Agriculture

Using the Megafan to relieve stress in dairy cattle

With every likelihood of increasingly hot British summers, the issue of heat stress for dairy cows is becoming an important consideration for UK dairy farmers. There are few places hotter and more stifling than a building filled with dairy cows or other livestock on a hot summer’s day.
Cows begin to suffer from heat stress at much lower temperatures than humans. If a farmer is beginning to feel the heat and humidity, then it is quite likely the milking cows are already under stress, and this can have a severe impact on milk production and fertility. It has been estimated that heat stress can result in the loss of up to four litres of milk per animal per day, as well as sharply reduced pregnancy rates.
Many farmers have addressed this problem by installing box fans in cattle sheds, but to achieve the required level of cooling a large number of units are usually required which can be noisy and expensive to run.
In a quest for ways to assist farmers with a better solution to this problem, T H White’s Dairy Manager Adrian Moore looked to the USA, where the issue of heat and humidity management in cattle sheds has been recognised for many years.
“Over there,” said Adrian, “the High Volume Low Speed (HVLS) fan has been developed since the mid-1990s. It started when an American professor and his students came up with the idea of using overhead paddle fans to optimise milk production by lowering heat stress in dairy cows. The professor took the concept to Walter Boyd, a mechanical engineer by trade and successful inventor and designer, who developed a highly efficient extended airfoil blade that would circulate a large column of air at just the right speed for a perfect cooling effect. High Volume Low Speed fan technology was born.”
T H White has now completed the first two HVLS ‘MegaFan’ installations in the UK. The very first application on this side of the Atlantic was for Jimmy Ludwell who farms at Holsworthy, North Devon. This comprised two 24ft (7.4m) units which have already proved their worth in maintaining a comfortable temperature and atmosphere in Jimmy’s cattle shed.
The second installation, this time for four 24ft fans, was for the Hawker family who farm 1,200 acres at Hullavington, Wiltshire, where they have a herd of 400 dairy cows. Ashton Hawker specified two 24ft fans in each of his two adjacent cattle sheds:
“After just a few weeks the MegaFans have already made a considerable difference,” said Ashton Hawker. “The beds are definitely drier, increasing comfort for the cows, and because the fans can be run in either direction they can also be used to extract air from the sheds, greatly improving the atmosphere. Now I am looking forward to the difference they will make in the hot months ahead.”
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