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.

Take-Home Messages

  • Dairy managers must evaluate each feed additive based on the “4 R” approach.
  • Feed manufacturers should add an additional “3 R’s” when selecting feed additives.
  • Each dairy manager must evaluate the choices of available feed additives and determine if a product is warranted.

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Evaluating Feed Additives at the Farm Level (4 R’s)

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:

  • Higher milk yield (peak milk and/or milk persistency)
  • Increase in milk components (protein and/or fat)
  • Greater dry matter intake
  • Stimulate rumen microbial synthesis of protein and/or volatile fatty acid (VFA) production
  • Increase digestion in the digestive tract
  • Stabilize rumen environment and pH
  • Improve growth (gain and/or feed efficiency)
  • Reduce heat stress effects
  • 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 .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.

Evaluating Feed Additives at the Industry Level (7 R’s)

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:

  • the ability to predict that the product can have a positive response of a wide range of feeding
  • 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 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.

Feed Additive Guidelines

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:

  • Recommended: include as needed
  • Experimental: additional research and study are needed
  • Evaluative: monitor on individual and specific situations
  • Not recommended: lacks economic responses to currently use
Table 1. Feed additive guidelines for dairy cows.
Anionic Salts and Products
1. Function: Cause the diet to be more acidic, increasing blood calcium levels by stimulating bone mobilization of calcium and calcium absorption from the small intestine.
2. Level: Reduce DCAD to –50 meq/kg using chloride sources (calcium chloride, ammonium chloride, Bio Chor, Animate, Soy Chor 44, Soy Chor 16, Nutro Clor, and hydrochloric acid treated feeds).
3. Cost: 40 to 75 cents per dry cow per day depending on product used
4. Benefit to Cost Ratio: 10:1
5. Feeding strategy: Feed to dry cows two to three weeks before calving. Adjust dietary calcium levels to 150 grams per day (50 grams inorganic). Raise dietary magnesium levels to 0.4%.
6. Status: Recommended
Aspergillus oryzae
1. Function: Stimulate fiber-digesting bacteria, stabilize rumen pH, and reduce heat stress.
2. Level: 3 grams per day
3. Cost: 3 cents per cow per day
4. Benefit to Cost Ratio: 6:1
5. Feeding strategy: High grain diets, low rumen pH conditions, and under heat stress (cows) and calves receiving a liquid diet.
6. Status: Evaluative
1. Function: Improve hooves by reducing heel warts, claw lesions, white line separations, sand cracks, and sole ulcers and increase milk yield through a metabolic route.
2. Level: 10 to 20 milligrams per cow per day for six months to one year
3. Cost: 8 to 10 cents per cow per day
4. Benefit to Cost Ratio: 4:1
5. Feeding strategy: Herds with chronic foot problems may require supplementation for six months before evaluation, and company recommends beginning supplementation at 15 months of age.
6. Status: Recommended
1. Function: Improve reproductive performance, immune response, and mastitis control.
2. Level: 200 to 300 mg per day
3. Cost: 10 cents per cow per day
4. Benefit to Cost Ratio: Not available
5. Feeding strategy: In early lactation and during mastitis-prone time periods
6. Status: Not recommended
Calcium Propionate
1. Function: Increase blood glucose and calcium levels.
2. Level: 120 to 225 grams
3. Cost: 80 cents per 454 grams
4. Benefit to Cost Ratio: Not available
5. Feeding strategy: Feed seven days prepartum to seven days postpartum or until appetite responds; unpalatable.
6. Status: Recommended
Protected Choline
1. Function: A methyl donor used to minimize fatty liver formation and to improve fat mobilization.
2. Level: 15g per day
3. Cost: 30 cents
4. Benefit to Cost Ratio: 2:1 (when protected)
5. Feeding strategy: Feed two weeks prepartum to eight weeks postpartrum to cows experiencing ketosis, weight loss, and high milk yield
6. Status: Recommended (rumen protected)
1. Function: Increase fiber digestibility by reducing fiber (cellulase and xylanase enzymes) and DM intake.
2. Level: Not clearly defined (enzymatic units per unit of feed dry matter).
3. Cost: 15 to 25 cents per cow per day
4. Benefit to Cost Ratio: 2 to 3:1 (Canadian data)
5. Feeding strategy: Increase fiber digestibility, treated 12 hours before feeding, spray on product more effective when applied to dry diets, and may be diet specific.
6. Status: Experimental
Magnesium Oxide
1. Function: Alkalinizer (raises rumen pH) and increases uptake of blood metabolites by the mammary gland raising fat test.
2. Level: 45 to 90 grams per day
3. Cost: 21 cents per pound
4. Benefit to Cost Ratio: Not available
5. Feeding strategy: With sodium-based buffers (ratio of 2 to 3 parts sodium bicarbonate to 1 part magnesium oxide).
6. Status: Recommended
Methionine Hydryoxy Analog
1. Function: Minimize fatty liver formation, control ketosis, and improve milk fat test.
2. Level: 30g per cow per day
3. Cost: $1.60 per 454 grams
4. Benefit to Cost Ratio: 2:1
5. Feeding strategy: Feed to cows in early lactation receiving high levels of concentrate and limited dietary protein.
6. Status: Evaluative
1. Function: Improve feed efficiency for lactating cow, reduce ketosis and displaced abomasums in transition cows by shifting rumen fermentation and microbial selection.
2. Level: 11g to 22g per ton of total ration dry matter consumed (250 to 400 mg/cow /day)
3. Cost: 3 cents per cow per day
4. Benefit to Cost Ratio: 5:1
5. Feeding strategy: Feed to dry cows (reduce metabolic disorders) and lactating cow (feed efficiency) while monitoring milk components to evaluate optimal levels of monensin.
6. Status: Recommended
Niacin (B3, Nicotinic Acid, and Nicotinamide)
1. Function: Coenzyme systems in biological reactions, improve energy balance in early lactation cows, control ketosis, and stimulate rumen protozoa.
2. Level: 6g per cow (preventive and prepartum) and 12g per cow (treatment and postpartum) unprotected, 2 to 3 grams protected.
3. Cost: 1 cent per gram (6 to 12 cents per cow per day) unprotected, 10 to 12 cents protected
4. Benefit to Cost Ratio: 6:1 (6 grams level)
5. Feeding strategy: High producing cows in negative energy balance, heavy dry cows, and ketotic-prone cows fed two weeks prepartum to peak dry matter intake (10 to 12 weeks postpartum).
6. Status: Evaluative
Probiotics (Bacterial Direct-Fed Microbes)
1. Function: Produce metabolic compounds that destroy undesirable organisms, provide enzymes improving nutrient availability, or detoxify harmful metabolites.
2. Level: Not clearly defined
3. Cost: 5 to 15 cents per cow per day
4. Benefit to Cost Ratio: Not available
5. Feeding strategy: Feed to calves on liquid diet, transition cows, and during stress conditions.
6. Status: Evaluative for cows; recommended for milk-fed calves
Propylene Glycol
1. Function: Source of blood glucose, stimulate an insulin response, and reducing fat mobilization.
2. Level: 225 to 454 grams per cow per day
3. Cost: $1.25 per 454 grams
4. Benefit to Cost Ratio: Not available
5. Feeding strategy: Drench cow starting at one week prepartum (preventative role) or after calving when signs of ketosis are observed (treatment role). Feeding is not as effective as drenching.
6. Status: Recommended
Silage Bacterial Inoculants
1. Function: To stimulate silage fermentation, reduce dry matter loss, decrease ensiling temperature, increase feed digestibility, improve forage surface stability, and increase VFA (lactate) production.
2. Level: 100,000 colony forming units (CFU) per gram of wet silage. Recommended bacteria include Lactobacillus plantarium, Lactobacillus buchneri, Lactobacillus acidilacti, Pediococcus cereviseai, Pediococcus pentacoccus, and/or Streptococcus faecium.
3. Cost: 60 cents to $2 per treated ton of silage
4. Benefit to Cost Ratio: 3:1 (feed recovery) to 7:1 (milk improvement)
5. Feeding strategy: Apply to wet silage (over 60% moisture); corn silage, haylage, and high moisture corn; low natural bacteria counts (first and last legume/grass silage and frost damaged corn silage); and under poor fermentation situations.
6. Status: Recommended
Sodium Bentonite
1. Function: A clay mineral used as a binder, shifts VFA patterns, slows rate of passage, and exchanges mineral ions. Field claims to tie up mycotoxins have been reported.
2. Level: 450 to 700g per day (rumen effect), 110 grams for mycotoxin effect
3. Cost: 15 cents per 454 grams
4. Benefit to Cost Ratio: Not available
5. Feeding strategy: With high grain diets, loose stool conditions, presence of mold, low fat test, and dirt eating.
6. Status: Evaluative
Sodium Bicarbonate/Sodium Sesquicarbonate (Buffer)
1. Function: Increase dry matter intake and stabilize rumen pH.
2. Level: .75% of total ration dry matter intake
3. Cost: 6 cents per cow per day (bicarb = $0.19/454 grams; S Carb = $0.18/454 grams)
4. Benefit to Cost Ratio: 4:1 to 12:1
5. Feeding strategy: Feed 120 days postpartum with diets that are high in corn silage (over 50%), wet rations (over 55% moisture), lower fiber ration (<19% ADF), little hay (<2.2 kg), finely chopped forage, pelleted grain, slug feeding, and heat stress conditions.
6. Status: Recommended
Yeast Culture and Yeast
1. Function: Stimulate fiber-digesting bacteria, stabilize rumen environment, and utilize lactic acid.
2. Level: 10 to 120 g depending on yeast culture concentration.
3. Cost: 4 to 6 cents per cow per day
4. Benefit to Cost Ratio: 4:1
5. Feeding strategy: Two weeks prepartum to 10 weeks postpartum and during off-feed conditions and stress.
6. Status: Recommended
Yucca Extract
1. Function: Decrease urea nitrogen in plasma and milk by binding ammonia to the glycofraction extract of Yucca shidigera plant improving nitrogen efficiency in ruminant animals.
2. Level: 800 milligrams to 9 grams per day (depending on source)
3. Cost: 2 to 4 cents per cow per day ($1.28/454 grams for Micro Aid 1X)
4. Benefit to Cost Ratio: Not available
5. Feeding strategy: To cows with high BUN and MUN levels.
6. Status: Evaluative
Zinc Methionine
1. Function: Improve immune response, harden hooves, and lower somatic cell counts.
2. Level: 9g per day (Zinpro 40 trademark product)
3. Cost: 2 to 3 cents per cow per day
4. Benefit to Cost Ratio: 14:1
5. Feeding strategy: To cows experiencing foot disorders, high somatic cell counts, and wet environment.
6. Status: Recommended

Literature Cited

Duffield, T.F., D. Sandals, K.E. Leslie, K Lissemore, B.W. McBride, J.H. Lumsden, P. Dick, and R. Bagg. 1998. Efficacy of monensin for the prevention of subclinical ketosis in lactating cows. J. Dairy Sci. 81:2866

Erdman, R. A. 1990. Choline nutrition in dairy cattle. In NFIA Nut. Inst. Proc. Kansas City, MO.

Grummer, R. R., L. E. Armentano, and M. S. Marcus. 1987. Lactation response to short-term abomasal infusion of choline, inositol, and soy lecithin. J. Dairy Sci. 70:2518.

Hutjens, M. F. 1991. Feed additives. Vet Clinics North Am.: Food Animal Practice. 7:2:525.

Krehbiel, C.R., S.R. Rust, G.Zhand, and S.E. Gilliand. 2003. Bacterial direct-fed microbials in ruminant diets: Performance response and mode of action. J. Anim Sci (E.Suppl.2):E120-E132.

Kung, L. Jr. 2004. Direct-fed microbials for dairy cows and enzymes for lactating dairy cows: New theories and applications.

National Research Council. 2001. Nutrient Requirement of Dairy Cattle, 7th edition. National Academy Press. Washington, D.C. p. 192.

Overton, T.R, M.S Piepenbrink, and M.R. Waldron. 2000. Interactions of liver metabolism and health in transition dairy cows. Cornell Nutrition Conf. Proc. Cornell Univ, p. 251.

Seymour, W.M. 1998. Role of biotin in ruminant nutrition examined. Feedstuffs. 70:19:1.

Sharma, B. K., and R. A. Erdman. 1984. In vitro degradation of choline from selected feedstuffs and choline supplements. J. Dairy Sci. 72:2772.

Symanowski, J.T., H.B. Green, J.R. Wagner, J.I.D. Wilkinson, J.S. Davis, M.R. Himstedt, M.S. Allen, E. Block, J.J. Brennen, H.H. Head, J.J. Kennelly, J.N.
Nielsen, J.E. Nocek, J.J. Vand Der List, and L.W. Whitlow. 1999. Milk production and efficiency of cows fed monensin. J. Dairy Sci. 82 (suppl.1):75 (Abstr).

Weiss, W.P., and C. A. Zimmerly. 2000. Effects of biotin on metabolism and milk yield of dairy cows. Cornell Nutrition Conf. Proc. Cornell University. p. 22.

Yoon, I.K. and M.D. Stern. 1995. Influence of direct-fed microbials on rumenal microbial fermentation and performance of ruminants: A review. J. Animal Sci. 8:6:533.

Author Information

Michael F. Hutjens
University of Illinois, Urbana