The effects of water quality on milk production

Despite the importance of water to the dairy cow, which makes up 87% of milk, it is an aspect that is often overlooked.

Why is water necessary for the dairy cow?

Depending on stage of lactation, cows drink between 60 - 115 litres per day, essential for the following processes:

• To maintain normal digestion and metabolism of energy and nutrients
• To encourages the correct flow of feed through the digestive tract 
• To optimising growth
• For lactation 
• For reproduction and to maintain the environment for the developing foetus
• For the transport, in circulation, of nutrients and metabolites to and from tissues
• For the excretion of waste products

What affects water intake?

There are a number of factors that affect intake both directly and indirectly:

• Trough space is key to ensure sufficient water intake.  Work on 3.5inch minimum per cow.
   
• Cleanliness of water troughs will encourage intake, ensure troughs are cleaned out regularly.
   
• Water pressure will affect how quickly the trough fills up.  If there is reduced pressure the trough will take longer to fill and there will not be an adequate supply of water for all cows.  This is particularly important around milking time.
   
• Rations being fed i.e. mineral ion + protein content in feed, DM content of diet, pH of silage.
   
• Environmental temperature and humidity.

Water quality will affect intakes, which can be influenced by a number of factors including pH, mineral content, total dissolved solids, sulphur/sulphate levels, heavy metals/toxic compounds, unwanted microorganisms, odour/palatability, pesticides/nitrates.

Factors directly affecting water quality

pH is not generally a problem if water pH is between 5.5 - 9.5. However, if water is very acidic a reduction in milk yield and butter fat may been seen along with poor daily liveweight gain (DLWG) and a reduction in dry matter intake (DMI).  There is also a greater risk of acidosis.   If water is very alkaline problems associated with alkalosis will be seen, including reduced rumen synthesis.

Total dissolved solids (salinity) should be 500 mg/l or less, with problems occurring at levels over 3,000 mg/l, which often causes scouring in calves.

If water is unpalatable or smells cows may not drink enough to meet production needs.

Minerals can play a key role in water quality; the main ones are outlined below:

If water intake levels are sub-optimal and other influencing factors have been ruled out, farmers are recommended to consider sampling drinking water and have it tested to determine if there are any factors within the sample that might influence the overall water quality.

For further information on this topic, or to apply for subsidised one-to-one support available through the Farming Connect Whole Farm Plan service, contact Menter a Busnes on 01970 636565 or visit menterabusnes.co.uk/farmingconnect.