What is water’s role in herd health? A logical gut response is, “of course it’s important.”

Yet water is often overlooked.

How often do you consider the water delivery system as a factor when you or your veterinarian review herd health issues or death loss?

“The importance of water in bodily functions has been proven time and time again,” says Darin Madson, a veterinarian with Christensen Family Farms, Sleepy Eye, Minn. “Some of those functions include (the animal’s) structural integrity, temperature regulation and nutrient transportation. Water also has an important role in determining feed consumption.”

Most pork production inputs can be measured down to pennies on the dollar. “But what does less-than-adequate water availability cost within a modern production barn,” asks Madson. He offers the following example where the cost was measured by pig mortality.

Herd Description:

A restricted water supply can contribute to herd-health challenges and ultimately increased mortality.

Eighteen- to 21-day-old weaned pigs were commingled in a wean-to-finish barn in north central Iowa from five sow farms in Nebraska. The source sow farms are positive for porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae. 

During transport to the wean/finish site, pigs from all five sow farms are placed on the same trailer but separated by compartments. On average, 4,000 weaned pigs are produced each week.

Pigs seroconvert to PPRS virus during the mid-nursery phase. Other pathogens and secondary bacteria are managed through individual pig injections and strategic antibiotic pulsing through feed and drinking water. Two doses of Mycoplasma hyopneumoniae vaccine are given, depending on the season an Erysipelas antigen is added. Vaccines are given in the 4th and 6th week after placement. The finishing phase has had few clinical-health challenges, says Madson.

Site description:

In March 2005, weaned pigs were placed into the wean-to-finish barn in north central Iowa. The site consists of two double-long barns, each holding about 2,000 finishing pigs. The barns are deep pit, naturally ventilated, curtain-sided, with pit fans. Walls divide each barn into half, providing two separate airspaces per barn, as well as a center office and a load-in/load-out area.

Water supply:

A deep well supplies the water. The 1.5-inch well-water line enters each barn in the center-office area. There is a pressure regulator, and the water line reduces to a 3/4-inch PVC pipe. At this point, water can be directed into the rooms through a series of valves or a water medicator.

The room’s water lines also are 3/4-inch PVC pipe. Another pressure regulator and a flow meter are located before each line enters the room.

Case description:

In April 2005, the nursery phase was completed and half of the animals were transported to another site for finishing. About 4,000 finishing hogs then occupied the two-barn site. Twelve weeks into finishing, about 3 percent of the pigs in both barns developed a dry, nonproductive cough, notes Madson. By the 14th week, the cough spread to 6 percent of the pigs, with more cases of a wet, productive cough.

Both barns were placed on water-soluble tetracycline distributed through each barn’s water medicator. The tetracycline was administered at 10 mg per pound of body weight per day for a five-day treatment, says Madson.

Treatment response was moderate, leaving about 2 percent of the animals with a cough. But, mortality started to increase as the treatment phase ended, he adds. A higher mortality (10 animals) was seen in one barn compared to the other (three animals).

Necropsies showed mild pneumonic lesions, but death was determined to be caused by bleeding gastric ulcers or hemorrhagic bowel syndrome, says Madson.

Due to the HBS findings and mortality rate, another 3-day water treatment was applied in the barn with the higher death rate. The other barn was not retreated. The second treatment did not change the number of new gastric-ulcer cases or HBS deaths.

A third water-medication treatment was initiated, but it did not change the mortality rate. In all, the pigs were on water medication for 11 consecutive days.

When it comes to gastric ulcers and hemorrhagic bowel syndrome don’t overlook feed outages as a prospect as well.


During the third day of the last treatment, it was discovered that the drinking-waterflow rate was low. At the end of the water line, the rate was 320 mLs per minute. When bypassing the medicator, the flow rate doubled.

As noted, all water lines were 3/4-inch PVC pipe; the only deviation was the hose connecting the medicator to the water source. It was a 1/2-inch garden-type hose.


Once the medicator was bypassed and fresh water entered the barn, the water flow was restored to 750 mLs per minute. Mortality in the barn dropped from 15 deads during the week on medication, to four deads the week after. A few pigs still died because of gastric ulcers, but Madson suspects they were formed before the water flow was restored. No additional deaths were attributed to HBS.


Among Madson’s many conclusions, he found:

  • The water medicator’s arrangement reduced the water flow rate, at least partially due to the smaller hose size going from the medicator.
  • The reduced flow rate also could have been due to debris inside the medicator or the medicator’s age.
  • As a result, the water-flow rate supplied to the animals fell short, which triggered HBS and gastric ulcers.

Madson never discovered the cause of the original cough. It could have contributed to the gastric ulcers, HBS and death, he says. “However, the adjacent barn on the site can be considered a control group since the same disease challenge and level was present during the same time frame,” he notes.

The only difference between the two barns is that the one with the lower death rate had a 500-mLs-per-minute flow through the water medicator versus 350 mLs per minute in the other barn and compared to 750 mLs per minute when the medicator was bypassed.

The 11 days of medication in the one barn could have lead to palatability challenges, further limiting pigs’ water consumption, notes Madson. So, that could have contributed to the gastric ulcers and HBS.

Seasonal temperatures at the time (often exceeding 90° F), could have been a factor as well. “The increased temperatures could have driven animals off feed during hot days and caused them to eat only at night,” says Madson. This could have contributed to the gastric ulcers and HBS deaths. “During hot days if many pigs were consuming water at the same time the amount available could have been reduced, thus lowering consumption and contributing to the disease process.”

Of course, feed outages could contribute to gastric ulcers and HBS, and should not be overlooked. However, that wasn’t the case in this example. The barn has hopper-type feeders with a 400-pound feed capacity. No emergency feed orders were placed, nor were any feed hang-ups recorded.

So, water-supply problems were likely the culprit for this health hiccup, says Madson. More importantly it’s a situation that’s too often and easily overlooked.

Worth Repeating

Here are water-flow rates for various swine groups.

  • Nursing pigs - 250 mL per minute
  • Pigs 25 to 50 pounds - 500 mL per minute
  • Pigs 50 to 125 pounds - 750 mL  per minute
  • Pigs 125 to 300 pounds - 1,000 mL per minute
  • Sows and boars - 1,000 mL per minute

Source: Kansas  StateUniversity