Serum protein concentrations in horses with severe liver disease: a retrospective study and review of the literature.

The present retrospective study was undertaken to determine the frequency of hypoproteinemia and hypoalbuminemia in horses with natural occurring severe liver disease. The study represents a review of case records and laboratory data of 84 horses presented with acute or chronic liver disease to the University of California Veterinary Medical Teaching Hospital between 1973 and 1991. Forty horses (48%) had serum protein concentrations above the maximum reference value (7.7 g/dL). The increase in serum protein concentration was associated with hyperglobulinemia (P = .00005, R2 = .80). Only 13% (11/84) of the horses had serum albumin concentrations below the minimum reference range (2.5 g/dL), and hypoproteinemia was found in only 1 of these horses. Of these, 18% (9/51) of the horses with chronic liver disease and 6% (2/33) of the horses with acute liver disease had albumin concentrations below the minimum reference value. Globulin concentrations in 64% of the horses (54/84) were above the maximum reference value (4.0 g/dL). The present study indicates that hypoproteinemia and hypoalbuminemia are not common features in horses with severe liver disease.

A clinical trial of probiotic administration for prevention of Salmonella shedding in the postoperative period in horses with colic.

The purpose of this study was to evaluate the effects of probiotic administration on the prevalence of fecal shedding of Salmonella, the prevalence of postoperative diarrhea, the length of antimicrobial therapy, and the length of the hospitalization stay during the postoperative period in horses with colic. Two commercially available probiotics for horses were used in a double-blind prospective study of 200 horses undergoing surgery for colic. Probiotic or placebo was administered PO once a day for 7 days postoperatively, and fecal cultures for Salmonella were obtained daily for 10 days. After selection of 186 patients completing the treatment protocol, the results indicated that the commercial probiotic formulations had no effect on Salmonella shedding, prevalence of diarrhea, length of antimicrobial therapy, or length of hospitalization (P > .05). Twenty percent of the horses yielded 1 or more positive fecal cultures for Salmonella; of these horses, 74% were classified as asymptomatic shedders. Twenty-six percent of all horses had fluid diarrhea postoperatively, with only 12% of these horses having positive fecal cultures for Salmonella. The most common isolate was Salmonella krefeld (24 of 39 isolates). Among the different gastrointestinal disorders, horses with feed and sand impactions appeared to be more prone to shed Salmonella.

Total serum bile acids and the bile acid profile as tests of liver function.

Total serum bile acid assay for the evaluation of liver function has been available for many years but its application has been limited primarily by factors such as methodology, equipment and cost. New and improved methods for bile acid assay such as the radioimmunoassay or the hydroxysteroid dehydrogenase techniques have brought the assay for bile acids into the realm of the clinical laboratory. The efficacy of bile acids for clinical diagnostic use in the evaluation of liver function has not been firmly established. Newer methods using high pressure liquid chromatography to develop a profile of the different bile acids may clarify its usefulness and define its role among the many available tests of liver function in animals.

Quinidine administration increases steady state serum digoxin concentration in horses.

The aim of this study was to determine if quinidine administration increases steady state serum digoxin concentration in horses. Digoxin (0.01 mg/kg q. 12 h per os) was administered to 6 horses for 7 days. Steady state was confirmed by identifying statistically indistinguishable peak and trough serum digoxin concentrations on Days 4, 5, and 6. On Day 6, serum digoxin concentration was measured at baseline and 0.25, 0.5, 1, 2, 4, 6, 8 and 12 h after digoxin administration. On Day 7, quinidine (20 g at baseline and 10 g at 2, 4 and 6 h) was administered per os and serum digoxin concentration was measured at the same time intervals. Creatinine and renal digoxin clearances were measured on Days 6 and 7. Results indicated that there was approximately a doubling of serum digoxin concentration (from mean +/- s.d. 2.57 +/- 0.96 ng/ml at baseline to 4.28 +/- 1.31 at 15 min and 5.98 +/- 1.21 ng/ml at 30 min) after starting the administration of quinidine. This elevation persisted for the 12 h after starting quinidine administration. Renal digoxin and endogenous creatinine clearances decreased but the decrease in digoxin clearance was greater. Serum quinidine concentration achieved the therapeutic range (2-6 micrograms/ml) in 5 of the 6 horses. In summary, similar to findings in other species, quinidine administration increases steady state serum digoxin concentration in horses and this occurs, at least in part, due to a decrease in renal digoxin clearance. Some of the decrease in renal clearance is due to decreased glomerular filtration which is dissimilar to findings in other species.