Evaluation of the Relationship of Time of Day to Forage Nitrate Levels
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This study evaluated how nitrate levels in forage sorghum change throughout the day. Samples were taken every two hours from 8am to 6pm from four quadrants of a field on two separate days. The samples were analyzed for nitrate levels. The results showed no significant variation in nitrate levels due to time of day. However, there was a difference seen between the nitrate levels of samples taken on different days. The study will be repeated in the summer of 2008 to obtain more data.
![Evaluation of the Relationship of Time of Day to Forage Nitrate Levels LeValley, * R.C. 1 ; Pettijohn, M.B. 2 ; Selk, G.E. 3 ; Gallaway, M.R .4 ; Highfill, G.A. 5 ; New, M.G. 6 ; Zhang, H. 7 1. Extension Area Livestock Specialist, Oklahoma State University, Duncan, OK 73533 2. Extension Educator, Agriculture, Oklahoma State University, Grady County, Chickasha, OK 73018 3. Extension Animal Reproduction Specialist, Oklahoma State University, Stillwater, OK 74078 4. Extension Educator, Oklahoma State University, Stephens County, Duncan, OK 73533 5. Extension Area Livestock Specialist, Oklahoma State University, Enid, OK 73701 6. Extension Educator, Oklahoma State University, Comanche County, Lawton, OK 73501 7. Professor, Plant and Soil Sciences, Oklahoma State University, Stillwater, OK 74078 Abstract Forage sorghums are used by Oklahoma cattle producers for summer grazing or harvested for hay. While they can be very productive and high quality, they can also accumulate toxic levels of nitrate when stressed. Based on the assumption that the plant continues soil nitrate uptake during nighttime hours, followed by accelerated conversion of the nitrate to protein during daylight hours, Extension recommendations have been to wait until afternoon to cut forage sorghum for hay if anticipated nitrate levels are marginally high. To evaluate the significance of the change in nitrate concentration in forage sorghums during the day, samples were collected at two hour intervals from 8:00 am to 6:00 pm. A cooperator’s field was divided into quadrants. Two were sampled on day one and the remaining two quadrants sampled on day two. Three random samples, consisting of ten stems each, were taken from each quadrant at the specified interval, resulting in 18 samples per quadrant. The samples were analyzed at the OSU Soil, Water and Forage Analytical Laboratory (SWFAL) to determine the level of nitrates, (ppm NO3). Results were analyzed using SAS analysis of variance, with time of day, day, and interactions, as the potential sources of the variation in nitrates. There was no significant variation due to time of day; however there was a difference between days. The study will be repeated in the summer of 2008 to gain additional data. ,[object Object],[object Object],[object Object],Nitrate Toxicity in Ruminants Nitrate(NO 3 ) is converted to Nitrite (NO 2 ) in the rumen. Nitrite is absorbed through the rumen wall into blood stream. Nitrite converts Hemoglobin to Methemoglobin = reduced Oxygen transport. Oxygen supply to tissue decreases and asphyxiation occurs. ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Results In this trial, there was no significant relationship between time of day and nitrate levels in forage, there was however a difference in days. The study will be repeated in the summer of 2008 to gain additional data.](https://image.slidesharecdn.com/nitrate-time-of-day-poster-nacaa-08-1220375188116929-8/85/Evaluation-of-the-Relationship-of-Time-of-Day-to-Forage-Nitrate-Levels-1-320.jpg)
