Effect of frusemide on transvascular fluid fluxes across the lung in exercising horses

Reasons for performing study: Frusemide (Fru) is widely prescribed for management of racehorses experiencing EIPH. The effect of Fru in the lung appears to be a reduction in transcapillary pressures and inhibition of the erythrocyte anion exchange, which may lead to attenuation of transpulmonary fluid fluxes during exercise. Hypothesis: Treatment with Fru will attenuate transpulmonary fluid fluxes in horses during high intensity exercise. Methods: In a crossover study, 6 race‐fit Standardbred horses were treated with 250 mg of Fru i.v. (FruTr) or placebo (Con) 4 h before exercise on a high speed treadmill until fatigue. Arterial and central mixed venous blood, as well as CO₂ elimination and O₂ uptake, were sampled. Volume changes across the lung and transvascular fluid fluxes were calculated from changes in haemoglobin, packed cell volume, plasma protein and cardiac output (Q). Results: During exercise, Q increased in both Con and FruTr, with Q being significantly lower in FruTr (mean ± s.e. 301.8 ± 8.5 l/min at fatigue) compared to Con (336.5 ± 15.6 l/min) (P<0.01). At rest frusemide had no effect on erythrocyte (J_ER) and transvascular (J_V‐A) fluid fluxes across the lung. Exercise had a significant effect on J_ER and J_V‐A (P≤0.02). During exercise, J_ER (at fatigue 14.6 ± 2.3 l/min and 11.6 ± 2.2 l/min in Con and FruTr, respectively) and J_V‐A (at fatigue14.9 ± 2.3 l/min and 12.0 ± 2.2 l/min in Con and FruTr, respectively) were not significantly different between Con and FruTr (P = 0.6 and P = 0.8 for J_ER and J_V‐A, respectively). Conclusions and clinical importance: Fru does not have a measurable effect on J_ER and J_V‐A. Cardiac output was reduced in FruTr, suggesting that there were also smaller changes in the capillary recruitment and transvascular transmural hydrostatic pressures; however, this did not effect J_V‐A. Therefore, Fru at the dose of 250 mg does not appear to be an effective treatment for regulating pulmonary transvascular forces during exercise in horses.     

Fasciola hepatica: effects on blood constituents and liver minerals in fallow deer (Dama dama)

Haematological and serum biochemical constituents as well as the liver mineral concentrations can be affected by Fasciola hepatica. The present study compares the blood and liver constituents in 19 fallow deer with fascioliosis and in 43 without it. Blood samples, gastro-intestinal tract, lungs and liver were taken from 62 male and female fallow deer that were shot, aged 6 months and over, in enclosures, between 1999 and 2001 in Slovenia. Samples were analysed and the means of various parameters of blood and liver were determined. Significant differences in blood were found in the mean cell volume, total serum proteins, sodium, and calcium; and in liver and calcium and copper were higher in animals without fascioliosis. Mean cell haemoglobin concentration, eosinophils, basophils, lymphocytes, monocytes, alanine aminotransferase, urea, glucose and copper in blood were significantly higher in animals with fascioliosis. It has been concluded that some of the values in fallow deer like in other domestic ruminants are the sensitive indicators of liver cell damage in fascioliosis.     

Bestimmung der osmotischen Resistenz von Eberspermien und deren Beziehungen zur Konservierungsfähigkeit von Samenproben

Contents Determination of the osmotic resistance of boar spermatozoa and the relations to sperm freezing and long storage The osmotic behaviour of fresh boar spermatozoa (482 ejaculates from 34 A.I. boars) was examined in a standard medium but with different osmotic pressures ranging from 150 mosm/kg till 500 mosm/kg. The percentage of spermatozoa with normal acrosomal ridge (NAR) was determined after incubation of 0.2 ml fresh semen in 3 ml of the osmotic test solutions at 39° C for 15 and 120 min. In the non-isotonic media % NAR decreased and could be quantified depending to incubation time and to the different osmolalities; NAR decreased strongest at 150 or 500 mosm/kg and after 120 min incubation time. Differences in % NAR were large between ejaculates and between boars but low within boars and statistically significant correlations had been found to % NAR and motility in froren/thawed semen samples or stored samples. Still higher correlations were found by calculation of an osmotic resistance test-value (ORT-value) which is defined as follows: ORT = 1/2 % NAR in isotonic medium/(after 15 min) +% NAR in 150 or 500 mosm/kg/(after 15 or 120 min) ORT-values can be calculated for hypotonic (150 mosm/kg) as well as for hypertonic (500 mosm/kg) test solutions and for 15 and 120 minutes incubation time. The hypotonic ORT-value for 120 min. is the most accurate; the values varied from 34 till 83 between ejaculates and from 44 till 76 between boars with a low variability within boars. Grouping of boars by their ORT-values in “good”, “moderate” and “poor” corresponded to a similar grouping of these boars by their semen quality (% NAR and motility) in preserved semen samples. Also a grouping of single ejaculates by their ORT-values corresponded to a similar qualitative classification of these ejaculates. ORT seems to become a good and practicable assessment test for the selection of boars suitable dor deep freezing or long storage of their spermatozoa. On the other hand preservation techniques too can be examined by ORT. But more investigations with this test must be done especially its relation to the fertilization capacity of semen samples with different ORT-values.     

Impact of lactic acid fermentation in the large intestine on acute lactic acidosis in cattle

Microbial and fermentation changes in the ingesta of the large intestine and their influence on the pathogenesis of acute lactic acidosis were studied in 4 cows fitted with permanent cannulas in the ileum and cecum. Feed mixture containing 65% of maize was infused into the cecum for several days in amounts of 2 and 4 kg per day. The daily amount was divided in 8 equal portions and given with 3 l of warm physiologic saline solution. During the period of ad libitum feeding of hay, the pH values in cecal digesta were 7.4 to 7.6 and the amount of total volatile fatty acids 40-60 mmol/kg with high molar percentage (87-90 mol%) of acetic acid. As to lactic acid only the L(+) lactic isomer was found in a concentration of about 0.4 mmol/kg. Infusion of low amounts of starch induced mild lactic acid fermentation in the cecum associated with a pronounced increase in the concentration of L(+) and D (-) lactic acid to peak levels of 80 +/- 10 mmol/kg and 7 +/- 1 mmol/kg, respectively. Lactic acid fermentation ceased within 2 to 3 days indicating that the gut microflora had adapted to the starch infusion. Slight decreases of blood pH and bicarbonates in blood as well as a moderate increase of netto acid-base excretion in urine indicated mild changes of acid-base balance, but clinically no pathological symptoms were observed. Higher amounts of infused starch caused pronounced lactic acid production in the large intestine which persisted throughout the experiment. Peak L(+) and D(-) lactic acid concentration in cecal digesta reached on the average 137 +/- 16 mmol/kg and 45 +/- 7 mmol/kg respectively. Significant decreases of blood pH values from 7.41 +/- 0.02 to 7.18 +/- 0.08 (P < 0.001), actual bicarbonate from 28.2 +/- 3.2 to 11.0 +/- 2.6 mmol/l (P < 0.001) and base excess from 3.9 +/- 3.6 to -15.2 +/- 3.8 mmol/l (P < 0.001) were observed. D (-) lactic acid concentration in blood increased to 3.2 +/- 0.4 mmol/l, but L(+) lactic acid values remained unchanged under 1 mmol/l. Clear clinical symptoms of indigestion and intoxication characterized by severe inappetence, ruminal stasis and general weakness were also observed. Typical clinical symptoms of disease as well as blood and urine changes in acid-base balance indicated that lactic acid fermentation in the large intestine contributes considerably to the pathogenesis of acute ruminant lactic acidosis.     

An outbreak of Lawsonia intracellularis infection in a standardbred herd in Ontario

An outbreak of protein-losing enteropathy associated with Lawsonia intracelluaris infection was diagnosed in 6 standardbred foals from a farm in Ontario. Wildlife exposure may have been involved in the perpetuation of disease in this outbreak. The clinical presentation, treatment, outcomes, and pathological findings are described.     

P‐56 Evaluation of the association between Giardia infection and pruritic skin disease in dogs

Intestinal parasites have been anecdotally associated with pruritus in dogs. A relationship was proposed when the elimination of a specific parasite resolved the pruritus, and re‐infection with a parasite caused the pruritus to recur. Ascarids, coccidia, hookworms, tapeworms and whipworms have all been incriminated. Recent reports in the human and veterinary literature have suggested that there may be a relationship between Giardia infection and the development of pruritus and other allergic signs. In order to determine if there is an association between infection with Giardia and pruritus in dogs, faecal samples were collected from 71 pruritic dogs and 101 clinically normal dogs. Three faecal samples from each animal were analysed using a zinc‐sulphate concentration technique for the presence of Giardia cysts, and one randomly selected faecal sample from each dog was analysed with an ELISA for Giardia‐specific antigen. Ten of 101 dogs (9.9%) in the clinically normal group tested positive with the ELISA, and Giardia cysts were detected in the faeces of seven of these antigen‐positive dogs. No Giardia cysts were found in the dogs that tested negative with the ELISA. None of the dogs in the pruritic group tested positive for Giardia by either method. The results indicated a negative association between Giardia infection and pruritic skin disease (P = 0.006). Cephalexin was commonly used in the pruritic group, but not in the control group, and may therefore be an explanatory variable. Funding: Ontario Veterinary College Pet Trust.     

Rhodococcus equi pleuropneumonia in an adult horse

A 10-year-old warmblood gelding was evaluated for intermittent pyrexia, dullness, weight loss, and progressive respiratory disease. Multifocal necrotic pneumonia and pleuritis due to Rhodococcus equi infection was diagnosed. Case management is discussed, as well as factors that may have led to this rare cause of pleuropneumonia in an adult horse.