Risk factors associated with presence of Salmonella in pigs in Canada

Abstract

Carriers of Salmonella in finishing pigs are believed to be a main source of carcass and pork contamination at the slaughterhouse and during meat processing. To better control the presence of Salmonella at the farm and slaughter, it is important to adequately identify on-farm risk factors associated with presence of these bacteria in animals. Thus a study was performed to identify the risk factors associated with the presence of Salmonella in live animals and on carcasses from 312 herds in Canada. A questionnaire was designed to gather information on several factors present on the farm and was completed by the producers. Results from the multivariate logistic regression analyses of all the factors indicated a significant effect of the type of feed grind (p = 0.0001), pen size (p=0.006), truck load capacity (p=0.008), clinical signs of salmonellosis (p=0.03) and a marginal effect of number of sources of finishing pigs (p = 0.098). Carcasses from highly contaminated herds were more likely of being Salmonella positive. Limiting the presence of Salmonella in the meat should therefore begin by reducing the number of herds highly contaminated by Salmonella.

Associations between the proportion of Salmonella seropositive slaughter pigs and the presence of herd level risk factors for introduction and transmission of Salmonella in 34 Danish organic, outdoor (non-organic) and indoor finishing-pig farms

“…Lo Fo Wong et al (2004) reported that pigs in herds recruiting from more than three supplier herds had three-times higher odds to test seropositive than pigs in herds which bred their own replacement stock or recruited from a maximum of three supplier herds. Likewise, Quessy et al (2005) found that the odds were lower with one source of finishing pigs than with two or more sources (OR = 0.31). There is consensus among authors that the purchase of pigs from infected herds is a risk factor for introduction of Salmonella.…”

“…Each link in the food chain has its share of responsibility for reducing the risk of food borne diseases . , and Quessy et al (2005) showed that infection during the finishing phase in the herd is the major source of Salmonella found in slaughter pigs. In order to control Salmonella in pigs we need to quantify possible risk factors and develop effective management strategies in pig herds.…”

Feed-borne Outbreak of Salmonella Cubana in Swedish Pig Farms: Risk Factors and Factors Affecting the Restriction Period in Infected Farms

“…In previous studies, a lower prevalence of salmonella in pigs fed whey has been shown [ 20 , 21 , 11 ]. Several studies also indicate dry or pelleted feed as a significant risk factor, compared to wet feed [ 1 , 7 , 15 , 16 ]. This effect could not be demonstrated in this study.…”

“…The variables concerning farm hygiene, farmer's attitude, quality of performance by sanitation firm and difficulty of cleaning were subjective and might be expected to depend on the perception of the individual veterinarian responding to the questions. Several studies on risk factors for salmonella infection in pigs have been published ([ 2 , 10 , 21 , 1 , 11 , 7 , 16 ], among others). Many of these use a cross-sectional approach, but sometimes a cohort design has been employed.…”

A Review of Prevention and Control Methods of Salmonella species in Swine Production and the Role of Dietary Non-Nutritional Additives

“…It was demonstrated that the introduction of Salmonella into the herd through infected purchased pigs increases Salmonella prevalence at slaughter (Van der Heijden et al, 2005). In gilts, Davies and Hilton (2000) reported an increased Salmonella excretion after introduction of animals into a new herd, whereas Quessy et al (2005) showed increased odds of sero-positivity when purchasing replacement stock was made from multiples supplier.…”