Beef farmers were reminded of the importance in getting airflow right in their slatted sheds at a recent seminar.
Speaking at the Teagasc Winter Beef Seminar, which took place on the farm of Richard and Raymond Carter near Stradbally, Co. Laois, last week, Donal Lynch from XL Vets warned beef finishers of the risks associated with poor airflow in a slatted shed.
He explained that reoccurring cases of pneumonia on farms during winter housing can often be attributed to issues arising from ventilation.
One of the main ventilation issues noted in conventional slatted sheds, according to the Tullamore-based vet, is the vented sheeting on the sides of cattle sheds not allowing sufficient air in.
He explained: “In an ideal shed, for every 500kg animal you need half a square metre outlet in the roof.”
The large-animal vet noted that a typical three-bay double shed, with a feed passage in the middle, housing 50 500kg cattle (25 each side) needs a one-foot gap at the top of the roof.
He said that where there is a canopy over the gap in the roof, there should be a clearance of one foot (see below).
However, while this is generally the case in most ‘grant spec’ slatted sheds, Donal added: “While we need 0.5m2/animal on the top of a shed, you need twice that per animal on the sides.”
He explained that this is where the issue arises with ventilation in most slatted sheds. The sides are often covered with ventilated sheeting which “reduces the open area by a factor of 20”.
He told farmers at the seminar that where the sides of a shed are not facing the prevailing weather, “a shed for beef cattle is better with nothing on the sides than vented sheeting”.
What happens when not enough air can get in?
Donal explained that when a shed is filled with cattle, they warm the air, causing it to rise and exit via the vent at the top of the shed.
However, when sufficient air cannot re-enter the sides of the shed via the vented sheeting, it is sucked into the shed from the manhole outside via the slatted tank.
“A slatted shed filled with beef cattle with vented sheeting on the sides that has a good air outlet but not a good enough air inlet will see stale air being driven out through the outlet and sucked in through the tank – creating a draught,” he said.
“So the air is sucked in through the manhole outside, through the empty tank and up underneath the cattle leaving them lying in a draught all the time and that’s why you would often see cattle struggling to thrive in a shed with wrong ventilation.”
He stressed: “Not only should farmers sort out their air inlets but they should cover their agitation point outside also, with anything to stop cool air from being sucked in.”
The vet suggested that farmers who are having problems with ventilation, but need shelter from the weather, should fix the base of the sheets out two foot from the wall, to allow the air in from underneath the sheet.
He stressed that big cattle “don’t get cold” in the winter and noted that a 650kg beef animal has a stomach containing about 50kg of feed.
“So their stomach is like a 50kg vat of fermenting feed, it’s like an oven inside them, heating them up so you never need to worry about them being cold.
“What you do need to worry about is shelter so you will need to be practical in where the weather comes from,” he acknowledged.
“You have to build a shed for the most days of weather that we have here.”
Concluding, the vet noted that “Yorkshire boarding is a lot better for ventilation than vented sheeting” but noted that in most cases “space boarding would suffice”.