Feed Additives for Dairy Cattle

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 (Hutjens, 1991). Several feed additives contain nutrients, such as sodium in sodium bicarbonate or protein in yeast culture. Feed additives are not a requirement, nor are they a guarantee for high productivity or profitability.

 

Four factors can be considered to determine if a feed additive should be used: anticipated response, economic return, available research, and field responses (Hutjens, 1991). Response refers to expected performance changes the user could expect or anticipate when a feed additive is included. Several examples are listed below:

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 .45 kg, every cow must produce .38 kg 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 nonresponsive cows). One guideline is an additive should return $2 or more for each dollar invested to cover nonresponsive cows and field conditions that 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 (to determine whether 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.

 

Feed industry personnel and consultants may evaluate feed additives using a slightly different approach; the 7 R’s include the basic 4 R’s as listed above, plus reliability, repeatability, and relativity.

Reliability is based on the research database that has been published on a feed additive:

Repeatability represents the statistical data results (mean and standard deviation). Each feed consultant must determine what level of risk 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 ration levels of potassium to less than 1 percent, adapt a “no dry period” for third- and over-lactation cows, and/or drench each three lactation cows with a calcium gel product.

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 products that have limited research and results, but are marketed on the concept that the products are identical to the industry-based standard. One example is sodium bicarbonate, a chemically defined product that has no unique processing to make it more soluble or rumen active versus inert.

 

Interest in feed additives will continue and will be influenced by new research results, advertising, and profit margins. Table 1 outlines additives in six categories with information that will assist dairy farmers, consultants, feed company nutritionists, and veterinarians in deciding whether an additive should be included. Current status is classified in the following ways:

 

Table 1. Feed additive guidelines for dairy cows.

 

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