Major Health Challenges in Large Swine Production Systems

Estimates of the economic impact of specific diseases on the U.S. swine industry are available for very few diseases. Recent research estimated the annual cost of PRRS in the U.S. to be approximately $560 million.¹ However, more comprehensive estimates of the impact of all major health challenges have not been published . A comprehensive estimate of all major swine health challenges is needed to facilitate industry benchmarking and to help guide animal health related investments in the industry. The objective of this study was to rank and quantify productivity and economic losses in the swine industry due to the major health challenges. Information on production and economic impacts was obtained through use of face-to-face, personal interviews. The focus of the study was on the segment of the U.S. industry producing more than 150,000 pigs per year. This segment currently markets just under half of the pigs sold annually in the U.S.

Materials and methods

The companies producing more than 150,000 pigs per year were identified. This population of companies was further segmented by size, vertical integration, and geographic location in order to assure representation of the entire population of interest. Production companies with 7,500 to 25,000 sows were considered "medium" sized while companies with more than 25,000 sows were considered "large." Vertically integrated companies for the purposes of this project were defined as those that have integrated live animal production, slaughter, and processing. Only companies with more than 25,000 sows were segmented as integrated or not integrated since very few producers with fewer than 25,000 sows are vertically integrated. The U.S. was divided into three geographic regions based upon USDA's 10-region classification. The groups are East (Appalachian, Delta, Northeast, Southeast), Midwest (Cornbelt, Lake States), and West (Northern Plains, Pacific Northwest, Southern Plains, Mountain). This segmentation scheme resulted in nine segments (Table 1) . Two production companies from each of the nine segments were selected for inclusion in the study. A third medium-sized company in the West was surveyed for a total of 19 surveys. When production companies had major operations in more than one geographic location, each location was considered a separate entity. Selection of companies was based on the anticipated willingness to participate and availability of interviewees during the timeline of the project and, therefore, not random. Only one company asked to participate declined.

Table 1. Number of companies surveyed in each segment of the population of interest

Geographic
Location

Size and vertical integration

	7,500 to 25,000 sows, not integrated	More than 25,000 sows, not integrated	More than 25,000 sows integrated
East	2	2	2
Midwest	2	2	2
West	3	2	2

A survey was developed and administered to a single veterinarian at each company through face-to-face, personal interviews. The same interviewer administered all of the surveys in a consistent manner to minimize any differences in the results attributable to differences in how the surveys were administered. All of the surveys were conducted between November of 2005 and February of 2006.

Results

The relative rankings for each of the health challenges are reported here. The ranking of health challenges according to the productivity losses attributed to each in the breeding, nursery, and finishing herds are reported in Figures 1, 2 and 3.

Breeding herd

In the breeding herd, PRRSV was the most frequently ranked health challenge (Figure 1). It was ranked as a health challenge resulting in productivity losses in the breeding herd for 18 of the 19 companies surveyed. Further, it was ranked as number one (1 being the health challenge with the greatest productivity losses) in every one of the 18 companies that ranked it. PRRSV was also ranked as a health challenge in combination with Salmonella and PCV2 by 2 companies. Swine influenza was ranked as often as PRRSV and with the second greatest productivity losses (average rank of 3 .7) when ranked. Swine influenza in combination with PCV2 was also ranked 11th by one company.

Economic Cost of Major Health Challenges in Large US Swine Production Systems - Image 1

Economic Cost of Major Health Challenges in Large US Swine Production Systems - Image 1

Clostridia 1 diseases as a group were identified as the next most significant health challenge in the breeding herd. Clostridium perfringens type A was ranked as a health challenge in IS of the 19 companies with an average rank of 4.1, Clostridium difficille ranked in 9 of the 19 companies with average rank of 7.1, and Clostridium perfringens type C ranked in 4 of 19 companies with average rank of 5.8. Rotavirus alone or in combination with E. coli was cited as a breeding herd health challenge for IS of the 19 companies. As a single pathogen it was cited as a health challenge in 10 companies with an average rank of 5.3. In combination with E. coli, rotavirus was cited as a health challenge for 7 companies with an average rank of 4.9, higher than that of rotavirus alone. Streptococcus suis and Coccidia were cited as a health challenge for 14 and 12 companies with an average rank of 7.0 and 6.0, respectively lIeitis and Mycoplasma hyopneumoniae were ranked for 13 and 12 companies with an average rank of 6.2 and 7.3, respectively. The last three on the list of health challenges in the breeding herd cited for more than half the companies were greasy pig disease, E. coli. and Haemophilus parasuis.

Nursery herd

In the nursery herd , PRRSV was the most frequently ranked health challenge (Figure 2). As in the breeding herd, it was ranked as a health challenge in 18 of the 19 companies surveyed and was ranked as the number one health challenge in all but one of the 18 companies in which it ranked. PRRSV was also ranked as a major health challenge in combination with Salmonella and PCV2 for 2 companies. Haemophilus parasuis and swine influenza were also ranked as a health challenge for 18 of the 19 companies with an average rank of 4.1 and 4.3. Swine influenza also ranked as health challenge in combination with PCV2 for one company. Streptococcus suis was cited as a health challenge for 17 of 19 companies with an average rank of 4.1. E. coli was ranked for IS companies with an average rank of 5.2. Greasy pig, Mycoplasma hyopneumoniae, Pastuerella multocida, and Bordatella bronchiseptica complete the list of health challenges cited for more than half the companies. PMW, PRRS in combination with PCV2, and SIV in combination with PCV2 were all cited as nursery problems in a small percentage of the companies surveyed, but when cited, the productivity losses associated with them were ranked relatively high . At the time the surveys were completed, Porcine Circovirus Associated Diseases (PCVAD) had not yet been adopted.

Economic Cost of Major Health Challenges in Large US Swine Production Systems - Image 2

Economic Cost of Major Health Challenges in Large US Swine Production Systems - Image 2

Finishing herd

In the finishing herd, swine influenza, Mycoplasma hyopneumoniae, and PRRSV were the top three. Swine influenza was cited as a health challenge in the finisher for 18 of 19 companies surveyed with an average rank of 3.1. Swine influenza in combination with PCV2 was cited as a health challenge for 3 herds with an average rank of 3.3. PRRSV was ranked as a health challenge for 16 of the 19 companies with an average rank of 3.1. PRRS in combination with Mycoplasma hyopneumoniae was ranked as a health challenge for 11 companies with an average rank of 4.0. PRRS in combination with PCV2 was ranked for 5 companies with an average rank of 2.4.

While a relatively infrequent health challenge in the finisher at the time the survey was conducted, when PRRSV in combination with PCV2 was cited as a problem, productivity losses were ranked greater, on average, than for any other health challenge in finishing . Ileitis was ranked as a health challenge for 14 of the 19 companies surveyed with an average rank of 4.9. Ileitis in combination with Salmonella was ranked by a single company with an average rank of3.0. PMWS was ranked by 10 companies with an average rank of 4.0. PCV2 in combination with swine influenza was ranked for 3 companies with an average rank of 3.3. Six other health challenges were ranked for more than half of the companies surveyed. They were gastric ulcers, Pasteurella multocida, Haemophilus para suis, Streptococcus suis, hemorrhagic bowel syndrome, and Actinobacillus suis.

Discussion

The information generated by this survey is valuable for industry benchmarking and to help guide animal health related investments in the industry. However, several limitations of the approach used should be kept in mind . The quality of the results from the survey are only as good as the participant's knowledge of productivity losses and health -related expenditures associated with specific health challenges. Sorting out the impact of individual health challenges over time , when multiple health challenges may be present, was subjective. To minimize this limitation, the design of the survey and the method of administration were formulated to facilitate a rigorous and common thought process for the participating veterinarians. They were guided through a series of questions starting with identification and subjective ranking of each health challenge and culminating in the estimation of ranges of productivity losses and health -related expenditures in affected herds. In addition, the participant s were informed of the content of the survey to-face interview so that they were prepared. Participants were also quizzed and screened for their ability to provide good estimates for the questions in the survey.

It is also important to note that only the segment of the U.S. industry producing more than 150,000 pigs per year was included in the study population . Extrapolation of the results to the entire U.S. industry should be done with caution. Another limitation was that the selection of surveyed companies was not random. However, the companies surveyed represented nearly half of the pigs marketed in the study population and approximately one-quarter of the pigs marketed in the U.S.

It is interesting to note that PMWS and PCV2 in combination with PRRSV were both ranked among the more important health challenges. Anecdotal evidence suggests that the losses associated with PCV2 would not have ranked this high had the survey been conducted earlier. Likewise, the rankings likely have increased since the survey was conducted.

References

¹ Neuman, E.J, Kliebenstein, J.B. , Johnson, C D., Mabry, Lw., Bush, E.J., Seitzinger, A.H., Green, A.L., Zimmerman, lJ. 2005. Assessment of the economic impact of porcine reproductive and respiratory syndrome on swine production in the United States. J Am Vet Med Assoc. 227(3):385-92.

By Derald Holtkamp (DVM, Iowa State University, Ames), Hans Rotto (DVM, Innovative Agriculture Solutions, Ames, Iowa), and Roberto Garcia (DVM, Merial Ltd., Duluth , Georgia)
Swine News newsletter 2007 (Volume 30, Number 03)
North Carolina State University Cooperative Extension Service - Swine Husbandry