Cows Need Salt to Avoid Grass Tetany
Salt helps neutralize nitrates causing grass tetany.
by Heather Smith Thomas
Grass tetany, or grass staggers, affects mature cattle grazing lush forage after weather changes, like freezing early spring pastures or sudden growth after rainfall following drought.
This problem is associated with magnesium deficiency, calcium deficiency and excess potassium in the blood of affected animals. During cool, wet conditions or regrowth after frost or drought damage, sodium levels in certain forage plants plummet, while nitrogen and potassium levels spike. Recommended prevention has been supplemental dietary magnesium. Many producers feed high levels to try to prevent losses. Standard treatment for acute cases has been oral and/or intravenous magnesium.
After examining cattle lost in 2001 following spring frosts in the Midwest, Thomas Swerczek, a veterinary pathologist in the Department of Veterinary Science at the University of Kentucky (UK), found more clues about the cause and prevention of grass tetany.
A few years earlier, he collaborated with William McCaw, a veterinarian working with several purebred herds trying to find answers to health problems. Swerczek found a farm with healthy cattle where the owner was feeding loose salt rather than mineral mixes. Most farmers in that area fed mineral mixes and salt/mineral blocks, and he found that cattle often overate mineral mixes to get the little bit of salt in them.
The farmer with healthy cattle wasn’t feeding any magnesium.
“He’d been in the cattle business more than 40 years and had never had a case of grass tetany,” says Swerczek.
“This was a hint that maybe it wasn’t necessary to feed magnesium to prevent grass tetany. Later, when I got several problem herds off the mineral mix, they quickly turned around. Most of the cows had been suffering from diarrhea, wasting away, and within 24-48 hours they improved, after giving them plain loose salt instead of mineral,” he adds.
He was working with a herd of about 1,000 Angus and drove through that farm with the manager. They came across a cow that had been down for several days in spite of multiple treatments with magnesium and calcium.
Swerczek had some sea salt and put it in front of that cow. Three hours later she’d gotten up and wandered off. There were other cattle in the herd showing signs of grass tetany and going down. “I told the manager to put a handful of salt in front of them or get it into their mouths. Those cows came out of it,” he says.
“We had massive losses in Kentucky one year due to an unusual winter with warm spells. Grass and clover grew early, then we had a hard freeze in April. Cattle went down by the thousands with grass tetany and bloat. People were using bloat blocks, but this didn’t help, because they didn’t have salt. The farmers who had salt out didn’t lose cattle,” says Swerczek.
The reason cows go down with grass tetany is that they are short on magnesium and calcium, but he admits he didn’t know why salt worked. Then he discovered a connection between grass tetany and nitrates.
“We’d been taught that nitrate is not toxic — that nitrite is the problem, but I found that nitrate is 100 times more important in grass tetany than nitrite,” he says.
Why it works
The body must get rid of nitrate and it does this through the cations (ions having a net positive charge), especially sodium. “When there isn’t adequate salt in the blood, the body grabs onto the most available cation, which would be magnesium and then calcium,” he explains. When the spike of nitrate occurs — when the cow consumes frost-damaged forage — her body uses magnesium to combine with and get rid of the nitrate, which depletes the body’s magnesium, and this is why she goes down.
“If there’s enough salt available, the body can grab onto the sodium and cows don’t go down with grass tetany. If they don’t have salt on the day this hits, they go down. It has to be there all the time and it can’t be hard salt blocks because cattle can’t eat enough when they suddenly need it.”
Swerczek found that on some farms — even though farmers supplied salt — cattle weren’t eating enough of it. Potassium level in grass was spiking (15 times higher than normal) after a hard frost, especially when lush and highly fertilized.
“Since the cation potassium and sodium are so close together, these minerals can substitute for one another. When potassium spikes, even though cattle have salt available, they won’t eat it because the body thinks they already have enough.” They are sodium-starved, but their bodies didn’t know the difference between excess amount of potassium and too little sodium.
“The body is usually able to keep sodium levels within normal range, but when it drops, you only have a few hours before that animal dies. If you feed salt, and the animals eat it, they’ll be fine — as long as they have plenty of water,” Swerczek says.
Editor’s Note: Heather Smith Thomas is a cattlewoman and freelance writer from Salmon, Idaho.
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FAQs
“If there's enough salt available, the body can grab onto the sodium and cows don't go down with grass tetany. If they don't have salt on the day this hits, they go down. It has to be there all the time and it can't be hard salt blocks because cattle can't eat enough when they suddenly need it.”
How to prevent grass tetany in cows? ›
Feeding high magnesium or high “mag” mineral supplements is the preferred method to reduce the occurrence of grass tetany. High mag mineral mixes are available at most feed stores and contain higher inclusions of magnesium oxide than other complete mineral mixes.
Why does a cow need salt? ›
Salt is a necessary mineral that needs to be consumed daily by the cow. This mineral plays many roles in the overall function of the cow. These functions are things like reproduction, aid in proper nerve and muscle functions, blood flow, body pH regulation, water retention, and even sweating.
What happens if cows don't get salt? ›
Sodium deficiency in ruminants can cause reduced appetite, reduced water intake, weight loss, reduced milk production and pica (an appetite for substances that are largely non-nutritive). Milk is 87 percent water, so a cow that is not drinking enough water will have a significant drop in milk production.
What causes tetany in cows? ›
Grass tetany occurs when there is not enough magnesium in the blood. Adequate magnesium levels are required for proper brain and nerve function. The magnesium status of cows depends mainly on the balance between the amount of magnesium absorbed from the rumen and that lost in the milk.
How to treat calcium deficiency in cows? ›
To prevent calcium deficiency, do not dehorn your cows. Let the cows have some sun in the cool hours, so they will produce vitamin D and absorb more calcium. Feed the cows with legume fodders, maize fodder and tree leaves that are rich in calcium. Give them a mineral mixture in either the drinking water or feed.
How do you prevent tetanus in cattle? ›
Prevention. Undertaking surgical procedures (such as castration) properly, in a clean environment, with disinfected instruments and surgical area, will significantly reduce the risk of tetanus. The same rules apply to calving, be as clean as possible and minimise contamination.
Why do animals need salt? ›
Animal feed salt for intake of extra minerals
Sodium and chloride must not be lacking. Sodium is important for the functioning of the central nervous system, while chloride regulates the balance between acids and bases in the stomach. Together these two essential nutrients keep the fluid balance at the right level.
Do cows need salt in the winter time? ›
Some basic recommendations for winter mineral supplementation programs are: Always provide trace mineralized salt as a minimum. Supplement phosphorous when forage is dormant unless distiller's grain is being used as a protein source.
What is the best salt for cows? ›
Maclik Mineral Brick is suitable for all classes and species of livestock. The Brick has a moderate content of Copper and Cobalt together with a satisfactory level of all the important trace minerals. The bulk content is common salt.
Daily salt requirement for mature cattle is less than 1 oz/head/day; however, voluntary intake often exceeds minimum needs. Because there are practical limits to the amount of salt cattle eat, salt can be used to restrict the consumption of highly palatable feeds such as grains and supplements.
Are salt licks bad for cows? ›
When consumed in the right amounts, Champion's Choice® Salt, in the form of salt licks or feed, can help your beef cattle maintain normal appetite and body weight, as well as help increase feed consumption and weight gain in heifers and stockers by promoting faster growth.
Do cattle need salt in the summer? ›
If you feed salt or trace mineralized salt as a supplement during the summer, you may think that you are giving cattle what they need — but, while cattle do need salt, their nutritional needs are not necessarily met by salt blocks or trace mineralized salt blocks alone.
How do I stop tetany? ›
Care and Treatment
If you have a mild case of hypocalcemia, the most common cause of tetany, your provider may suggest the following treatments to restore healthy calcium levels: Calcium supplements. Vitamin D supplements. Magnesium tablets.
What triggers tetany? ›
Tetany usually is caused by low calcium levels, and hypoparathyroidism that causes low calcium levels also causes long term tetany.
What is the prognosis for grass tetany in cattle? ›
Grass tetany is considered a serious emergency disease as death can occur within hours of clinical signs. In many cases, animals may be found dead in the morning, becoming clinical during the overnight.
How do I know if my cow has grass tetany? ›
for most farmers, the first sign of a grass tetany outbreak is finding dead cows. Usually there is froth from the mouth and nose, and the ground is rubbed where the animal's legs moved violently before she died. Excitement and muscular spasms (tetany) are the most common symptoms.
How do you prevent mineral deficiency in cattle? ›
The best way to make sure a deficiency doesn't sneak up on your herd is to offer a complete cattle mineral at all times. Purina® Wind and Rain® Minerals are expertly-formulated and balanced to maximize trace mineral absorption, paying dividends through optimized herd performance.
How do you prevent copper deficiency in cattle? ›
Copper supplementation can be administered by oral drench, injection, in licks, feed and water, and by administration of fertilizer on to pasture. Good quality feed (lucerne hay) will contain copper. Be careful when supplementing animals with copper to avoid inadvertent overdosing which may result in copper poisoning.
How do you prevent white muscle disease in cattle? ›
To prevent white muscle disease within four weeks after birth, cows are given 15 mg of selenium, usually as sodium selenite four weeks before calving. To prevent the delayed type, calves are given 5 mg of selenium at two to four weeks of age and twice more at monthly intervals.
