Interpretive Summary: Identification of resilient sows in porcine reproductive and respiratory syndrome virus–infected farms
By: Anne Wallace
Porcine reproductive and respiratory syndrome virus (PRRSV) increases piglet mortality. Therefore, identifying resilient sows whose reproductive performance is minimally affected by PRRSV is necessary. In this study published in the August 2019 issue of the Journal of Animal Science, the authors’ goal was to determine how genetics affects PRRSV resilience and to develop a phenotyping strategy to identify resilient sows.
Among 517 gilts, resilient (R) and susceptible (S) animals were categorized based on their blood antibody titer to PRRSV at 7- and 21-days post-vaccination (S phenotype had higher antibody titers than R phenotype). Sows were then transferred to a PRRSV-positive production farm where the following parameters were tracked for 3 years: number of piglets born alive (NBA), stillborn (NSB), mummified (NMU), lost piglets per litter (NLP), and total number born per litter (NTB).
There was minimal impact of PRRSV farm health status on the reproductive performance of R sows—NLP and NMU were significantly lower in R compared to S sows. Interestingly, R phenotype was also associated with lower piglet mortality under PRRSV negative conditions. The authors note that antibody titer might, therefore, serve as a proxy for identifying R versus S phenotype.
To conclude, if resilience phenotype to PRRSV can be identified based on blood antibody titers, this test may serve as a valuable tool to aid farm productivity and profitability. Because R sows had overall lower piglet mortality than S animals under all conditions in this study, more extensive research looking at the relationship between R and S phenotype and other reproductive stressors (e.g., environmental, other infections) may be warranted.
To view the article, visit the Journal of Animal Science.