By Lee Johnston, University of Minnesota West Central Research and Outreach Center, and Jerry Shurson, Brigit Lozinski and Pedro Urriola, University of Minnesota Department of Animal Science
Recently, pork producers have told us about their challenges getting weaned pigs to thrive in the nursery. They are having problems getting pigs started on feed, keeping them healthy during the early nursery period and achieving the desired level of pig performance.
After evaluating a variety of possible causes, producers are wondering if water quality is a contributing factor. When we are asked, “Could bad water on the farm be a cause for reduced health and growth performance of these challenged nursery pigs?,” our immediate answer was “Maybe, but how bad is your water?” The answer to these questions depends on how “bad water” is defined. Although producers and their consultants may indicate that they have bad water or good water, there is no universally accepted standard for characterizing “bad” or “good” water.
We explored the scientific literature in an attempt to find a definition for bad or good water. The most widely quoted standards (Table 1) for quality of water fed to livestock comes from the U.S. National Research Council (1974) and the Canadian Council of Minister of the Environment (1987 and 2005). Unfortunately, these water quality standards appear to rely heavily on recommended maximum concentrations of contaminants for humans, are based on data obtained decades ago, and have not been evaluated extensively for their application to practical pig feeding situations.
As we searched for a definition of water quality, we also looked for controlled studies that might clarify the effects of water quality on pig health and performance. In the past, researchers have evaluated a wide array of water characteristics such as total dissolved solids, sulfates, nitrates and hardness. However, results from published studies have not been very consistent.
In one experiment (McLeese et al., 1992), increasing TDS content of water 20-fold had no effect on average daily gain, average daily fed intake or feed efficiency of weanling pigs fed a medicated diet. However, the same researchers repeated the experiment while feeding a non-medicated diet and found that increased TDS in water marginally decreased ADG, but significantly depressed feed efficiency of weanling pigs. Many studies have reported an increased incidence of scours with increasing sulfate concentration of water, but the effects on pig growth performance are inconsistent.
The inconsistent responses to water quality in studies conducted about 15 to 30 years ago may not be applicable to today’s modern production systems. Most of the previous research was not conducted using newly weaned pigs. There has been tremendous improvement in the genetic growth potential of pigs, weaning ages are younger (21 days versus 28 days), diet composition has changed and there is a desire to use less in-feed antimicrobials, so it seems that the effects of water quality on pig performance and health need to be re-evaluated under modern production conditions.
Another contributing factor that may influence water quality could be the water distribution system on a farm. Water quality could deteriorate as it flows through water pipes and drinkers due to the presence of biofilms, microbial contaminates or mineral deposits. Consequently, cleaning and maintenance of the water distribution system could prevent this deterioration of water quality. There are numerous anecdotal reports on the effectiveness of cleaning procedures and various water treatments, but very few results of controlled studies designed to evaluate these procedures and treatments have been published. Understanding the efficacy of these procedures and treatments with water of differing quality would be useful to pork producers and their advisers.
In 1992, Canadian researchers (McLeese et al., 1992) stated, “However, the current literature is neither conclusive nor thorough with respect to the impact of water quality on pig health, welfare and productivity.”
It seems we are still in this position in 2018 with incomplete understanding of water quality impacts on pig performance. As pork producers strive to continuously improve pig health and performance in their production systems, we need a much better understanding of the impacts of water quality on performance of pigs in modern pork production settings.