He identified the main animal housing problems and put forward some solutions. We look in detail at these issues in the panel below.
Moisture comes from the animals in the form of faeces/urine, at a rate of up to 45 litres per animal per day. Respiration can be responsible for up to 10 litres per day and there is rainfall that can also enter the shed.
Moisture may also arise from leaking troughs, poor gutters/downpipes, condensation etc.
Moisture in the shed supports microbial activity and promotes respiratory pathogens. It absorbs energy, requiring the animal to use more energy to stay warm instead of using this energy to grow and thrive. Moisture can be a transport medium for disease to pass from one area to another, infecting more animals on the way.
It also can increase stress, through slippy floors, poor feeding areas, dirty coats etc.
Fresh air kills airborne bugs. 100pc fresh air kills bugs 10 times faster than an environment with 50pc fresh air.
Where there is a lack of fresh air, these bugs have a much greater chance of survival. Gaseous emissions increase and there are more smells and dampness in the air.
Required to move air at a rate of between 0.2 and 0.5metres/second. Anything above this rate could be deemed as too much air speed and causes excessive energy losses where animals may huddle together to keep warm and they also maybe avoiding certain areas of the building. This then requires a higher intake of feed for a lower production rate. At an air speed of two metres per second a calf needs to have a nine degree increase in temperature to provide the same level of growth.
If there is too low a rate of air speed then smells may be evident in the building as they are not been removed. Also bugs, respiration and moisture are not being removed, causing further animal problems.
Sheds should have a very good drainage system in place to ensure that all moisture is removed from the animal bed. A slope of one in 20 is required below straw.
Adequate amounts of straw should be used, and the 'kneeling test' should be applied is see that this is happening. You should be able to kneel down in the animal bedding and have two dry knees when you stand up! If there are wet patches on your knees there isn`t enough straw being used.
All gutters, downpipes, drinking troughs should be in perfect working order.
To ensure adequate fresh air is available to the animal there must be an inlet and an outlet. The roof should not be flat and should have a slope of greater than 17 degrees. The outlet areas at the ridge should be a minimum of 0.04msq per calf and 0.1msq for an adult.
The inlet area is also very important and should be at least twice and up to four times the area of the outlet. Jamie favours using Yorkshire boarding for inlet spacing as it provides access for air to get in while preventing rain from entering the shed.
He also stated that draughts at animal level should be avoided at all costs.
Large openings do not control air speed, they increase them. Large openings may create stress at animal level and they should have diffuse openings, like space boarding, Yorkshire boarding, wind breakers. Correct air speed will reduce the risk of stagnant areas and smells in the building.
Jamie highlighted that around 50pc of naturally ventilated sheds, old and new are not fit for purpose. Assess your own sheds for the above three points and make corrections if required.