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Elements of a “good” winter mineral

Cow-calf mineral requirements vary with time of year

It won’t be long before most cow-calf operators will be bring their cow herd home from pasture to overwinter. They should also be shopping for a good beef cow mineral.

I think of a “good” overwintering cow mineral as one that helps meet the mineral and vitamin requirements of the early- to mid-gestating beef cow by complementing those nutrients found in forages and feedstuffs fed until the calving season. It should be tasty to cows and reasonably priced, which in today’s market is between 11 to 15 cents per head, daily.

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In contrast, a “bad” overwintering cow mineral fails in what a “good” mineral does well. A poor mineral often contains excessive levels of inexpensive ingredients such as limestone and salt as well as low levels of more expensive essential nutrients such as phosphorus and vitamins. Its’ nutrition usually reflects a bottom-barrel price of less than 10 cents per head per day.

To avoid penny-pinching regret later on, this is how I build a good cattle mineral from the ground up.

First, I balance a cow mineral for calcium (Ca) and phosphorus (P). An average gestating beef cow needs 25 grams of Ca and 18 grams of P per day. In order to complement typical Prairie mixed forages; a cattle mineral fed at 70-80 grams per head might contain nominal calcium, but should contain at least seven to eight per cent phosphorus. As cows approach calving, a new breeder-type mineral might be formulated with higher eight to 12 per cent P, because pre- and post-calving cows’ requirement increases by 25-50 per cent.

I often have a built-in buffer over basic gestation cow mineral requirements to account for environment, which can take this mineral up to 10 per cent Ca and 10 per cent P. In such a case, there might be more calcium than needed (without compromising health and nutrition), but it is necessary in order to take advantage of more economical phosphorus sources such as dicalcium phosphate.

Aside from meeting these Ca and P levels, our good overwintering cow mineral will probably not need added potassium (K), since Prairie forages often contain high to excessive levels beyond the cows’ requirement. In addition, magnesium (Mg) levels in overwintering forages are modest, so I add only low levels to a gestation cow mineral, however, I have no problem adding more magnesium during periods of grass tetany in early spring. Likewise, I like to see about 10 per cent salt added to assure adequate mineral intake, even though most producers put out loose or block salt to meet this requirement.

While such Ca, P, K and Mg are formulated in percentages in our good cow mineral, adequate levels of trace minerals are added in part per million (ppm) and should follow NRC recommended levels for gestating beef cows. On a complete feed basis, we should supply: copper – 10 ppm, zinc – 30 ppm, manganese – 40 ppm, cobalt – 0.1 ppm, iodine – 0.5 ppm and selenium – 0.3 ppm.

Nutrients need to be available

The success of trace mineral supplementation is not only based on their concentration in the overall diet, but their biological availability. Once they reach every cow’s digestive tract, the source of essential trace minerals should have good absorption and once inside the cow’s tissues should be well retained and metabolized. Their bioavailability should also not be reduced by antagonistic elements inadvertently consumed by beef cows.

Most trace minerals added to standard gestation cow mineral are usually from rock sources. These sources have limited bioavailability, but are acceptable for meeting the essential trace mineral requirements of pregnant cows within a few of months from calving. Afterwards, some producers change to a breeder-type cow mineral formulated with organic/chelated trace minerals to assure pre-calving cows will achieve higher respective requirements. Such two-tier mineral feeding programs are the result of years of sound university research, which showed performance and health benefits during the gestation and subsequent calving season.

Aside from meeting macro- and trace-mineral levels from acceptable rock or even organic sources, we should not overlook supplementation of the essential fat-soluble vitamins A, D, and E in a good gestation mineral. About 100,000 IU of vitamin A, 5,000-10,000 IU of vitamin D and 50-200 IU of vitamin E should be fed to each beef cow, daily.

From these macro-, trace- mineral and vitamin parameters, our good overwintering cow mineral needs one more thing — “good” and consistent feed intake. Either fed loose, mixed with grain or a total mixed diet; most cattle mineral should be eaten at the rate of two to four ounces (56-112 g) to prevent most related deficiencies. If salt is added by the producer and makes up at least 25 per cent of the purchased cattle mineral, then cattle mineral should be provided accordingly.

Today, I find many beef producers are not shopping for the lowest formulated/cost cattle mineral, but a good cow mineral that helps their overwintering gestation cows meet their respective mineral and vitamin requirements for optimum performance.

About the author

Columnist

Peter Vitti is an independent livestock nutritionist and consultant based in Winnipeg. To reach him call 204-254-7497 or by email at [email protected]

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