Don’t buy into myths about mineral/vitamin requirements

Fall and early winter are not the time to cut back on supplements

A reddish tinge on the hide of a black Angus animal could mean a couple things. It could indicate a mineral deficiency or could be just too much sun.

Autumn is a good time for producers to determine the best type of cattle mineral and how they will provide it to their early-gestation beef cows. In doing so, they should avoid five common myths when they consider outside advice. Producers can effectively meet important mineral and vitamin requirements of their cow herd now and in the months ahead.

For example, I was driving down some back roads and saw a herd of Black Angus cattle with a few cows and calves with a rough red sheen to them. I was always taught in school that a red coat colour is a clear sign of copper deficiency. However, it’s a myth that all black cattle with red hair coats suffer from poor copper status. It could be something else such as a bad sunburn, which brings us to our first of five myths:

1. Trace mineral and vitamin deficiencies cause specific deficiency symptoms: Rather than causing clear-cut visible signs, these deficiencies usually underlie general ailments such as increase in sickness. For example, a Colorado study showed that about one-third of pre-conditioned calves that received vaccinations were still getting sick immediately after they entered feedlots. The researchers speculated such morbidity was due to poor mineral supplementation starting with their originating cow-calf herds. I agree, because adequate intake of essential copper, zinc and selenium is part of enzyme systems that irreplaceably support good immune function.

2. Exceeding mineral requirements will promote performance responses: Most of the time once a daily amount of 125-150 mg of copper is provided to most beef cows — it satisfies their vital and performance functions. It should also alleviate any problems with antagonistic minerals, such as molybdenum that binds dietary copper in cattle. The notable mineral and vitamin requirements in gestation beef cows is illustrated in the accompanying table.

3. Cattle minerals with the highest nutrient levels are the best value: As a beef nutritionist, I have reviewed many feed labels of commercial cattle minerals. For instance, mineral A has 3,000 ppm copper and Mineral B has 4,000 ppm copper and both are fed at 50 g per head daily. It doesn’t necessarily mean that Mineral B is the better choice. Sometimes both are good values. In one unrelated incident, I reviewed a cattle mineral that had very high levels of Vitamin A and this could have been the cause of some performance issues that I saw in a set of bred heifers. In another situation, feeding high levels of zinc may have influenced a copper deficiency.

Graphic: National Research Council (1996).

4. Minerals do not have to be fed during early gestation: One of my friends feeds salt blocks (no copper, zinc, selenium or vitamins) to his beef cow herd. Just because they are in early gestation and their weaned calves are sold doesn’t mean that they should ever be deprived of a sound mineral and vitamin program. Granted, their NRC mineral and vitamin maintenance and production requirements are low compared to other times of the year, but they steadily increase until the calving season in the spring.

5. Feeding trace mineral blocks is good enough: Another friend buys trace mineral blocks during the fall in order to save money. He believes the natural vitamins in pasture and harvested hay bales are “good enough” to meet his cow herd’s requirements. I don’t agree, because vitamins A, D and E are often inadequate, variable and degrade over time in all forages. In addition, the quality and level of vitamins in commercial mineral are steady and guaranteed.

As a beef nutritionist, I can appreciate that some of these myths may make sense, but they are pure fiction and should be avoided. I believe an early-gestation cow mineral should be provided (four ounces per head daily) that meets their above respective NRC macro-, trace mineral and vitamin requirements. It’s these cows’ best mineral and vitamin value.

About the author


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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