1.    Introduction

The climate conditions inside a cow house with different constructions and various outside climate conditions can be simulated with the model ANIPRO[1]. With the model ANIPRO calculations for uninsulated and insulated cow houses have been made for the Tomsk area with outside temperatures from +10° C down to -28°C and with a relative humidity of 83% of the outside air.

The cow house for the housing of 120 cows has a length of 73 m and a width of 17,5 m. The height of the side walls are 2,5 m and the height of the ridge is 7,25 m. The milking cows have a production of 25,5 kg milk per day and an average bodyweight of 600 kg.

Two types of building construction for the housing of cows have been tested:

TA:          Construction with nil thermal insulation with a heat resistance of the outer walls

of 0,3 m²k/W and of the roof of 0,07 m²K/W

TC:          Construction with heavy thermal insulation with a heat resistance of the outer walls of 2,2 m²K/W and of the roof of 2 m²K/W

Heat resistance wall construction:

Nil insulation: wallboard panels uninsulated  – 0,3 m²K/W

Heavy insulated: Sandwich panels with 0,07 m polystyrene foam  – 2,2 m²K/W

Heat resistance heavy insulated roof construction:

Nil insulation: Fibre cement sheets without insulation – 0,07 m²K/W

Heavy insulated: Fibre cement sheets with 0,07 m polystyrene foam – 2,0 m²K/W

The ventilation in the cow houses has been created by natural ventilation with stack effect. Stack effect is based on the different of height of the air inlet and the air outlet. The cow houses are provided with an open ridge and closable sidewall openings. Two rates of natural ventilation has been calculated:

Rate 1: Low ventilation with air inlet openings in the side walls of 0,01 m and of 0,02 m in the open ridge.

Rate 2: High natural ventilation with air inlet openings in the side walls of 0,8 m and of 0,8 m in the open ridge.

In table 1 the calculated combinations of building constructions and rates of ventilation are shown.

Table 1 Combinations of building constructions and ventilation rates.

The results of the calculations are given in the tables 2, 3, 4, and 5 at the outside temperatures –28, -20, -10, 0 and +10 °C.

2.    Results

Inside Temperature (°C) – Air temperature inside of the cow house

Relative Humidity (%)  – Relative humidity of the air inside the cow house

CO₂ concentration (%) – Concentration of carbon dioxide in the air inside the cow house

Air changes (/h) – Air changes per hour of the air inside the cow house

Roof condition – Condition of the roof inside the cow house: Dry; Condensation or Ice

Table 2: Results of inside climate conditions at different outside temperatures of an uninsulated cow house with low ventilation (TA1).

Table 3: Results of inside climate conditions at different outside temperatures of an uninsulated cow house with high ventilation (TA2).

*) outside the model limits

Table 4: Results of inside climate conditions at different outside temperatures of an insulated cow house with low ventilation (TC1).

Table 5: Results of inside climate conditions at different outside temperatures of an insulated cow house with high ventilation (TC2).

*) outside the model limits

1.1.1     Conclusions

For the housing of milking cows in an area with extreme low outside temperatures a building construction with heavy insulation and a low ventilation rate gives the best performance. The inside temperatures will increase and the chance for freezing surfaces, such as walls, roofs or floors, will be the less.

December 2005

If you are interested to find out more on this subject, don’t hesitate to contact us or leave your contact details and we will contact you.