The objective of this study was to develop prediction models for the serum IgG concentration in critically ill calves based on indirect assays and to assess if the predictive ability of the models could be improved by inclusion of age, clinical covariates, and/or laboratory covariates. Seventy-eight critically ill calves between 1 and 13 days old were selected from 1 farm. Statistical models to predict IgG concentration from the results of the radial immunodiffusion test, the gold standard, were built as a function of indirect assays of serum and plasma protein concentrations, zinc sulfate (ZnSO4) turbidity and transmittance, and serum γ-glutamyl transferase (GGT) activity. For each assay 4 models were built: without covariates, with age, with age and clinical covariates (infection and dehydration status), and with age and laboratory covariates (fibrinogen concentration and packed cell volume). For the protein models, dehydration status (clinical model) and fibrinogen concentration (laboratory model) were selected for inclusion owing to their statistical significance. These variables increased the coefficient of determination (R2) of the models by ≥ 7% but did not significantly improve the sensitivity or specificity of the models to predict passive transfer with a cutoff IgG concentration of 1000 mg/dL. For the GGT assay, including age as a covariate increased the R2 of the model by 3%. For the ZnSO4 turbidity test, none of the covariates were statistically significant. Overall, the R2 of the models ranged from 34% to 62%. This study has provided insight into the importance of adjusting for covariates when using indirect assays to predict IgG concentration in critically ill calves. Results also indicate that ZnSO4 transmittance and turbidity assays could be used advantageously in a field setting.

OBJECTIVE To evaluate physical compatibility of small animal (SAE) and large animal (LAE) injectable formulations of enrofloxacin with select IV fluids and drugs. SAMPLE 162 admixtures containing SAE or LAE with saline (0.9% NaCl) solution, lactated Ringer solution (LRS), Plasma-Lyte A (PLA), 6% hydroxyethylstarch 130/0.4 (HES), metoclopramide, or ampicillin-sulbactam. PROCEDURES In the first of 2 simultaneously conducted experiments, admixtures containing enrofloxacin (10 mg/kg) and a volume of IV fluid that would be administered over a 20-minute period when dosed at the maintenance infusion rate (40 mL/kg/d for saline solution, LRS, and PLA and 20 mL/kg/d for HES) were created. In the second experiment, enrofloxacin (10 mg/kg) was admixed with saline solution (40 mL/kg/d) and metoclopramide (2 mg/kg/d) or ampicillin-sulbactam (30 mg/kg). In both experiments, admixture components were infused into a flask over 20 minutes assuming patient weights of 5, 10, and 20 kg. Admixtures were created by use of undiluted SAE and SAE diluted 1:1 with saline solution and undiluted LAE and LAE diluted 1:1 and 1:10 with saline solution. Admixtures were assessed for physical incompatibility at 0, 15, 30, and 60 minutes after completion of mixing. Physical incompatibility was defined as gross precipitation, cloudiness, Tyndall effect, or change in turbidity. RESULTS Admixtures containing undiluted SAE or LAE were physically incompatible with saline solution, PLA, LRS, and HES. Because saline solution was used to dilute SAE and LAE, all admixtures containing diluted SAE or LAE were also physically incompatible. Physical compatibility of enrofloxacin with metoclopramide or ampicillin-sulbactam could not be assessed because those admixtures also contained saline solution. CONCLUSIONS AND CLINICAL RELEVANCE Enrofloxacin was physically incompatible with all tested solutions.

Salmonella stained antigen has been widely used in Malaysia for detection of Salmonella infection in poultry. Growth phase of four Salmonella enterica serovar Pullorum (SP 9-25, SP 14/11, SP 690/79 and SP 7107/07) used in the antigen production were investigated based on colony enumeration and turbidity. This study aimed to determine the growth curve and the difference between S. Pullorum isolates based on turbidity measurement and spread plate technique for optimisation towards biomass production of salmonella antigen using bioreactor. Current production of the antigen used conventional methods and the number of bacterial cells is low and with several other drawbacks. The isolates were cultured in nutrient broth, incubated aerobically with constant shake for 48 hours to determine the lag, exponential, stationary and the death phase of the bacteria. Turbidity of the bacterial cells was measured using spectrophotometer and the colony was counted using total plate count every four hours. Based on the colony forming unit per milliliter, SP 690/79 strain showed the fastest growth where this bacteria achieved its mid-exponential growth at 8 hours. This is followed by SP 14/11 where this strain demonstrated the mid-exponential growth at 12 hours. The other two strains (SP 9-25 and SP 7107-07) are the slowest growth where their mid-exponential growth was measured at 14 hours. However, SP 690/79also the fastest strain entering the death phase which demonstrates the difference growth of the S. Pullorum strains. This study demonstrates that each S. Pullorum strains multiplying and dying at different phase though in the same serovar.