Keep cows hydrated in hot weather

Water is the single most important requirement for cows at pasture, and with the recent hot weather, providing enough good quality water is more important than ever, says DairyCo extension officer Chris Coxon.



“Milk yield is closely related to water quality, availability and intake. A lack of water can lead to reduced dry matter intakes, lower milk yields and a loss in body condition,” says Mr Coxon. “Milk is composed of nearly 87% water and lactating dairy cows need at least 60 litres per day with some high yielding cattle needing up to 100 litres.


One way to quickly check that cows are getting enough water is by looking at their dung, explains Mr Coxon. “Manure that is too firm can be a sign that the cows’ water requirements are not being met.


“Dairy cows are social animals and like to drink together. Add this to the fact that peak water requirements are after each milking and in the late afternoon and early evening and pressure on trough space can be high. You need enough space for at least 10% of the herd to be drinking at any one time. Depending on cow size each animal needs about 70cm of space at the trough. So a 100 cow herd requires at least 7m trough space. To allow cows to drink freely the rim of the water trough should be 75cm above ground level.”


Cows also have a sensitive sense of smell and will choose not to drink tainted or dirty water. Troughs must be cleaned out regularly, he says.


“Water flow should be sufficient to allow rapid refilling of the trough, so that plenty of water is always in front of the cow. Cows can drink up to 14 litres per minute, so 10 cows drinking at the same time can consume 140 litres in 60 seconds!


Where water pressure is low booster pumps or extra covered storage tanks that can fill during off peak periods can be used, says Mr Coxon. “Where water pressure is adequate, poor flow rates may be improved by using a larger supply pipe. Doubling the diameter of this pipe can increase flow to the trough by up to six times. Many troughs are fitted with the wrong pattern of ball valve and these should be replaced where necessary. Ball valves conforming to British Standards have interchangeable orifices and floats and it is important to use the right combination of these for each trough.


“Water bowsers are an effective short term solution in areas of low water pressure or where troughs are yet to be installed. But at over £2,000 for a new 500 gallon water bowers it’s worth having looking at buying second hand. You can also find a large selection of water bowsers for sale at a range of prices on the internet,” he says.