One of the most effective disinfectants for the rearing of healthy calves is already available in an abundance on farms and it's "free" because it is nothing more than plenty of fresh air, said Liam Gannon of Volac.
"If there are viruses in the air outside generally on a cold day those viruses will generally only last about 20 minutes and within the calf shed when you have 20, 30 or 40 calves there, those viruses will last for up to 24 hours."
He stressed that it is very important to get adequate volumes of fresh air through the calf housing and the challenge is to "get the foul air out and fresh air in as quickly as possible".
He said that a calf requires about 2.3sqm of housing until they go out to grass.
"You can get away with 1.6-1.7sqm per calf but everything needs to be very right when you are putting big numbers of calves tight together," he said. In the ideal situation the shed would be positioned and laid out so as to suck the foul air out through ventilation in the roof, but in most situations that is not the case as the calf housing has not been custom designed and built.
The guideline for adequate ventilation is 0.04msq per calf and generally the air inlet should be twice the size of the air outlet and normally divided between both sides of the building so generally for 40 calves the provision for outlet should be 1.6sqm.
Generally the inlet should be divided between both sides of the house and the outlet would be through the roof.
Where there is a strong flow of air through the building, the level of viruses will generally be low "but it is also important that the calves are protected from draughts and if you want to avoid problems you should have a solid partition to about four feet high so that the calves will not be hit by any draught coming in".
The guideline is that after allowing for drainage fall of 1:20 and adequate bedding in the pen, the solid wall or partition should be about six feet high.
Above that it tends to be a lot of vented sheeting that has gone into housing above the wall in recent years.
"The problem with the vented sheeting is that it does not slow the wind down massively and generally vented sheeting is only 5-10pc porous which would not give near the requirement for adequate ventilation to get enough fresh air into the building," he said.
"Some farmers are using space boarding but there is a lot of confusion and the preferable type of boarding is Yorkshire Boarding which has a six inch board and a gap of 1.5-2 inch which will be dictated by location of the building and the surrounds, eg if the outside surrounds is sheltered the gap needs to be at the larger end of the scale," he explained.
"If you are having problems the Yorkshire Boarding is a great way to get more fresh air into the building but the gap between the boards is critical to get the flow of air coming in at about less than walking speed to get adequate fresh air and at the same time prevent draughts" he said.
For someone constructing calf housing, a six feet high solid wall with Yorkshire Boarding for five feet above that to the eve should be adequate and the boarding is a lot cheaper than using cladding, said Mr Gannon.
He stressed the importance of the fall in the floor being not less than 1:20. Otherwise the bedding will be holding water and cooling down the calves.
"Temperature for the calves should be around 15C to keep them moving and not burning up energy trying to keep warm.
"If you are having trouble with poor drainage, you can put pallets down under the bedding. There is a bit of extra work involved but it will save time in treating sick calves and could be a solution to keep them up off the wet environment.
"An alternative if the fall in the floor is not adequate could be to put down four to six inches of bark mulch and bedding on top of that and allow the water to drain away," he explained.
The farmers were warned not to go "into the calf house with a hose and start cleaning down, for every litre of water you put into the calf house it is going to take a calf four hours to basically get rid in terms of evaporating that water out of the calf shed so you are cooling the whole thing down."
They were advised to check the drinking bowls in the calf house and don't have them dripping water because it is going to take time to get that extra moisture out of the building.
"Milk or milk replacer should be fed warm. If we want to warm up we drink a bowl of hot soup. It is the same with the calf, the warm milk is going to warm that calf up.
"The other thing is that they don't want to be lying in a draught. They should have a good bed of straw and that means that you should not be able to see the calf's legs or basically see his back, only able to see his head on the top of the bedding," he said.
Good bedding may be scarce this year, but for those who can get it, it will save on veterinary costs later on.
Get enough beestings in, plenty of fresh air, no draughts and a good bed of straw beneath them can save a lot of time and effort during the season.
"Some people will put calf coats on and think that they are a great job, which they are if you have a sick calf, because the calf with the coat will do better.
"It might sound topical to be using calf coats, but you have to ask yourself the question why are you using calf coats," he said, suggesting that in general they should not be necessary.
The calf housing should be cleaned out every two weeks and there should be a disinfection foot bath at the entrance to the house and used every time entering or leaving the house to avoid spread of any infection.
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