Test forage to protect cow health

There is no room for straw in a post-calving ration, when a lactating cow’s protein and energy requirements are 25 percent greater than pre-calving. | File photo

Producers advised to ask for a wet chemistry test on forage samples rather than near infrared reflectance spectroscopy

Low snowfall and relatively dry winter conditions are raising concerns about spring pasture conditions. Ensuring proper nutrition for cows after calving could be more of a challenge than usual.

Livestock nutritionist Barry Yaremcio of Yaremcio Ag Consulting said there is a good quantity of hay available in most areas to get producers through to spring grazing, in whatever shape pastures might be.

However, higher rainfall early in last year’s growing season likely diluted nutrient levels in hay converted to baled forage. It also resulted in low phosphorus content. Nutrient content in hay two years old or more is negligible.

That indicates the importance of testing feed to ensure cows receive the nutrients they need.

“Forage testing is critical, even more so than in what we consider a more normal year, and if you have hay left over from last year or if you’re going to have hay left over this spring to feed in the fall of 2021, that two-year-old hay, all the vitamin precursors will be oxidized out and there’s nothing there to supply to the cow,” Yaremcio told an online session organized by the Battle River Research Group.

“Once you start feeding the two-year-old hay, you have to start feeding vitamins.”

He recommended that producers ask for a wet chemistry test on forage samples, as opposed to the near infrared reflectance spectroscopy (NIRS) test because the former is more accurate.

Results will guide producers on any needed supplementary nutrition.

Yaremcio said there is no room for straw in a post-calving ration, when a lactating cow’s protein and energy requirements are 25 percent greater than pre-calving.

He provided data for two different rations for the average 1,450-pound cow: one with 65 lb. of oat silage and 12 lb. of barley grain; and another with 35 lb. of alfalfa/grass hay and six lb. of barley grain.

“If you’re using oats instead of barley, you’re going to need 10 percent more by weight because oats is typically 10 percent less in energy and 10 percent less in protein.”

That adjustment is not necessary if feeding brown oat varieties that have a higher fat content, he added.

If pasture forage proves short in the coming season, early weaning is an option to ensure cows go into next winter in good condition. Yaremcio said calves can be weaned as early as 120 days.

If that is the plan, those calves should be kept with their mothers in the weaning pen for a few days beforehand so they get familiar with the feed and water. Though the cows will eat the creep feed as well, Yaremcio said it is worth the extra feed and cost to ensure calves manage well at weaning.

He also provided advice on salt and mineral supplements. Consumption is about 25 percent higher on loose material than blocks, which producers need to consider. A herd of 100 cows should consume 25 kilograms of salt per week, as a general guide. Salt should be mixed with any mineral supplement, since cows may crave salt but do not seek out minerals.

“In Western Canada, copper, manganese, zinc and selenium are deficient. There’s no question about that but the deficiency can be anyplace from 50 to 75 percent of what is required,” said Yaremcio.

“Iodine and cobalt are virtually non-existent. You need to feed either a pre-made mineral combination with the higher trace mineral levels or a fortified trace mineral salt with selenium.”

Yaremcio does not recommend use of blue salt.

“If you have a whole bunch of blue blocks, keep them in the shed. Next fall or next winter, when you can see weather is going to get bad, put those blocks of salt up against the front of the box on the truck and leave them there. That way when you’re bucking drifts getting home through a snowstorm you should have enough ballast in the back so you’ve got traction to get home.”

Cows that are thin after their calves are weaned should be fed separately, if facilities and conditions allow, and given grain plus free-choice alfalfa/grass hay.

Though the cost of doing this is higher initially, Yaremcio said a cow that is 200 pounds too light going into winter will need an extra 1,400 lb. of hay just to stay warm. Given that calculation, it is more cost-effective to feed thin cows early to get them into better shape before they face winter conditions.

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