by: Stephen B. Blezinger

Part 4

Over the last few issues we have taken an in-depth look at vitamin nutrition in beef cattle – primarily those cattle in the cow-calf sector of the production pipeline. As we look past the breeding and calf production part of the industry and consider the next stages, stocker, preconditioning/background and feedlot stages we start seeing a need for more than just the basics – A, D and E.

In general, we seldom supplement other vitamins to breeding cows. There generally isn't a great need since, under normal circumstances, the rumen bacteria will synthesize all the B-vitamins necessary for the cow. As long as she is on a predominately forage-based diet, vitamin synthesis occurs as an acceptable level. But the emphasis here is under NORMAL conditions. Over the last two to three years cattle producers have seen a lot of abnormal conditions, mostly related to drought conditions. These low moisture and subsequently poor forage conditions created situations that were anything but normal. In situations such as these other supplemental dietary vitamins may be necessary.

Additional vitamin levels may also be necessary for growing calves as they are weaned and enter the next production stages. This creates a significant amount of stress on the animal. In some cases this results in significant digestive upset. In some cases this can result in depression of rumen function. Again, in these situations vitamin synthesis in the rumen may be depressed resulting in deficiency for a period of time until the animals rumen is “straightened out.”

Finally, in the feed lot stages, cattle are moved onto a high grain diet with very little forage fed. Again, due to low dietary forage, additional vitamins are often needed to balance the animals needs and to potentially offset problem conditions like polioencephalomacia (PEM) that can be addressed my adding thiamin to the diet.

These are a few examples of why we have to look beyond the basic vitamin A, D and E.

Other Vitamins of Concern

There are quite a number of other vitamins that bear consideration in beef cattle diets. Vitamins K and C have long been known to play an important role in mammals. Likewise, the B-vitamins are also well known to be critical, especially when in short supply. The following list breaks out the B-vitamins (also known as the B-vitamin complex) by their letter as well as the name they are also known by:

Vitamin B1 -- Thiamine

Vitamin B2 -- Riboflavin

Vitamin B3 -- Niacin

Vitamin B5 -- Pantothenic acid

Vitamin B6 -- Pyridoxine

Vitamin B7 -- Biotin

Vitamin B9 -- Folic acid

Vitamin B12 -- Cobalomin/


There are other vitamins that have been identified but our understanding of their role in cattle nutrition is so limited that they are not covered here.

Vitamin K

As with many of the water-soluble vitamins in cattle on most high forage diets, the rumen bacteria make vitamin K in quantities to meet the needs of cattle under most conditions. One exception to this is when cattle are fed moldy sweet clover hay or silage as well as other moldy legumes. These harvested and stored plants, when contaminated by certain types of mold can produce Dicumarol (the active substance found in some rat poisons). Dicumarol can interfere with the function of vitamin K in the production of prothrombin by the liver (Vitamin K is essential to prothrombin production). Prothrombin is necessary for proper blood clotting in the animal and low levels lengthen clotting time and can contribute to internal bleeding. This can especially be a problem if the animal becomes injured are requires a surgical procedure (including basic processing such as dehorning or castration.)

Care should always be taken if it appears that legume sources may not have been harvested and put up properly resulting in molding of the forage material. Proper curing and or the use of a preservative (buffered propionic acid or a prop acid blend) will guard against this potential problem. In the event of an occurrence, however, vitamin K administration and removal of the moldy feed are the most effective ways to overcome this condition.

No definitive guidelines exist for cattle requirements for vitamin K in the animal's diet. If a potential problem exists, contact your veterinarian and a cattle nutritionist for assistance with feeding rates.

Vitamin C

We've all been told by our mommas to eat oranges or other citrus fruits as a good source of vitamin C. Vitamin C has long been known as an effective antioxidant as well as an immune system “stimulant” which can help ward of infections such as the common cold virus. Commonly dietary vitamin C is completely destroyed in the rumen of healthy animals. Research into the use of C in stressed cattle diets, however, has shown some effectiveness in helping these animals offset some of the immune response depression common with the stresses of weaning, transportation and handling. Vitamin C supplementation in milk replacers has improved the health of young calves.

As with Vitamin K, no definitive guidelines exist for dietary requirements for Vitamin C in cattle.


The B-vitamin complex includes thiamin, biotin, riboflavin, niacin, pantothenic acid, pyridoxine, folic acid, vitamin B12 and choline, all of which are known as water-soluble vitamins. Once the rumen becomes functional, bacterial synthesis is considered to supply the normal requirement of cattle. Milk is a source of B-vitamins for the calf. But while the rumen provides for much of the cow's B-vitamin requirements, as indicated above, many circumstances indicate a need for supplementation in the animal's diet.

Most research of B-vitamins in cattle has involved dietary supplementation. Because dietary B-vitamins are often destroyed in the rumen, many studies probably did not succeed in truly affecting B-vitamin status of the animal. However, supplementation of receiving cattle with dietary B-vitamins has improved performance and health during the first 30 days on feed. Most of the benefit seems to occur from supplementation during the first 10 days after receiving. Animals most likely to benefit from B-vitamin supplementation are those with increased requirements related to stress or disease and reduced intake. Ruminal production of B-vitamins is highly correlated with energy consumption. Most B-vitamins are not stored in substantial amounts and therefore vitamin status could become depleted if feed intake is low and requirements high in the stressed or sick calves. As an example, feeder calves hauled ~1000 miles had very low blood concentrations of vitamin B6; even a mild respiratory infection (IBR) significantly reduced blood levels of B6, pantothenic acid, B12 and vitamin C.

A common deficiency symptom of most B-vitamins is depressed appetite. Consequently, B-vitamin injections are often given to sick cattle as insurance. Effectiveness of B-vitamin injections has not been proven. The overall effects of stress and disease on B-vitamin status in cattle are not known, but this information is crucial for development of effective B-vitamin injectables and related protocols.

Cattle with reduced intakes due to stress or disease may suffer from short-term B-vitamin deficiencies, due to reduced synthesis, increased requirements, and limited reserves of B vitamins within the body. Preliminary evidence suggests that activating the immune system to fight off infection or develop immunity rapidly depletes B-vitamins important to the immune response.

Some comments about specific B-vitamins:


Thiamin deficiency in the form of polioencephalomalacia (PEM) occurs occasionally in cattle, most commonly in cattle fed high grain diets. It results from destruction of thiamin in the rumen by a thiamin-degrading enzyme or production of compounds structurally similar to thiamin (analogs) that block the action of thiamin. Thiamin is required to activate enzymes involved in carbohydrate metabolism and is particularly important for normal brain function. Symptoms of deficiency include reduced appetite, apathy, incoordination, progressive blindness, convulsions and death. The head may be bent towards the back. The disease is reversible if treated before the brain is severely damaged. The treatment is intravenous or intramuscular injection of thiamin (thiamin hydrochloride or other forms). Normal dosage rates are 200 to 500 milligrams for calves and up to 1000 to 2000 mg for adult cattle. Most injected thiamin is excreted within 24 hours. As such, multiple injections of thiamin (two to four times a day for up to two days) are occasionally recommended. Of all the B vitamins, thiamin is usually the most limiting on grain diets.

The presence of high sulfur levels in the diet have been shown to reduce thiamin levels, i.e. creating a thiamin deficiency. Supplemental thiamin in the diet has shown to improve animal performance and offset the signs of conditions such as PEM.

Vitamin B12

Vitamin B12 is manufactured by rumen bacteria. It contains the trace element cobalt, which must be provided in the diet. Cobalt concentrations in feeds are not well known and therefore cattle diets are supplemented with cobalt at approximately 0.1 ppm to ensure adequate production of vitamin B12. Vitamin B12 is the only B-vitamin stored in substantial amounts in the liver. When animals are transported or stressed, the breakdown of body tissue, including liver, increases blood concentrations of vitamin B12. Ruminal production of vitamin B12 is lowest, and production of B12 analogs is highest, on grain-based diets (as compared to forage-based diets). Vitamin B12 deficiency is unlikely unless diets are deficient in cobalt for a prolonged period. The symptoms can include poor appetite, retarded growth, and poor condition.


Niacin is an essential component of two important enzyme co-factors (NADH, NADPH). These molecules are involved in more than 200 reactions in the metabolism of carbohydrates, fatty acids, and amino acids. Niacin supplementation of cattle on corn grain or corn silage diets has improved gain and feed efficiency by up to 5 and 10 percent respectively, and appears to be useful in adapting cattle to urea.

Choline supplementation of rations for fattening cattle has appeared to increase performance in Washington State trials, but has not been effective in most other areas of the United States. Niacin has also been shown to improve performance of feedlot cattle.


You can tell from this discussion that we know a lot about vitamin nutrition in cattle. This discussion also tells you that we have much left to learn. Remember that in feeding vitamins a little can go a long way. Always make sure you have highly accurate information when determining what levels you need to be feedings.

Dr. Steve Blezinger is and nutritional and management consultant with an office in Sulphur Springs Texas. He can be reached at 667 CR 4711 Sulphur Springs, TX 75482, by phone at (903) 885-7992 or by e-mail at [email protected] For more information please visit us on Facebook at Reveille Livestock Concepts.

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