|
|||
|
|
||
|
|
|
|
|
|||
|
|
||
Large Animal Science Sample Lesson
LA007 Biosecurity and Healthy Livestock
MAIN IDEA: Why should producers purchase and maintain healthy livestock; how do diseases travel among animals; and what steps can producers take to maximize biosecurity? Unhealthy livestock cost producers money in two ways: 1) by increasing medication costs for treatment and 2) by reducing performance through depressed growth rate or increased mortality. Diseases in the livestock industry move between animals and farms, most often between animals of the same species. Biosecurity includes practices that keep animals from contracting diseases from herd mates or livestock on other farms. TYPES OF DISEASE TRANSMISSION Horizontal disease transmission occurs between animals from different farms or between animals of similar age or production status. Horizontal transmission can occur through the addition of new animals to a herd, disease carried by rodents or birds, manure on boots or in dirty trucks, or by viruses that travel through the air. An example of horizontal disease transmission would be the transfer of transmissible gastroenteritis (TGE) by birds between herds of swine. Diseases can pass from older to younger animals via vertical transmission. Diseases already occurring on a farm reside in older animals already possessing a high level of immunity. Young animals without immunity often contract these diseases from older animals. Vaccination or moving young animals to a remote location for their entire lives prevents vertical transmission. An example of vertical transmission would be the transfer of Johnes disease in cattle from dam to offspring. REDUCING HORIZONTAL DISEASE TRANSMISSION THROUGH BIOSECURITY The addition of new animals to a herd threatens biosecurity. Producers should purchase animals based on past disease history of the source herd. Veterinarians of potential livestock sources should be consulted for information on the disease status and vaccines routinely administered to animals in the source herd. The health status of the source herd should be matched with the health status of the new herd as closely as possible. All newly introduced livestock should be isolated for a period of time and blood tested to ensure freedom from diseases that are not already present in the new herd. During the isolation period, animals should be vaccinated for diseases known to be present in the new herd and observed for clinical signs of diseases. Only after a successful isolation and immunization program should new animals be introduced into the main herd. Disease can travel via manure on boots and clothing, so boots and clothes should be changed after contact with other animals of the same species. Restricting visitors who work with livestock reduces the odds of bringing in unknown diseases. Washing boots in disinfectant between groups of animals also reduces disease transmission between groups. Manure on trucks can carry diseases among farms, so trucks should be cleaned and disinfected after hauling livestock. Rendering trucks and vehicles of sales people who travel from farm to farm are also a potential source of disease organisms. Rodent and bird control can reduce the opportunity for these pests to transmit disease. Operations located very close to one another can transmit some diseases via the air. Certain viruses are capable of crossing small air spaces to infect other animals. REDUCING VERTICAL DISEASE TRANSMISSION THROUGH BIOSECURITY Biosecurity practices to reduce the vertical transmission of disease include ensuring that young animals acquire maternal antibodies from their mother's colostrum (the antibody-rich first milk produced after parturition). Segregating animals by age and vaccinating for appropriate diseases also reduce the chance of vertical disease transmission. Tending to livestock from youngest to oldest helps prevent producers from carrying diseases from older animals to younger ones. SUMMARY: Control costs and production losses caused by disease outbreaks threaten the profitability of any livestock enterprise. Biosecurity practices to reduce horizontal and vertical disease transmission keep livestock healthy and producers profitable. EXERCISES: 1. Research two infectious diseases that affect one species of livestock. Make a chart indicating the symptoms, prevention and treatment for the diseases. 2. Contact an extermination company and ask about acceptable means of rodent and bird control in and around livestock facilities. 3. Develop a biosecurity plan for a hypothetical or actual livestock production facility. INTERNET RESOURCES:
** USDA APHIS - Biosecurity Practices of U.S. Dairy Herds
** Bovine Alliance on Management and Nutrition - An Introduction to Infectious Disease Control on Farms (Biosecurity)
** California Department of Food and Agriculture - Animal Health
** Iowa Beef Center - Feedlot Biosecurity an Increasing Iowa Concern
** Texas A&M - Biosecurity for Exotic Fowl
** Texas A&M - Poultry Facility Biosecurity TEST:
1. Name two ways diseased animals cost producers money. 2. Define biosecurity. 3. Differentiate between vertical and horizontal disease transmission.
4. List four ways diseases can travel from farm to farm. 5. Animals should always be tended to from oldest to youngest. TRUE or FALSE?
------------------------------------------------------------------------ END OF STUDENT SECTION
TEACHER'S GUIDELA007 Biosecurity and Healthy LivestockOBJECTIVE: Students should be able to explain why is it important to purchase and maintain healthy livestock, how diseases travel among animals and what steps producers can take to maximize biosecurity. PREPARATION: Review the material in this lesson and the Internet Resources. INTERNET RESOURCES:
** USDA APHIS - Biosecurity Practices of U.S. Dairy Herds
** Bovine Alliance on Management and Nutrition - An Introduction to Infectious Disease Control on Farms (Biosecurity)
** California Department of Food and Agriculture - Animal Health
** Iowa Beef Center - Feedlot Biosecurity an Increasing Iowa Concern
** Texas A&M - Biosecurity for Exotic Fowl
** Texas A&M - Poultry Facility Biosecurity REFERENCES: Pork Quality Assurance: a program of America's Pork Producers. 1997. National Pork Producers Council, Des Moines, IA. IMPORTANT TERMS: colostrum, horizontal disease transmission, maternal antibodies, transmissible gastroenteritis, TGE, vaccination, vertical disease transmission. EXTENSION: Contact a local large-scale livestock operation (preferably poultry or swine). Ask them to share their biosecurity plan. Report your findings to the class. Or as a local large animal veterinarian to speak on local livestock disease concerns. EXERCISE ANSWERS: 1. Answers will vary, but should include symptoms, prevention and treatment for both diseases. Some of the links listed under Internet Resources provide a good starting point, or you may wish to do a Web search to find information. 2. Extermination companies should provide information about acceptable, safe methods of rodent and bird control. 3. Biosecurity plans should include items like the following: isolation of incoming animals, ensuring adequate colostrum intake, age segregation when possible, control of human and vehicular traffic in and around the facility, changing clothes and boots after contacting other livestock, rodent and bird control, and tending to animals from youngest to oldest. TEST KEY: 1. Name two ways diseased animals cost producers money. Correct answers include: increased mortality, reduced performance or increased medication costs. 2. Define biosecurity. Biosecurity is the term used for practices that keep livestock from contracting diseases from herd mates or from livestock on other farms. 3. Differentiate between vertical and horizontal disease transmission. Vertical transmission is the transfer of disease from older, immune animals to younger animals on the same farm. Horizontal transmission is the transfer of disease between farms or among animals of similar age or production status. 4. List four ways diseases can travel from farm to farm. Correct answers include: new herd additions, manure on boots or clothing, manure in or on dirty trucks, birds, rodents or by the air. 5. Animals should always be tended to from oldest to youngest. TRUE or FALSE? FALSE. Animals should be tended to from youngest to oldest, so that young animals are not exposed to diseases for which they do not have immunity. CROSSWORD PUZZLE ANSWERS:
Across: 3. Visitors, 6. Horizontal, 8. Trucks, 11. Boots, 12. Rodents, 14. Medication, 15. Maternal. END TEACHER'S GUIDE
To subscribe to AgEdNet.com or
for a "free trial", |
|
HOME | SUBSCRIBERS | VISITORS | ORDER | CONTACT US | TERMS & USAGE Copyright © 1995-2010 Stewart-Peterson. All Rights Reserved. STEWART-PETERSON and AGEDNET.COM are Registered Trademarks of Stewart-Peterson, Inc. AgEdNet.com®, a service of Stewart-Peterson, Inc. 137 South Main Street, West Bend, WI 53095 |
