By JoAnn Alumbaugh
U.S. producers have robust export markets and a lower cost of production than many other countries, but Joe Connor, DVM, says cost of production could be even lower if producers could focus on eliminating diseases rather than controlling them.
Connor, who serves as advisor to the Carthage System and as a consultant to Carthage (Ill.) Veterinary Service Ltd, told Pig Health Today that disease is an input that “really changes that cost of production…At some point we need to ask ourselves, ‘Can we eliminate those particular agents and then remove them from the equation as far as contributing to the cost of production?’”
He noted that porcine epidemic diarrhea virus (PEDV) and porcine delta corona virus (PDCV) were introduced in 2013 and early 2014, but the incidence of both viruses has decreased to below 0.2% on a weekly basis in breeding herds, according to a 2019 report from the Swine Health Monitoring Program. The industry has effectively intensified biosecurity and other tools to reduce the incidence. Connor said, “We know how to eliminate these viruses on an individual herd basis quite cost effectively and can do likewise across the industry.”
Unlike PEDV and PDCV, Mycoplasma hyopneumoniae (M. hyo) has been present in US herds for many years, but veterinarians now know its impact on a breed-to-wean and growing pig population is more costly than previously thought. In addition, when M. hyo is a co-infection with porcine reproductive and respiratory syndrome virus or swine influenza, that cost goes up dramatically, Connor said.
Where do we start?
Disease elimination starts at the herd level, Connor said, then it generally moves to area, regional and national eradication.
Eradicating a disease is always driven by the available tools, but the first question is always “Will the pathogen re-enter the pig population?” While there are never guarantees a disease won’t reappear, the veterinary community has been successful in identifying and modifying cost-effective tools to help producers achieve successful disease elimination, Connor said.
“For years we thought aerosol transmission of M. hyo was the way herds became re-infected, particularly in pig-dense areas,” he said. “A study [a few] years ago showed that we can have populations remain M. hyo negative even in pig-dense areas,” Connor said. There are always unknown factors in terms of disease introduction, but Connor said the industry has the tools to eliminate M. hyo and improve the health and productivity of growing pig populations.
Farms best suited to eliminate disease are those with segregated production, because “segregated production changes the dynamics of the cost of elimination and the steps you can use to eliminate a disease,” he noted.
Since 2014, the industry has moved forward aggressively with strategies that increase bioexclusion and biocontainment at individual sites, Connor said. This includes significant biosecurity improvements in transportation.
Could old diseases re-emerge?
The industry probably missed the opportunity to eliminate swine dysentery (caused by a small, spiral-shaped bacterium call Brachyspira hyodysenteriae) when its prevalence was low, Connor said. It is now increasing in some geographical areas.
“We want to take the opportunity when prevalence is low to try to eliminate these pathogens,” Connor said.
The pork industry has done a good job of reducing the amount of antibiotics used in feed, but Connor said that might open the door for some bacterial pathogens.
“When we think about bacteria such as Streptococcus suis and Haemophilus parasuis, we have to move to other control methods, primarily those involving vaccines or exposure methods, since we don’t use antimicrobials in the same way we did previously.”
What we’ve learned
“Through our experience with the introduction of PEDV, we know viruses can transfer through certain feed ingredients. As we think about the risk of African swine fever, we also know from research studies that it and other viruses can survive in certain feed ingredients,” Connor said.
He tells producers that it’s important to continue to fund current practical research.
“We’re learning what we can do in the short term to reduce the risk of those viruses through time and storage temperature of high-risk ingredients, auditing of feed mills and feed-transport biosecurity — these things have really come to the forefront.
“Lastly in that arena, we’ve learned that feed mitigants will reduce, if not fully inactivate, some viruses,” he continued.
Veterinarians and producers are constantly learning about new tools and strategies to ultimately eradicate diseases. Connor believes it’s a worthy goal and one the industry should strive to achieve to remain globally competitive and sustainable.
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