Evaluation of nitrate and prussic-acid risk in annual forages submitted by producers to a commercial forage testing laboratory in Nebraska

My objective was to determine whether there is a relationship between nitrate (NO3-N) toxicity risk and prussic-acid (HCN) toxicity risk in annual forages for grazing livestock. Throughout the grazing seasons in 2021, 2022, and 2023, livestock producers submitted annual forages known for accumulating both NO3-N and HCN to Ward Laboratories Inc. (Kearney, NE). Properly submitted samples were tested for both NO3-N and HCN (n = 201). Regression analysis and ANOVA were performed. Additionally, samples were broken down by “risk of toxicity” to determine whether risk of ruminant animal health issues was related to NO3-N and HCN. Average NO3-N concentration was not statistically significantly different by forage specie group; however millet was lower in HCN compared with other forage species. Samples submitted in November were lower in NO3-N than samples submitted in August, September, and October (Figure 2). However, there was no statistical difference in HCN concentration based on the month samples were submitted. The concentrations of NO3-N and HCN were not correlated (R2