Water doesn’t get the attention it deserves because it is abundant, easy to access and inexpensive, but that will change in the future, said John Patience, PhD, professor of animal science at Iowa State University.

“We’re going to see…increasing conflict for limited water resources between urban populations, industrial users and agriculture,” Patience told Pig Health Today. “Now is the time for us to think about how we can use water most efficiently and effectively because it isn’t always going to be abundant, and it isn’t always going to be inexpensive.”

Vitally Important
It’s difficult to think of functions in the body that don’t involve water. About 10% to 15% of the water a grow-finish pig consumes every day is generated by metabolism, Patience said. The pig can produce some of its own water to help meet its needs — but by no means all of it.

Water represents about 80% of the weight of a newborn piglet and is the most essential of all nutrients, yet swine professionals often overlook assessing the quantity and quality of water delivered to pigs, he pointed out.

Water plays an important role in helping pigs maintain a constant temperature and is critical in terms of acid-base balance.

“Water is also involved in transport and movement of nutrients to the cells and waste away from the cells, and of course, the removal of waste products.”

Requirements Difficult to Measure
Water requirements aren’t well understood because they’re difficult to measure, Patience said. When other nutrients are measured, researchers can assign different levels to pigs, but water has more variables.

“The kidney can adjust to modest deficiencies by conserving water,” he explained. In addition, pigs may drink more water than they need. “We call that luxury consumption. A pig will drink excess water if it’s bored or hungry.”

Additionally, pigs will waste a lot of water, depending on the water-delivery system.

“If we take just a standard, fixed-in-place nipple drinker, at least 30% of the water that flows through it will be wasted. If you measured water flow through the nipple, that won’t give you the pig’s requirement. That’s the requirement plus waste,” he said.

Patience has done work where adjustments were included for waste, and then he related the quantity of water consumed to the amount of feed consumed for a ratio.

“A growing pig consumes about 2.6 times as much water as feed. And a finishing pig will consume about 2.3 times as much water as it consumes in feed,” he said. “In hot weather, their requirement obviously increases.”

Weaned Pigs Need Help with Water
If the pig can’t get enough water it won’t eat as much feed. However, simply increasing water intake above the normal requirement is not going to increase feed intake, Patience said.

“We hear sometimes, ‘Well, I’m going to do this to the water and it will increase consumption, and therefore the pig will eat more feed.’ That’s not true,” he said.

However, if the flow rate from the nipple drinker is too slow, then feed intake will be impaired.

“We want to make sure the nipple-drinker flow rate is sufficient in that a pig can easily access the amount of water it requires because of the relationship between water intake and feed intake,” Patience said. Flow rate should be 2 to 4 cups per minute, depending on the age of the pig.

The other problem with newly weaned pigs is that they don’t always find the nipple drinker.

“We have to help them find water so they can get going,” he added. Every experiment Patience has done in which water intake of newly weaned pigs was measured on a daily basis, water intake is high on average for the first 3 or 4 days after weaning, then it goes down for 3 or 4 days, and then it starts to rise in concert with feed intake.

“We’re very puzzled by that,” he said. “We need more research to understand the pig’s motivation for drinking in that very early weaning period.”

Water for Sows
Water is important to the nursing sow because she is producing milk, and about 85% of milk is water. The sow needs to consume a lot of water to produce enough milk for her piglets.

A direct relationship exists between sow health and pig health in terms of water, Patience said.

“If the sow isn’t drinking enough water, she’s not producing enough milk, and the piglets aren’t drinking enough milk so they aren’t growing. There’s a 4:1 relationship between piglet growth and milk consumption. In other words, if the piglet is gaining 250 grams (~ half a pound) a day, then that piglet has to drink a liter (34 ounces or 4.2 cups) of milk every day.”

The growing pig only retains about 8% of the water it consumes in growth. In the lactating sow, about 40% to 50% of the water she consumes goes out in milk. Sows that are not drinking much water tend to be the sows whose litters are not growing very quickly, Patience said. Those sows tend to be lethargic and may need help to increase the amount of water they drink.

“We want to do everything we can to get that newly farrowed sow drinking as much water as we can as soon after farrowing as possible,” he said. “If that doesn’t happen, then the litter is going to suffer.

“Producers should pay very close attention to that newly farrowed sow,” Patience added. “This relationship [to water] in the first 3 days after farrowing is very strong. It’s one of the phases in the pig’s life cycle where we think water intake may not be where we want it to be.”

Quality Also Critical
“We’re delivering more medications through the water, and contaminants in the water can influence the stability of the medication,” Patience explained.

Biofilm can accumulate in the water lines, so producers need to keep the water-delivery system clean.

“Most producers don’t do this, but I believe that we should be chlorinating our water, just to be on the safe side,” Patience said. “Chlorinating water for pigs has great merit, and it will help to slow down the accumulation of biofilm.”

High iron and/or the pH of the water are other variables to watch when delivering medication through the water, he said. Check with your veterinarian or supplier to ensure your water is compatible with the medication.

More Research Needed
Patience has dedicated a good part of his career to answering questions related to water quantity and quality, but more research is needed. As the most important nutrient, it deserves more attention. As he pointed out, water could become an increasingly limited resource in the future.

“More research is needed on water usage and requirements of newly weaned pigs and newly farrowed sows, in particular,” Patience said.

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