Evaluating a field nitrate test for sudangrass hay to prevent nitrate poisoning


Schlegel ML. 2009. Evaluating a field nitrate test for sudangrass hay to prevent nitrate poisoning. In Ward A, Treiber K, Schmidt D, Coslik A, Maslanka M, Eds. Proceedings of the Eighth Conference on Zoo and Wildlife Nutrition, AZA Nutrition Advisory Group, Tulsa, OK.


The objective of this study was to compare a field nitrate test using two different test strips to the hay nitrate concentrations determined at a commercial laboratory. Twelve samples of sudangrass hay collected in 2006 through 2008 were used to compare the nitrate concentration determined at a commercial laboratory using the RQflex Reflectometer method to those determined by a field nitrate test. A 1 g ground hay sample was weighed into a 250 ml Erlenmeyer flask. To the flask, 100 ml of distilled deionized water was added and the solution shaken for 30 s. The hay was allowed to soak for 30 min, with the flask shaken every 10 min. After 30 min, the solution was tested with either Precision Nitrate Test Strips (Precision Labs, Inc., Cottonwood, Arizona 86326) or with Quick Dip Aquarium Test Strips Nitrate/Nitrite (Jungle Laboratories Corp. Cibolo, Texas 78108). Microsoft Excel was used to calculate a Paired, two-tailed T-test and the relationship (r2) between the results of the field nitrate test using the Precision or Quick Dip test strips to the results determined at the commercial laboratory. The results determined with Quick Dip test strips had a greater relationship to those determined by the commercial laboratory than the those using the Precision test strips (r2 = 0.92 and 0.88, respectively). The improved precision using the Quick Dip test strips was due to the greater color change associated with increasing nitrate concentration allowing the technician to more accurately estimate the concentration.

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