Poster
Stocking the cattle producers toolbox: on-farm guidance for preventing cattle death loss due to nitrate poisoning from contaminated water sources
| Date/Time: |
9/11/2025
|
| Author: |
Brittany A Hirsch |
| Clinic: |
Kansas State University College of Veterinary Medicine |
| City, State, ZIP: |
Manhattan, KS 66502 |
B.A. Hirsch, BS
;
C.J. Hanthorn, DVM, MS
;
S. Charnas, DVM
;
M.W. Sanderson, DVM
;
S.A Fritz, DVM, DABVT
;
1College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506
2Center for Outcomes Research and Epidemiology, Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506
3Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506
4Kansas Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506
Introduction:
Nitrate toxicosis from consumption of contaminated drinking water is a common cause of acute death in cattle. Water sources can become contaminated by fertilizer runoff or hauling water in tanks that have previously contained fertilizer. Semi-quantitative colorimetric test strips are used to test nitrate levels in human drinking water but are not widely utilized to test livestock water sources. Quantitative testing of contaminants in cattle drinking water is not routinely practiced, likely due to lengthy turn-around times that are not conducive to timely decision making. Quantitative testing is most commonly utilized following a toxicosis event. The use of test strips is potentially a quick and inexpensive alternative to help cattle producers avoid catastrophic losses. The objective of this study was to determine if commercially available semi-quantitative colorimetric test strips designed for human drinking water can be used as a high sensitivity screening test to identify elevated nitrate concentrations in water samples for the purpose of preventing nitrate toxicosis in cattle.
Materials and methods:
Six commercially available brands of test strips were used to measure nitrate concentrations in water samples with known concentrations. Water samples containing 0, 50, 75, 100, 250, and 500 ppm nitrate were prepared, and concentrations were verified via ion chromatography. Ten volunteers, blinded to test brand and with no prior experience using the nitrate test strips, were instructed to test the water samples and record the nitrate levels according to the manufacturer-provided instructions and color scale. No significant observer (p=1.0) or observer sex (p=0.656) effect was identified. Concentrations were dichotomized where ≥100 ppm nitrate was considered as a positive sample and <100 ppm nitrate was a negative sample, resulting in a 50% proportion of positive samples. Test strip performance was analyzed for sensitivity, specificity, and false negative risk (at 50% prevalence).
Results:
Sensitivities of the tests ranged from 22.5% to 97.5%. False negative risk of the tests (at 50% prevalence) ranged from 55.71% to 96.67%. Two test strip brands had high values for sensitivity (≥90%), with few false negative test results. Two other test strip brands had low values for sensitivity (<50%), and the remaining two brands had moderate sensitivity values. All test strip brands were purchased for less than $1.00 per test strip.
Significance:
A high level of variability in accuracy exists among commercially available test strip brands, highlighting the disparity in quality among available test strips. Due to this variability, some of the tested brands of colorimetric strips appreciably outperformed others as a screening tool for nitrate concentration; therefore, cattle producers should be judicious when purchasing and utilizing test strips. High accuracy brands may serve as a useful and economical tool for cattle producers and veterinarians to utilize for on-farm water safety screening; whereas low-accuracy brands could potentially be hazardous due to a risk of false negative test results. Confirmatory testing is still recommended in cases where water nitrate concentrations approach 100 ppm. The judicious selection and use of semi-quantitative nitrate test strips has the potential to help cattle producers prevent catastrophic losses due to nitrate contamination of water sources.
