DairyCo

The Hidden Loss - Bad Ventilation

Published 1 May 08

"Bad ventilation is a hidden loss - you can't see it but it's there," says Michael Thwaites, who farms at Dykes House Farm, Leyburn, Wensleydale. "You don't get an invoice each month to show you how much you are losing but it is just as real as something like the feed cost on your farm."  

Michael, who milks 90 organic cows, recently invited his discussion group, the Yorkshire Organic Dairy Discussion Group, to come and look at some of the changes he has made to help combat bad ventilation in his calf housing and other buildings.  Jamie Robertson, a buildings and ventilation specialist from Aberdeen, was there to help demonstrate the real costs of poor ventilation during calf rearing and to talk about some simple things producers can do to help.

Michael says: "You can walk into a building and know straightaway that there is a problem with ventilation. It smells musty, the humidity feels high and it simply feels too hot to be healthy. We have been tackling the problems of poor ventilation in our calf housing for a year or two at Dykes House Farm so it was a good location to discuss the issues and solutions."

The Yorkshire Organic Dairy Discussion Group is a 15 member discussion group which pulls in dairy farmers from a 30 mile radius. It is run under the BIDS scheme which is funded 50:50 between Defra and DairyCo (the organisation that replaced the Milk Development Council). The group is facilitated by Joanne Speed, DairyCo extension officer in the north.

Michael explains why poor ventilation became a problem in his calf housing and how he tackled it:

"We had converted an old stone building into calf accommodation. It only had three small windows for air flow and you could tell as soon as you walked into the building that it was an unhealthy place to be: it smelt damp and you could feel the moisture in the air. We also knew there was a problem because we were getting lots of cases of pneumonia and scour, and the calves simply weren't thriving."

He continues: "It's hard to really quantify the costs to your business of calves not thriving or simply not growing as you would like them to but it doesn't mean it's not there. Unlike a beef unit, where they weigh calves to note weight gain, on the dairy unit we don't do that. But we simply knew that our calves weren't doing right. "

Michael smoke tested the building, using pellets from a builders' merchant, and found there was almost no air movement at all. He decided to install an extractor fan and timer, at a cost of only a couple of hundred pounds, and it's made a huge difference.

"The fan isn't on the whole time," Michael says. "It runs for about five minutes, four times an hour, and that's enough to clear the air completely. There is a totally different feel and smell to the air in the building and our scour and pneumonia cases have dropped right off.

"At the meeting Jamie Robertson stressed the importance of keeping calves in a very dry environment as bacteria and viruses thrive in damp conditions," Michael adds. "He said the practice of swilling down calf sheds after feeding should be avoided at all costs and that the best investment for any calf shed would be a stiff brush and squeegee to remove dampness as soon as possible after feeding. "Even if the extractor fan in my building saves the life of only one calf it has paid for itself and I can see how much healthy all the calves in the unit are."

But Michael doesn't stop there: "After the success in the calf building I looked at ventilation for animals right through our system and checked all of the buildings we use to house cattle. Most didn't need a huge amount of work, just a few minor things that made all the difference. "We were just putting in new cow housing so I made sure good ventilation was a top priority. For example, we left a one inch gap between every layer of roof sheets. In a really heavy downpour we can get a slight bit of rain getting in, but I think the good ventilation it brings far outweighs a few drips.

"We also installed proper Yorkshire boarding, rather than space boarding," he explains. "The site is rather exposed here and we needed to stop the wind from blowing right through the building. I'm after ventilation not draughts! Keeping animals in draughty buildings weakens their immune system and makes them more susceptible to disease. "You also need somewhere for the stale air to exit the cow housing. Removing the roof ridge allows the air that has risen to the top of the building to escape, thus avoiding it cooling, and dropping back down into the building as stale air.

"The good thing about bringing the discussion group here was that it was a real chance to hear everyone else's views on what we have done and what else we could do," he says. "As a group we're open with our figures and pick each other's brains to get the best tips about what is working and what isn't. "We always meet on farm so we can see what we are talking about in practical terms. I simply don't think you can get this in the same way in a meeting room. Like all farmers, we're practical and we want to touch it, feel it and measure it before we believe it!

"Jamie Robertson was able to throw some different ideas and experiences into the discussion and talked about some of the other things you can do to improve ventilation. He really helped us see the cost of poor ventilation in calf housing and gave me confidence that what we had done was right. I'm sure many of the other group members took some ideas home to use on their own buildings," Michael concludes.