Efficacy of a multivalent vaccine in the prevention of porcine respiratory disease complex

Porcine Respiratory Disease Complex (PRDC) is a multifactorial syndrome which is a source of heavy economical losses. Its control implies herd management and therapeutic measures (vaccines, antimicrobials). Objective of this study was to assess efficacy of a multivalent vaccine to prevent PRDC and related losses in a Philippine herd.

The study was performed in a farrow-to-finish herd with1,400 sows having a history of respiratory diseases (isolation of Pasteurella multocida, Bordetella bronchiseptica and Streptococcus suis from lung samples). Twenty sows were randomly allocated to a Tested (T) or Control (C) group according to parity. Sows in the C group were not vaccinated whereas sows in the T group received a multivalent inactivated vaccine twice, respectively 5 and 3 weeks pre-farrowing. The tested vaccine comprised bacterins and toxoids of Pasteurella multocida, Bordetella bronchiseptica, Actinobacillus pleuropneumoniae (App) and bacterins of Streptococcus suis, Haemophilus parasuis (Hps) and Mycoplasma hyopneumoniae (Mhyo), (Suigen® PRDC, Virbac). All piglets born from vaccinated sows received the same tested vaccine at 3 and 5 weeks of age instead of the routine respiratory vaccine program (against App, Hps and Mhyo) which was applied to piglets from control sows. The tested vaccine was injected intramuscularly at the dose of 2 ml per sow and 1.5 ml per piglet. Pigs were housed in collective pens per group from weaning to slaughtering during which respiratory cases were recorded according to a standardized clinical examination. Mortality and morbidity rates due to respiratory cases were compared between groups by the Fisher’s exact test. The Return On Investment (ROI) per vaccinated piglet was calculated as the ratio between earning and vaccination cost, earning being the mean difference of profit between groups (price of pig weight produced minus feed, vaccine and antibiotic treatment costs).

Respectively 94 and 96 piglets were included in T and C groups. No side effects were observed after vaccination of sows or piglets. Mortality and morbidity rates from weaning to slaughtering were significantly lower in T group than in C group (respectively 10.8% and 24.4% for mortality and 21.7% and 38.9% for morbidity, p< 0.05). The ROI of the tested vaccine per piglet was equal to 4.2.

Reduced incidence of respiratory cases from weaning to slaughtering may be due to passive immunity acquired from vaccinated sows followed by active immunization of vaccinated piglets. As a consequence less antibiotic treatments were necessary in T group and higher total pig weight was produced, reflected in a positive ROI of the vaccine program tested.

Disclosure of Interest: None Declared.