Use of quality management tools to control PRRS
Research reported at the 2000 annual meeting of the American Association of Swine Practitioners demonstrates that the Continuous-Improvement measurement tools commonly referred to as Statistical Process Control (SPC) can cost-effectively measure progress of intervention strategies for the control of PRRSV in a herd.
The work reported the application of SPC measurement methods in a particular production unit to document the effects of vaccination against PRRS. When vaccination program changes were instituted, Continuous Improvement (CI) measurement tools permitted the managers to quickly identify any cost savings from the change, and — more importantly — the net effect on production and profitability.
The production unit studied was vaccinating only the sow herd against the PRRS virus, with no vaccination of piglets (figure 1.) During 1998's low market prices, the operation dropped vaccination entirely to save costs.
Soon afterward, the operation broke both with a reproductive form of PRRS and then a respiratory form in the growing-pig population.
The producer elected to return to vaccinating sows to control PRRS virus in the breeding herd. Over time, virus monitoring allowed the operation to determine that the vaccine had successfully prevented transmission of PRRSV from sow to piglet.
The next step then was to clean up the continuous-flow nursery that was contaminated with endemic PRRS virus. There, mortality had more than doubled, from 4.5 percent on a group basis to 9.7% (figure 2.) Daily gain had decreased from 0.7 lbs to 0.65 lbs.
Because sow vaccination had produced pigs free of PRRS virus at birth, the operation was able to use a modified-live PRRS vaccine (Ingelvac
Then, using Continuous Improvement tools that noted the process changes in an events log and then compared those events to any changes caused in key productivity measures, the operation was able to objectively measure changes in performances. The CI tools helped the operation management not only understand the consequences of the changes, but more importantly to do so quickly, while the process was ongoing. CI tools give management the ability to discard or continue a production practice while the process is ongoing — not months later.
In this study, when vaccinated pigs entered the nursery, growth rate improved to 0.77 lbs per day, 0.07 lbs better than the pre-outbreak performance. Mortality dropped to 4.4% per group — back to the pre-outbreak baseline performance. Clearly as a result of the use of vaccine — both in sows and in pigs before they entered the nursery, vaccination provided a high return.
Application
Looking at the big picture
“An incredible amount of data is generated that's not utilized nearly as effectively as it could be,” notes Boehringer Ingelheim Vetmedica, Inc.'s Dr. Dale Polson. “Process behavior charts allow you to take that data and choose the most important aspects to track, and then track them in a way that's much easier to interpret than anything we use currently in the industry.”
The list of things to measure isn't daunting. Key measures of breeding herd performance include annual pigs per sow and pigs per crate, litter size, and breeding productivity. Factors affecting each aspect of production can also be as basic, Polson says.
To more information
Use of Process Improvement/SPC as Part of a PRRS Control Strategy. Kolb JR, Walter D, Graham L. Proceedings of American Association of Swine Practitioners, May 2000; 211-213.