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Healthy Balance:
The normal modern large hog farm is a huge test of people's skills at producing hogs. We confine over 10,000 animals on a site that is maybe no larger than 10 acres and expect them to thrive and
grow without creating any problems. I have often heard it said that hog producers must be optimists or very foolish, to invest and work with the hog profit cycle. I have met very few foolish
producers therefore I surmise that you are all great optimists. But establishing a permanent population of that size in such a small area with all ages of animal present is definitely risky. What
would happen if that was a population of people? I dread to think, but I am sure I would not be applying for the job of managing that set up.
The farm is a dynamic population with continuous movement of animals through the system. It is an ideal environment for the development of hog specific micro-organisms. I am not referring to
disease causing organisms, just general "bugs". Each unit will develop its own unique range of "hog bugs". These micro-organisms do not create an infectious disease state but they do have appreciable
affects on the hog performance. Buildings can be hog sick. The real test of the performance affect of these bugs is to monitor the performance of a new or depopulated farm. Do growth rates and
conversions for the different sections of the farm on each batch of throughput and watch as the farm reaches full stocking the slow deterioration in performance even though there may be no evidence
whatsoever of any disease or sign of any disease causing organism on blood test.
To minimise the affect of hog sick buildings a good hygiene programme should be established and rigidly enforced for the total building. An "all in all out" system should operate. Hogs born each
week should form a group and operate as an intact group right through to slaughter. Sick or injured animals that have to be removed from the group should never be introduced to younger stock but
reared outside the group system totally.
Both for disease and non-disease causing organisms a balance must be maintained within the farm. The hog, his immunity, and his comfort on one side balancing the bug population on the other. More Info.
Anything that may tip the balance in favour of the bug side will create a problem or anything that interferes with the hog's immunity or comfort will do similarly. Aids to help the hog maintain the
balance are the disinfection and vaccination programmes and also the proper use of antibiotics. Continuous dependence on antibiotics to prevent disease is a very unprofitable situation and in this
predicament the comment "Antibiotics are an excuse for bad management" would be appropriate. More Info.
Some very interesting work By Prof. T.S. Stahly, Prof. D.R. Zimmerman & N.H.Williams (ASL-R1160) of Iowa State University (1994) on the "impact of immune system activation on the rate,
efficiency and composition of growth and amino acid needs of pigs fed from 13 to 250 pounds body weight". Well worth a read. More Info.
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Health Risks:
Listing the precautions to be taken by a farm for setting up a bio-security programme is a detail that you should discus with your veterinarian. More Info. I will confine my comments to peculiarities that I
have seen in the operation of these programmes.
Imagine the scenario, feed system breakdown eventually the repairman arrives. He showers in, dresses up in unit overalls and inspects the damage. His tools and spare parts are in the vehicle
outside, so out he goes and brings them into the farm. Major fault in the procedure - there is a risk of bringing in dung from another source from contact with the vehicle and of course his tools
which have more than likely been down in some other unit are brought in without proper attention. All equipment especially tools that have to be introduced into the unit should be clean and
fumigated. In a breakdown situation an estimate of what may be required should be made prior to the repairman showering in and if he has to return to his vehicle at a minimum he should change out of
the unit clothes and footwear.
It is a good idea to use a visitor's book to record all non-farm staff entries to the farm. It is a useful record for future reference as well as being a declaration that the visitor is complying
with your specific requirements re prior hog contact.
The introduction of new genes into the farm holds the greatest potential risk of introducing new disease agents. More Info. The method used is dependent on the safety level required.
Method of introduction:
- AI - frozen and fresh semen: Fresh semen is widely used but carries the risk of transmission of some viral diseases. Frozen semen performance is improving but in general it is not used for
the transfer of genes except by some breeding companies.
- Hysterectomy: Expensive, great care required to rear the transferred piglets, mainly used by breeding companies in the transfer of genes
- Boar semen imports, females bred on unit: Gene input confined to male semen imports, no live animal imported. The female breeding strategy needs to be well planned and adhered to. Drawback
is that genetic improvement is slowed down.
- Boar semen and pure-bred female imports: Live animal imports of about 5% of herd size annually. Small quarantine required. Maintaining a small pure-bred herd (10% of main herd size) within
the main herd to keep an even supply of replacement gilt available to the commercial herd is difficult.
- Boars and commercial female imports: Importing all your replacement animals means large numbers entering per year. If the commercial herd cull is at 40% then you require approximately 45%
of herd size inputted per year (over 3.5% per month). Very large quarantine required and very strict supervision necessary.
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Control Measures:
The elimination of any possible contact between stock on the farm and:
- Other hogs
- Dung from other farms
- Natural vectors: birds, vermin etc.
- Pets: dogs, cats etc.
- Humans with flu.
More Info.
The sites selected for new hog farms should be well isolated, away from existing units and away from routes known to be used for hog transport. The density of hog farms in an area, their size and
the prevailing disease status, will determine the risks of air borne disease spread.
The herd vaccination programme and its correct implementation will offer insurance against certain disease outbreaks. When did you last check the amount of vaccines purchased
and compare it to what is required under your programme? Has your staff been trained in how to vaccinate properly, the use of correct length needles and vaccination site? More Info.
In situations where there is no vaccine available discuss with your veterinarian procedures for maintaining low levels of active organisms within the farm and thereby maintain a challenge to the
breeding herd and maintain a high immunity transfer. After a disease outbreak on a farm the immunity level to that organism is very high with the result that the volume of bug around the farm drops
down. As the animal is no longer been challenged its immunity drops with time and it therefore can become susceptible to another disease outbreak at a later time. However if there is a continuous
introduction of a small number of susceptible animals (your replacement gilts) into the herd this will keep the organism active but not at a level that will generate a disease. Discuss with your
veterinarian and devise a strategy.
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Outbreak:
Disease outbreaks do occur even in the best-regulated farms. A sudden outbreak without any prior symptoms e.g. flu outbreak can have a devastating affect on staff moral. To see a whole house of
pigs stretched out and panting is a frightening experience. It can be very beneficial to bring your veterinarian into the farm to explain to the staff the disease, its affect and the implications for
themselves. Always remember how you feel when you get the flu and have a little sympathy for the animal. Sick animals do not require feed but should have easy access to clean water, they will drink
liquid long before their appetite returns. Do you medicate the water system to prevent secondary infections?
In outbreak situations keep the animal as comfortable as possible. If hog intake has dropped then their heat generation has reduced so be sure that the ventilation system can cope and keep the
environment fresh with a stable temperature. The environment must be kept stable with minimum temperature fluctuation. Very small quantities of feed should be offered and if not consumed by the
animals it should be removed before adding more. Keep feed fresh. Keep disturbance to a minimum and let the animal rest. Nature is wonderful and given a little help (by the veterinarian) the animals
will overcome the challenge and thrive on.
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Useful links:
Research Articles on Swine Health
Health Index
Research Articles on Swine Diseases
Disease Index
Research Articles on Ventilation
Ventilation Index
Research Articles on Management
Management Index
Research Articles on Reproductive Failures
Article List Reproductive Failures
Research Articles covering Pests
Article List Pests
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General Research Articles:
Index by Disease giving the most recent article published
Disease Article Index
Index of proceedings 1986-1999 Amererican Association of Swine Practitioners
Index of proceedings AASP bibliography
Diseases & Reports
U.S. Animal Health Association
Directory of Health related sites
Internet-health-directory.com
The PRRS Page
South Dakota State University
Animal Productivity and Health Information Network - APHIN
Animal Productivity and Health Information Network
National Animal Health Monitoring System (US) - Swine Reports
US Agriculture
Ontario Animal Health Surveillance Network - Swine
Ontario Agriculture
Martindale's Health Science Guide
University of California, Irvine
Centre for the Epidemology of Infectious Disease
Oxford University
Mystery Swine Disease - Human affect
Chronic Illness Areas
Iowa State List of diseases
Iowa State University
Swine Health - Freedom From Disease Canada
Canswine
Introduction of a new disease
University of Hawaii
Swine Disease
University of Illinois
The Pig Site - New Web site - check out Health Database
The Pig Site
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