Researcher tracks elusive disease

Post weaning Multi-systemic Wasting Syndrome (PMWS) has caused "lots of problems" in Saskatchewan where it was first discovered in 1994, says Tiffany Cottrell, a British veterinarian carrying out graduate research at the University of Guelph. She recently confirmed the presence of the disease in Ontario.

No one is sure how it is spreading or how to treat it. "It seems to be self-limiting, but people in Saskatchewan who had it just had to put up with it," Cottrell says of PMWS, which can take up to three years to run its course on a farm.

Mortality averages 10 per cent, but a few severely affected herds lost 90 per cent of their nursery pigs.

Affected pigs between six and 14 weeks old show diarrhea, and dyspnea (laboured breathing), are coughing, pale, wasting and possibly jaundiced. Following its initial discovery, further investigation discovered the disease in at least one Saskatchewan herd in 1991.

"Diagnostic methods have become available looking for circo virus as the associated causative agent, although no one has published that it is, " Cottrell explains. Researchers have discovered Porcine Circo Virus (PCV), the smallest known virus, measuring just 17 nanometers in diameter, in all PMWS cases, but to date no one has been able to induce experimentally the disease using the virus.

Depopulation is not a promising option because no one has found a way to rid infected premises of PCV. Cottrell says the virus is closely related to Chicken Anemia Virus which poultrymen have found difficult to eliminate.

PCV has been found in Spain, Australia, France, Germany, Ireland the United Kingdom, France and Belgium and many U.S. states. Countries believed free may simply not have sampled adequately.

Cottrell found the impact of PMWS was greatest on Saskatche-wan's geographically isolated herds, some of which are free of Mycoplasma and Porcine Reproductive and Respiratory Syndrome. "They're much cleaner to start with, so when a disease like this comes along they're more susceptible to it," she says.

Cottrell says the fact Saskatchewan had PRRS-free herds actually sped the discovery of PMWS: "If the initial outbreak had happened here we would have just said that's another manifestation of PRRS and not really looked for anything else."

Cottrell says like PRRS, PMWS "appears to cause immuno suppression and act in concert with other diseases."

Most of the 25 Ontario herds participating in Cottrell's study tested positive for PCV. "Many of these farms aren't showing any manifestations of the disease," she observes, some display chronic symptoms and two show "an out-and-out epidemic of the disease."

Her samples were derived from "a portion of" the Ontario herds experiencing problems and referred by private veterinarians, as well as a sample of "the cleanest herds I can find." Cottrell currently samples three pigs in each herd using a Polymerase Chain Reaction test, which magnifies the virus.

She concedes her current methodology could turn up three negative pigs in an otherwise positive herd. In future, Cottrell plans to increase accuracy by sampling more animals using an ELISA test which measures antibodies that show up when an animal has been challenged by disease. As her research won't reveal an objective picture of the situation in Ontario for about three months - beyond practising good animal husbandry to maximize herd productivity and performance - there aren't any recommendations available yet for producers.

Cottrell confides, however: "My feeling is that this disease is endemic in Ontario. I don't know how widespread it is, and I don't yet know if the virus is related to the disease." - Robert Irwin

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Going holistic hog

Huron county pork producers Ron and Trudy Kassies have all but eliminated antibiotics from their herd in favour of a holistic approach

BY BERNARD TOBIN

If it works in the home, it should work in the barn. In simple terms, that's Londesborough pork producer Ron Kassies' herd health theory. A couple of years ago, while their daughter Robyn suffered through chronic ear infections, Ron and his wife Trudy decided to give homeopathic remedies a try. When the remedy succeeded in clearing Robyn's troubles after penicillin had failed, Kassies wondered whether homeopathic remedies could also benefit his 80 sows and the 1,600 market hogs he produced annually.

The answer was a resounding yes, says Kassies. He hasn't vaccinated a pig in four years and uses no growth promoters or medication in feeds, with one exception: A medicated creep feed is fed to young pigs because he can't buy small quantities of non-medicated product.

Kassies produces what he calls "holistic pork" using homeopathic remedies to prevent and treat disease. He and Trudy are trying to develop a niche market for the product. Currently, about five per cent of their production is processed into everything from smoked hams and cottage rolls to bacon and farmers sausage at Hensall's Metzger Meats. The products are vacuum packed, returned to the Kassies' farm freezer and then sold to a growing number of clients. The rest of their production goes into the Ontario pool.

"We get a lot of repeats and we're picking up new customers. We started with one pig per month. Now we're up to four pigs per month," Kassies says. They would like to increase their freezer sales to 15 or 20 per cent of tota l sales.

Until earlier this year, Ron had relied on word of mouth to push the product, but he now gets marketing help from brother Andy, who distributes flyers in the London area.

He targets quality conscious consumers who take a greater interest in how their food is produced, but "the biggest attraction is still taste," he adds. "People who try it, like it."

Kassies keeps medical costs low by emphasizing disease prevention. There are some 6,000 homeopathic remedies used for prevention and treatment of disease. His current homeopathic regimen was prescribed by Goderich veterinarian Bill Schilthuis, who has been investigated and subsequently suspended by the Ontario Veterinary College for dispensing homeopathic advice to farmers.

While Ron refrains from passing judgment on the Schilthuis-OVC predicament, he credits Schilthuis' homeopathic regimen for his pigs' clean bill of health. Kassies' approach begins with hydrogen peroxide medicators in drinking water. Other than a few bouts with scours, his pigs have been relatively healthy since he made the switch from conventional medicine.

For scours treatment, Ron administers a remedy in the pigs' water consisting of about 20 compounds, including sulphur and herbal extracts camellia and echinacea.

Good pig production, according to Kassies' definition, also includes the health of the operator. Ron says having his pigs housed outdoors also improves herd health and reduces pig and operator stress. His modified open-front barn contains 10 pens, each housing 50 pigs. The 50- X 12-foot pens with dry feeders provide twice the space per pig of conventional confinement operations.

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Ventilate, don't vaccinate

What is the first thing we do when we get ill? Besides taking our medication and resting in bed (usually too limited), we reflect on what may have caused us to become ill. In many cases, it is simply a matter of too much work, not enough rest and exposure to pathogens (stress to the body).

Compounding this can be the environment, stuffy homes and barns in the winter, or even going back and forth from air conditioned spaces to the hot outside in summer.

What does this have to do with pig production? A holistic approach to health is an important method to ensuring we do not become ill. Inside the barn, the same approach can also pay dividends. In particular, the ventilation system should be an integral part of the whole herd health program, not just needles for sick animals.

The fall is a good time to consider the role fresh air plays. Large and rapid outside temperature fluctuations are a typical problem every fall, placing a strain on the ventilation system and stress on the animals. Early fall is the time to make sure you do not get caught with an unexpected health break due to ventilation-related stresses.

A number of items can be reviewed:

* For fan and dual-ventilated barns, zero the static pressure manometer.

* Check inlets to be sure they close uniformly and completely, and adjust any weights or other mechanical components to allow them to close properly as fans slow down. A smoke test will also reveal air patterns and leakage at the inlets and other locations.

* Reset controls and inlet systems to reflect the approaching cool weather.

* Have the heating system completely cleaned and inspected.

* Check fans from the inside and outside for any potential component failure from vibrations, or other stresses. Clean completely, especially the louvres, which will prevent cold air leakage when they turn off.

* Consider back draft dampers for the stage 2 fans, and have the summer fan insulated covers handy for the first cold snap.

* Verify fan, inlet and heater operation from the control(s) by simulating different conditions - adjusting set point at the control, warming the sensor with your hand, or cooling it with a glass of cold water.

* Check the alarm system and high-low temperature set points.

* Consider including a ventilation specialist in your herd health program to check over the system and prepare an inspection report, to ensure you do not miss anything.

* Once the heating system is required, verify relative humidity control in the 50-65 per cent range.

Careful effort before cold weather allows maintenance and repairs in ideal weather conditions and ensures a proper job.
Ron MacDonald is an agricultural engineer with Agviro Inc., Guelph

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