A cow isolated from the herdBringing new or returning animals onto a farm may introduce diseases to a livestock herd. Even borrowing a breeding animal may compromise the biosecurity of a farm. Isolation of sick, new or returning animals will bolster your herd health and biosecurity programs.


Although the term quarantine applies to isolating new or returning animals that are not known to be ill, and isolation refers to keeping sick animals separate from healthy ones, in both cases a space is needed that meets the definition of an isolation area.

An isolation area should:

  • Provide an air space, water source and feed source separate from the rest of your livestock.

  • Prevent direct contact with the rest of your livestock.

  • Provide a clean, dry, comfortable resting space for the animal(s).

  • Provide transition to a new ration.

  • Provide adequate restraint facilities for examinations and administration of treatments.

  • Allow equipment storage in that area (e.g., shovels, halters, buckets, etc.) for use only in the isolation area.

  • Prevent the movement of equipment and manure from the isolation area to other locations with livestock.

  • Ensure workers clean hands and boots and change clothes before going to other areas.

  • Be easy to clean and disinfect.

  • Prevent access to other animals like pet dogs or wildlife.

Housing of Different Animal Groups

Young animals acquire infectious diseases primarily through exposure to older infected or carrier animals. To minimize disease transmission, housing and management systems should minimize contact between youngstock and older animals. Younger animals need time to develop immunity to diseases. Although the following recommendations are written for cattle, similar principles apply to all livestock:

  • Separate pre-weaned dairy calves from all other age groups.
  • House each dairy calf in an individual pen or hutch.
  • Place hutches away from dairy barn exhaust fans.
  • House 4 to 8-month-old dairy calves in small groups separate from older heifers.
  • House yearling and breeding age dairy heifers separately.
  • Separate replacement heifers from cows.
  • Separate dry dairy cows from milking cows.
  • If overwintered on pasture, move cows to a clean pasture for calving.
  • Milk mastitic, treated, or sick cows last, and disinfect the milking claw between such animals.
  • Provide adequate pen, stall, or bedded area per animal.
  • Provide adequate feed bunk length and water trough access per animal.
  • Organize chore routines to feed and milk isolated cattle after the main herd.
  • Prevent fence line contact between your stock and other animals.

Pre-Purchase Process for Livestock

Even buying or borrowing a bull, ram, or buck could compromise the biosecurity of your farm. Review the following checklist before purchasing new animals.

Organic livestock farms will recognize that careful examination of animals is needed since treatment options are more limited.

Ask your veterinarian to contact the source herd's veterinarian. Test and vaccinate as needed. The key point is to determine the vaccination and health status not for just the individuals you are buying, but also of the herd of origin.

Ask specifically about the following conditions:

  • Mastitis (in dairy animals)
  • Culture cows for Strep. ag, Staph. aureus, and Mycoplasma. Conduct a series of three bulk tank or individual cultures plus somatic cell count (SCC).
  • Purchase open or bred heifers to minimize the risk of mastitis (but recognize the risk will not be zero).
  • Hoof health
  • Inspect for hairy heel warts (cattle), foot rot, foot scald (small ruminants), and lameness. Isolate and treat any problems upon arrival.
  • Vaccination status
  • Ask for records of initial vaccination series and boosters for respiratory diseases, leptospirosis, bovine viral diarrhea (BVD) in cattle, clostridial diseases (CD Tet in small ruminants), and rabies.
  • Booster or initiate a vaccination series to match your herd vaccination program. Consult with your veterinarian about your routine and purchased-animal vaccination programs.
  • Boost vaccines three weeks prior to movement, if appropriate.
  • Herd health status
  • History of abortions. In cattle, diagnoses of neosporosis, leptospirosis, salmonellosis, BVD, lymphoma, or Johne's Disease. In small ruminants, diagnoses of Johne's, leptospirosis (Leptospira interrogans), vibrio (Campylobacter fetus), chlamydia (Chlamydia psittaci), toxoplasmosis (Toxoplasma gondii), or listeriosis (Listeria monocytogenes).
  • Breeding soundness exam prior to purchasing male breeding stock.
  • Test results negative for persistent infection (PI) with BVD in cattle.
  • Serologic status for bovine leukosis virus (BLV) in cattle, Johne's Disease (JD or MAP) in cattle and small ruminants; caprine arthritis encephalitis (CAE) in goats; ovine progressive pneumonia (OPP) in sheep and goats; scrapie in sheep.
  • Deworming/antiparasitic program
  • Check fecal: conduct egg count and test anthelmintic (drug treatment for parasitic worms) resistance in small ruminants. Get history of past deworming practices.
  • Check for signs of lice, mange, ringworm, and warts. Use pour-on or other insecticide upon arrival, if indicated.

Post-Purchase Management of Animals

The ability of tests to find the presence of a disease (sensitivity) is limited, so testing alone does not eliminate the risks inherent to purchasing animals. Therefore, post-purchase management of incoming animals, as well as management of the home herd, are important control points.

  • Identify new arrivals and segregate for at least 2–3 weeks.
  • Use separate housing, feeding, and birthing areas (ideal).
  • Use separate housing and feeding areas (acceptable).
  • Prevent contact with other livestock (minimum acceptable).
  • Do not use an old barn that could compromise stall comfort, air quality, or feed management as an isolation facility.
  • Booster vaccines, if necessary.
  • Minimize stress.
  • Provide clean, comfortable housing with good ventilation.
  • Consult nutritionist to develop transition ration. Change to new ration slowly.
  • Inspect and treat feet for warts, scald, or lameness.
  • Prevent manure from moving from the isolation area to the rest of the herd.
  • Milk new and isolated dairy animals last.
  • Observe and examine frequently for early disease detection.
  • Plan and prepare in advance.
  • Monitor aggressively. Early recognition is crucial to preventing spread of disease.
  • Identify and train staff who will monitor health.
  • Create written protocols for monitoring and treatment with criteria such as fever, signs of infection, lameness, or off-feed.

Animal Importation

Map of 2003 monkeypox in United States

Map of 2003 Midwest Monkeypox Outbreak. Source: Eric Pierce, Wikimedia

Anyone who has brought an animal from one U.S. state to another knows that they must meet certain regulatory requirements. These restrictions are designed to prevent the introduction of diseases that are not currently present in the state.

Although the restrictions vary by species, there are some similarities in the process. Because some diseases can spread from one species of animal to another—or even to humans—it is critical that all animal importers follow the applicable restrictions.

The importation into the U.S. of monkey pox with African rats in 2003 is an example of what can happen if adequate safeguards are not followed to ensure the health of the animals entering this country.

The United States is free of many diseases that occur in other parts of the world. Foot and mouth disease is a well-known example. Inspection of imported animals and feedstuffs plays a critical role in preventing the introduction of such diseases.

Control programs are in place for a number of diseases that have been nearly eradicated from the U.S., including brucellosis and tuberculosis. These still exist in geographic regions where wildlife (bison and deer, respectively) serve as a reservoir for disease and periodically infect livestock.

Any required testing must be done in the state or country of origin. Additional information on how to find state regulations pertaining to the importation of animals is available on the USDA APHIS State Regulations for Importing Animals web page.

Reportable/Notifiable Diseases

A disease or condition that is considered reportable must be brought to the attention of the federal and state veterinary authorities within prompt, defined timeframes, in accordance with national and state regulations. Reportable disease regulatory authorities require federal and state reporting from any individual, producer, veterinarian, laboratory personnel, wildlife or zoo personnel, researcher, public health official, or others with knowledge of a notifiable disease.

If a producer's veterinarian confirms after testing that a livestock disease is considered reportable, they will contact the state veterinarian to initiate the regulatory process. A livestock producer may also directly contact their state veterinarian as well.

A PDF document entitled, U.S. National List of Reportable Animal Diseases (NLRAD) Framework, describes the national program and lists the current nationally reportable and monitored diseases in the document appendix.

Resistance to Infection

Strengthening livestock resistance to diseases is a good preventative method.