High levels of nitrate in feed can be deadly for cattle, cause spontaneous abortions and early delivery. If cattle are lucky enough to be able to survive nitrate poisoning, it can take quite awhile for them to recover. Nitrates are linked to hundreds of cow deaths in the state of Missouri alone. With the long winter and hay shortages in certain parts of the country, many farmers are giving feed that they wouldn’t normally. What do you need to know to prevent nitrate poisoning in your cattle?
Nitrates Linked to Cow Deaths
An article from the University of Missouri Extension that was published in Hay & Forage Grower warns of nitrates in hay causing cow deaths. Livestock specialist Eldon Cole of Mount Vernon, Missouri shared two recent cases of hay toxicity during a MU Extension teleconference. In one case, a farmer fed forage to his 70 cows. The next day, 40 were dead. In another case, 20 cows died. In both instances, producers had used nitrogen or poultry litter to increase forage growth the previous fall.
It’s been a tough winter. Shortages of quality hay and grass followed droughts starting way back in 2017 and lasted through last summer. Hay shortages have been an ongoing challenge in some parts of the country. Pair that with a long winter, and scenarios like Cole described are sadly, somewhat expected. Many farmers are feeding hay they would not normally feed because of the shortages. But farmers need to use caution when feeding hay from unknown sources.
Nitrates Aren’t Always Evenly Distributed
It’s advised to pay close attention when feeding Sudan grass, millet, barnyard grass or other forage not usually baled for hay. High levels of nitrate can concentrate in grass, usually in the stems. It’s important to remember that nitrates in the grass aren’t always evenly distributed. University of Missouri Veterinary toxicologist Tim Evans says,
“In one case, with 14 dead cows, a farmer sent four hay samples,” Evan said. “Two samples had no nitrate, one had moderate nitrate, while the fourth had toxic levels over 1 percent nitrate.”
How it Happens
Nitrate converts to nitrite in the cow’s rumen. Then, nitrite in the blood blocks oxygen uptake. As a result, death or abortion can occur very quickly.
In the last month alone, Evans says that he’s aware of 150 confirmed cases of cows dying due to consuming hay with toxic nitrate levels. It’s extremely important to test forage and form safe rations.
“Testing low-quality forage for nitrate is urgent,” Evans said. “We’re trying to get word out. Producers need to know potential problems.”
Oat Hay Concerns
John Dhuyvetter, Extension livestock systems specialist at the North Central Research Extension Center near Minot, North Dakota says that oat hay can also be high in nitrates. That’s especially true if it’s grown under stressful conditions like drought. NDSU News recently published an article with tips on how to reduce the nitrates in oat hay.
“With the droughty summer in central and western regions of the state, it is not surprising some cattlemen are finding nitrate levels in oat hay that are of concern,” Dhuyvetter says.
The most important thing is having the forage tested. It’s recommended to dilute oat hay with low nitrate feeds if the oat hay as anywhere in between 1,500 to 3,500 parts per million (ppm) of nitrate nitrogen. If you have pregnant cows, nitrate levels below 1,000 ppm are considered safe. Hay with less than 1,500 ppm are considered safe for all other classes of cattle.
“Oat hay testing 2,500 ppm of nitrate, if fed at only a fourth of the ration, would bring the ration to 625 ppm and well below the level for animal safety,” Dhuyvetter says. “However, it means all animals must eat an equal mix of feeds and no cow gets an opportunity to eat primarily the high-oat hay. Grinding and blending through a mixer helps ensure this is the case.”
Another way to do it is to introduce very limited amounts of high-nitrate feed, and slowly increase it to an acceptable limit. Feeding a small amount over grain that’s easily digested can help reduce nitrate absorption.
Test, Test, Test
To avoid unnecessary cattle loss, make sure that you’re giving high quality feed. Have it tested. Remember that nitrates in grass isn’t always evenly distributed. Watch out for higher nitrates in oat hay, Sudan grass, millet, barnyard grass or other forage not usually baled for hay.
In a related Ag Nook story titled, “Hay Market Stakeout“, learn about regional differences impacting hay prices.
Also be sure to check-out this popular Ag Nook article titled, “Cut Down Cattle Feed Costs with these Tips“.