Journal of Veterinary Internal Medicine最新文献

Background: Omeprazole preparations vary in bioavailability in horses.

Hypothesis/objectives: To characterize the pharmacokinetics and pharmacodynamics of an existing enteric-coated oral omeprazole paste (REF) and a novel, in-feed, enteric-coated dry granule preparation (NOV).

Animals: Twelve Standardbred/Thoroughbred mares free from clinical disease.

Methods: A prospective, blinded randomized interventional study was trial, conducted in 3 parts: (a) bioavailability study, (b) dose titration study, and (c) comparative clinical pharmacodynamic study, each using a blocked crossover design.

Results: Consistent with the larger dose administered, Cmax (median, 1032 ng/mL; range, 576-1766) and AUC0-24 (median, 63.9 μg/mL*min; range, 42.4-152.4) were greater after single oral administration of NOV than REF (282.7 ng/mL; range, 94.8-390.2, and 319 23.8 μg/mL*min; range, 8.2-42.3, respectively; both P = .004). No differences were observed between products for absolute oral bioavailability (NOV 55% range, 15-88; REF 17% range, 10-77; P = .25). Treatment with both preparations was associated with reduced gastric squamous ulcer scores and increased pH of gastric fluid. Bioequivalence was demonstrated for pharmacodynamic measures with the exception of % time pH <4, despite differences in dose rate and subsequent plasma omeprazole concentrations.

Conclusions and clinical importance: The findings of this study indicate that the NOV product would be a suitable alternative to the reference product, and confirm that plasma concentrations of omeprazole and omeprazole dose do not predict drug pharmacodynamics in horses.

Background: Bovine respiratory disease (BRD) is a major problem affecting beef cattle after arrival to feedlots. Alternatives to antibiotics are needed for prevention.

Hypothesis: Stimulation of pulmonary innate immune responses at the time of arrival to a feedlot reduces the occurrence and severity of BRD.

Animals: Sixty beef steers at high risk of BRD.

Methods: Randomized, double-blinded, placebo-controlled study. Calves received saline or a lysate of Staphylococcus aureus and Escherichia coli by aerosol, at 16 hours after feedlot arrival. Calves were monitored for 28 days for disease outcomes and levels of Mycoplasma bovis and Mannheimia haemolytica in nasal swabs.

Results: Death from M bovis pneumonia was significantly greater in lysate-treated animals (6/29, 24%) compared to controls (1/29, 3%; odds ratio = 10.2; 95% confidence interval [CI] = 1.1-96.0; P = .04). By 28 days after arrival, 29/29 lysate-treated calves had ultrasonographic pulmonary consolidation compared to 24/29 control calves (P = .05). Lysate-treated calves had lower weight gain compared to control calves (-8.8 kg, 95% CI = -17.1 to -0.5; P = .04), and higher body temperatures on days 4, 7, and 21 (0.19°C; 95% CI = 0.01-0.37; P = .04). Nasal M bovis numbers increased over time and were higher in lysate-treated calves (0.76 log CFU, 95% CI = 0.3-1.2; P = .001).

Conclusions and clinical importance: Aerosol administration of a bacterial lysate exacerbated BRD in healthy high-risk beef calves, suggesting that respiratory tract inflammation adversely affects how calves respond to subsequent natural infection with M bovis and other respiratory pathogens.

Background: Marked strong ion (metabolic) acidosis in neonatal diarrheic calves usually is corrected by IV administration of NaHCO₃ . The distribution space for IV-administered bicarbonate, called the apparent bicarbonate space (ABS), appears to depend on initial plasma bicarbonate concentration (cHCO₃ ) and varies considerably in calves.

Objective: To determine whether ABS was associated with initial plasma cHCO₃ and other acid-base variables.

Animals: Twenty-five neonatal diarrheic calves with acidemia and metabolic acidosis.

Methods: Prospective observational study using a convenience sample. Calves received NaHCO₃ (10 mmol/kg) and glucose (1.4 mmol/kg) IV in a crystalloid solution at 25 mL/kg over 60 minutes. The ABS (L/kg) was calculated at 4 time points over 2 hours after the end of the infusion. The relationship between ABS and initial acid-base variables was characterized using nonlinear, linear, and stepwise regression.

Results: The median value for ABS calculated from the initial plasma cHCO₃ increased from 0.53 L/kg (range, 0.40-0.79) at the end of IV infusion to 0.96 L/kg (range, 0.54-1.23) 120 minutes later. Data obtained at the end of infusion provided the best fit to initial plasma cHCO₃ and jugular venous blood Pco₂ , such that: ABS = 0.41 + 1.06/cHCO₃ and ABS = 0.87-0.0082 × Pco₂ .

Conclusions and clinical importance: The observed median value for ABS of 0.53 L/kg in our study was similar to the empirically used value of 0.6. However, ABS values varied widely and were increased in calves with severe metabolic acidosis. We therefore recommend calculating ABS using the initial plasma cHCO₃ or venous blood Pco₂ , if respective measurements are available.

Background: Refractometry is used to assess transfer of passive immunity (TPI), but studies evaluating different refractometers and appropriate thresholds for recommended target immunoglobulin G (IgG) concentrations for beef calves are limited.

Objectives: To evaluate test performance of digital (DSTP) and optical (OSTP) serum total protein (STP) refractometers and a digital Brix (DBRIX) refractometer for assessment of passive immunity in beef calves.

Animals: A total of 398 beef calves from 6 herds, 1 to 7 days of age.

Methods: Serum IgG concentration was estimated by DSTP, OSTP, and DBRIX, and measured by radial immunodiffusion (RID). Correlation coefficients (r) among results were calculated. Optimal STP and Brix thresholds for identification of IgG <10, <16, and <24 g/L were determined using interval likelihood ratios. Refractometer performance and agreement were assessed using areas under the curve (AUC), diagnostic test characteristics, Cohen's kappa (κ), and Bland-Altman analysis.

Results: Refractometer results were highly correlated with RID (r = 0.82-0.91) and with each other (r = 0.91-0.95), and overall test performance was excellent (AUC = 0.93-0.99). The STP concentrations of ≤5.1, ≤5.1, and ≤5.7 g/dL and Brix percentages of ≤7.9%, ≤8.3%, and ≤8.7% indicated IgG concentrations <10, <16, and <24 g/L, respectively. Agreement of refractometers with RID was variable (κ = 0.46-0.80) and among refractometers was substantial (κ = 0.62-0.89).

Conclusions and clinical importance: All refractometers showed good utility as monitoring tools for assessment of TPI in beef calves.