Critical Decisions with Feed Additives

Comments by James I. Sprague PhD Livestock Nutritionist

Why are additives used?

Most feedlot operations consult with nutritionist and veterinarians to evaluate the alternatives for feed additives and nutrient additions to rations. (Costs and benefits are always important.)
Examples of critical decisions are: (1) to stimulate gain and feed efficiency by feeding the ionophores Rumensin, Bovatec, or Cattlyst, (2) for control of liver abscesses and some improvement in feed efficiency by feeding Tylan or low levels of tetracyclines, (3) control of respiratory diseases with a high level of tetracyclines (CTC and OTC), or a combination of Aureomycin and Sulmet called AS700, (4) controlling coccidiosis by using Deccox or other product, (5) “direct fed microbial” including yeast cultures to stimulate rumen action and/or lower tract digestion, and finally (6) an extra level of a nutrient like iodine or zinc.

Nutrition levels and management affect additives used.

Feed additives are not a substitute for good ration and bunk nutrition. Starting rations may need different additives than growing or finish rations. For example in my former consulting work some of our clients used Bovatec and Aureomycin in the starting ration and Rumensin and Tylan in the finish ration. In another case we used Deccox in the starting ration and Rumensin/Tylan in the finish rations. High energy rations that contained ground alfalfa hay complicate the incidence of feedlot bloat, so Rumensin/Tylan combination was selected. Deccox and Aureomycin can be use together.

Combination of additives

The major feed additives have Food and Drug clearances to be used in combination. The best examples are Rumensin/Tylan and Bovatec/Aureomycin. There are no restrictions about using microbial additives along with the pharmaceutical additives.

Selection…Rumensin vs. Bovatec

It is recognized by many feeders and their nutritionist that Rumensin not only gives the improvement of feed efficiency, but also controls feedlot bloat in many cases. It also is an important feed additive because it is cleared with Tylan for superior control of liver abscess. Caution…be sure to keep the horses away from the bunk if Rumensin is used since it is toxic to horses.

Bovatec, the other major ionophores in use in the US, also gives outstanding feed efficiency and is cleared with Aureomycin for the broad spectrum health benefits including modest control of liver abscesses. With Bovatec, I suggest the maximum feeding rate to help control feedlot bloat. (Note this clearance for Bovatec/Aureomycin is specific for Aureomycin and not a generic chlortetracycline.) Bovatec would work well in finish rations with roughages other than ground alfalfa hay.

Extra level of a “buffer” plus iodine & zinc.

In some cases an extra level of a feed ingredients, such as finely ground limestone, dolomite limestone (Min-Ad), or sodium bicarbonate, may be used like a feed additive to help assist in overcoming a management problem of rumen acidosis. Organic iodine (EDDI) and zinc methionine (ZinPro) are routinely used to help control foot rot. (Caution…maximum iodine level is controlled by FDA.)

Make sure it is legal.

This is one of the roles of the consulting nutritionist is to recommend not only efficacious additives but to assist feedlots to make sure the levels and combinations are legal.