The one good thing about the 2024 growing year is that it has provided a lot of talking points.  This year there is a significant possibility that nitrates could be an issue in some harvested forages.  Elevated plant nitrate levels are the result of the plant’s inability to convert soil nitrate into plant proteins due to growth being slowed by environmental conditions.  Soil nitrates are taken up through the roots and once in the plant are converted to nitrite, then ammonia, then amino acids, and finally to plant proteins.  Virtually all of our forage crops are susceptible to excessive nitrate accumulation.  Some are more susceptible than others, and fields where there were high weed populations can increase the problem.

Anything that can slow plant growth, can lead to a buildup of plant nitrates.  Drought, cold temperatures, and even excessive cloud cover all slow the plant’s biological processes and prevent normal plant conversions.  The greatest risk is when these occur during or immediately following pollination.  However, just because there are stress conditions does not mean that the nitrates in the plant will be high.  If the soil moisture is low the plant will have difficulty taking up the nitrates.

If it isn’t your normal practice, this year it would be advisable to add nitrate testing to your forage analysis.  As with any forage contaminant, the impact that it could have on animal health is dependent on the species and stage of production.  For nitrates, pigs are the most susceptible, followed by cattle, sheep, and horses.  Also, young and old stock alike are more at risk. The following are guidelines for nitrate concentrations:

Guidelines for nitrate concentrations

• <0.1% Nitrate-N (dry matter basis): Feed is safe
• 0.2% Nitrate-N (dry matter basis): Feed is probably safe, limit to no more than 50% of the diet for pregnant animals
• 0.2 to 0.35% Nitrate-N (dry matter basis): Do not feed to pregnant animals, limit to less than 50% of diet for other animals
• >0.35% Nitrate-N (dry matter basis): High risk, should not be fed.

Since we rely on the conversion of nitrates in the plant during growth, nitrate levels will not be reduced in harvested forages.  However, fermentation can reduce the concentration of nitrates in silage from 10 to 65%.   Hay and fermented feeds that are marginal-to-high in nitrates will need to be blended with low nitrate forages to reduce the percentage provided in the final ration.  These ingredients should be well blended to prevent the animal from getting a “slug” of high nitrate forage.  If you are unable to blend the forages, feed a low nitrate forage first.  Allow the animal to fill up on the lower nitrate forage and then provide the higher nitrate product later in the day.

Programs on salmonella and birthing management

I would like to remind you of our programs that will be held between now and the holidays.  On November 14^th, we will host a program with the OSU College of Veterinary Preventive Medicine called “Busting Salmonella”.  The program will discuss BMP’s for the management of Salmonella dubin and general disease control and prevention in dairy calves.  It will be held at Fisher Auditorium on the OSU-Wooster campus from 9:00 AM to noon.  The event is free, but we ask that you submit a courtesy registration by calling our office.

I also have two dystocia/birthing management clinics scheduled for mid-November and early December.  The first is on November 19^th and will be geared toward small ruminant producers and the second is on December 3^rd for cattle producers.  Both programs will run from 6:00 PM to 8:30 PM at Fisher Auditorium on the OSU CFAES Wooster Campus.  The programs will discuss: the normal birthing process, potential causes of birthing complications, correcting mispresented fetuses, and how to deal with post-birthing complications.  In addition to the presentations, you will get a chance to practice providing assistance with our dystocia/birthing simulators.  The programs are free and we ask that you make a courtesy reservation by calling the OSU Extension office.  As always, I hope that you have a safe and prosperous harvest season.  If you have any questions or would like to register for one of our programs, please contact me at 330-264-8722 or yost.77@osu.edu.

John Yost is an extension educator IV, Agriculture and Natural Resources, at OSU Extension-Wayne County.
This article was previously published in The Daily Record.