This NebGuide addresses how certain activities increase the changes livestock will be exposed to contagious diseases.
David R. Smith, Extension Dairy/Beef Veterinarian
Outbreaks of dangerous contagious livestock diseases, e.g. foot-and-mouth disease, could be economically devastating to the U.S. In 2001 an outbreak of foot-and-mouth disease in the United Kingdom led to the slaughter of more than 6 million animals and cost approximately $13.5 billion to control. Foreign animal diseases like foot-and-mouth disease, hog cholera and African swine fever are an ever present threat to U.S. livestock. But we also have contagious diseases within our borders to worry about, including salmonellosis, bovine viral diarrhea, Johne’s disease, pseudorabies and porcine reproductive and respiratory syndrome virus.
It is wise to understand how certain activities increase the chance that our herds will be exposed to contagious foreign or domestic animal diseases. Clearly, the introduction of livestock is the single greatest threat for exposing a herd to contagious disease. However, pathogens can be introduced other ways — for example with movement of birds and wildlife, feed and bedding, air- or water-borne particles, or farm visitors.
The risk for disease posed by visitors should be assessed critically. In some cases even a very small probability of disease transmission can have tremendous impact (e.g. the introduction of foot-and-mouth disease). Some operations cannot accept any risk for contagious disease and strictly prohibit visitors. Usually simple biosecurity principles like those listed below can be used to minimize the risk to acceptable levels.
Require visitors to check in. Some visitors pose a greater biosecurity risk than others. Visitors with recent exposure to livestock are more likely to carry in pathogens. Ask if visitors have been on farms, or had other recent contact with livestock:
- Yes, in the U.S.: Some producers require 24 hours since contact with other livestock.
- Yes, in another country: Require five days from visiting farms in a foreign country. Require that clothes are laundered and that shoes and personal items are cleaned thoroughly and wiped with a cloth dampened with a bleach solution (5 teaspoons of household bleach in 1 gallon of water).
Visitors from other countries that have not recently visited farms are not likely to present a serious biosecurity risk; however, it is prudent to require all foreign visitors to meet a “five day from departure” requirement. Prohibit visitors from bringing imported meat or milk products that lack USDA approval.
Require clean outerwear and boots. Visitors should wear clean clothing and have bathed since visiting another livestock facility. It may be prudent to provide clean coveralls, rubber or disposable boots, and facilities to wash hands or shower.
Minimize contacts. The closer visitors are to livestock, the greater the risk for transmission. Don’t allow direct physical contact with livestock unless necessary. Visitors’ pets should not be allowed near livestock facilities. Whenever possible, prevent vehicles that have been on other farms from entering livestock pens, feed alleys or feed preparation areas.
Some livestock groups are more susceptible to contagious disease than others. Typically pregnant animals and young stock should be most protected from close contact with visitors.
Farm personnel should follow a similar protocol when visiting livestock facilities in the U.S. or other countries, and when they return from another country they should observe the five-day time restriction until animal contact.
Visit the University of Nebraska–Lincoln Extension Publications Web site for more publications.
Index: Animal Diseases
Issued January 2007