Are your buildings ready to house cows again?
Published 1 August 08
Are your buildings ready to house cows
Before bringing cows indoors this autumn there are a few areas to think about to ensure cow comfort.
"There are things you can do now that don't cost a huge amount and don't involve major remodelling of your buildings but can make a real difference to the cows' environment," says DairyCo extension officer and housing specialist, Richard Davies.
Temperature and ventilation
Dairy cows need to maintain a constant body temperature of 38.8ºC (+/- 0.5ºC) and are sensitive to air temperature, radiant temperature, air velocity and relative humidity.
Richard explains: "When a cow becomes heat stressed her feed intake declines dramatically and effects milk yield. Fertility also suffers and studies have shown heat stress can increase embryonic losses. Often cases of clinical mastitis increase as well.
Richard continues: "As humidity increases animals become heat stressed more quickly, which is why cows become heat stressed during the housing period. It is crucial appropriate ventilation is in place to reduce the risk of heat stress and its associated production and health problems."
Farmers may be aware of ventilation issues in some buildings after last year's warm, wet winter, suggests Richard. "But to test ventilation and humidity cattle need to be living in buildings as their dynamics change once cattle are inside."
Your extension officer can tell you about a calculation that will work out if a building has ventilation problems, based on its dimensions and cattle numbers.
"Natural ventilation is the least troublesome, most efficient and least expensive system to provide the best environment within buildings," continues Richard. "You're aiming to provide a continuous stream of fresh air to every animal at all times of the day and night. But perhaps even more important is adequate provision for hot, stale air to leave: as this air exits it allows fresh air to be drawn in.
"Hot air rises and builds up in the apex of the roof where it grows stale and condenses. The water then drips down onto bedding, increasing moisture content and creating a suitable environment for bacteria to flourish."
Richard continues: "There are a few basic rules when looking at humidity and outlets for this air. The flatter the roof, the harder it is to ventilate. It's often odd-shaped buildings, lean-tos or buildings, whose use has been changed to housing, where problems are found.
"Often the solution to poor ventilation is cheap and there's no need to invest in fans that can end up blowing stale air around the building. If you follow the correct safety procedures, creating more outlets for stale air to leave is a cheap and effective way to improve ventilation.
"As a useful rule of thumb there should be 5cm of ridge opening for every 3m of building width."
But Richard adds: "Fans can have a place in the ventilation of large, multi-span or unusual shaped buildings.
"It's also important to ensure there's adequate inlet ventilation. As a guide the inlet should be twice the area of the outlet. It's a capital expense, but to allow the amount of air admitted through the inlets to be varied according to weather conditions, consider installing curtains to the sides of cubicle buildings."
Food and water
"On average cows drink about 61 litres of water a day but high yielding cows may require more," says Richard. "Demand for water peaks with the completion of milking and around sunset when up to 50% of cows' daily requirements can be consumed.
"You need to ensure there is adequate trough capacity, bearing in mind the flow rate of your water supply. And you need to provide adequate trough space to allow 10% of the herd to drink at any one time. A single animal drinking will require about 700mm of trough space. The surface area of the trough should be 1m² for every 60 cows in the group.
"Water troughs should also be located at the correct height for the cow. The edge of the trough should be 850mm from the floor the cow stands on. The water level should be between 50mm and 100mm below the edge of the trough to minimise splashing.
"Make sure the water provided for cows is clean and fresh. Cows have a sense of smell 17 times more sensitive than humans so if the water smells to you it will be much worse for the cow. More, smaller troughs which see a greater number of water changes are preferable to large troughs where the water movement is slow," Richard explains.
"If you don't have the time needed to regularly empty and clean out water troughs think about installing tipping troughs or troughs with large bore drain holes. These cost about £300 each but you can't beat them if you want to keep your water clean.
Walking surfaces and light
"You want the surface your cows walk on to be comfortable and not damaging to the foot, and one that allows them to express their natural behaviour. Although making major changes to floor surfaces is a big job there are some things that can be done now that will make a difference," says Richard.
"Some producers are putting mats down to protect cows' feet at pressure points, such as areas where the cow is turning sharply. These help reduce damage to the cow's foot in these high stress areas."
He adds: "I'm seeing a lot of farmers who are successfully using outside loafing areas adjacent to the cow housing. Producers tell me they see more cows expressing heat in these areas, which of course has a knock-on effect on fertility.
"Make sure your cow housing is adequately lit to allow animals to move confidentially around the building and see their food. It also allows you to see them expressing heat," concludes Richard.
DairyCo's Effective use of water on dairy farms booklet and Housing the 21st Century Cow, which brings together independent information on all aspects of building design and specifications, are available from DairyCo on 02476 478695.
"One thing you really need to find time to do before cows come indoors is to check all gutters and downpipes to ensure they're not bringing extra, unnecessary moisture into or around the buildings," says Jamie Robertson, a buildings and ventilation specialist from Aberdeen.
"High levels of moisture in cow livestock buildings will support the bacteria that cause disease," he says. "Look at the moisture that goes into your buildings and the surrounding area. It's amazing just how much rainwater falls on your roof space and you need to make sure it's not adding to your problems.
"A building of just 20m by 30m creates a roof area of 600m2 for rainwater collect. With an average rainfall of 40 inches, that means the area collects 600 tonnes of rainwater a year. If two of your down pipes are broken it means 300 tonnes of water running where you don't want it to."
Jamie continues: "Water that is not flowing where it should causes problems in buildings, and not only poses disease and biosecurity risks, but you may well be paying unnecessarily for it to be disposed of via the slurry store."