wheat field

A Look at Feed Additives for Beef Cattle

By Dr. Aimee Hafla, Ph.D., PAS

Increasing consumer pressure to reduce or eliminate the use of antibiotics continues to motivate livestock producers to evaluate novel feed additives that offer health and production benefits, but do not require veterinary oversight. However, sorting through the growing selection of products and ingredients can leave even a well-versed nutritionist confused. The following is a brief description of some available technologies and the potential benefits they offer.


Ionophores are possibly the most commonly used feed additive in the beef cattle industry, with 90.5% of feedlots with 1000+ animals using an ionophore.  Ionophores are classified as an antibiotic by the FDA and their primary mode of action is to disrupt the movement of ions across the membranes of certain bacteria found in the rumen. This results in a shift toward the type of bacterial populations that produce propionate, which is the most favorable volatile fatty acid in relation to animal performance. Additionally, ionophores prevent and control the occurrence of coccidiosis, which can be particularly problematic for young cattle. A combined analysis containing the results of 169 feedlot trials found that the use of Monensin sodium (Rumensin) improved feed conversion of feedlot cattle by 6.4%. Even though ionophores are classified as antibiotics, they are not considered medically important to humans, and therefore can be purchased and used with no veterinary oversight. However, they are typically not allowed in “natural” branded feeding programs.


Probiotics (Direct-Fed Microbials) are live and viable, naturally occurring microorganisms, which provide a health benefit to the host that consumes them. Probiotic products can include bacteria and yeasts, or a mix of these organisms. Research conducted with feedlot cattle indicates that live yeast improves diet digestibility and may stabilize rumen pH by mitigating excessive lactic acid production, ideally, this will result in improved nutrient utilization. Several studies have documented the health benefits of feeding yeast in receiving cattle, which include a reduction in cattle pulled for repeat treatments and an increase in appetite. Current research is focusing on the potential use of yeast products to reduce the occurrence of liver abscesses in feedlot cattle.

The use of bacteria based probiotics in beef cattle began as a pre-harvest food safety measure, by reducing fecal shedding of pathogens, such as E.coli. Bacteria that produce lactic acid in the rumen may help mitigate low rumen pH by enabling the growth of the bacteria that use lactic acid. Lactic acid- utilizing bacteria help prevent the accumulation of lactic acid, also contributing to pH stabilization. Furthermore, the physical presence or “peppering” of beneficial bacteria on the walls of the lower gut may prevent the attachment and growth of pathogens.


Prebiotics are non-digestible substrates that provide nutrition to the beneficial gut bacteria and/or protect against pathogenic organisms. Mannan- and fructo-oligosaccharides, found in yeast fractions, attract and bind pathogens so they can be flushed from the digestive tract without causing disease. These compounds, sometimes referred to as “refined functional carbohydrates”, can be very effective at binding gram-negative bacteria, such as Salmonella and E. coli.

Often, yeast culture components (prebiotics) will be combined with whole live yeast in one product. Those types of products make up a significant proportion of the research trials evaluating “direct-fed microbials”. The effectiveness of yeast-based direct-fed microbials originates from both the yeast organism and the prebiotic component. Tri-Lution® is a patented combination of lactic acid-producing bacteria, yeast, and prebiotic nutrients.  These ingredients have been combined to support and balance a healthy rumen and GI tract, stimulate feed and water consumption, and to help reduce pathogen pressure. Tri-Lution® is the ideal product to help cattle cope with stressful situations, such as weaning and receiving.


Enzymes are specialized proteins that speed up chemical reactions, such as breaking down organic compounds in feed into substances that are then readily usable by the animal or microbes. Different enzymes work on specific substrates, for example, amylolytic enzymes degrade starches and fibrolytic enzymes degrade fiber. The purpose of supplementing enzymes to ruminant livestock is to enhance the digestibility of feedstuffs. For example, starch availability in corn is significantly impacted by processing, moisture, and prolamine content, but ruminal starch digestibility can be enhanced by supplementation with a starch digesting enzyme. Responses to enzyme supplementation in beef cattle consuming high-grain diets can vary, depending on the activity of the enzyme and digestibility of the diet. Evaluation of diet digestibility and that of individual ingredients is necessary when considering the use of a feed enzyme product. A fecal starch analysis done by your nutritionist can help determine if starch digestion is optimal or if there are opportunities for improvement.

Maximiser® is a blend of enzymes, direct-fed microbials, and nutrients formulated to enhance digestibility and nutrient utilization when supplemented to beef cattle. Multi-enzyme technology ensures the enhanced breakdown of the starches, fibers, and proteins commonly found in feedlot diets. Yeast and bacteria components promote rumen and gut health, contributing to greater nutrient absorption and utilization.

Essential Oils

Essential oils are bioactive metabolites produced by plants as a means of defense, rather than for growth or reproduction.  Some common essential oils include cinnamaldehyde (cinnamon extract) and capsicum annuum (hot pepper extract). Various essential oils have been found to alter rumen microbial populations, impact ruminal fermentation, and to have broad antimicrobial properties when evaluated with in vitro (test tube) trials. Specifically, essential oils appear to have similar ruminal effects as ionophores, shifting fermentation toward propionate and decreasing ammonia concentration and methane production.  However, evidence supporting the use of essential oils in feedlot cattle raised in commercial production systems is limited and documentation of improvements in performance is highly variable. More robust research has been conducted in nonruminants, where cinnamaldehyde appeared to act as an immune enhancer and capsicum was found to improve blood flow in the GI tract. More research is necessary to determine what combinations and dosages of essential oils provide notable benefits to beef cattle producers.

Due to variability in environmental conditions, diets, stress, and physiological status of cattle, products containing a blend of probiotics, prebiotics, and/or enzymes best capture the benefits of the various modes of action. Consider Tri-Lution® to help cattle through stressful weaning and receiving periods and follow up with Maximiser® for continuous rumen health and improved performance through the rest of the feeding period. For questions and guidance, please contact your local Agri-King area manager. AK

feed additives for beef cattle