Investigation on vaccination efficacy and piglets' maternal immunity in a Hungarian large-scale pig farm

Background: in commercial pig farms, lowering the costs associated with treatment of clinically sick animals and avoiding losses caused by subclinical diseases are prerequisites of efficient production. Apart from minimizing disease challenge by reducing the germ load, diseases can also be controlled by increasing the animals' specific resistance by vaccination. In order to protect the piglets, vaccines can be administered either indirectly to the sows, and thus the maternal antibodies can be transmitted to the piglets via colostrum, or directly to the piglets. Objectives: The aim of the study was to examine piglets' maternal antibody levels against Mycoplasma hyopneumoniae, Escherichia coli and porcine circovirus type 2 (PCV2) in a Hungarian commercial pig farm. Piglets were vaccinated against PCV2, and its efficacy was also investigated. Materials and Methods: Blood samples of twenty piglets, originating from five sows were collected at the age of 7, 14, 21, 28, and 38 days (D7, 014, 021, D28 and D38, respectively). M. hyopneumoniae, E. coli and PCV2 antibody levels were assessed in the samples. Piglets' bodyweight was also measured each time when blood samples were collected. Results and Discussion: M. hyopneumoniae antibody levels were in the negative range in each piglet's sample throughout the experiment, showing that the investigated sows and their piglets are susceptible to the disease caused by the bacterium. PCV2 antibody levels constantly and significantly decreased between D7 and D28. By D38, due to PCV-2 vaccination on D24, a remarkable but not significant increase was observable, however, despite the vaccination, 50% of the piglets remained in the negative range. E. coil antibody levels also decreased continuously; proportion of piglets in the positive range decreased from 45 to 39% between 07 and D28. PCV2 and E. coil antibody values and their variations by time were mainly determined by the sow. Presumably, due to the low values, the same effect was not detectable in M. hyopneumoniae antibodies. No correlation was found between piglets' bodyweight and serum antibody levels.