Benefits of water for animals


Water is easily overlooked until it is absent. In other words, it is often the forgotten ingredient and not the prioritized parameter to consider when production problems arise. Reduction in water intake can be the first indication of health problems. Therefore, water availability and quality are extremely important for animal health and productivity.  

poultry and swine image
selko logo

Do you know that water is the most important nutrient for animals?

Water is involved in all basic physiological functions

  • temperature control 

Water is able to store a large amount of heat in liquid form and then lose heat upon evaporation. This makes it extremely important in temperature regulation. Water aids in the removal of excess heat from the body

  • digestive processes 

is involved in digestion and metabolism of nutrients and in the elimination of waste materials.

  • excretion 

Animals' bodies consist mostly of water

  • Approximately 70-80% of a piglet’s body is water.
  • Approximately 55%-75% of poultry's body is water
  • Water represents around 65% of the weight of the egg

Water is consumed in larger quantities

  • Many factors can influence water intake, such as, environment, accessibility, animal physiology and health status.  

Water to feed ratios in broiler by season (Source: McCreery, D. Water consumption behaviour in broilers. Agricultural and Food Sciences. 2015.)

  • As a rule of thumb, broilers and pigs drink 2-3 L of water for 1 kg of feed intake. 

Relation between daily water and feed intake post-weaning (days 0-21) (Source: Fleuren, M. et al. Water intake of newly weaned pigs. Is there a link with (gut) health? Zero Zinc Summit 2022.

Water plays vital roles in early life and health of animals

For piglets, for example, the importance of water intake is even more at weaning, as piglets are less prone to eating dry food and compensate by drinking water. Therefore, stimulating water intake post-weaning is a necessary approach.

Effect of water quality on animal performance and health

First and foremost, it is important that animals have access to clean, fresh, and safe water at all times. This essential resource is typically provided through nipples, cup drinkers, or troughs. It's crucial to note that the flow of water and the height of the nipples or cups play a significant role in the amount of water consumed by animals.

The most common water quality challenges affecting animal production include high concentrations of minerals, sulphates, nitrates and nitrites, bacterial contamination, growth of blue-green algae, and chemical contamination associated with agricultural and industrial activities.

Water quality also depends on its source and poor hygiene when storing it can represent a health concern.

key properties related to water quality table
biofilm illustration and pipe image

Have you heard about biofim?

Do you know that slime in the internal surface of the pipes? That is biofilm.

Biofilm is an accumulation of microorganisms and (in)organic matter bound by extracellular polymer substances attached to the inner surfaces of pipes and storage tanks in water systems. Biofilm itself provides an environment for bacterial replication.

Controlling biofilm is an important step in keeping good quality water. Flushing water through pipes combined with a good disinfection protocol can be effective in removing/controlling it.

Can low quality water affect the growth and health of swine and poultry?

Limiting water availability to animals will depress production, and poor-quality water is often a factor limiting the intake. Considering that water is consumed in large quantities, if water quality is low, there is an increased risk that water contaminants could reach a level that may be harmful. If the water quality is compromised, not only performance if negatively affected but also health and welfare.

Water intake in the first-second weeks of broiler production and pig nursery phase is low in relation to the volume of plumbing systems, creating slow flow rates, while environmental temperatures are often high to prevent chilling of the animals. This creates ideal condition for bacterial multiplication in slow‚Äźmoving, warm water. High bacterial challenge from contaminated water at this time of life can lower growth rates, decrease water/feed intake and result in scour/wet litter depending on contamination type.

Nonetheless, pigs and broilers will survive and even grow with inadequate water intake, but not to their potential. 

Monitoring water quality

If there is any doubt concerning the water quality, samples should be sent to a laboratory for analysis. A variety of tests is available: of these, pH, hardness, alkalinity, and microbiology are good initial screening. Click on the blue tick icon below to learn more about water quality:
  • <7 = acidic
  • >7 = alkaline
  • < 4 = pathogenic bacteria struggle to grow

pH can affect chlorination, antibiotic/vitamins stability, vaccination efficacy

  • Total divalent ions present in water. Ca and Mg are the most common
  • The unit is ppm per CaCO3 equivalents
  • “Hard water” has higher CaCO3 equivalents than “soft water”

Hard water is not harmful to animals. However, in the long term, it can clog the drinking nipples. Sodium carbonate can be used to soften hard waste.


Ability of water to keep its pH stable. It mainly occurs due to the presence of carbonates in water


Yeast, mould, Enterobacteria and coli are the initial screening test for microbial analysis.

If higher levels, the source of contamination needs to be treated.

There is no direct relation between hardness and pH - hard water does not necessarily have a high pH, and soft water a low pH. 

Alkalinity and hardness differences and similarities:

  1. Alkalinity is the capability of water to resist pH changes or total amount of bases present in water. Hardness measures the total amount of divalent saltsch
  2. The unit of measurement is the same (ppm in CaCO3 equivalents)
  3. Both come from limestone or dolomite sources in nature. When the water passes through rocks, it takes minerals. Limestone and dolomite dissolve in water, Ca and Mg ions, and carbonates are mixed with water. Ca and Mg ions cause water hardness, and the alkalinity occurs due to carbonates
table for maximum recommended  microbiology value in water

It is important to follow the physiochemical/microbiology water guidelines recommended by the farm vet and/or local authorities.

*Based on different sources.

Water quality may change over time, and therefore one should not rely on past analysis. Water testing should be done routinely (at least once a year, twice is advisable), whereas any unusual changes in organoleptic properties, animals eating or drinking habits, performance or health should immediately trigger the need for water testing.

For water sample collection, always, collect at entrance of the water line, and the last nipple drinker of the system, as contamination through the line changes (see table on right). Allow water to run for a few minutes to obtain a representative sample. Keep samples refrigerated and send them to a lab as soon as possible. Also collect a sample at the water source (i.e., tank), as this gives insight into the contamination within the water system.

Table: Microorganisms count (UFC/mL) through the water line. Adapted from: Macari, M. and Amaral, L.A. Importancia da qualidade da agua na criacao de frangos de corte: tipos, vantagens e desvantagens. Anais da Apinco. 1997.

table image microorganisms count through the water line

Manage water quality

When lab analyses show that microorganisms count is above the maximum recommended, a cleaning of the water system is needed. Cleaning is also advised after use of medication or other additives with risk for biofilm development.

General recommendation:

  1. Flush the drinking water system with clean water (pressure 2 to 3 bar). Flushing water through pipes can be effective, especially in addressing well-developed biofilms from smooth pipe interiors, such as PVC.
  2. Use hydrogen peroxide for 24-48 h to loosen the biofilm (empty house). Hydrogen peroxide is more effective in removing biofilm than chloric products. Chloric products are very effective in preventing biofilm formation.

Do not forget to clean storage tanks.

Treatment of the water line in houses with animals is possible but requires suitable chemical agents. Lower concentrations of some chemicals are well tolerated and can slowly remove biofilm without detriment to the animals or to water flow.

There are many water treatments available: filtration, chlorination, acidification, among others. Chlorination and acidification are the most used methods to keep a good water quality.


Chlorination and acidification: worldwide use to manage water quality

Chlorine in water

Chlorination relies on the effects of hypochlorous acid to kill bacteria and other microorganisms. Free chlorine at 3-5 ppm residual, kills E. coli in 10 seconds. If the bacteria are exposed for less time or at lower levels, they may still be present when the water is consumed. In a farm, bacteria are introduced into the water on an ongoing basis. Maintaining a chlorine residual of will keep these bacteria in check.

For clean water, 3-5 ppm free chlorine provides adequate microbial control in a short contact time. ORP readings will be around 650–700 mV. At this ORP value, pathogenic bacteria such as E. coli or Salmonella are killed within 20 seconds.

*650-700 mV = 3-5 ppm free chlorine


table - survival time of microorganisms versus ORP values
Graph - chlorine reaction

Chlorine is pH dependent. At a pH 5-6, the free chlorine is nearly 100% hypochlorous acid (HOCl) - very effective at killing bacteria. As the pH drops below 4, it starts to convert to Cl2 (chlorine gas). Above pH 6, it starts to convert to the hypochlorite ion (OCl-), which acts predominantly as an oxidizer. Water that is at a pH ≥ 7 may need to be lowered for the chlorine to be at the optimum efficiency as biocidal.

ph range and microbial growth

Microorganisms have pH limits below/above which they will not grow. Most pathogenic microorganisms, such as E. coli, Salmonella, Clostridium, stop growing at a pH of 4.5. 

Lowering water pH to below 4 (or < 4.2) is an effective way to prevent the growth of microorganisms and keep a good water quality (in the figure – almost 85% of the water samples were of good quality when water pH was < 4).

good water quality graph
chicken drinking image

What organic acids do to control bacteria?

We need to know the mode of action of organic acids:

  • bacteriostatic effect (ability to reduce the pH of the water by dissociation of its molecules – each molecule donates an H+)
  • bactericidal effect (intracellular effect of the undissociated molecules of organic acids – pH reduction, depletion of bacteria energy, interference of DNA replication).

Free acids cause a sharp decrease of the water pH, limiting their inclusion level. As higher doses could impact water intake. Water pH should stay above 3.5-3.7 (depending on animal species) to guarantee a proper water intake. By buffering an acid blend, the pH decrease is less sharp and remains at a higher level. The latter means that products containing buffered acids may be dosed at a higher level, resulting in more undissociated molecules reaching the digestive system of the animals.
Water acidification is not only important for the water itself, but also interesting for young animals, especially in the first-second week of the broiler’s cycle or pig’s nursery phase. This is because the stomach/proventriculus in this period lacks sufficient capacity to acidify its own content by hydrochloric acid.

Organic acids added via water increase the speed at which the stomach contents reach the optimal pH value, where the proteolytic enzyme pepsin has its optimum efficacy (pH 3-4).

Organic acids via water improve the zootechnical performance of animals

Improve water intake
Improve feed intake
Reduce and stabilise the pH of water
Improve feed digestion
water intake graph

Selko water acidifer which consists of blend of free and organic acids improve piglet water intake.

Average daily water intake (with 83% confidence interval as error bars) of weaned piglets with or without Selko water acidifier for 42 days. Bars within measurements with different superscripts differ (p < 0.05). 

feed intake graph

Selko water acidifer which consists of blend of free and organic acids improve piglet water intake.

Daily gain (left) and feed intake (right) averages (with 83% confidence interval as error bars) of weaned piglets with or without Selko water acidifier for 42 day. Bars within measurments with different superscripts differ (p <0.05)

selko water acidifier titration graph

Blend of free and buffered organic acids (Selko Water Acidifier – green) reduces and stabilises the pH of the water. This is based on Selko data.

Table - ph of digestive tract when a blend of free and buffered organic acids was applied in water

Furthermore, they improve feed digestion due to stomach/crop/proventriculus pH reduction (see table). This is particularly important for young pigs/birds, as the pH in the stomach is relatively high.

pH of digestive tract when a blend of free and buffered organic acids was applied in water. 

x,y, P=0.07. a,b, P<0.05. Selko data.

A compilation of 36 R&D/commercial studies (16 with piglets and 20 with broilers; conducted in collaboration with research facilities, universities and farmers in different countries, thereby covering different production systems, climate, and housing conditions) show that buffered organic acids improve the zootechnical performance piglets and broilers. 

The use of organic acid blends designed to support animal health and efficient production can help support producers’ businesses during all times.

selko ph infographic for poultry
selko ph infographic for swine

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