORS) containing bicarbonate and high levels of soluble fibre was fed for 3 consecutive feedings an hour before the portion of milk. For each calf, both feeding programs were repeated twice at a one-week interval. Immediately following administration of the 99mTC-sulfur-colloid-containing milk, the calves were imaged with the gamma camera positioned lateral and ventral to the abomasum. Additional right lateral and ventral views of the abomasum were collected at 15, 30, 45, 60, 90, 120, 150, 180, 210, and 240 min after administration of the radionuclide. Blood glucose determination were performed at one-hour intervals for 7 h after feeding milk to evaluate milk digestibility in both feeding programs. No significant differences in the results of the glucose absorption test or in the radionuclide counts of the abomasum were found between both feeding programs. Scintigraphic evaluation of abomasal emptying was found to be a useful technique for visualization of milk clotting and to test the effect of an ORS on milk digestibility.

Oral rehydration solution therapy in the management of children with rotavirus diarrhea.

Rotavirus infections are the most common cause of gastroenteritis among children younger than 3 years of age and are associated with sporadic outbreaks of diarrhea in elderly and immunocompromised patients. Oral rehydration solutions (ORS) are formulated to correct dehydration and acidosis. Currently, ORS do not promote intestinal healing; however, investigators are examining the role of nutrition in promoting intestinal healing. This article reviews the composition of several ORS in human medicine and summarizes our current knowledge of the nutritional treatment of rotavirus diarrhea and intestinal healing.

High-performance liquid chromatographic assay of (+/-)-lactic acid and its enantiomers in calf serum.

Two high-performance liquid chromatographic methods are described for the determination of lactic acid and its enantiomers in calf serum. A 300x8.0 mm I.D. column packed with sulfonated styrene-divinylbenzene copolymer and a 50x4.6 mm ODS column with N,N-dioctyl-L-alanine were used. UV detection was at 205 and 236 nm for the non-chiral and chiral assays, respectively. Both assays demonstrated excellent linear relationships between peak area ratios and serum concentrations over a range of 0.5 to 20 mM, based on 100 microl bovine serum. Recovery was complete. Inter- and within-batch bias and relative standard deviation were <15%.

Examination of metabolism of viscera drained by the portal vein in neonatal calves, using short-term intravenous infusions of glutamine and other nutrients.

OBJECTIVE: To quantify glutamine use in viscera drained by the portal vein in neonatal calves and to assess the relative nutritional importance of glutamine, glucose, and acetate for enterocytes. ANIMALS: 5 healthy neonatal calves. PROCEDURE: A femoral artery, jugular vein, and the portal vein were surgically cannulated in each calf. Blood flow in the portal vein was measured by use of an ultrasonographic transit-time flow probe. A series of solutions was infused on 4 days for each calf. On the infusion days, acetate, glucose, glutamine, and saline (0.9% NaCl; control) solutions were administered IV during 1-hour periods via the jugular vein. Venous and arterial blood samples were collected during the last 15 minutes of each 1-hour infusion. RESULTS: Uptake of glutamine and glucose by viscera drained by the portal vein was 0.3+/-1.1 and 1.9+/-3.1 micromol/kg0.75/min, respectively, during saline infusion. During acetate, glucose, and saline infusions, glucose was a greater source of energy for the intestines than was glutamine. However, during glutamine infusion, uptake of glutamine by viscera drained by the portal vein increased significantly (29.9+/-11.2 micromol/kg0.75/min), which was associated with an increase in ammonia production (7.0+/-0.5 micromol/kg0.75/min). Toxicosis was not associated with IV administration of glutamine. CONCLUSION: Glutamine infusion resulted in an increase in glutamine uptake by viscera drained by the portal vein, which was associated with an increase in ammonia production and a slight increase in oxygen consumption. CLINICAL RELEVANCE: These solutions may be used to develop treatments that enhance healing of intestines of diarrheic calves.

Nutrient uptake by viscera drained by the portal vein in neonatal calves during intravenous infusion of glutamine.

OBJECTIVE: To quantify glutamine use by viscera drained by the portal vein in neonatal calves and to determine whether uptake could be stimulated by long-term IV infusion or long-term use of oral supplements. ANIMALS: 4 healthy neonatal calves. PROCEDURE: A femoral artery, jugular vein, and the portal vein were surgically cannulated in each calf. Blood flow in the portal vein was measured, using an ultrasonic transit-time flow probe. Calves were given an IV infusion of glutamine on days 6, 8, and 10 after surgery. Before the first infusion, calves were fed a diet of milk only. The diet was supplemented with glutamine for the second and third infusions. Glutamine was administered via the jugular vein during a 5-hour period. Venous and arterial blood samples were collected every hour for 5 hours. RESULTS: During glutamine infusion, uptake of glutamine by viscera drained by the portal vein increased in association with increased production of ammonia. Glutamine supplementation of the diet did not alter glutamine uptake. Glutamine infusion did not increase viscera uptake of indispensable amino acids. Long-term use of glutamine supplements or infusion of glutamine for periods of more than 1 hour increased glutamine uptake by viscera. Arterial leucine concentration and uptake of leucine by the viscera decreased during glutamine infusion, indicating that leucine became the limiting factor. CONCLUSION: Glutamine administration (supplements or infusions) to calves may require that a mixture of amino acids be provided to improve effectiveness. CLINICAL RELEVANCE: Glutamine may be beneficial in treatments designed to promote intestinal healing in diarrheic calves.

Long-term surgical preparation of portal vein-drained viscera for determination of their nutritional requirements in preruminant calves.

OBJECTIVE: To develop a surgical preparation to study the nutrient concentration difference across the portal vein-drained viscera of preruminant calves over a 2-week period. ANIMALS: 9 healthy preruminant male Holstein calves. PROCEDURE: A bilateral subcostal approach was used to reach the portal area to provide access for proper placement of an ultrasonic transit time flow probe around the portal vein. The umbilical vein was used as an entry point for the portal vein catheter. The femoral artery was also catheterized. Calves were observed daily, and food intake was recorded. Body weight was recorded weekly. The calves were euthanatized, and necropsy was performed 2 weeks after surgery. RESULTS: Of the 9 calves, 7 recovered without surgical complications. Within 24 hours of surgery, 1 calf developed an intestinal hernia at the flank incision that was surgically repaired without further complications. One calf was euthanatized a week after surgery because it developed septicemia secondary to catheter-related infection. CONCLUSION: The bilateral subcostal approach provided access to the portal area, and the umbilical vein was useful as an entry point. Application of an ultrasonic flow probe provided consistent measurements of blood flow over a 2-week period. CLINICAL RELEVANCE: These results may have implications for development of treatment to promote gastrointestinal tract healing in calves with diarrhea.

Determination of lactose and xylose malabsorption in preruminant diarrheic calves.

In preliminary studies feeding the poorly absorbed carbohydrate sorbitol at 2.3 g/kg body weight as an indication of maximal fermentative capacity failed to produce the expected large increase in breath hydrogen excretion but did produce a transient diarrhea in five out of six control calves. Twelve healthy control and eighteen diarrheic calves were fed lactose or D-xylose on consecutive days at 1.15 g/kg body weight and a concentration of 46 g/L. Breath and blood samples were collected at 1 h intervals from 0 to 7 h. After administration of lactose, there was a significant increase in breath hydrogen excretion in diarrheic versus control calves. The increase in plasma glucose concentrations was delayed in diarrheic calves but the area under the absorption curve was similar in control and diarrheic calves. After administration of D-xylose, breath hydrogen excretion did not increase significantly but plasma D-xylose concentrations were significantly reduced in diarrheic calves. The pathogens commonly isolated from the feces were Cryptosporidium species, rotavirus and coronavirus. The number of pathogens and the severity of the calves' acid-base deficit were not related to the severity of carbohydrate malabsorption. Decreased absorption of lactose and D-xylose may be the result of intestinal villous atrophy caused by viral or parasite infection. It was concluded that carbohydrate malabsorption rather than a specific lactose maldigestion is a significant problem in diarrheic calves. Diarrheic calves appear to digest and absorb lactose when fed in small amounts.

Isolation of a major form of pepsinogen from gastric mucosa of horses.

In mammalian species studied previously, pepsinogen consisted of biochemically different groups of isozymogens. By use of gel filtration chromatography and electrophoresis, we isolated a predominant pepsinogen from the gastric mucosa of a horse. Peptide mapping with V8 protease revealed differences with its porcine homologue. However, porcine and equine pepsinogens, when activated to pepsin, had a similar pattern of activity when hemoglobin was used as substrate. Those results suggest that differences must exist in the primary structure of the pepsinogens of the 2 species.

Radioimmunoassay of serum pepsinogen in relation to gastric (pars oesophagea) ulceration in swine herds.

A radioimmunoassay for the detection of serum swine pepsinogens is described. The sensitivity and reproducibility of the assay were satisfactory for its clinical use. In normal pigs, the serum pepsinogen level was 1.51 +/- 0.56 ng/mL. Cases with parakeratosis, erosions and ulcerations of the pars oesophagea had elevated pepsinogen levels (5.15 +/- 1.98 ng/mL).

A retrospective study of nineteen ataxic horses.

A retrospective study of 19 ataxic horses admitted to the College of Veterinary Medicine of the University of Montreal during the period of January 1985 to December 1988 is presented. There were 11 cases of cervical vertebral malformation, four of equine degenerative myeloencephalopathy, two of equine protozoal myeloencephalitis, one each of vertebral osteomyelitis and intervertebral disc protrusion. The clinical diagnosis of ataxia in horses requires neurological, radiographic, myelographic, and laboratory examinations.