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How much salt do cows need when on pasture?

Certain questions about salt have got to be licked. If that requires some salty language, so be it.

Cows need salt in their diets but when they’re out on the range, providing it along with other necessary minerals requires attention.

How much salt do cows need?

Alberta Agriculture livestock and forage specialist Barry Yaremcio said the amount depends to a large extent on the type of feed available in the pasture.

However, research conducted by forage specialist Rob Hand in the mid-1990s held some surprises about consumption.

“He found that it was an average of 4.8 days between visits when cows went to the salt and mineral feeder. Yearlings were 2.6 days and calves 3.1 days. So, they come when they feel like it,” said Yaremcio.

“The kicker, though, is the amount that they eat ranged anywhere from one to 770 grams per visit per day. So basically what happened was they stayed away for three or four days and then they just pigged out on the salt-mineral combination.”

Cows ate up to 774 grams per visit and yearlings licked up 816 grams, on average.

“The one that really caught my attention is these calves out on pasture. They ate up to 1,140 grams per day.”

Generally speaking, a 1,300 to 1,400 pound cow requires 35 to 45 grams of salt per day, said Yaremcio. That means a herd of 100 cows should go through a 55 lb. bag of salt-mineral in about a week, as a rough guideline.

Though cattle have the ability to crave salt when they need it, they don’t have the same innate sense when it comes to minerals.

Research in Nebraska tested cows’ nutritional wisdom by putting various minerals in separate pots or feeders. The cows, all given the same alfalfa-brome hay, ended up overindulging in limestone even though their feed was already high in calcium.

“It’s up to us to provide a balance of what’s required,” said Yaremcio, because cattle won’t seek out sources of mineral in which they are deficient.

However, mineral needs vary across Western Canada, he added.

“Many years ago, they determined that cobalt and iodine in Western Canada is virtually non-existent in any feeds that are grown locally,” said Yaremcio. That’s why blue salt, which contains cobalt and iodine, has long been so common.

The region also lacks other vital minerals.

“Across Western Canada, generally copper, manganese, zinc and selenium are deficient.”

That’s why switching from blue salt to a fortified trace mineral product might pay off. Another study by Hand showed a 25 lb. improvement in weaning weights when cows and calves were provided with the latter type.

Yaremcio recommends the use of fortified salt as opposed to blue salt year round, unless mineral is already being delivered in a feed ration.

When it comes to the question of block versus loose salt and mineral, either one works fine in summer, although high winds can sometimes sweep away loose product. If salt boxes aren’t protected from rain, loose salt can also cake up and be hard for cattle to ingest, or partially dissolve and wash away.

However, loose salt-mineral has major advantages in winter.

“When we had –25, –30 degree temperatures, licking on a block of salt is no different than you and me going out to the John Deere tractor and trying to lick the fender,” said Yaremcio.

“You’ll get 25 percent improvement in salt intake in loose form when it’s cold, just because it’s easier for them to eat.”

As for placement of the salt and mineral, he recommends putting it near the loafing or sleeping area if improved intake is desired. That way restless cows have easy access because they eat most of their salt at night.

Cattle don’t like the tastes of phosphorus and magnesium, which are bitter, or calcium, which dries out the mouth. Offering salt and minerals together provides a better chance of sufficient intake.

If they’re still not eating enough mineral, Yaremcio suggests adding dried molasses or another tasty feed to the salt-mineral mix.

“What you want to do is monitor the intake of the salt and mineral so that you adjust the amount of molasses that you include in the mixture to get the right amount of intake on average.”

When buying salt and mineral, Yaremcio recommends checking the labels for the various concentrations to ensure value and correct type.

And need will vary by region. For example, the high molybdenum levels in Manitoba and high sulfur levels in Alberta tend to tie up copper, so a mix with higher supplemental copper is likely to be needed.

Cattle requirements also vary as the grazing season progresses, Yaremcio said. Calcium content in feed tends to decline over summer so the mineral mix may need to be changed accordingly.

Salt content in the water is also a consideration. Some regions of Alberta already have sufficient salt in the water. That might require mineral to be provided in silage or some other feed palatable to the cattle.

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