How often do you consider the water delivery system as a factor when troubleshooting for pig disease and/or death loss in a pork production system?

“The importance of water in bodily functions has been proven time and time again,” says Darin Madson, a swine veterinarian with Christensen Family Farms, Sleepy Eye, Minn..

 “Some of these functions include structural integrity, temperature regulation, and nutrient transportation. Water also has an important role in determining feed consumption.

At the same time, says Madson, “we do not always attribute disease and/or death loss to the availability of water.” Even though the water source may be easily visible, “many times it is overlooked in a modern confinement barn when disease processes are present.”

Many inputs in the pork industry today can be measured down to pennies on the dollar, according to Madson. “But what does less-than-adequate water availability cost within a modern production barn?”

To answer, Madson provides the following example where, he says, the cost of inadequate water was measured by pig mortality:

Herd description
Eighteen to 21‑day‑old weaned pigs were commingled in a wean‑to‑finish barn in north central Iowa (WinnebagoCounty) from five sow farms located in Nebraska. The source sow farms are PRRS virus‑ and Mycoplasma hyopneumoniae‑positive farms.

During transportation from the sow farm to the destination site, pigs from all five sow farms are placed on the same trailer but separated by compartments. On average, approximately 4,000 weaned pigs per week are produced.

Pigs seroconvert to PPRS virus during the mid‑nursery phase. Other pathogens and secondary bacteria are managed through individual pig injections and strategic pulsing of antibiotics in the feed, as well as in drinking water. Two doses of Mycoplasma hyopneumoniae vaccine are given during this phase of production and, depending on season, an Erysipelas rhusiopathiae antigen is added. The vaccines are generally given during the fourth and sixth weeks post-placement.

Very few clinical health challenges are seen in the finishing phase of production. The majority of clinical disease is seen on an individual animal basis. These challenges are managed the same as in the nursery phase.

 

A decreased water supply could be a factor in the incidence of pig mortality by hemorrhagic bowel syndrome and gastric ulceration.

Water-flow rates for swine
Age/weight:  Nursing pigs
Rate:  250 mL/minute

Age/weight:  25-50 pounds
Rate:  500 mL/minute

Age/weight:  50-125 pounds
Rate:  750 mL/minute

Age/weight:  125-300 pounds
Rate:  1,000 mL/minute

Age/weight:  Sows/boars
Rate:  1,000 mL/minute

Source: Kansas StateUniversity

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 a capacity of approximately 2,000 finishing animals. The barns are deep pit, naturally ventilated, curtain‑sided with pit fans and an 8‑foot manure storage capacity. Each barn is divided in half by walls, providing two separate airspaces per barn, a center office and a load-in/load-out area.

Water supply
Water on the site is supplied by a deep well. The 1-1/2-inch well water line enters each barn in the center office area. In this location, there is a pressure regulator and the water line is reduced to a 3/4-inch PVC pipe. At this point, the water can be directed through a series of valves into the rooms of the barn or through a water medicator.

The water lines within the rooms are also 3/4-inch PVC pipe. Prior to the line entering each room, there is another pressure regulator and a flow meter to measure how much water is being delivered to each room.

Case description
In April 2005, the nursery phase of production was completed and half the animals were transported to another site for the finishing phase.

Approximately 4,000 finishing animals were now occupying the two-barn site. At 12 weeks into the finishing phase (July 1, 2005), pigs in both barns were developing a mild cough. The cough was a dry, nonproductive cough that was present in 3 percent of the population. By week 14 of production, the cough had increased to about 5 to 6 percent of the population with more of these animals having a wet, productive cough.

At this time, both barns were placed on water‑soluble tetracycline distributed through the water medicator in each barn. The tetracycline was administered at 10 mg/lb. of body weight/per day for a five‑day treatment.

Response to treatment was moderate, resulting in 2 percent cough still present in the barns. Mortality within the barns began to increase toward the end of the treatment phase. A higher rate of mortality was seen in Barn #1 (10 animals), compared to Barn #2 (three animals).

Necropsy of these animals showed mild pneumonic lesions, but the cause of death was determined to be either bleeding gastric ulcers or hemorrhagic bowel syndrome (HBS).

Due to the HBS findings on necropsy and a higher rate of incidence, Barn #1 was placed on BMD® (Alpharma Animal Health, Fort Lee, N.J.) through the water medicator for a three‑day treatment with 1,000 mg/gallon of stock solution. Barn #2 did not incur the same mortality from HBS after the initial treatment of tetracycline was complete, and the decision was made not to further medicate that barn. This second treatment regime had no change on the number of new cases of gastric ulcers or HBS deaths in Barn #1.

 

Hot weather increases the demand for water from pigs and a restricted water supply could contribute to disease during the summer.

With continued mortality in Barn #1, a third treatment plan was initiated. Tylan® soluble (Elanco Animal Health, Indianapolis, Ind.) was administered at a rate of 20 g/gallon of stock solution through the water medicator. This also did not change the incidence of mortality from bleeding gastric ulcers and HBS. Tylan soluble was administered through the water medicator for three days. Barn #1 had now been on water medication for 11 consecutive days.

Intervention
During the third day of Tylan soluble water administration, it was realized that the drinking water flow rate in Barn #1 was low. At the end of the water line that was the source of the cup waterers in the barn, flow rate was approximately 320 mls/minute. Then bypassing the medicator and running fresh water into the rooms of the barn, the flow rate through the meter doubled.

As stated earlier, all the water lines in the barn were ¾-inch PVC pipe. This was the case for both fresh water administration, as well as medicated drinking water. The only deviation from the 3/4-inch PVC pipe is the hose that connects the medicator to the water source.

The water medicators were not plumbed directly into the ¾-inch PVC pipe in case the medicator needed to be replaced. The hose that was connecting the water medicator to the ¾-inch PVC pipe was a 1/2-inch garden‑type hose.

Results
After the medicator was bypassed and fresh water was supplied to the barn, the flow of water at the water cup was restored to 750 mls/minute. Mortality in Barn #1 decreased from 15 deads the previous week while on medication to four deads the week after. Mortality still occurred in a few animals because of gastric ulceration that may have been formed prior to restoring water flow to the barn, but no mortality was seen attributable to HBS.

 

In addition to looking at reduced water flow as a possible cause of disease, feed outages should not be overlooked.

Conclusion
Madson says he concluded, among other things, that:

  • When the water supplied to the barn was being directed through the medicator, the drinking water flow rate was decreased compared to bypassing the water medicator.
  • The reduction in size of the connecting hoses to the medicator was one reason for the decreased flow.
  • The reduced flow rate could also be due to malfunction of the medicator either due to debris in the internal structures of the medicator or the age of medicator.
  • An effect of these possible water restrictions was that the flow rate being supplied to the animals was less than adequate (see table for recommended water-flow rates for swine).
  • The decreased water supply in this example was assumed to be a major driver of the incidence of mortality by HBS and gastric ulceration.

Tissue diagnostics were not submitted for this case, so the specific pathogen causing the cough was never identified, explains Madson.

“The initial disease challenge may have contributed to the prevalence of death from gastric ulceration and HBS,” he says. “However, the adjacent barn on the site (Barn #2) can be considered a control group since the same disease challenge and level of disease were present in that barn during the same time frame.

“The water supply setup was similar to Barn #1 with the only difference being the drinking water flow rate while on medication. The flow rate was 500 mls/minute through the water medicator and 750 mls/minute when bypassed. The higher flow rates in Barn #2 during medication could explain the difference in mortality from HBS and gastric ulcers compared to Barn #1.”

Water consumption also may have been decreased due to palatability of the medication in the drinking water, says Madson. This also could be a reason for increased mortality from gastric ulceration and possible HBS.

Time of year might also have been a factor in the increased mortality rates, says Madson. There were many days in July 2005 where temperatures were above 90 degrees F., he says. “The increased temperatures during this case could have driven animals off feed during the hot days and caused them to consume feed only during the night.

“This effect could be a possible explanation for gastric ulceration and HBS deaths. The demand for water would increase during these hot days. If many animals were trying to consume water at the same time, the amount of water supplied to each could have been decreased, thus resulting in lower consumption rates and contributing to the disease process.”

Madson says that another possible reason for mortality due to gastric ulceration and HBS could be feed outages, so this should not be overlooked.

In this example, however, the barn has hopper‑type feeders that have the capacity to hold 300 to 400 pounds of feed. Further, there were no emergency feed orders placed to the feed mill during the time frame and feed hang‑ups were not noted in the history when the producer was questioned, he says, so water supply problems were likely the culprit.

Editor’s note: This article is based primarily on information that was presented at the 2005 Iowa State University Swine Disease Conference for Swine Practitioners held last November in Ames.