Description of practices adopted in response to porcine reproductive and respiratory syndrome outbreaks among breeding herds in the United States from 2019-2021

Objectives: Describe and benchmark strategies and practices used in the field across the United States to control and eliminate porcine reproductive and respiratory syndrome (PRRS) virus in response to PRRS outbreaks from 2019 to 2021. Materials and methods: A voluntary survey was used to collect information on practices implemented in response to PRRS outbreaks in different herds from 2019 to 2021. Information about herd demographic characteristics, biomanagement practices, diagnostic test and testing results, and production data were collected, collated, standardized, and described according to the herd’s outbreak characteristics. Results: A diversity of biomanagement practices were observed among 86 herd outbreaks. The median time to stability (TTS) was 38.0 weeks (interquartile range (IQR), 32.0-49.0 weeks), and time to baseline productivity (TTBP) was 22.0 weeks (IQR, 15.0-26.0 weeks). The median total production losses (TL) was 3675 pigs per 1000 sows (IQR, 2356-6845 pigs per 1000 sows); TTS and TTBP were longer and TL higher than a study reported ten years ago (26.6 weeks, 16.5 weeks, and 2217 pigs/1000 sows, respectively). Herd closure strategy, herd interventions such as live virus inoculation and modified-live virus vaccine, and biomanagement strategies to reduce virus transmission among sows and pigs were inconsistent among the studied herds. Implications: Under the conditions of this study, management practices used during PRRS outbreaks were highly diverse among herds. In addition, herd closure, interventions, and biomanagement strategies were inconsistent. The TTS and TTBP were longer, and TL was higher than reported 10 years ago.