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Abstract

Objective

To determine optimal zinc sulfate test solution concentration tor detecting failure ot passive transfer in calves.

Animals

235 calves (1 to 8 days old) from a calf-rearing operation in central Washington state.

Procedure

Zinc sulfate turbidity tests, using 200-, 250-, 300-, 350-, and 400-mg/L test solutions, were performed on calf serum. These increasing concentrations were evaluated for detection of failure of passive transfer Using 1,000 mg of IgG,/dl as the threshold for adequate passive transfer, sensitivity, specificity, and accuracy of classification were determined by comparing the zinc sulfate test results with serum IgG, concentration (mg/dl) measured by radial immunodiffusion.

Results

The 200-mg/L zinc sulfate turbidity test solution was 100% sensitive; however, specificity was only 25 5% Increasing concentrations of zinc sulfate test solution up to 350 mg/L improved specificity with either no change or small decreases in sensitivity.

Conclusion and Clinical Relevance

The endpoint of the traditional 208-mg/L zinc sulfate turbidity test for failure of passive transfer in calves is too high. Increased test solution concentrations improve specificity with only minor adverse effects on sensitivity. (Am J Vet Res 1996;57:1711–1713)

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To examine stability of -glutamyltransferase (GGT) activity in stored serum from neonatal calves.

Animals

10 commercial beef calves between 36 and 60 hours old.

Procedure

Serum samples were obtained from the calves, and each sample was divided into 8 aliquots. Serum GGT activity was measured on day 0 (fresh) and days 1, 2, 3, and 4 of refrigerated storage (4 C) and weeks 1, 2, and 3 of frozen storage (−20 C).

Results

Serum GGT activities for each of the refrigerated aliquots did not significantly differ from day zero, with serum GGT activity (expressed as a percentage of initial activity) > 99% on all 4 days. Serum GGT activity in frozen aliquots decreased significantly after 1 and 2 weeks of frozen storage, 97 and 98%, respectively; however, this decrease in GGT activity was not biologically significant. The observed GGT activity did not decrease significantly in the samples stored frozen for 3 weeks; these samples retained 99% of initial activity.

Conclusion

The observed stability of serum GGT activity indicates that serum may be obtained, stored, and batch processed at a later time. This stability during storage is important to the success of a bovine passive transfer monitoring program based on GGT activity. (Am J Vet Res 1997;58:354-355)

Free access
in American Journal of Veterinary Research

Objective

To examine the ability of several commonly used tests for evaluation of passive transfer of immunoglobulin to predict mortality in dairy replacement heifers.

Design

Prospective observational study.

Animals

246 dairy replacement heifers between 1 and 8 days of age.

Procedure

Using serum samples obtained from each calf, total serum protein concentration and results of zinc sulfate turbidity, sodium sulfite turbidity, radial immunodiffusion, and glutaraldehyde coagulation were determined. Calves were monitored for 100 days, and relative risks for death were calculated. Logistic regression models predicting death also were developed.

Results

None of the logistic regression models detected a significant association between test results and mortality. The greatest relative risks of mortality were observed in calves with serum protein concentrations < 4.5 g/dl, serum IgG, concentrations < 500 mg/dl, and sodium sulfite test scores < 1+.

Clinical Implications

Calves with lower passive transfer values had increased risk of death; however, failure of passive transfer is not an infallible predictor of mortality. (J Am Vet Med Assoc 1996;208:2047-2049)

Free access
in Journal of the American Veterinary Medical Association