By Alyssa Cornelison and John Patience, Iowa State University
Our main priority as pork producers is keeping our pigs healthy and growing. Though we implement many practices to give pigs the best care possible, we cannot always protect them from a health challenge.
When a health challenge threatens our farm, it is not hard to see the consequences: reduced feed intake and growth, increased mortality and increased days required to reach market weight. These consequences can compound, negatively influencing financial return. Porcine reproductive and respiratory syndrome virus and swine influenza are two of the more financially impactful diseases and are unfortunately very familiar to U.S. pork producers. Holtkamp et al. (2012) estimated financial losses due to a PRRSV infection to be $633.91 million annually ($4.67 per full value pig marketed) in the United States. Losses to the U.S. pig industry due to SIV have not yet been quantified, though they are also expected to be very high.
In order to quantify economic losses attributed to a health challenge, we conducted an experiment on a commercial hog research farm in central Iowa. Three grow-finish hog barns experienced naturally occurring infections of PRRSV and SIV. Barns were characterized according to health status as low challenge (LC), moderate challenge (MC) and high challenge (HC), based on diagnostic assessment and supplemented with other indicators of health such as mortality.
The MC and HC barns were positive for PRRSV and SIV and experienced 7.6% and 19.8% mortality, respectively. The LC barn was only positive for PRRSV and had 3.3% mortality. As expected, the MC and HC barns had reduced growth rates of 8% and 15% (P < 0.01), decreased number of marketable pigs by 9.8% and 21% (P < 0.01) and increased days to reach market weight by 10 and 15 (P < 0.01) days respectively, in comparison to the LC barn.
We looked at the financial impact on wean-to-finish barns in two ways: by standardizing the turn to a constant 133 days or to a standardized weight of 130 kilograms, as these are the two main marketing methods: fixed days or fixed weight. In either scenario, financial losses can be severe. There was a lost opportunity of $7.95 and $24.38 per pig sold in the MC and HC barns in comparison to the LC barn when pigs were marketed to a common weight of 130 kilograms (Table 1). When pigs were marketed to a common day, there was a lost opportunity of $11.81 and $27.13 per pig sold in the MC and HC barns in comparison to the LC barn (Table 2).
While these values apply specifically to a PRRSV and SIV challenge, they provide an indication of the potential losses that can occur when pigs experience a health challenge.
This study helps to put numbers to the impact of a health challenge of PRRSV and SIV. Health challenges impair pig performance and survivability, all influencing profitability. Unfortunately, there is no “silver bullet” to minimizing these losses. Focused and intensive efforts to maintain biosecurity is a good beginning.
Furthermore, there is a large amount of research being done to help us understand how disease influences production systems and how we can decrease their impact.