Don't Take Vitamins for Granted
Livestock Update, November 2003
Mark L. Wahlberg, Extension Animal Scientist, VA Tech
Cattle normally do not need much in the way of supplemental vitamins as long as they are eating a diet consisting of green forage. This forage may be either in stored form or as pasture. The key vitamins of concern with cattle are:
In addition, forages which are more advanced in maturity have a greatly reduced level of carotene, thus much less Vitamin A. It would seem that much of the hay made this year contains a lower level of Vitamin A activity than normal.
Vitamin A can be added to feeds. It can also be injected into cattle. Cattle require at least 30,000 International Units (IU) of Vitamin A daily.
Cattle require about 3000 IU of Vitamin D daily. It can be added to feeds and also injected.
Cattle require 50 to 150 IU daily. It can be fed or injected. Injectible Selenium products also contain Vitamin E.
Toxicity of these 3 vitamins is unlikely. The risk of toxicity is least with Vitamin E, in fact toxicity of cattle to Vitamin E has not been demonstrated. Vitamin D toxicity results in high blood Calcium and abnormalities in bone mineralization. Vitamin A toxicity is also quite rare, in part because the rumen microbes are able to break down Vitamin A that is consumed in the diet directly.
Based on this background information these recommendations concerning vitamin supplementation for cattle have been developed:
Trace mineral mixes are the typical form in which vitamins are supplemented to cattle. If cattle consumed an average of 4 ounces of mineral daily, and using the required amounts of vitamins described previously, we can calculate the concentration of these vitamins which are needed in trace mineral mixes. Those calculated values are approximately: Vitamin A = 120,000 IU / pound of product, Vitamin D = 12,000 IU / pound of product, and Vitamin E = 150 to 500 IU / pound of product.
However, due to the several reasons listed above, the recommended levels of vitamins in trace mineral products for cattle should be quite a bit higher. Toxicity is very unlikely, vitamins break down in storage, and intake of mineral products is quite difficult to accurately predict.
Recommended Levels of Minerals in Cattle Trace Minerals
(For Cattle Consuming Pasture and Hay Based Diets)
Vitamin A at 150,000 to 200,000 IU per pound,
Vitamin D at 20,000 to 50,000 IU per pound,
Vitamin E at 200 to 250 IU per pound
These levels in mineral products should provide adequate vitamin supplementation even when cattle are consuming over mature, lower quality forage for long periods of time. If cattle are being fed in dry lot, especially with rations containing high grain levels, a different approach to vitamin supplementation should be followed. Consult with a nutritionist when feeding cattle in these situations.
Because of the close association of Vitamin E and Selenium, you should also be looking at that item on the feed tag of a product you are considering feeding. Many Virginia producers operate on soils which are low in Selenium, thus the forages grown on those soils are also low in Selenium. Cattle should be fed a trace mineral which contains from 25 to 50 ppm of Selenium (also expressed as 0.0025 to 0.0050%).
Vitamins are not expensive to include in a mineral product. Because the hay that will be fed this winter may be quite a bit lower than normal for vitamins, deficiency may occur if proper vitamin supplementation is not provided.