Livestock to poorer growth rates and weaker immune systems,” Mr Sellers adds.
Assessing ventilation “It’s crucial to understand what you’re working with,” says Mr Sellers. “Cobwebs, condensation drips, wet bedding and stale smelling air are all signs of poor ventilation in calf housing. To get a more detailed picture, Mr Sellers recommends setting a smoke bomb off to show how quickly air is changed in a building. “Ideally the smoke should clear in two to three minutes,” he says.
Overcoming ventilation problems
Make improvements to existing sheds to increase calf performance Optimising ventilation inside a calf shed has a positive impact on health and growth rates. Building new calf housing provides the opportunity to incorporate ventilation and calf comfort into every aspect of the design, but while raw material costs remain high, this is not a realistic option for many farmers. However, for Matt Sellers, southern sales manager at Galebreaker, there is a lot to be said for working with what you have and taking steps to improve the air flow through calf housing. “Whether you’re converting a building to use for calf rearing, or improving the shed you’ve used for years, the principles behind creating a comfortable environment for calves are the same,” explains Mr Sellers. “In a nutshell, calves need an environment which is dry, warm, well ventilated and has sufficient space for the number of animals housed,” he says.
Optimal ventilation In a well-ventilated shed, clean air should come in from outside, either naturally or with mechanical help, circulate once and then be pushed out by the continuous flow of incoming air. “Each calf should be provided with the
same amount of fresh air without any draught exposure,” says Mr Sellers. In an inadequately ventilated calf shed, the air will typically recirculate around the shed, so calves continuously inhale the same air, increasing the risk of bacteria or viruses entering calves’ lungs. “Pneumonia in particular is associated with poor ventilation, as it spreads between calves which are sharing the same airspace rather than relying on physical contact between animals.” Pneumonia infections have an ongoing influence on productivity, as the disease results in 14.5% of dairy heifers failing to make it to first lactation1, while in beef calves the lung damage caused by pneumonia infection can reduce weight gain by up to 6kg per month2. “An overventilated shed can also cause problems, especially in winter, as the chilled environment will lead to calves using more energy to maintain body temperature leading
With ventilation, it is not a one-size-fits all approach, as the steps required to achieve optimal air flow depend on several factors. “Keeping calf housing as open as possible, while providing sufficient weatherproofing to protect against wind chill and rain, is a great start, as it can promote a good level of natural ventilation,” says Mr Sellers. However, if the air which can flow in and out naturally is insufficient, he recommends looking at mechanical options. “A fan system can effectively bring air into a calf shed, but fans alone will not achieve an even distribution of air. This can result in calves bunching together close to the fans, while the air further away from the fans becomes warm, damp and still,” he says. “Tube systems, such as VentTube Fresh, can effectively ventilate an entire calf shed. To achieve optimal ventilation, they should be designed specifically for the shed they are to be fitted in, considering shed dimensions, expected stocking density and age of calves. “Investment in creating an ideal environment for calves can pay dividends over time,” says Mr Sellers. “Providing optimal ventilation within calf sheds can help prevent disease and promote good growth rates and performance.” FG
Tube requirements There are several factors which a good supplier of tubes will consider when designing tube systems to suit your set-up. • Number of tubes – one tube system can ventilate a width of approximately 7.5– 9m, so in wider calf sheds it’s preferable to install two or more systems • Tube width – the right tube width ensures even air distribution and a constant speed of air flow throughout the shed • Number of holes – the right size and location of holes in the tube will ensure air reaches each calf without creating a draught.
References: 1. Brickell, J.S., McGowan, M.M., Pfeiffer, D.U., Wathes, D.C. (2009) Mortality in Holstein-Friesian calves and replacement heifers, in relation to body-weight and IGF-1 concentration, on 19 farms in England. Animal 3, 1175–1182 2. Williams, P. and Green, Laura E. (2007) Associations between lung lesions and grade and estimated daily live weight gain in bull beef at slaughter. In: 3rd Flagship Congress British-Cattle-VeterinaryAssociation, Glasgow, Scotland, 2007. Published in: Cattle Practice, Vol.15 (No.3). pp. 244-249.
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