RESUMEN
This paper explores the theoretical economic outcome of management changes that result in different levels of antimicrobial use (AMU) in two types of UK pig farm. A static farm economic pig production model (FEPM) was used on a representative 'Top-third' most profitable farm and a representative 'Mid-range' profitable farm. Three AMU theoretical management scenarios were investigated; (a) management changes leading to a reduction of AMU by 35% (AMU35); (b) more extensive management changes leading to a reduction of AMU by 95% (AMU95); and (c) implementing depopulation of the herd (AMU Depop). A sensitivity analysis was conducted to determine the effect of increases or decreases in pig revenue and feed price on farm gross margin under these scenarios. Over a single year, the AMU35 scenario was estimated to have a small positive impact (+3%) on both farm types. The other two AMU reduction scenarios had higher AMU reduction on farms but required higher variable cost and hence they resulted in lower farm profitability. There was a substantial reduction (up to -50%) in farm gross margin under these two AMU reduction scenarios in the modeled short-term time-period. The impact of the alternative AMU scenarios was slightly higher on a farm representing the 'Top-third' farm type, reducing farm gross margin further by 7% compared to the 'Mid-range' farm. Nevertheless, both farm types stay profitable under all three AMU scenarios. The results showed that in the modeled short-term implementing management changes that result in a reduction of on-farm AMU by 35% had a good economic outcome. In practice, the other two scenarios would be considered as longer-term strategies. Although both require higher initial costs to implement, the improved biosecurity and hygiene will benefit from lower disease occurrence for a longer term. Farm gross margins were, however, found to be highly sensitive to changes on market prices especially increasing feed prices. An increase of more than 15% in feed price moved a profitable farm into a loss-making farm. It will be economically challenging for uptakes of these, or similar, AMU reduction scenarios on farms if the market prices become un-favorable to pig farmers.
RESUMEN
BACKGROUND: Porcine reproductive and respiratory syndrome (PRRS) is a major endemic pig disease worldwide and is associated with considerable economic costs. METHODS: In Scotland, three abattoir surveys were conducted in 2006 (158 farms), 2012-2013 (94 farms) and 2017-2018 (97 farms) to estimate seroprevalence to PRRS virus (PRRSV) in commercial finishing pigs. These surveys covered around 79%, 59% and 66% of the Quality Meat Scotland assured farms slaughtering pigs in Scotland in 2006, 2012-13 and, 2017-18 respectively. In the 2006 survey, six pigs per farm were sampled and tested using the CIVTEST SUIS PRRS E/S test. In the 2012-2013 and 2017-2018 surveys, 10 pigs per farm were sampled and tested using the IDEXX PRRS X3 Ab test. A farm was considered positive if it had one or more seropositive samples. RESULTS: The prevalence of positive farms was 45.6% (95% CI: 38.0-53.4), 47.8% (95% CI: 38.1-57.9) and 45.4% (95% CI: 35.8-55.3) in the 2006, 2012-2013 and 2017-2018 surveys, respectively, and 70%-75.5% farms did not change their status between sampling periods. CONCLUSION: The prevalence of PRRSV exposure in Scottish pig herds was high and changed little from 2006 to 2018. These surveys have informed planning for a prospective PRRS control programme in Scotland.