New pig wasting disease made worse by poor management.
The swine industry has seen tremendous restructuring through the 1990s. A lower weaning age represents a primary management change that has affected this restructuring. Medicated early weaning, segregated early weaning, or just early (14-day) weaning greatly impacts the way sows and their early weaned pigs are managed. The pork industry has seen major improvements in performance from early weaning due to improved feeding regimes and decreased affect of disease pathogens.
Case Study No. 1 I was called to a farm that had recently sold their sows and had started purchasing early weaned pigs (14-18 days). The pig source was 500 miles from the nursery. The pigs were given an electrolyte solution in the water and a pelleted feed offered in feeders immediately after arriving from the farrowing source.
Seven days after arrival, 5-10% of the pigs seemed to be wasting away and not consuming feed. During my visit, I took many temperatures from affected pigs. All of the pigs had normal temperatures. I evaluated water flow rates to make sure water intake was adequate.
Pigs were uneven. I believed they were not properly sorted on arrival or a severe separation of the pigs had occurred. It is very important to properly sort pigs by sex and size after arrival. They can be fed better and the workload eased by putting together all disadvantaged pigs into one location.
I did postmortems on some of the wasting pigs and found no evidence of disease. The stomachs were empty and the lungs were free of pneumonia. The pigs showed no evidence of diarrhea or disease.
Tissues were sent to a diagnostic laboratory to rule out systemic, infectious, bacterial diseases such as Streptococcus suis or Haemophilus parasuis and viral diseases such as PRRS or multisystemic wasting disease. No infectious disease was identified.
A diagnosis of starvation and poor starting of the pigs was determined. In future groups, the following changes were made:
* An extra effort was made to sort the pigs for sex and size upon arrival. Plus, two pens were left empty so the fall-behind pigs could be sorted down at a later time.
* The bottoms of five-gal. buckets were cut off to make temporary waterers to help rehydrate the pigs after the long hauls. The waterers were left in the pens for 48 hours and then removed.
* All of the light and disadvantaged pigs were fed a gruel feed, which was a combination of milk replacer, the first stage diet and water. This was offered to the pigs for 15-20 min. three times a day.
* Feed budgets were generated that allowed for differences in the feeding of early stage diets to different weight pigs.
* More attention was paid to evaluating the temperature, humidity levels and other environmental considerations.
Wasting Disease A new disease that has recently impacted nursery pigs and is different from starvation and poor management is multisystemic wasting disease. This disease has increased rapidly in the last two years. Iowa State University's diagnostic laboratory diagnosed two cases in 1996, six cases in 1997 and 30 cases in the first quarter of 1998.
This disease was first identified in Canada and was originally thought to be from pigs with Canadian origin. This does not hold true today. A diverse population of swine farms is being affected by this disease. Large integrators, 200- to 300-sow farms and totally closed herds are being affected.
Clinical signs include wasting or thin and gaunt pigs and dyspnea or difficult breathing in 5- to 7-week-old pigs. Pigs are feverish and may have diarrhea. Pale pigs are often seen and yellow pigs can be identified. A typical pattern is 1-3 affected pigs/pen.
Poor management such as drafty buildings, overcrowding, poor air quality, and continuous-flow nurseries make the number of pigs affected much worse. This disease can be seen in the nursery but also in the early finisher phases up to 14 weeks of age. PRRS and other secondary diseases will greatly increase the death loss from multisystemic wasting disease.
Death loss can reach 5-15%. The disease is thought to be caused by a pathogenic Porcine Circovirus. Different strains of Porcine Circovirus have been around for many years and are the cause of congenital tremors or shaker pigs. There does not appear to be a correlation between herds that experience multisystemic wasting disease and a history of shaker pigs in their herds.
Treatment of pigs with multisystemic wasting disease is frustrating and often ineffective. Aspirin in the feed or water along with injections of iron to counteract the anemia have been helpful. Broad-spectrum antibiotics are warranted to help control the secondary bacterial infections. But nothing has been extremely effective at controlling and decreasing death loss.
No clinical problems are normally seen in sows. Diagnosis must be made by sending in tissues to a diagnostic lab familiar with this disease. Specific diagnostic lesions can be identified by histopathology tests. The epidemiological factors or how this disease is spread is unclear but diverse populations of swine herds are being affected.