[This article prepared by Russell Sawchuk from information provided by Dr. Colin Macaldowie, Moredun Research Institute in the United Kingdom, and as published in the Winter 2001 edition of Deer Farming, the Journal of the British Deer Farmers Association.]
Every responsible cervid producer today must develop and implement strategies and procedures for disease control and eradication on their farm. With CWD and FMD seemingly spreading so easily, caution and appropriate steps are essential to protect the health of your herds.
In this article, we will look at the steps you can take to protect your animals from infectious diseases.
It is often impossible to operate a completely closed management system. In most cases, replacement animals have to be acquired. If so, a number of things can be done to reduce the risks.
1. Ask yourself: is it really necessary to buy animals in the first place, or can you enhance your genetics with A.I. or embryo transplants?
2. Try and buy direct from as few farms as possible. Arrange a pre-purchase visit so the animals can be seen and the management standards assessed. Look critically at the best and the worst animals. Much information on the health status of livestock can be gained by looking at why you wouldn't want to buy!
3. The ideal is to always try and buy home-bred stock from one farm. If you are looking for pedigree animals, it should be easier to select from farms that breed their own replacements.
4. Animals covered under a health scheme (CWD monitoring program, TB Free Certification) should always be selected in preference to suppliers who do not subscribe to these programs.
5. Always record the exact origin of every animal. Such information may be of use if subsequent disease problems arise.
6. Ask about the disease and health history of the stock to be purchased as well as others on the farm. With the vendor's consent, corroborate this with information from other sources such as the vendor's vet.
7. Request and examine all documents relating to the health of the animals for sale including medicine books, health scheme certificates, etc. Request copies of all documents relevant to the animals you are about to buy.
8. If documentation is insufficient or if you have concerns about specific diseases, discuss with your own veterinarian whether any lab tests for disease need to be carried out before purchase. Seek advice on the accuracy and limitations of the tests as well as the number of animals that need to be tested to allow meaningful interpretation of the results. Have the vendor's vet do any pre-sale tests.
9. Decide on any vaccinations and other preventative treatments before removal from the source farm. If possible, arrange for treatments to be given before moving.
10. When transporting livestock, always use your own vehicle or one belonging to a reputable hauler. Always ensure that the vehicle is thoroughly cleaned and decontaminated with disinfectant before loading and after movement is complete. Whenever possible, arrange for animals to be transported direct from the point of sale to the destination farm. Avoid mixing animals from different sources on the same vehicle.
11. If buying at an auction, always buy through the ring to ensure traceability. Allow plenty of time for pre-sale inspections. Carefully examine the best and worst "draws" a seller has to offer. Again, always select health scheme accredited animals and ask to see all available health documents before bidding.
12. Always be prepared to walk away if problems or obstructions are encountered at any stage of the purchase process. However, always make sure that the vendor is never left with out-of-pocket costs.
Once animals are brought onto the farm from whatever source, it is important they are treated as a disease threat until proven otherwise. An effective quarantine takes into account the following factors.
1. The actual length of quarantine varies depending on the disease in question. As a general rule, six weeks should be sufficient to detect the presence of most acute disease problems.
2. For breeding requirements, six weeks is the minimum period. Ideally, they should be kept separate until after they have been tested or have successfully calved to guard against the possibility of spreading infectious abortions. Some diseases take months or years (CWD) to detect, so risk is never completely eliminated. This is why animals from a recognized health scheme are better choices.
3. Quarantine means complete isolation. To be successful, the area chosen must be completely secure from existing stock. Use a separate building or a double-fenced paddock with at least 10 feet separation from other stock. It is important that animals do NOT have nose-to-nose contact at any point.
4. People handling quarantined animals should have separate footwear and overalls. If at all possible, staff feeding quarantined animals should not handle other stock.
5. Upon arrival, dose all animals with an anthelmintic that is effective against inhibited and resistant gastro-intestinal worms. Yard or house them for 24 hours to ensure all worms are killed before turnout.
6. Regularly examine the animals during the quarantine period for signs of infectious disease. If you have any concerns, consult with your vet. Be sure everything is satisfactory before mixing new animals with existing stock.
Increased farm security involves making use of physical and chemical barriers to prevent disease entry and spread within your farm.
1. At farm boundaries, it is important to maintain a good stock-proof barrier, either by erecting, and properly maintaining, walls and fencing, or by making the best use of existing geographical features such as woodland, rivers and streams. Water may act as a good physical barrier, but it may also carry water-borne infectious agents e.g., salmonella and cryptosporidia from neighbouring farms, so it may be necessary to fence stock away from it.
2. Discourage the general public and other visitors from coming into direct contact with the livestock. Discourage unauthorized access to farm buildings by erecting signs citing disease prevention measures as the reason, and if necessary, secure building entrances and gates with locks.
3. Have a guest book or register where visitors (including your vet) sign in. If an infectious disease develops on your farm, this information may be useful in tracing the source and letting others know about it.
4. Ensure that contractors and visitors (including vets) coming onto the farm maintain high standards of hygiene and disinfect all equipment before use. Provide separate vehicle parking and a disinfection area near each entrance and well away from animal accommodations. Maintain stocks of disinfectant and provide hoses, clean water and brushes to allow boots and vehicles to be thoroughly cleaned of any mud or manure before applying disinfectant solutions. Refuse access to anyone who is not prepared to comply with your regulations. Remember to regularly clean and disinfect vehicles used within farm boundaries to stop disease from being carried around the farm.
5. Always consider security risks posed at other sites when stock is held away from home. Examine animals carefully when they return and always quarantine them as with newly purchased stock.
Hygiene and farm environment
Here are some steps you can take to prevent diseases from spreading.
1. Ensure provision of fresh clean water at all times to prevent animals wading through and drinking from contaminated watercourses.
2. Move feeders regularly to prevent excessive poaching of ground and associated contamination with manure. Remove or turn feeders over after use to prevent contamination with bird or animal faeces.
3. Try and adopt rotational clean grazing policies wherever possible to keep exposure to gastro-intestinal and lungworms to a minimum. Remember, "clean" grazing means grass that has not been grazed on for at least 12 months.
4. Adopt good pasture management practices to ensure grass is not overgrazed or allowed to become too infested with toxic plants such as Ragwort and St. John's Wort, or with thistles and thorns, which may cause foot abrasions leading to increased lameness problems.
5. Place disinfectant footbaths at the entrances to buildings and between separate areas within buildings. Fill regularly with approved disinfectant and replace every week. Make sure everyone uses them so that standing in a footbath becomes automatic.
6. Provide adequate, easily-cleaned and waterproof protective clothing for personnel handling animals. Use disposable gloves when handling or examining animals to reduce the risk of picking up and transferring infectious organisms, some of which may be harmful to humans. Always wash your hands thoroughly before leaving any animal accommodation area.
7. When possible, design or modify pens to allow animals to be kept in small batches depending on age, background and clinical or management history. This way, if a disease breaks out, it can be contained.
8. Keep the farm as tidy as possible to reduce the presence of vermin. Keep farm dogs under control and make sure they are wormed regularly.
9. Ensure that feed stores are secured against vermin, birds and cats and that they are watertight to guard against damp-induced spoilage of feed. Concentrates should be stored off the ground, preferably in sealed bags or pallets or in dedicated silos.
10. Feed only good quality conserved hay and silage that has been stored properly to prevent problems associated with fungal toxins or listeria bacteria.
Surveillance and response readiness
Successful disease prevention and surveillance relies on the three R's: Regular veterinary visits, Reports and Record keeping.
1. Prepare a written herd health plan outlining routine disease prevention measures such as vaccinations and anti-parasitic treatments. Update this plan on an annual basis.
2. Have regular visits from your vet to discuss your health plan and other disease prevention issues. Discuss the possibility of laboratory testing to identify certain infectious diseases that may be already on the farm.
3. Keep scrupulous records to detect problems with herd performance that may be attributed to the presence of infectious diseases. Keep records of all disease occurrences, medications, treatment programs and results. Ensure that your records system can retrieve and analyze all relevant data when required.
4. Try and develop a contingency plan in case a disease outbreak occur. It is usually easier to give cost-effective advice on how to limit losses if health risk factors can be identified in advance and problems tackled early, rather than attempting to respond with a reactive approach to disease control. These contingency plans should include provisions for insurance or access to government programs to cover costs due to disease losses.
Unfortunately, livestock diseases have now gone global. Prudent deer and elk producers must take the appropriate biosecurity measures to protect the health and wellness of their herds.