by Dr. Warren Bohnhoff, DVM

There are many feed additives and supplements on the market that are advertised to help improve cow health and increase production. One that has received much attention is niacin. Recent studies show that niacin does have a positive effect on the health and production of some dairy cows.

Understanding the basics of niacin
The major function of niacin is in the coenzyme forms of nicotinamide, a component of NAD and NADP. Enzymes containing NAD and NADP are important links in a series of reactions associated with carbohydrate, protein and lipid (fat) metabolism. They are especially important in the metabolic reactions which furnish energy to the animal. More than 40 biochemical reactions have been identified involving these coenzymes.

Deficiency - dairy cows
Niacin has been assumed to be synthesized in adequate amounts in the rumen to meet the needs of the dairy cows. However, evidence suggests that this may not be true for the high producing dairy cow in early lactation.

Reports indicate that 50 percent of dairy cows in high production herds go through borderline ketosis during early lactation. Supplementing ketotic cows with six to eight grams of niacin daily had a beneficial effect on the reversal of both subclinical and clinical ketosis.

Other workers have reported that supplemental niacin increased microbial protein synthesis. In one study, researchers reported increased dry matter intake of 1.8 pounds per cow.

Some research with whole cottonseed and heat-treated soybeans suggests that feeding niacin helps correct the dietary oil induced milk protein depression.

Fortification considerations
Much of the niacin in common feeds is in a bound form that is not available to animals. The bio-availability of niacin is 100 percent in soybean meal, zero in wheat and sorghum, and varies between 0-30 percent in corn. In calculating the niacin content of formulated diets, all niacin from cereal grain sources should probably be ignored.

General results of field experiments on niacin supplementation of lactating cows are positive for both milk production and fat test. Also enough positive evidence is available to recommend niacin when herds experience above average incidence of ketosis and fat cow problems. When used as a general dietary supplementation, a level of six grams per day is suggested, beginning at two to three weeks prepartum.

Niacin may help fatty liver
Evidence indicates that niacin inhibits fat mobilization and thus may prevent abnormal deposition of fat in the liver at calving time. Most evidence suggests feeding to be continued eight to twelve weeks after calving.

Be careful of deficiency
Even though niacin is one of several B-vitamins, is water soluble and very little is stored in the body, it is very important in numerous body functions. It is very important to make sure that the high producing cows in your herd have proper niacin levels, especially during early lactation. Two ounces of HP-Bio contains six grams of niacin. Talk to your ANC consultant about the niacin levels and availability in your ration.