Water is an essential nutrient which is often overlooked and given little attention. Plentiful, good quality water is essential for optimum swine production. Pigs obtain water from three sources: water contained in the feed, metabolic water and water consumed by drinking. Pigs can successfully tolerate a wide range of water quality and will adapt to water which contains compounds that impart a negative effect on performance. Above all else, pigs need sufficient quantities of water to maintain production levels.
Water is the most important nutrient for animals and humans. Without water, death can occur within a matter of days. Water has a major role in most physiological processes. It acts as a transport medium for hormones and other chemical messengers, nutrients, waste material, as well as ingested food in the gastrointestinal tract. Water has a major function in regulation body temperature, acts as a lubricant for skeletal joints and is a component of many basic chemical reactions. When assessing animal performance problems, the feed is typically analysed, whereas water analysis is often overlooked. In some instances, re-formulation of diets may be required to reduce the negative effects of poor quality water.
Water Sample Analysis
Analysis of water samples can be done in different ways. Bacterial analysis can determine if the water contains micro-organisms such as harmful bacteria. Chemical analysis is used to determine the mineral concentrations in water.
Many factors can affect water quality. The information in Table 1 illustrates some of the current accepted criteria used to determine water suitability for livestock production by the 1987 Canadian Task Force on Water Quality.
A typical water analysis should consist of several basic tests to evaluate a sample. Assays for Total Dissolved Solids (TDS), water pH, iron, hardness and nitrates/nitrites should be conducted.
TDS measure the sum of all inorganic material dissolved in a sample of water. All minerals elevate TDS, however only a few cause health problems. For example, high levels of calcium and magnesium have little effect on health while contributing to the TDS and hardness of the water. However, in some regions, sulfates are a major contributor to TDS. Elevated sulfate concentrations can cause diarrhoea problems for pigs. TDS levels below 1000 ppm should offer little concern for pigs. Water containing up to 3000 ppm is considered satisfactory for swine although some diarrhoea and performance reductions might occur in animals not accustomed to the water. If TDS is greater than 7000 ppm, the water is considered unfit for swine.
Water pH is determined by the hydrogen ion concentrations in the water. A pH of 7 indicates "neutral" water. Most samples are within the acceptable range of 6.5 to 8.5. It must be noted that elevated pH can reduce chlorination efficiency and low pH might cause the precipitation of some medications delivered through the water. This could lead to drug residues in the carcass if the precipitate is carried in the water offered to market weight pigs at a later date.
Iron is not itself considered a major safety concern, however low levels of iron in water can cause problems by supporting the growth of iron bacteria. These types of bacteria can cause foul odours and even plug water systems due to accumulation of dead and decaying bacteria. Iron levels of 0.3 ppm can stain laundry and bathroom fixtures. Settling tanks can be used to lower the iron content of water. Intense chlorination of the water may alleviate the iron problems; however relief will only be temporary and may need to be repeated regularly.
Water hardness has no effect on animal health. Hardness is caused by an accumulation of multi-valent metal cations such as calcium and magnesium. Hardness affects the cleansing ability of water and results in a build-up of scale in water systems. This, in turn, can impair the water delivery system and lead to problems associated with reduced water intake. Water with an elevated TDS is sometimes incorrectly called "hard" because hardness and a high mineral content can be very different. If hardness is < 50 mg/l then water is considered soft. Water is considered hard if it contains >121 mg/l CaCO3 ; and >300 mg/l water is considered very hard.
Nitrates and nitrites in water are considered serious potential hazards. Most nitrate problems are caused by decomposition of organic material and from runoff from heavily fertilized fields. Nitrates can move rapidly through soil and can caused persistent problems. Nitrates can react with haemoglobin to reduce the oxygen-carrying capacity of the blood. This can lead to serious problems, especially in human infants. Water containing over 100 mg nitrates/l (or 23 mg NO3-NO2-N/l) is potentially dangerous.
Nitrates and nitrites in the water can impair vitamin A utilization by pigs which reduces overall animal performance. However, the levels needed to cause problems ( > 750 mg nitrate/l of water) for pigs are far greater than those observed for water used in most practical conditions. Pigs are tolerant of most nitrate levels in the water, however producers need to be aware of nitrates hazardous nature, especially how it relates to human health concerns.
High sulphate concentrations are a problem often associated with poor well water quality. Sulphates can cause upsets in the gut of the pig which could result in diarrhoea, and possibly reduced performance. Sulphate levels in excess of 150 mg/l can affect water taste while levels in excess of 500 mg/l can have laxative effect. A period of adjustment may be required for the pigs to adapt and become accustomed to the water. The effect of sulphates depends somewhat on the type and size of affected animals; smaller pigs are affected to a greater degree than larger animals. Weanling pigs can be affected by relatively low levels of sulphates since, prior to weaning, they probably consumed very little water. However, recent evidence suggests that young pigs weaned at 3 weeks of age are able to tolerate relatively high levels of sulphate (~1600 mg/l) and maintain their growth performance even though diarrhoea was observed for these pigs (Patience et al. 1997a,b). Thus, poor animal performance cannot be directly linked to the observation of diarrhoea or scouring. The presence of scouring should not be necessarily interpreted as impaired growth and productivity. One must be able to separate the effects of water quality on diarrhoea from that on animal performance and then decide if performance is reduced.
Magnesium and sodium, by themselves, usually pose little risk to pigs. However, when associated with sulphates concerns can arise.
Water Requirements of Pigs
The water requirements for pigs are quite variable. In a newborn piglet, water accounts for up to 80% of the body weight. This proportion decreases to approximately 50% in market weight and adult animals. Many factors, such as the environment, diet constituents, feed allowance, boredom, access to waterers, age, season of the year and the stage of the breeding cycle can influence the water needs of the pig. Some of these factors are listed in Table 2.
Quantifying water consumption is a perplexing problem. Questions have been raised as to whether pigs will overconsume water. Pigs drink to satisfy their physiological need for water as well as to alleviate feelings of hunger and/or boredom. Such feelings can increase the water intake several fold over requirements. Water consumed above requirement is eliminated as urine. However, overconsumption does waste water and increases the amount, and volume of slurry produced.
For ad libitum-fed pigs having free access to water, the water intake will be approximately 2.2 to 2.8 times the level of intake. That is, a pig consuming 2 kg of feed per day will consume at least 4.5 l of water per day. Extra water may be required due to increased environmental temperature, excess mineral/protein or health considerations. The extra amount needed has not been well defined since water disappearance can be greatly affected by wastage.
Wet feeding and the use of wet/dry feeders have been suggested as methods to reduce excess water intake in pigs. For growing and finishing pigs, there is evidence of improvements in feed efficiency using wet/dry feeder systems. Also, water wastage was dramatically reduced. This, in turn, is a benefit in that manure storage requirements are decreased. The major concern with wet (liquid) feeding has to do with the potential for spoilage and mold problems from wastage. Therefore, feeder management and cleaning procedures will increase. Caution must be used when attempting to utilize these types of feeding systems with newly weaned pigs. It appears that these pigs need to learn how to use the feeders. This could add to the existing problems encountered for newly weaned pigs which need to acclimate themsleves to receiving water and dry feed rather than sows milk. Suggested water requirements for weanling pigs are 1.8-2.5 l/day; for grow-finish pigs up to 7.0 l/d.
Both physiological and behavioural factors affect water consumption by dry and gestating sows. Dry sows will consume additional water to achieve a feeling of satiety since they are limit fed. When housed in individual gestation stalls, sows will consume additional water and play with drinkers to alleviate boredom. This can create wet, dirty conditions in the barn. Providing water in a properly designed trough, rather than water nipples, is a useful method to reduce waste and spillage by dry sows. Requirement estimates vary, however intakes of 5.5-9 l/day are suggested.
Piglets and Lactating Sows
Nursing sows have the highest requirement for water due to the demands of milk synthesis. Most nursing sows will drink approximately 17-22 litres per day and spend at least 15 minutes or more at the drinker. However, large variations can occur since there are usually large differences among the sows themselves. At farrowing time, sows can be sluggish and may not want to drink. Encouraging the sows to increase their activity level and thus stimulate drinking is encouraged to promote improved performance. It may be necessary to provide water in the feed troughs for several days post-farrowing to assist intake. Subsequently, water offered through nipple drinkers with flow rates between 1-2 l/min seems most appropriate.
Piglets may require water immediately after birth, especially when the sows are not milking well. A dish-type drinker, or poultry waterer is a good method to provide water for young piglets. Whether providing water stimulates intake of creep feed is still up for debate, however most evidence suggests providing water for new-born piglets, especially in warm conditions.
Water Delivery Systems
The most common method of providing water for pigs is with nipple drinkers. They are relatively inexpensive, easy to maintain and usually free of fouling. Nipple drinkers encourage waste and require scheduled monitoring to observe and correct any problems that occur. At present, they are the delivery method of choice for all classes of swine except for newborn piglets where dish drinkers are preferable.
Wet/dry feeder systems that utilize a nipple drinker inside the feeding bowl are becoming more popular. This system somewhat combines features from both nipple and dish drinkers. There is evidence to indicate that these type of systems may increase intake and reduce water wastage. The reduced wastage may be of greater importance when using this type of system.
Regardless of the type of water delivery system utilized on the farm, it is important that the system maintain flow rates that are necessary for optimum health and productivity. Table 3 lists some information regarding this situation. For weanling and grower pigs, flow rates of
750 to 1,000 ml/min are suggested, whereas for nursing sows, adequate amounts of water can be obtained with flow rates from 1,000 to 2,000 ml/min. Keep in mind that, the higher the flow rate, the more potential for excessive wastage.
Liquid feeding offers an alternative to separate feeders and waterers for pigs. The feed and water are combined in a slurry form and offered to the pigs. The objective of liquid feeding is to increase feed intake, however reducing water wastage could be an important benefit. Caution must be used when considering using liquid feeding since equipment may freeze during the winter conditions experienced in Manitoba. Typically, a water:feed ratio of 2.5:1 is utilized in liquid feeding systems. This ratio can change depending upon the type of diet being fed, the class of swine being fed and the environmental conditions within the barn.
Solutions/Suggestions to Overcome Water Quality Concerns
Dietary changes might be warranted in response to water quality concerns. Removal of salt from the diet is a typical response since most diets usually contain a safety margin. However, if too much salt is removed from the feed, then a chloride deficiency could occur. This could depress the appetite of the pigs. If salt is to be removed from the diet, then routine water sampling should be undertaken to ensure the mineral content of the water has not changed.
Lowering the nutrient density of the diet may reduce scouring caused by weaning stresses and poor quality water. However, pig growth may be impaired. Thus, another approach would be to reduce all stresses on the pig by improving the overall environment (ie. drafts, humidity, crowding, disease). The pig will be able to handle poor quality water with less impact on its health and productivity.
Poor quality water can often disrupt delivery systems (eg. plug screens). Improving the delivery system may reduce some problems associated with low water intakes caused by fouled water lines. At present, there is no economical process to remove excess sulphates. Reverse osmosis will work, however it is a very expensive procedure. Chlorination can disinfect and destroy harmful bacteria and other organisms. Its effectiveness depends on the severity and type of water quality concerns. Water softeners are sometimes used to alter water quality. The most common type of softener is an ion-exchange unit in which sodium replaces calcium and magnesium. This will reduce water hardness while having no effect on overall mineral load and increasing the sodium level of the softened water.
Adequate supplies of good quality water are critical for intensive, modern pig production. Poor quality water, often containing high levels of sulphates, can lead to diarrhoea in newly weaned pigs while having minimal effect on performance. When a water quality problem is encountered, one has to determine whether the problem is merely diarrhoea, or if animal performance is reduced. Then steps can be taken to alleviate the problem. Elimination of water quality problems is difficult since there is no economical water treatment system available to remove sulphates. Other problems can be more effectively managed by reducing the sources of the problem. Water wastage continues to be a concern in hog operations. Improved feeding and water delivery systems are being introduced to reduce excessive spillage and decrease slurry output.
Alberta Agriculture, Food and Rural Development. 1996. Water for Swine; Well Water Quality for Swine. Agdex 440/68-1,2.
Fraser, D. Patience, J.F., Phillips, P.A. and McLeese, J.M. 1990. Water for piglets and lactating sows: quantity, quality and quandaries. in W.Haresign and D.J.A. Cole (editors). Recent Advances in Animal Nutrition. London:Butterworths. Pages 137-160.
Kansas State University. 1995. Swine Nutrition Guide.
McLeese, J.M., Patience, J.F., Wolynetz, M. S. and Christison, G.I. 1991. Evaluation of the quality of ground water supplies used on Saskatchewan swine farms. Can J. Anim. Sci. 71:191-203.
McLeese, J.M., Tremblay, M.L., Patience, J.F. and Christison, G.I. 1992. Water intake patterns in the weanling pig: effect of water quality, antibiotics and probiotics. Anim. Prod. 54:135-142.
Patience., J.F. 1989. Water quality and quantity: importance in animal and poultry production. in T.P. Lyons (Ed.) Biotechnology in the Feed Industry. Alltech Technical Publ., Nicholasville. KY. Pages 121-138.
Patience, J., Possberg, N. and Gillis, D. 1997a. Water Quality and Weanling Pig Performance - Effect of well water high in sulphate and iron on weanling pigs: performance. In 1997 Annual Report of Prairie Swine Centre Inc. (in press).
Patience, J., Possberg, N. and Gillis, D. 1997b. Water Quality and Weanling Pig Performance - Effect of well water high in sulphate and iron on weanling pigs: blood and tissue analysis. In 1997 Annual Report of Prairie Swine Centre Inc. (in press).
Prairie Swine Centre Inc. 1995. Swine Nutrition Guide 2nd Edition.
Table 1. Canadian Water Quality Guidelines for Livestock.
Item Maximum Recommended Limit (mg/l)
|Nitrate and nitrite||100|
Heavy Metals and Trace Ions
Note: Adapted from the Task Force on Water Quality Guidelines, 1987
1. 5.0 if not added to feed
Table 2. Factors Affecting Water Intake of Pigs.1
|Boredom||Warm water temperature|
|Heat stress||High mineral levels in water|
|Dietary mineral levels|
|Dietary protein levels|
|Moderate mineral levels in water|
|Type of feed|
1. Source: Swine Nutrition Guide, 2nd Edition
Table 3. Recommended Nipple Drinker Flow Rates for Swine1
Class of Swine Recommended flow rate, ml/min2
1. Source: Swine Nutrition Guide,2nd Edition
2. Estimates only.