title: Economic efficiency analysis of different strategies to control post-weaning multi-systemic wasting syndrome and porcine circovirus type 2 subclinical infection in 3-weekly batch system farms.
abstract: The study assessed the economic efficiency of different strategies for the control of post-weaning multi-systemic wasting syndrome (PMWS) and porcine circovirus type 2 subclinical infection (PCV2SI), which have a major economic impact on the pig farming industry worldwide. The control strategies investigated consisted on the combination of up to 5 different control measures. The control measures considered were: (1) PCV2 vaccination of piglets (vac); (2) ensuring age adjusted diet for growers (diets); (3) reduction of stocking density (stock); (4) improvement of biosecurity measures (bios); and (5) total depopulation and repopulation of the farm for the elimination of other major pathogens (DPRP). A model was developed to simulate 5 years production of a pig farm with a 3-weekly batch system and with 100 sows. A PMWS/PCV2SI disease and economic model, based on PMWS severity scores, was linked to the production model in order to assess disease losses. This PMWS severity scores depends on the combination post-weaning mortality, PMWS morbidity in younger pigs and proportion of PCV2 infected pigs observed on farms. The economic analysis investigated eleven different farm scenarios, depending on the number of risk factors present before the intervention. For each strategy, an investment appraisal assessed the extra costs and benefits of reducing a given PMWS severity score to the average score of a slightly affected farm. The net present value obtained for each strategy was then multiplied by the corresponding probability of success to obtain an expected value. A stochastic simulation was performed to account for uncertainty and variability. For moderately affected farms PCV2 vaccination alone was the most cost-efficient strategy, but for highly affected farms it was either PCV2 vaccination alone or in combination with biosecurity measures, with the marginal profitability between 'vac' and 'vac+bios' being small. Other strategies such as 'diets', 'vac+diets' and 'bios+diets' were frequently identified as the second or third best strategy. The mean expected values of the best strategy for a moderately and a highly affected farm were £14,739 and £57,648 after 5 years, respectively. This is the first study to compare economic efficiency of control strategies for PMWS and PCV2SI. The results demonstrate the economic value of PCV2 vaccination, and highlight that on highly affected farms biosecurity measures are required to achieve optimal profitability. The model developed has potential as a farm-level decision support tool for the control of this economically important syndrome.
authors: Royal Veterinary College, London AL9 7TA, United Kingdom. palarcon@rvc.ac.uk
authors: Pablo
authors: P
authors: Alarcon
authors: Jonathan
authors: J
authors: Rushton
authors: Heiko
authors: H
authors: Nathues
authors: Barbara
authors: B
authors: Wieland
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D000956:Antigens, Viral / Q000097:blood*; D058345:Asymptomatic Infections / Q000191:economics*; D017925:Circovirus / Q000302:isolation & purification; D003430:Cross-Sectional Studies; D005260:Female; D008137:Longitudinal Studies; D008297:Male; D008954:Models, Biological; D016133:Polymerase Chain Reaction / Q000662:veterinary; D053570:Porcine Postweaning Multisystemic Wasting Syndrome / Q000191:economics* / Q000382:microbiology / Q000517:prevention & control*; D011795:Surveys and Questionnaires; D013552:Swine; D006113:United Kingdom / Q000453:epidemiology; D014611:Vaccination / Q000662:veterinary*
chemical_list: D000956:Antigens, Viral
references: Prev Vet Med. 2013 Jun 1;110(2):88-102
references: 23490147
references: J Am Vet Med Assoc. 2007 Jan 15;230(2):244-50
references: 17223759
references: Vaccine. 2008 Jun 25;26(27-28):3443-51
references: 18513842
references: Virus Res. 2012 Mar;164(1-2):10-9
references: 22056845
references: J Vet Diagn Invest. 2002 Nov;14(6):449-56
references: 12423025
references: Vet J. 2011 Jul;189(1):58-62
references: 20691624
references: Clin Vaccine Immunol. 2011 Oct;18(10):1644-9
references: 21852549
references: Prev Vet Med. 2011 Sep 1;101(3-4):182-91
references: 21741715
references: Vet Pathol. 2000 May;37(3):254-63
references: 10810990
references: Res Vet Sci. 2004 Oct;77(2):177-84
references: 15196908
references: Prev Vet Med. 2011 Jan 1;98(1):19-28
references: 21036410
references: Vet Rec. 2001 Sep 22;149(12):357-61
references: 11594382
references: Prev Vet Med. 2003 Nov 12;61(3):209-25
references: 14554144
references: Vet Rec. 2012 Jun 9;170(23):596
references: 22645151
references: Prev Vet Med. 2011 Mar 1;98(4):250-8
references: 21239076
references: Vet Pathol. 2004 Nov;41(6):624-40
references: 15557072
references: Virus Res. 2012 Mar;164(1-2):20-32
references: 21959087
references: J Vet Diagn Invest. 2007 Nov;19(6):591-615
references: 17998548
references: Transbound Emerg Dis. 2012 Mar;59 Suppl 1:60-7
references: 22252114
references: Vet Rec. 2007 Jun 2;160(22):751-62
references: 17545645