Analyze Slaughter Check Results Before Implementing Changes

Slaughter checks are management tools that can be used to make sure that parasites, pneumonia, etc. are not robbing your herd of its optimum performance. Fall and spring are the usual times for slaughter checks. Slaughter check results require both interpretation and economic evaluation. The loss of productivity in terms of growth rate, feed conversion, and carcass merit, as well as the control measures may be quite costly, and only performance records will show their bottom line effect. The importance of good record keeping can not be over-emphasized. Knowing the numbers will allow you to figure the cost/benefit ratio of vaccinating, medicating, or upgrading facilities and production practices. Be sure that a net economic benefit can be realized before spending any money on control or treatment measures. Following are some guidelines which may be helpful for analyzing slaughter check results using the PIGMON method.

Mange

New herds start and usually remain mange free. Mange can be introduced through live-animal introductions or contaminated bedding.

Mange is scored by severity (0-3), and scores in mange free herds average less than .7 and often much lower with most scores being 0 to 1. An average score of 1 or higher is highly indicative of mange. A skin scraping should be performed before any treatment begins to be sure of the diagnosis.

If mange is present in a herd, the best long-term solution is eradication. Once mange is eradicated in the sow herd, offsite barns can then be filled with 'clean' pigs and no further treatment or prevention should be needed.

Worms

Worms are rarely found in pigs raised in AIAO facilities on total slats, because there is less exposure to manure containing the eggs. If pigs are in a flush-gutter or solid floor facility, or if pigs are outside, worm infestations are likely. Re-infection is also more likely due to higher exposure levels, but eventually a good immune level is reached.

Worm migration (the round worm or ascarid) causes characteristic lesions called 'milk spots' on the livers of affected pigs. The degree of infestation may be graded as mild or severe. Generally, either none or several pigs have liver lesions. Occasionally a low percentage (<10%) of pigs in a barn are affected and treatment may not be needed.

Liver lesions do heal in about 30 days, so positive scores indicate recent infection. Strategy for control is dependent on the timing of treatment. Worming before exposure occurs will not prevent worms.

Snouts

Snouts are scored on a scale of 0-5. In this system, a score of 0 is a perfect nasal turbinate. Individual scores of 1 and 2 indicate subclinical infection or poor environmental conditions. An average score greater than 2 is consistent with clinical rhinitis and diagnostic tests should be performed and corrective action taken. Some cases require vaccination or other intervention. Most herds today have average scores of less than 1, do not vaccinate, and rely on good biosecurity for control.

Lungs

Lung scores are often the area of most concern, but also more difficult to interpret. Pneumonia levels can vary greatly, and the resulting effect on production is more difficult to assess, as are the treatment and control measures.

Lungs are scored by degree of pneumonia (consolidation). This may vary from 1 percent to more than 50 percent. The prevalence (number of affected pigs / total number checked) also varies from 0 to 100 percent. Groups of pigs with a prevalence of less than 30 percent and average lung scores of less than 2 percent have good pneumonia control. Scores of 5 to 10 percent or higher and a prevalence greater than 70 percent suggest a degree of pneumonia in those pigs that may have benefited from some type of intervention strategy such as vaccination, treatment or better environment.

If you need assistance in diagnostics or interpretation of slaughter check results, call your veterinarian or Dr. Darwin Kohler at Babcock Swine. Dr. Kohler may also be contacted via e-mail at drkohler@means.net.