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Veterinary 

Biologics:

Use and Regulation

United States Department of Agriculture

Animal and Plant Health Inspection Service

Program Aid No. 1713
The U.S. Department of Agriculture (USDA) prohibits 

discrimination in all its programs and activities on the basis 

of race, color, national origin, sex, religion, age, disability,

political beliefs, sexual orientation, or marital or family status.

(Not all prohibited bases apply to all programs.) Persons with

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of program information (Braille, large print, audiotape, etc.)

should contact USDA’s TARGET Center at (202) 720–2600

(voice and TDD).

To file a complaint of discrimination, write USDA, Director,

Office of Civil Rights, Room 326–W, Whitten Building, 

1400 Independence Avenue, SW, Washington, DC 20250 

or call (202) 720–5964 (voice and TDD). USDA is an equal

opportunity provider and employer.

This publication is a major revision of the unnumbered leaflet

issued under the same title in August 1987 and slightly

revised October 1989.

Issued March 2002

Cover photo: A microbiologist observes cell cultures grown in

a roller bottle. USDA photographer Ken Hammond
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What Are Veterinary Biologics?

Veterinary biologics are products designed to

diagnose, prevent, or treat animal diseases.

They generally work through some immunological method or process. Immunity is the body’s

ability to ward off disease, and there are two

types: active immunity, which can be acquired 

by the body when it successfully overcomes 

a natural infection or responds to vaccination,

and passive immunity, which involves the 

transfer of antibodies from immunized animals 

to nonimmune animals. This transfer may be

accomplished by serum injection or, in the 

newborn, by oral administration of serum 

or the mother’s first milk.

Veterinary biologics are used to protect 

or diagnose disease in a variety of animals,

including farm animals, household pets, poultry,

fish, and fur-bearers, both domestic and wild.

Most biologics leave no chemical residues in

animals, unlike some pharmaceutical products.

Furthermore, most disease organisms do not

develop resistance to the immune response

produced by a veterinary biologic.

Types of Veterinary Biologics

• Vaccines—made from viruses, bacteria,

spores, or other disease-causing agents.

The organisms in a vaccine are always living

except in certain viral vaccines, where the

agent is killed. The living organisms in a

vaccine may be modified by culture or natural

selection so that they do not cause disease.

Veterinary 

Biologics:

Use and Regulation
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• Bacterins and Bacterin–Toxoids—inactivated

cultures of bacteria or other nonviral organisms. If the product contains an inactivated

toxin that is immunogenic, it is called a

bacterin–toxoid.

• Bacterial Extracts—purified preparations that

contain selected highly immunogenic portions 

of organisms.

• Vaccines with Bacterins or Bacterin–-

Toxoids—combinations of biological products

that may be found in a single container or may

be sold in separate containers within the same

package.

• Toxoids—similar to bacterin-toxoids except

that they have been purified to remove

bacterial cells.

• Antiserums and Antitoxins—products

containing antibodies, usually from specifically

immunized animals. If the antibody neutralizes 

a specific toxin, it is called an antitoxin.

Figure 1—A microbiologist inoculates eggs free of specific

diseases to determine the viral titer of a poultry vaccine.

USDA photographer Ken Hammond
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• Allergenic Extracts—used to diagnose animal

allergies to substances like pollen, dust, fleas,

and even foods, and to desensitize animals

allergic to these substances.

• Diagnostics—substances that help detect

infection by causing a telltale reaction in 

animals or in laboratory test systems.

• Miscellaneous Products—a category that

includes immune stimulants which, when properly administered, may be used to treat certain

types of tumors and resistant skin infections.

Figure 2—A technician prepares cell cultures for staining.

USDA photographer Ken Hammond
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ACTIVE IMMUNITY

IMMUNIZED

▲Antigen

Antibodies

Serum

1st Milk

Oral/Injection

About 60 years ago, there were perhaps half 

a dozen of these products available; at the end 

of 2001, there were 2,494 different biologics

available for use against 197 different animal

diseases. This ever-expanding array of veterinary

biologics means better animal health care but

also reinforces the need for strict regulation.

Biologics must be handled with care from the

initial stages of manufacturing to their final usage.

Improperly stored or administered biologics could

cause adverse reactions, failure to immunize,

inaccurate diagnoses, or other harm to animals.

How Veterinary Biologics Are Regulated

Regulation of veterinary biologics began soon

after the turn of the twentieth century because

farmers and animal health officials were having

poor results with many biological products. Some

were ineffective; worse yet, others were contaminated. The most costly such instance was an

outbreak of foot-and-mouth disease in 1909,
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caused by a contaminated vaccinia virus

imported into the United States to produce

smallpox vaccine.

Under the 1913 Virus–Serum–Toxin Act,

further amended by the 1985 Food Security 

Act, the U.S. Department of Agriculture’s 

(USDA) Animal and Plant Health Inspection

Service (APHIS) is responsible for ensuring 

that all veterinary biologics produced in or

imported into the United States are pure, safe,

potent, and effective. This regulatory activity 

is accomplished by the Center for Veterinary

Biologics (CVB) in Ames, IA.

A Federal license is required in order to 

manufacture biologics for domestic use and 

for most exports. A USDA permit is required 

in order to import biologics for transit shipment,

research, or distribution and sale in the United

States. Manufacturers must obtain an establishment license and an individual license for each

product marketed. These licenses and permits 

are issued by CVB.

PASSIVE IMMUNITY

NONIMMUNIZED

Injection
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Biologics Exempt From Federal

Licensure

• Products manufactured by veterinarians that

are intended solely for use with their clients’

animals under a veterinarian–client–patient

relationship 

• Products manufactured by individuals or

companies for use only in their own animals

• Products manufactured in States with acceptable veterinary biologics regulatory programs

and for sale only in those States

• Products manufactured for export in

accordance with the Federal Food, Drug, 

and Cosmetic Act as amended by the Export

Reform Enhancement Act of 1996.

Other veterinary biological products used in the

United States are licensed or permitted by

USDA–APHIS–CVB.

APHIS’ Role in Safeguarding Biologics

APHIS inspects licensed and permitted manufacturers to be sure that facilities are adequate and

properly maintained. Officials examine production

methods and records to assure that they comply

with Federal requirements. Such close supervision is vital because biologics are produced in

live systems that have the potential for change 

if not properly controlled and maintained. Each

production run of a biologic—not just the initial

one—must be tested to assure that consistent

satisfactory production is being maintained.

APHIS is responsible for assuring that

licensees maintain proper quality control of the

veterinary biologics they produce and continually

develop reference standards and test methods 

to improve product evaluation. Each serial or

batch of veterinary biological products is tested

for purity, safety, and potency by the licensee.
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Samples of each serial are also submitted for

random quality assurance testing by APHIS. No

licensed biological product may be released until

APHIS officials substantiate that all required tests

have been satisfactorily concluded.

What You Can Do To Keep Biologics

Safe and Effective

Look for the U.S. veterinary license number 

on the product label when buying veterinary

biologics. This assures that the product has been

manufactured and tested under USDA standards.

Under Federal law, all information on the labels 

of USDA-licensed biologics and in accompanying

literature must be approved by APHIS. Labels

should include the product’s name and serial

number, complete directions for use, the name

and address of the manufacturer, license or

permit number, the number of doses and quantity

of contents, storage instructions, precautions,

and expiration date. Labels for products used 

in meat-producing animals will also contain withholding instructions for waiting a certain number

of days before slaughtering the animal.

Figure 3—The ultimate goal is to provide pure, safe, potent,

and efficacious products in the hands of the end user.

APHIS photographer Anson Eaglin
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Purchase biologics from a reputable outlet. Careful handling by wholesalers and retailers is essential

to the potency and effectiveness of these products.

Buy only as much product as is needed for a specific job; an oversupply that must be stored beyond 

the expiration date could lose potency and become

worthless. Never use a biological product after the

expiration date on the label.

ROUTES OF VACCINATION

Oral Spray

Injection Nose/Eye Drops

Immersion

Use care in storing and handling veterinary

biologics. Most products must be kept chilled

throughout shipment and stored in a refrigerated

area at 35 to 45 degrees Fahrenheit.

Consult your veterinarian before beginning an

immunization program. Only someone with special

training and knowledge of animal diseases and

experience in using veterinary biologics can advise

you on which products to use. Make sure animals
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are healthy before vaccinating them; overwork,

exposure to inclement weather, and lack of proper

feed may interfere with animals’ ability to develop

immunity.

Some General Rules for Administration

of Veterinary Biologics

1. Read and follow label recommendations.

2. Use sanitary procedures and avoid

contamination.

3. Carefully cleanse and disinfect site of

inoculation.

4. Use sterile instruments for injectable products.

5. Administer the full recommendation dose.

6. Mix biologics only if the instructions specify 

to do so.

7. Observe withholding times when administering

products to meat-producing animals.

8. Do not save unused contents of multiple-dose

containers.

Followup is extremely important. Keep records

of vaccinations, including serial numbers of products. This information may be used in tracing the

cause of unsatisfactory results if a product fails to

do what the label said it would, or if it produces

unexpected results or adverse side effects.

Should a veterinary biologic prove ineffective,

notify the licensed manufacturer and also the

CVB. The toll-free phone number at the Center 

is (800) 752–6255. Because few products are

tested as thoroughly as federally licensed or

permitted veterinary biologics, it is important 

to notify USDA of any problems so appropriate

action may be taken.
For More Information

More information about the APHIS role in

regulating veterinary biologics is available 

from all three of the Center’s units:

Licensing and Policy Development Unit

Inspection and Compliance Unit

Center for Veterinary Biologics

510 South 17th St., Suite 104

Ames, IA 50010

(515) 232–5785

Laboratory

Center for Veterinary Biologics

P.O. Box 844

1800 Dayton Avenue

Ames, IA 50010

(515) 663–7331

The CVB’s Web site is

<www.aphis.usda.gov/vs/cvb>.