Evaluation of an autogenous Salmonella Typhimurium vaccine in pigs in Northern Ireland

Salmonella Typhimurium has been a constant problem on a 1,000 sow unit from birth to bacon. Clinical signs included scour, ill thrift and high mortality during the first 8 weeks post-weaning. Acidification of diets and the use of antibiotics has been the traditional approach for controlling clinical signs of disease. Since the introduction of new genetics in 2014 and PRRSv (Porcine Reproductive and Respiratory virus) in 2015, there has been an increase in clinical signs of salmonellosis and it has been more difficult to control it with the traditional approach. Furthermore, around 10% of pigs in each batch had very poor quality when moving from the weaning to the finishing accommodation.

The aim of the study was to assess the performance of an autogenous Salmonella vaccine and compare it to a control of unvaccinated pigs.

Faecal samples were taken from all weaner pens and clinically affected pigs with scour. The samples were sent to AniCon Lab GmbH (Germany) for analysis. Salmonella Typhimurium was isolated from all the faecal samples. An autogenous vaccine was made for this farm. Two groups were randomly selected. Each group had 500 pigs. In the vaccinated group, the pregnant sows were vaccinated 3 weeks before farrowing. The piglets from these sows were vaccinated a week before weaning. The diet from the vaccinated pigs was not acidified or medicated. The factors taken into account for analytic purposes were the weight in and out, DLWG (Daily Live Weight Gain), FCE (Feed Conversion Efficacy), mortality and number of poor pigs per batch. Data was analysed using JMP version 9.0.3 (SAS Institute Inc., Cary, NC, USA) at a significant level of 0.05.

There was a significant difference (p< 0.05) between vaccinated pigs (2.3% mortality, 3 poor pigs per batch ie 0.6%) and unvaccinated pigs (5.3% mortality, 42 poor pigs per batch i.e. 8.4%). Results were better in vaccinated pigs when compared with unvaccinated pigs for DLWG (598 vs 519) and FCE (1.37 vs. 1.4).

Salmonella is a major cause of food-borne illness in humans. Most salmonellosis outbreaks occur in weaner pigs, and although disease in adults and piglets is infrequent infection is not. Salmonella infection in pig herds is much more common than disease and involves limited invasion of tissues, including mesenteric lymph nodes, tonsils, intestine or bladder. This is a very important consideration for both pig and human health and welfare. The results of the present study show that vaccinated pigs thrive more evenly grow faster and there is less mortality. This can indirectly result in the reduced use of antibiotics.

Disclosure of Interest: None Declared.