Ensuring a healthy environment for housed cattle was one of the main discussion topics at the recent Cairngorms monitor farm meeting, hosted by George and Fiona Gordon and their son Charles.
The Gordons farm a number of units near Strathdon, 45 miles west of Aberdeen. This family farming business, based around the home farm of Lost, is one of the network of Quality Meat Scotland (QMS) monitor farms throughout Scotland.
As on many livestock farms, the Gordons’ breeding cattle are winter-housed in a variety of buildings, ranging from a modern, purpose built, open-fronted, south facing shed, with exterior, locking feed barriers, to adapted centuries old, thick stone walled, slate roofed buildings.
The community group discussion was led by Jamie Robertson of Livestock Management Services, who told the group that the three main considerations for a healthy environment for housed cattle are: moisture, fresh air and air speed.
Mr Robertson said: “A clean, dry, well ventilated, but not draughty shed, offers the potential to considerably improve disease control, particularly in young calves, whose immune systems have not fully developed. If the energy of these young animals is sapped by being in a chilling and/or damp, contaminated environment, where bugs often thrive, they are more vulnerable to infection from diseases like pneumonia, Johne’s and cryptosporidium.”
At the previous monitor farm meeting the group had discussed the calf health benefits of a well-bedded creep area, where they could lie, away from the more contaminated cattle accommodation.
He told the group: “Each day one cow produces 35 litres (7.7 gallons) of urine and faeces, plus 10 litres (2.2 gallons) of moisture in exhaled breath making a total of 45 litres (10 gallons) of moisture per cow, per day.”
Using a group of the Gordons’ 36 cows and calves in one building to illustrate his point, Mr Robertson explained that collectively the cows produced a total of over 1.5 tonnes (355 gallons) of liquid each day.
He emphasised that in addition to ample bedding, ventilation - particularly through the roof ridge - is crucial for effective moisture management. “You need around 0.1 square metre per cow and 0.04 square metre per calf, air outlet area at the roof ridge.”
Using the same 36 cows and calves, which were in a 24 metre long shed, Mr Robertson calculated that a total open roof ridge area of 5.4 square metres, which would be at least 200 mm wide, is needed to help ensure good ventilation for that particular group.
“As stale air and moisture rises and goes out through the roof, it should suck fresh air in, but not a chilling draught, especially at animal height, which chills and stresses the animals, suppressing their performance and productivity. And remember, if young calves are chilled, their energy is sapped, making them much more vulnerable to infections.”
Mr Robertson recommended that air entering through large openings at animal level, should be diffused with something like space or Yorkshire boarding, or curtains. “You want fresh air, not wind!”
A few days before the meeting, snow had blown in at the south west corner of the Gordons’ south facing, open fronted, cattle building, prompting Charles Gordon to put wind break curtains over this corner. “The curtains certainly stopped the snow,” said Mr Gordon. “And when I went into the corner the curtains are protecting, I was amazed at the difference they made to what had previously been a noticeably colder part of the shed.”
The north-facing back area of this particular cattle building is enclosed on three sides. Mr Robertson advised that to draw fresh air into the back of an enclosed area, create horizontal openings in the back wall, above animal height, which can be closed if the weather changes for the worse.
Calf pneumonia has been an annual problem in another of the Gordons’ sheds, which is also used for storage and as a workshop, with the cattle penned in one side. Another building joins onto the back wall of the side where the cattle are housed. Mr Robertson ignited a smoke bomb in this shed to demonstrate the air circulation.
“The first option to get fresh air into such an enclosed area is to create openings in the exterior walls, but if this isn’t feasible then a fan with a plastic duct, above tractor and machinery height, is often the best solution. Simply opening the door would seem the most logical, but this would create a chilling and energy sapping draught.”
Mr Robertson told the group that a calf’s lungs are not fully mature until it is three months old. “This results in young calves being unable to expel inhaled particles so locate calf creep feeders where the cleanest, freshest air is, and reduce the amount of dust around calves, for example bedding with straw choppers.
“Dust created when bedding finishing cattle using straw choppers can also create problems. If a group of cattle have early signs of a respiratory infection and have started coughing, back off using the straw chopper for at least a week.”
The next Cairngorms monitor farm meeting will be on June 11th. For general information on monitor farms, plus detailed reports of meetings, visit www.qmscotland.co.uk/monitor-farms