SPECIAL REPORT: Better water, better pig health
Biofilm and water system management in animal production translate into better health, efficiency and performance
By Sarah Muirhead
Clean water sounds simple, but inside a modern hog barn it’s a living system that can quietly reshape health, performance, and the success of every treatment put through the lines, according to Dr. Gabi Doughan of Iowa State University.
During Kemin’s 2025 Intestinal Health Symposium, Doughan shed light on waterline ecology. She talked about how mineral scale becomes scaffolding for mixed biofilms, how warm barns, nutrient pulses, oral vaccines and supplements could feed microbial growth, and why open, dead-end systems invite contamination that sampling at the well alone can’t fully evaluate.Doughan also presented evidence that challenges old assumptions. While pigs may be able to handle a wide range of water chemical analytes, she noted that research has demonstrated that treated water and cleaned waterlines can reduce mortality and improve average daily gain and feed conversion.It was also noted that groundwater isn’t always safer; the right geology could move pathogens deep into aquifers, and room taps often show higher microbial loads than the source due to biofilm shedding. Likewise, field data shows biofilms rebound within days after a terminal clean, which explains why visual checks mislead and why continuous disinfection is essential between deep cleans.Medication efficacy lives or dies by the details, said Doughan. For instance, pH, hardness, temperature, and disinfectants can potentially inactivate or precipitate drugs; out-of-the-box medicators can misdose, and dirty stock buckets cross-contaminate. Doughan said sequencing of scraped waterline biofilms has revealed the presence of antimicrobial resistance genes, including integrons (evidence of potential multiple drug resistance) and markers linked to human drugs like colistin and fosfomycin. Further work needs to be completed to evaluate if these genes are expressed and utilized by bacteria. Phenotypic tests confirmed growth of swine pathogens Staphylococcus hyicus and F18 E. coli on plates infused with water concentrations of chlortetracycline and lincomycin, proving resistance where it matters most: at on-farm concentrations.On the basis of what is currently known, Doughan recommends monitoring on-farm water quality more frequently. “If we don't know what's going on in our water systems, we're not going to be able to control it,” she said recommending at least once-a-year testing. “I’d recommend to test as many times as you can because water quality can actually change if you have a well. In fact, an aquifer’s water quality can change even within a few days,” Doughan said. She said too that more frequent testing can help determine optimal testing times.
When it comes to sampling, Doughan recommends sampling water from multiple locations -- wells and rooms -- to understand what the well is contributing into the system and what the system itself is contributing. It also helps in identifying what coliform quantities are in those rooms.“We also need to test at decision points and opportunities to clean. Because when we have these water quality results, we can take actionable items to determine what chemistries we need, what other water management mechanisms need to be put in place and when we need to clean water lines.” Terminal line cleaning is essential to keep on top of any biofilm shedding events within those systems.
“We also need to target chemistry both to remove the mineral deposits and the biology. So, if we're only removing the biology, there may still be bacteria lingering within those mineral deposits in those water lines,” Doughan said.The poultry industry has gone to flushing systems routinely, which has helped to ensure debris is being removed especially from the dead ends.Finally, it is critical to maintain water treatment efficacy. Water medications are some of the strongest tools in place for treating disease and need to be done in the right way. That comes down to making sure we are ensuring our medicators are dosing appropriately, maintaining the medicators over time, and to have clean stock buckets with lids and bucket liners.“It seems pretty simple, but they're straightforward things that can already impact the water system,” said Doughan.
Watch the full presentation from Dr. Doughan and access all content from the 2025 Kemin Intestinal Health Symposium at kemin.com/symposium.
BONUS COVERAGEDr. Gabi Doughan, Iowa State University, joins Feedstuffs in Focus to discuss fixing hidden performance robbers in swine barns. Dr. Doughan was part of the 2025 Kemin Intestinal Health Symposium.
Listen to our interview