Guidance on improving water provision for dairy cows

Cattle farmers typically ask for advice on feed issues like rations, intakes, palatability, presentation and trough space.

But when it comes to what is arguably the cows’ most important nutrient – water – they are less consistent.

Yet water becomes very important for both housed and grazed cows during the summer.

Water is required for optimal rumen fermentation and makes up at least 87% of milk.

See also: 6 housing tips for better dairy production and welfare

A cow giving 30 litres of milk a day, on a silage-based mixed ration when the temperature is 20C, will drink more than 100 litres of water a day. That’s three litres of water for every litre of milk.

Easy access to good-quality fresh water is therefore really important to optimise production. Most farms have room to make improvements and, therefore, gains in health and production.

The two main points to consider are the cows’ access to water and the quality of the water available.

1. Access

Look at what the cows are telling you – is there ever an empty trough, or animals waiting for their turn to have a drink?

It is important to ensure heifers and submissive cows do not have to wait or are pushed away from the trough.

Cows with repeated restricted water access (twice a day versus ad-lib) show a decrease in yield of 2.5% and a 1.7% drop in butterfat.

Time and space
For optimum health and production, the cow should spend three to five hours a day eating, 30 minutes drinking, 12-14 hours lying and two to three hours socialising or, for example, showing oestrus.

Milking accounts for several hours, so the less time cows spend queuing or trekking to a water trough, the better.

The AHDB recommends 10% of cows should be able to drink at any one time. To allow enough space for this, 10cm of water trough space is required for each cow in the herd.

The recommended height for a water trough is 850mm from the floor. Ideally, there would be a 3.6m passageway behind the trough to allow two cows to pass behind those drinking.

Filling speed
A minimum flow rate of 10 litres a minute is recommended, but what is actually required will depend, in part, on the size of the trough.

Trough fill may be improved with wider pipes, pumps, or a reserve tank to use in times of high demand.

Access for all
Remember, the thirstiest and most vulnerable cows are those that are about to, or have just given birth.

Good water supply to dry cows can really help to improve their dry matter intakes (particularly where the ration contains a lot of straw).

Sufficient intakes after calving will reduce negative energy balance and all the associated health issues.

A cow may not get up to drink for a while after calving, so it is worth taking her a large bucket of warm water.

2. Quality

Bacteria levels
If you are not using mains water, consider the farm’s water treatment.

Ultraviolet filters only work at a certain flow rate and don’t work on murky water. If you have a header tank, this could allow bacteria to proliferate before it even reaches the drinking troughs.

Natural water sources are often preferred by cows, but these need to be managed carefully. Cows should not drink from streams that have passed through another livestock farm, as this risks transmission of diseases such as Johne’s or TB.

Consider the mineral content of the water. 

High levels of iron and manganese can not only reduce palatability, but increase oxidative stress on the cows.

This weakens their immune function and may result in increased mastitis, higher somatic cell counts, retained foetal membranes or poorer fertility.

Look at the pH of the drinking water. Water that is too acidic could potentially contribute to sub-acute ruminal acidosis. As with many aspects of dairy farming, attention to detail here is key, but this increased care will be rewarded with improvements in performance.

Each month, we’ll be bringing practical advice from an XLVets practice on a range of different subjects, the advice in this article is from veterinary Kiera Schubert.