Influence of colostrum supply on Salmonella spp. seroprevalence in piglet rearing and possibilities to increase colostrum production by optimised feeding

Abstract

A commercial farm study investigated whether colostrum production and antibody transfer can be improved by extra feeding in late pregnancy sows, and whether such improvements have an influence on disease status (measured as Salmonella spp. seroprevalence) in piglets, using a rapid and cost effective, ELISA-based estimation method (IDEXX Swine Salmonella spp. Ab Test). Four farms with established high Salmonella spp. seroprevalence were selected, and 16 sows in each farrowing group were selected over six farrowing cycles for the feeding experiment (n=368). One half (n=184) of the sows were fed a conventional feed following official nutrient recommendations concerning energy, amino acids and minerals when they entered the farrowing pen. The other half (n=184) received 1.25 kg of a test feed daily containing fibre rich cereals (barley, oats), a fibre component (soy husks) and potassium diformate in addition to the conventional feed until two days post-partum. Blood samples were taken from two light and two heavy piglets aged 2 d in each litter (n=1,469) and at the end of rearing (approximately nine weeks old; average body weight of 25 kg; n=588). In the test-fed group, piglet immunocrit value (as a measure of immunoglobulin transfer) was significantly improved (P<0.0219; K:0.1226±0.0437; V: 0.1278±0.0406). A moderate correlation (r=0.40935; P<0.0001) was found between immunocrit value and Salmonella spp. antibodies at 2 d old. There was no correlation between immunocrit value and Salmonella spp. antibodies at the end of the rearing period (r=0.09914), when the pigs were around nine weeks of age. Despite better colostrum supply, the animals in the test group did not show a significantly lower prevalence of Salmonella spp. seroprevalence (test group optical density (OD) 9.8000±17.4954%; control group OD 8.9486±14.2426%; P<0.5344) at nine weeks of age. It could be shown that the colostrum supply can be optimised by providing sows with extra feed. The moderate correlation between immunocrit and Salmonella spp. antibodies on the second day of life suggests that measuring antibodies by rapid, cost effective ELISA could be a practical tool to for the estimation of colostrum supply and the corresponding health of piglets. A suspected effect of reduced colostrum supply on the Salmonella spp. seroprevalence at the end of piglet rearing was not detectable. Other effects (e.g. hygiene) seem to be more significant.