Relationships between colostrum supply of suckling piglets and Salmonella prevalence in piglet rearing

BACKGROUND: Despite years of effort, the proportion of serologically Salmonella-conspicuous pig farms has not been significantly reduced. Incoming piglets are considered to be a significant source of Salmonella for feeder-to-finish-farms. Therefore it is important for farrow-to-feeder-farms to deliver Salmonella-inconspicuous piglets. The aim of the present study was to establish a possible link between an inadequate colostrum supply as a side effect of steadily increasing number of piglets born alive and weaned per sow and increasing Salmonella seroprevalence in piglet rearing on Salmonella-conspicuous farms. METHODS: Twenty four farms in total were selected for this study. Half of the farms (n = 12) had been detected as Salmonella-conspicuous in previous serological tests on piglets (25 kg) and remaining farms (n = 12) had appeared Salmonella-inconspicuous. Every farm was visited once 24–28 h after the main day of farrowing. For sampling, four sows were randomly selected on each farm. The parity, the litter weight and the litter size were recorded. The sow and six of her piglets were selected for blood sampling (two light-weight, two medium-weight and two heavy-weight piglets respectively). In addition, the colostrum supply of newborn piglets was estimated by using the immunocrit. RESULTS: The lightest piglets on Salmonella-inconspicuous and Salmonella-conspicuous farms showed a significant difference (p < 0.0339) in the colostrum supply (estimated by immunocrit). While light-weighted piglets in Salmonella-inconspicuous farms had an average immunocrit of 0.100 (±0.04) light-weighted piglets in Salmonella-conspicuous farms had an average immunocrit of 0.087 (±0.04). There was no significant difference (p > 0.05) in the factors body weight, litter weight, parity and litter size. CONCLUSION: The study provides preliminary evidence that when comparing Salmonella-inconspicuous farms with Salmonella-conspicuous ones, the colostrum supply may be a critical factor that needs to be considered. The fact that there is no difference in body weight between the two groups of farms suggests that there may be differences in farrowing management and especially colostrum management. Further studies are now required to investigate what causes the various colostrum supply on the respective farms and what long-term effects the individual colostrum supply might have on Salmonella prevalence at abattoir.