Current Progressive Dairy digital edition

0209 PD: Feed additives: Which, when and why

Michael F. Hutjens Published on 14 January 2009
Feeding high-producing cows continues to challenge dairy farmers and nutritionists. Also, dairy profit margins vary as milk prices and feed costs shift yearly.

Feed costs represent the largest input cost to produce milk (estimated to be 35 to 50 percent).

Feed additives are a group of feed ingredients that can cause a desired animal response in a non-nutrient role such as pH shift, growth or metabolic modifier.



Several feed additives contain nutrients such as sodium in sodium bicarbonate or protein in yeast culture. Feed additives are not a requirement or guarantee for high productivity or profitability.

Evaluating feed additives at the farm level (4 R’s)
Four factors can be considered to determine if a feed additive should be used:
1. anticipated response
2. economic return
3. available research
4. field responses

Response refers to expected performance changes the user could expect or anticipate when a feed additive is included.

Examples include higher milk yield (peak milk or milk persistency), increase in milk components (protein and fat), greater dry matter intake, stimulate rumen microbial growth, increase digestion, stabilize rumen environment and pH, improve feed efficiency, minimize weight loss, reduce heat-stress effects or improve health (such as less ketosis, reduce acidosis or improve immune response).

Returns reflect the profitability of using a selected additive. If milk improvement is the measurable response, a break-even point can be calculated.


For example, a consultant recommends an additive that raises feed cost 10 cents per day. If milk is valued at 12 cents per 0.45 kilograms, every cow must produce 0.38 kilograms more milk to cover the added cost associated with the additive.

Another consideration is if all cows receive the additive, but only cows fresh less than 100 days respond. Responding cows must cover the additive costs for all cows (responsive and non-responsive cows).

One guideline is an additive should return two dollars or more for each dollar invested to cover non-responsive cows and field conditions, which could minimize the anticipated response.

Research is essential to determine if experimentally measured responses can be expected in the field.

Studies should be conducted under controlled and unbiased conditions, have statistically analyzed results (determines if the differences are repeatable) and have been conducted under experimental designs that would be similar to field situations. Results obtained on individual farms are the economic payoff.

Dairy managers and nutritionists must have data to compare and measure responses.


Several tools to measure results (to evaluate responses on a farm) include DHI milk records (peak milk, persistency, milk components and milk curves), reproductive summaries, somatic cell count data, dry matter intake, heifer growth charts, body condition graphs and herd health profiles which will allow critical evaluation of a selected additive.

Evaluating feed additives at the industry level (7 R’s)
Feed industry personnel and consultants may evaluate feed additive using a slightly different approach; the seven R’s, the basic four R’s as listed above plus:
5. reliability
6. repeatability
7. relativity

Reliability is based on the research database that has been published on a feed additive. It should:
• predict that the product can have a positive response in a wide range of feedings
• establish a normal curve of response in various studies
• minimize the risk of not obtaining a positive benefit-to-cost ration

Repeatability represents the statistical data results (mean and standard deviation).

Each feed consultant must determine what level of risk she or he will assume when selecting each feed additive. The bottom line is the probability of a profitable response. Relativity refers to other products, management changes or on-farm practices that could replace the feed additive being used.

For example, an anionic product could be removed if the nutritionist could reduce close-up ration levels of potassium to less than 1 percent (ration change), adapt a “no dry period” for third and over lactation cows (management change) or drench each three-lactation cow with a calcium gel product (on-farm practice change).

A second aspect of industry selection of a feed additive is which commercial product should be purchased. “Me too syndrome” is a term referring to a product that has limited research, but marketed on the concept that their product is similar or identical to the industry base standard additive.

Conducting unbiased research that can be published in a technical journal can cost $15,000 to $50,000 per trial and require one to three years to complete.

Three different types of “me too” situations can exist in the field.

Situation 1: “Me too” same product
Sodium bicarbonate is an example of this type of product. The “me too” product may be structurally or chemically identical. The initial commercial product has conducted extensive studies, published in scientific journals and established a solid basis for field applications.

A second product appears on the market indicating their product is the same. Sodium bicarbonate is a chemically-defined product. The dilemma is critical to future product development if dairy managers and nutritionists shift to the new and cheaper product.

Situation 2: “Me too” similar product
Yeast cultures are examples of this type of comparison. The “me too” product functions in a similar manner, but are not identical (as in situation one). Dairy farmers and nutritionists can ask for product- specific research data to determine if the feed additive has been evaluated in controlled studies.

Situation 3: “Me too” general product
Silage inoculants are examples of this type of product. The “me too” concept products claim similar benefits and results, but have different components, microbes, enzymes or ingredients.

In the case of silage inoculants, these products can have variable bacterial counts (colony forming units), different bacteria, viability or recommended ways of storing and applying. Dairy farmers and nutritionists need to ask for specific research data for the product.

Evaluating feed additives
Interest in feed additives will continue and will be influenced by new research results, advertising and profit margins. An update on anionic products, biotin and yeast culture illustrate the importance of applying variation principles.

A review of current research on these products, as well as a table that outlines additives in six categories, can be found online at: and will assist dairy farmers, consultants, feed company nutritionists and veterinarians in deciding if an additive should be included.

• Feed additives can be evaluated using the seven R’s for nutritionists and the four R’s for dairy managers.
• Variation in feed additives can be evaluated using repeatability, reliability and relativity.
• Application of the “me too” syndrome is important to future research and product development. PD

References omitted but are available upon request at

—Excerpts from University of Illinois Extension website

Michael J. Hutjens
Department of Animal Sciences, University of Illinois