Safety and reproductive performance in sows after vaccination: a randomized controlled trial

Although reproductive vaccines are essential in swine herd health programs, evidence on their safety across different physiological stages remains limited. This study evaluated the clinical and reproductive safety of Porcilis^® EPL in sows and gilts under commercial field conditions. In a randomized, blinded, controlled trial, 200 females were allocated to treated or control groups within five physiological categories, of which 190 completed the study. Sows received a single dose and gilts a two-dose protocol. Clinical parameters (body condition, rectal temperature, general health, feed intake) and injection-site reactions were monitored for 14 days post-vaccination. Reproductive outcomes, including conception, litter size, stillbirths, mummification, and neonatal viability, were recorded. PCR testing for PCV2, PCV3, and PPV was performed on non-viable piglets. The vaccine was well tolerated, with no systemic adverse reactions and only mild, self-limiting injection-site swellings in some treated females. Body condition and temperature profiles remained within physiological limits. Reproductive performance did not differ between groups (p > 0.05). Pathogen detection frequencies were similar across treatments, indicating that vaccination did not measurably alter fetal susceptibility to endemic PCV2, PCV3, or PPV. Porcilis^® EPL showed excellent clinical and reproductive safety when administered during different physiological stages in sows and gilts. The vaccine did not affect fertility, gestational outcomes, or perinatal survival and did not measurably alter pathogen detection under field conditions with natural pathogen exposure, supporting its safe integration into breeding herd vaccination programs. PCR detection of PCV2, PCV3, and PPV was included as an exploratory epidemiological assessment to distinguish vaccine-specific effects from endemic pathogen circulation. No differences were observed between groups, supporting that Porcilis^® EPL did not influence susceptibility to non-target pathogens.