Milk comprises almost 90 percent water, so it’s not surprising that a cow’s water intake has a major effect on her milk production.
When you provide a proper fresh water supply, cows drink more, eat more and produce more milk.
It sounds simple, but the amounts of water involved are significant. One kilogram of dry matter intake utilises up to five litres of water. Cows need at least three litres of water to produce one litre of milk. This means that high-yielding cows need more than 150 litres of fresh water every day! And depending on hot and dry climates, this amount can even be higher. Cows like to drink fast – up to 20 litres of water per minute. If they can’t, their water intake may fall and their milk yield will suffer. A 40 percent reduction in water intake can cut milk production by 25 percent. It is essential that you meet all your cows’ drinking needs. Cows like to drink when they eat and just after milking. They prefer a large, calm drinking surface from which they can drink quickly and without stress. Such natural drinking behaviour promotes further eating, even more drinking and thus greater milk yields.
Three to four metres is needed around the water trough to reduce pushing and shoving. This is important for submissive cows to be able to drink without being afraid of being pushed away from the water supply by dominant cows.
There are different opinions about the best drinking temperature of water for the highest milk yield. Most researchers say that the optimal temperature for drinking water for cows is between 15°C and 17°C. At this temperature the cows will maximise water intake.
Don’t forget that the simple act of cleaning water tanks at least once a week can have an impact on milk production. Cows like to drink clean, fresh water. They are even more sensitive than people to poor quality water. As you walk by a water tank, ask yourself if you would drink that water. If the answer is ‘no’ then the water needs to be cleaned.
Water quality can be compromised by high levels of bacteria, chemicals, organic matter and minerals. Unfortunately, sometimes what may be said to be a tolerable level of contamination still hurts the cow, since cows are very sensitive to water quality problems. If you are not sure about the quality of the water, take some samples for analysis. Take these water samples from the cow’s water tank or water bowl; not back at the well. Proper sample handling is essential. Use containers supplied by the water-testing lab. Samples to be analysed for bacteria should be kept cool (on ice) and delivered to the lab within six hours. It is recommended that water be analysed at least once per year regardless of perceived problems. Maintain good records of water analysis from year to year so that you can prove when contamination occurred, if necessary.
Water supply and source
Water troughs instead of water bowls are recommended for use in loose housing systems. There must always be two water troughs per group of animals, so even low-ranking cows have good opportunities for drinking. Each water trough should be able to hold 200 to 300 litres of water and the water flow should supply at least 10 litres per minute. The water trough volume can be reduced to about 100 litres if the water flows at 20 litres per minute. On the basis of farm studies (Appendix 5), the length of water troughs should be five centimetres per cow with an optimal height of 60 to 90 centimetres. Reducing the height by five to eight centimetres may be logical for Jersey cows. Water depth should be a minimum of eight centimetres to allow the animal to submerge its muzzle two-and-a-half to five centimetres. Provide at least one water trough for every 15 to 20 cows, or a minimum of 60 centimetres of tank space per 20 cows. At least two sources of water are needed in the resting area for each group of cows. For a tied-up system it is very clear that the optimal situation is that each cow has its own water bowl.
Positioning and barn planning
Lactating cows should be close to a water supply, especially during periods of heat stress or bitter cold and frozen surfaces. Under these conditions, try to place a clean supply of water near shaded or otherwise cooled resting areas and on safe slopes if frozen. Take care to avoid excessive water accumulation in lots or other resting areas, as that may increase the incidence of mastitis and other diseases in the herd. Cows tend to drink most of their daily water close to milking time, often straight after milking, so it would be beneficial to have water available in the feeding area as well as the return lane from the parlour, or next to the exit from a robotic milking system. Many farmers have installed extra water troughs near the parlour exit or they have put water in the parlour. To avoid the risk of manure pollution, make sure that water bowls are not installed too low.
Like people, cows prefer to eat, then drink, eat, then drink and so on. Water troughs need to be easily accessible, within 15 metres from the feeding table.
Research (Appendix 6) shows that submissive cows use a water bowl less frequently than their more aggressive partner using the same water bowl. These cows consume less water and feed, and produce milk with less milk fat. Social interactions such as this may be important for producers who house their cattle in stanchion or tied-up barns where pairs of cattle share a common water bowl. Sometimes, simply moving cattle from one stall to another can eliminate the problem.