Scott Dee Announces Retirement; Reflects on Top 10 Lessons Learned

By Dr. Scott Dee, Pipestone

As some of you may know, I have decided to enter phased retirement at Pipestone after 35 years in veterinary medicine. Throughout my career, my primary goal has been to create new knowledge to help swine veterinarians and pork producers protect their herds from infectious disease challenges, such as porcine reproductive and respiratory syndrome (PRRS), porcine epidemic diarrhea (PED) and African swine fever (ASF).

When Jennifer Shike invited me to share my reflections with Farm Journal’s PORK, I thought it would be fun to review my favorite research projects, the primary discovery from each one, and how the outcomes were applied on the farm. For historical purposes, projects 1-4 were conducted during my PhD program as a swine practitioner in Morris, Minn., 5-7 were generated during my 12-year tenure as a faculty member at the University of Minnesota College of Veterinary Medicine and 8-10 are products of my 12 years at Pipestone.

Here we go: my Top 10!

1. Nursery depopulation: A strategy to control post-weaning PRRS

Discovery: If PRRS virus is circulating in the nursery, depopulating the nursery will eliminate the virus from the site.

Application: Advanced the development of all in/all out by site animal flow.

2. The role of the replacement gilt in the control of PRRS virus in the breeding herd

Discovery: Continuous introduction of naïve replacement gilts to an endemically infected sow farm perpetuates the circulation of PRRS virus.

Application: Initiated the concept and use of the gilt development unit (GDU) and laid the groundwork for manipulating the flow of incoming replacement gilts (herd closure) to control and eliminate PRRS virus.

3. Breeding herd subpopulations

Discovery: Homogenous PRRS virus exposure in the breeding herd is difficult to achieve via natural spread of the virus, resulting in subpopulations or “pockets” of naïve animals, which co-exist alongside of infected animals, thereby, perpetuating chronic viral shedding.

Application: Advanced the use of whole herd vaccination and/or live virus exposure in the sow herd to eliminate naïve subpopulations and reduce shedding.

^{A flash back to my early years as a swine practitioner in Morris, Minn.}

4. Elimination of PRRSV from the breeding herd using test and removal

Discovery: Proof of concept that PRRS virus elimination from the sow herd was possible.

Application: Led the way for the development of more efficient methods to eliminate PRRS virus, such as herd closure.

5. Mechanical transmission of PRRSV: The snowball from hell model

Discovery: Demonstrated that PRRS virus could be spread mechanically across long distances via a combination of personnel, fomites, and transport.

Application: Advanced the development of D&D (disinfection and downtime) rooms for supply entry to farms, along with the importance of efficacious transport sanitation and controlled personnel entry (boot benches).

6. Long-distance airborne transport of PRRS virus

Discovery: Airborne transport of viable PRRS virus could occur at least out to 9 km (5.4 miles).

Application: Proof of concept that airborne spread of PRRS virus was real, leading to a greater acceptance of air filtration to mitigate risk.

7. The use of air filtration for the management of airborne diseases: The production region model

Discovery: Proof of concept that air filtration could significantly reduce the risk of airborne PRRS virus infection of swine populations.

Application: Advanced the use of air filtration across the North American swine industry.

^{I’m grateful for the opportunity to devote more time to research during my time with Pipestone.}

8. Transmission of PEDV via feed

Discovery: Proof of concept that viruses could be transmitted through natural feeding behavior.

Application: Original thought which eventually changed human behavior regarding the consideration of feed as a vehicle for virus transport and transmission.

9. Survival of viruses in feed: The transboundary and transcontinental models

Discovery: Viruses of veterinary significance, including ASFV, pseudorabies virus, foot-and-mouth disease virus, classical swine fever virus, Senecavirus A, PRRSV and PEDV can survive for extended periods of time in select feed ingredients.

Application: Advanced the development of “Responsible Imports” (controlled holding time and temperature) for feed imports and the use of additives at the mill to manage this risk. Led to the development of national programs across numerous countries, including Canada, Australia and Denmark.

10. Introduction of Senecavirus to a naïve national swine herd through feed imports from an endemically infected country

Discovery: The risk of viral introduction via feed imports can occur in the real world.

Application: Validated published laboratory data on the risk of feed and justified the importance of a feed biosecurity plan at the domestic and transboundary levels.

^{The topic that gets me most excited today is studying disease transmission in feed. Photo by National Pork Board and the Pork Checkoff.}

There you have it – 35 years condensed into <1000 words. In the end, I hope this work has been helpful to you, to your farm, to your practice, and to our industry. As I taper my time with Pipestone over the next few years, I hope to keep learning and delivering relevant information to this great industry and noble profession.

In closing, a very sincere thanks to Jennifer Shike and PORK for the opportunity to share my thoughts. A shout-out to many friends and mentors: the late Al Leman, the late Carlos Pijoan, Montse Torremorell, Han Soo Joo, Tom Molitor, the late Rod Johnson, Luke Minion, Gordon Spronk, Barry Kerkaert and the entire Pipestone team. Kudos to Satoshi, Jean Paul, Eduardo, Andrea, Laura, Jennifer and Jenny who did most of the work. To the farmers who welcomed me and appreciated my ideas out of “left field”: Roger Koosman, the Madsons, the Martys, the Lindors, Bob Dykhuis, Don Buhl and Randy and Seth Spronk. To the scientists who helped me advance the risk of feed: Eric Nelson, Diego Diel, Megan Niederwerder, the FADDL team and Paul Sundberg and SHIC which provided the funding for these projects.

Finally, all the love to Lisa, Nicholas and Ellen, my parents Dick and Pauline Dee, sister Julie and brother-in-law Karlos, and brother Andy.

See you down the road and best of luck to you all. Thanks for the friendships, the conversations, the challenges, and the memories; I will never forget any of you.

Your friend for life,
Scott Dee

^{I really believe that a good mix of right brain and left brain makes a difference in how you approach problems. The musical side with imagination has brought a lot to the table for me as a scientist over the years.}

Read More About Dee’s Research Findings:

Wake-Up Call: Pigs Contract Senecavirus A Through Imported Feed