Effect of vaccination against pdmH1N1(2009) influenza virus on reproductive performance

Swine influenza is a worldwide appearing pathogen which causes important losses in swine production. The disease is characterized by sudden onset, coughing, dyspnea and fever. Apart from these clinical signs, swine influenza can also result (directly or indirectly) in abortion, fetal death or other reproductive disorders. Since 2009, the subtype pdmH1N1(2009) has been isolated with an increasing prevalence in pigs worldwide, likely indicating that this subtype has become established in the swine population. The aim of the current study was to assess the reproductive performance parameters before and after a vaccination against pdmH1N1(2009) influenza virus in pdmH1N1(2009) affected herds. Therefore, the reproductive performance parameters of 42 farms were assessed six months before and six months after vaccination with an inactivated panH1N1 vaccine.

Reproductive performance parameters of vaccinated sows against pdmH1N1(2009) influenza virus were determined using an application observation sheet in 42 commercial pig farms that were either serologically or virologically pdmH1N1(2009) positive. The performance data were compared based on sows organizer data of the respective farm for the time points six months before and six months after vaccination to determine the site-specific level of reproductive performance before and after vaccination; with special emphasis on return to estrus and the abortion rate of sows. The collection of data was distributed throughout the year to exclude seasonal influences. Statistically all data were analyzed by Testimate Version 6.5.

Valid data regarding the return to estrus could be collected for 42 farms. Before vaccination the return to estrus was between 3.4% to 33.3% (Ø 13.2% ± 7.4) and after the implementation of vaccination between 2.3% to 24.1% (Ø 9.6% ± 5.0). Therefore, a mean improvement of 3.6% could be detected six months after vaccination (p = 0.0095). Valid data to abortion rate exist in 23 application observation sheets of the 42 of investigated farms, which show a decline in the abortion rate from 3.1% ± 2.9 (min: 0.2%; max: 10.0%) before use of the inactivated pdmH1N1(2009) vaccine to 1.6% ± 1.9 (min: 0.0%; max: 6.4%) post vaccination (p = 0.0266).

According to the results the abortion rate and the return to estrus could be significantly diminished six months after vaccination in comparison to the performance data six months before the establishment of vaccination. Owing to the vaccination with a inactivated pdmH1N1(2009) vaccine reproduction failures in farms with detection of this virus could be significantly reduced.

Disclosure of Interest: None Declared.