Development of a sanitary risk index for Salmonella seroprevalence in Belgian pig farms.
The aim of this study was to develop a scientifically based Sanitary Risk Index (SRI), defined as an objective measure of the Salmonella seroprevalence in a pig herd based on the risk factors being present on the farm. Therefore, an observational epidemiological study was adopted to infer risk factors for the Salmonella seroprevalence of market pigs. A total of 204 Belgian farrow-to-finish pig herds were included in this cross-sectional study. The antibody titre to Salmonella in sera was analysed by means of an enzyme-linked immunosorbent assay (ELISA) for an average of 58 finisher pigs on each farm. A detailed questionnaire, covering an extensive range of potential risk factors was completed by each participating pig producer. Pearson correlation coefficients between the average sample to positive ratio (S/P)-value of a herd and the within-herd proportion of seropositive pigs were high. Significant risk factors associated with the average S/P-value of a herd were identified by a general linear mixed model. Feeding of meal, providing wet feed, having a hygienic-lock facility, using boot baths, applying the strict all in/all out procedure, programming the temperature in the zone of thermal neutrality and disinfecting between batches were all associated with lower average S/P-values. Sampling in summer, using a clean downtime, decreasing floor space per animal as well as increasing herd size were related with higher average S/P-values. The SRI consists of the above-specified risk factors together with their relative weight. Determining the Salmonella risk of a new herd by the SRI is primarily based on the quantification of the farm specific risk factors present and results in an average S/P-value of the herd. The model was validated using a set of conventional farms. In conclusion, the SRI is a useful preliminary screening tool which forms the basis for targeted sampling but cannot replace the serological herd classification with regard to Salmonella prevalence.
Hautekiet
Veerle
V
Laboratory for Quality Care in Animal Production, KU Leuven, Bijzondere Weg 12, Lovenjoel, Belgium. Veerle.Hautekiet@biw.kuleuven.be
Geert
Verbeke
V
Marc
Vandebroeck
V
Rony
Geers
G
D000822:Animal Husbandry / Q000379:methods / Q000592:standards*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001530:Belgium / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary; D005260:Female; D006920:Hygiene; D008297:Male; D011156:Population Density; D012307:Risk Factors; D012475:Salmonella / Q000276:immunology*; D012481:Salmonella Infections, Animal / Q000453:epidemiology*; D012621:Seasons; D016036:Seroepidemiologic Studies; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology*
D000907:Antibodies, Bacterial