It's not easy to measure, and there is relatively little research, but water is one of the most important components to producing healthy pigs.
“Most nutritionists would suggest that as long as water is made freely available to the pig, deficiency symptoms can be avoided, so they would suggest that further research is not needed,” says John Patience, professor in the Department of Animal Science, Iowa State University. “Sadly, the assumed absence of deficiency symptoms is based more on a lack of investigation than on any empirical scientific evidence.”
Patience says the one aspect of water utilization that has received considerable scientific attention in the past decade is the method of supply, driven more to avoid excessive use than to determine the minimum physiological needs of the pig. “As the supply of water becomes an issue in more pork-producing regions, and as the cost of handling manure increases, further investigation of water delivery methods can be anticipated.”
Water, functioning as a solvent, is responsible for the movement of nutrients to cells and for the movement of metabolic end products from the cells for removal via the kidneys, lungs and gut. Water also moves hormones and other chemical signals within and among cells, tissues and organs.
“Water is an inherent component of many chemical reactions,” explains Patience. “Simple but common examples include oxidation of carbohydrates, amino acids, and fatty acids, which release water and hydrolytic reactions that consume water. Indeed, it is impossible to think of a significant metabolic function in the body that does not involve water either directly or indirectly.”
According to Patience, the content of the water in the pig’s body changes as the proportion of lean to lipid tissue declines with increasing body weight. Thus, the body of a newborn piglet contains about 85% water, and this declines to about 50% at market weight.
“In recently weaned pigs, the main clinical sign is failure to thrive,” says C. Scanlon Daniels, veterinarian and owner of Circle H Headquarters, LLC, in Dalhart, Texas. “It can be caused by changes in water pressure, overstocking or poor water-height adjustment.”
Water availability is closely tied to feed intake, he notes. “Review the number of pigs per water space and the kind of waterer being used. Watch for behaviors that limit access for other pigs.”
The quality of a water sample is evaluated according to three broad criteria: physical, chemical, and microbiological, Patience says. Physical criteria include factors like color, turbidity and odor. If any of these indicators are high, producers should look for the cause, which he says may have health and/or productivity implications.
“Water can be contaminated with very serious microbial contaminants, which can pose serious threats to the health and well-being of pigs,” says Patience. “Chlorination, or another form of disinfection, can control some organisms but not all, so water supplies need to be carefully evaluated in terms of their potential for contamination. Newer technologies also are evolving.”
“Water is a central constituent of the body of the pig, fulfilling many critical functions essential to life,” says Patience. “Its unique chemical structure makes it particularly effective in fulfilling these important roles.”
The quality of drinking water can be a serious problem, but it tends to be isolated in regions known to possess aquifers containing problematic minerals such as sulfates, iron, manganese or nitrates.
“Although water is abundant and inexpensive in many parts of the world where pigs are raised, the prospect of greater agricultural and non-agricultural demand on water resources suggests that both cost and availability could become issues,” Patience says. “Therefore, the most efficient use of this valuable resource is essential.”