Biosecurity programs, designed to prevent new disease entry and control diseases that already exist, have two parts:

• Procedures used every day to keep new swine disease pathogens from entering a swine herd, and

• Diagnostic Sampling

  Managing the diseases that are already present in the herd.

Routine diagnostic sampling is needed to accomplish both tasks.

Diseases in today's swine herds have become very complex, often involving both bacteria and viruses. Consequently, diagnosing disease is less straightforward. In order to completely understand disease entry and movement within a herd, it is necessary to routinely collect samples from pigs and interpret diagnostic results.

Historically, diagnostics have been used to help guide producers in making treatment decisions. Today, however, population testing is influencing so much more of our treatment decisions.

Producer Training

For example, routine herd monitoring helps guide decisions on gilt entry and semen into breeding herds and the movement of weaned pigs into nurseries. Sampling populations helps narrow the age at which specific pathogen exposure is occurring, which helps guide vaccination recommendations.

Increasingly, routine sampling is also being used to measure our success with disease eradication programs.

Pork producers have certainly taken a much more active role in the investigation of disease within their herds. This makes sense because they are in the barn every day and often are the first to recognize abnormalities. Once trained how to perform necropsies and identify lesions, timely samples can easily be collected.

At Swine Vet Center, conducting posting clinics and training sessions have been valuable in helping producers learn these important techniques.

Quality Sample Collection

We have also developed detailed posters to showcase lesions that occur with common diseases. Displaying these posters in hog barns has helped producers narrow down a preliminary diagnosis.

Available technology, such as digital cameras and videos, has also expedited our clinic's ability to get a preliminary diagnosis of a swine disease. Producers can send images of what they are seeing, which, with a good herd health history, helps the veterinarian formulate initial treatment recommendations.

When deciding to take any type of sample, it is important to remember that poor-quality samples will almost always yield poor-quality diagnostic results.

When selecting pigs for sample collection, make sure that the pigs are representative of the clinical or visual abnormalities you are observing within the group. Chronically infected pigs are often immune-suppressed and can be infected by several insignificant pathogens that will make diagnostic interpretation difficult.

On the other hand, pigs that died acutely or rapidly for reasons unrelated to the current condition, or that are visibly healthy, may not elicit any meaningful results.

Collecting Tissue Samples

When collecting tissue samples for disease diagnosis, we recommend sampling from at least two pigs that have recently begun showing clinical signs, and preferably, have not been treated.

Although treatment doesn't necessarily influence viral diagnostics, in a high percentage of cases there is often a secondary bacterial component that may be masked by previous antibiotic treatment.

As long as time and effort is being taken to identify, necropsy and collect samples for a disease diagnosis, we recommend that a complete set of tissues be collected.

Although clinical signs or lesions may suggest a specific organ or system is involved, submitting a complete set of tissues has helped identify other unsuspected pathogens.

Always use a clean knife and take a systematic approach to tissue collection. Begin sampling at the pig's head and neck, taking tonsil and lymph node samples, before moving through the thoracic cavity to collect lung and heart samples. If other lesions are visible, samples of those should also be taken at this time.

Once in the abdominal cavity, collect liver, kidney and spleen samples. Finish by taking samples of the intestinal system, collecting colon and small intestine samples.

Remember, when dealing with respiratory disease cases, it is important to take multiple pieces of lung. Similarly, when dealing with an enteric case, multiple pieces of small intestine and colon are warranted. Separate small intestine and colon samples when packaging tissues and keep them separate from all other tissues collected.

For clients who perform their own sampling, Swine Vet Center has found that a necropsy kit, including bags labeled with each tissue type, has been helpful.

For every tissue sample taken, be sure to cut a small piece (⅓ to ⅝ in. thick) to fix in 10% formalin. These tissues can be combined and placed in a ratio of at least five parts formalin to one part tissue. If clinical signs in the group include neurologic or joint problems, samples that include those tissues should also be taken.

Next Page: Live Animal Submission