Feed additives are specialized ingredients mixed into cattle rations to improve average daily gain, enhance feed efficiency and prevent metabolic diseases like acidosis and bloat. Whether managing a cow-calf herd, stockers on pasture or a finishing operation in the feedlot, understanding the regulatory landscape is essential for legal compliance and animal performance.
“Responsible feed additive use is important. Store medicated feeds properly. Observe product expiration dates,” says Brandi Karisch, University of Mississippi associate Extension and research professor. “Use feed additives only for their intended purposes. Follow label directions and pay attention to label warnings.”
In an episode of “Doc Talk,” Dr. Dan Thomson discusses various common feed additives used in cattle management. He says these are ingredients mixed into rations to:
- Improve feed efficiency — more gain from the same feed
- Reduce disease and digestive problems — acidosis, bloat and coccidiosis
- Support overall animal health and performance
- Help manage behavior and reproduction, such as estrus suppression in heifers
There are two classes of feed additives — nonmedicated and medicated.
Nonmedicated Feed Additives
Nonmedicated feed additives include probiotics, prebiotics, enzymes, phytogenics and many other compounds.
According to the Beef Quality Assurance (BQA) field guide, the following feed additives are available over the counter without a direct veterinary prescription — unless labeled for feeding in combination with a veterinary feed directive (VFD) medication such as ionophores, prebiotics, probiotics, fermentation products, enzymes and coccidiostats
Medicated Feed Additives
Medicated feed additives include antibiotics, antimicrobials, anticoccidials, antiparasitics, sulfonamidics, hormones, antibloat compounds and beta-agonists.
The federal veterinary feed directive stipulates medically important antibiotics are prohibited for use as growth promotants and cannot be fed without a veterinary prescription. The FDA requires a VFD for all feed-use antibiotics that could potentially impact human antibiotic resistance.
The BQA Manual (pages 116 to 119) explains the FDA regulations and the types of medicated feeds available. Page 118 has a table of approved feed additives including withdrawal and approved combinations.
What is a Veterinary Feed Directive?
If a cattle producer needs to use a VFD feed medication, they must obtain the VFD from the veterinarian with whom they have a veterinarian-client-patient relationship (VCPR).
The veterinarian must be licensed to practice in the state in which the cattle are located. The only FDA-approved VFD feed medications are those used for treatment or control of specific diseases. The longest duration any VFD can have is 180 days unless specifically limited by the label.
There are no FDA-approved VFD medications for treatment, control or prevention of foot rot or pinkeye.
All VFD records must be kept and be available for inspection for two years by the issuing VCPR veterinarian, the cattle producer and the feed mill distributing the VFD medication.
There are several FDA-approved feed medications that do not require a VFD. However, if used in feed at the same time as a VFD drug, that concurrent use must be authorized and approved on the VFD. Notable among these are ionophores and parasite control medications. Visit with your veterinarian for more detailed information.
What is a VCPR?
A valid VCPR is required for producers to use all prescription medications, extra-label use of nonprescription medications and all FDA feed medications that require a VFD.
Veterinarians are trained to evaluate individual and groups of animals within a herd system and provide integrative management plans to prevent diseases or problems from occurring in the future. Working with a herd veterinarian to develop operation-specific protocols can improve management, record keeping and provide employee training opportunities. An established VCPR allows the veterinarian to diagnose animals, prescribe medications and drug therapy to treat, control or prevent disease and issue certificates of veterinary inspection (CVIs) or health certificates.
Residue avoidance in meat and milk products is a team effort that starts with the VCPR. Written and signed VCPRs are recommended for record keeping. VCPRs should be renewed annually, based on state or federal guidelines. Producers are encouraged to schedule yearly consultations with their veterinarian to review current practices and to develop and set goals for the next year and consider areas for improvement.
What are Ionophers?
According to Karisch, ionophores are antimicrobial compounds that modify microbial fermentation in the rumen, allowing cattle to get more energy from the feed consumed. Ionophores inhibit or depress the growth of certain rumen microorganisms. This alters the rumen fermentation process in several ways.
“The benefits of including ionophores in beef cattle diets are well documented,” she says. “Ionophores generally improve feed efficiency from 5% to 10% and improve rate of gain by 2% to 7%.”
What are Buffers, Yeast Cultures and Bloat Prevention Aids?
Karisch says buffers can be added to beef cattle diets to reduce fluctuations in rumen pH. This helps reduce the incidence of acidosis when adapting cattle to high-grain diets or when feeding cattle concentrate feedstuffs such as wheat at high levels.
Yeast cultures may improve feed efficiency, gain and health in cattle.
“Yeast-based products affect dry-matter intake, rumen pH and nutrient digestibility,” she explains. “But some studies show no benefits from adding yeast cultures to beef cattle diets. Yeast cultures can be used in receiving diets of both low- and high-stress cattle.”
Poloxalene can be fed to help prevent bloat on legume and other lush pasture. It can be mixed with feed or offered in block form.
“For product effectiveness, cattle must consume adequate quantities of poloxalene,” Karisch says. “It is still important to use other bloat-prevention measures, such as filling cattle up on hay before turning them out onto lush pasture, to be safe when dealing with high bloat risk.”
What are Beta-agonists?
Beta-agonists are a class of growth‑promoting feed additives used late in the feeding period to improve growth rate, feed efficiency and carcass leanness in cattle.
In feedlots, they are used as nonnutritive feed additives near the end of the finishing period to:
- Increase average daily gain
- Improve feed conversion
- Shift nutrients toward more muscle and less fat, improving carcass yield
Fly and Parasite Control
Oral larvicides are fed to cattle through a feed ration or mineral to kill fly larvae as they hatch in the manure.
Karisch stresses they are effective only when animals consume the proper amount of the active ingredient. Oral larvicides do not control migrating adult flies. Adult flies can still be a problem if a producer is using an oral larvicide but a neighbor is not practicing any fly control. Other common fly control feed additives are insect growth regulators that disrupt fly life cycles.
She says many anthelmintics or dewormers are available as feed additives.
“Anthelmintics are advantageous when handling animals is difficult,” she explains. “As with other feed additives, effectiveness of anthelmintics delivered through feed depends on cattle consuming adequate quantities of the product.”
Both Karisch and Thomson stress feed additives can be great tools to use alongside good nutrition and management to keep animals healthier and more efficient. They encourage producers to work with their veterinarian and develop a plan that fits their program.
