The benefits of combining soaking lines with high-velocity ventilation
Updated: Aug 23, 2019
The goal of this article is to demonstrate the benefits of having a soaking line in addition to proper ventilation in a dairy farm. To understand how soaking system work, we need to comprehend the basic principal of sweating and evaporation.
To make this simple, imagine yourself on a hot summer day in your bedroom with all the windows open, but there is no wind coming in. You will sweat and become uncomfortable; your first reaction will be to stand up to reduce skin contact with your warm bed sheets and maybe drink a cold glass of water. Although this effect is temporary, you want something longer to cool yourself down. Having a small fan on your desk will help you reduce your body temperature by creating air movement. The combination of sweat and air movement will result in an evaporative cooling effect, where a fraction of your body heat will be absorbed by the sweat and evaporates into the air as a gas making humidity rise.
The air movement velocity provided by your small fan doesn’t decrease the temperature in your room, the movement of air only provides the feeling of cooling. Yet, this hot summer day is brutal, and your small fan can’t keep up. You decide to take a cold shower, leaving your hair wet, you put yourself in front of the fan. This is when you realize you hit the jackpot, you are in your comfort zone, the heat discomfort is gone, and you start to enjoy life again.
Now replace the above scenario by your nearest dairy farm and yourself with the several cows living in it. The same story happens when cows become hot, but at a much lower temperature than us (20°C-68 °F). When cows start to enter their discomfort temperature zone, we call it heat stress. Unfortunately cooling a dairy farm with a large AC unit is not realistic and cost-effective, so we developed the soaking line to help fans become more effective on cooling cattle down.
Problems occurred by heat stress and solved by ventilation + soaking
Decrease in milk production
Decline in immunity fertility
Reduced birth/growth rate
Reduction of dry matter intake
Increase of time standing up
Increase of water intake
Increase in respiration rate
Increase of feet issues
How soaking line work
Soaking lines are the swimming pools or cold showers you take to cool yourself, but on a larger scale for cows. They are usually installed along the feed line, over the holding area and after the exit parlor. There are two critical points to know when you install soaking lines:
Avoid at all time blasting water elsewhere than onto the cow body. The nozzles radius of the system should be at a maximum of 170° to eliminate the risk of getting the feed and bedding soaked in water. To avoid this, the ventilation setup should work closely with the soaking line, when soaking is activated, all recirculation fans should reduce their speed. This can be achieved with a good control and paired with a variable frequency drive.
The soaking must produce large droplets at low pressure. The spraying time needs to be long enough to soak the hide/coat of the cow entirely from neck till tail to avoid creating an insulating layer. It is trapping the heat between the skin of the cow and the thin layer of water stuck in the hair coat of the cow. Therefore, it’s like putting a winter coat on your cow when she is in heat stress.
When the temperature climbs above 20°C (68 °F), sprinklers should be activated and set to spray by sequences, for example, spraying during 1 to 3 minutes every 12-15 minutes interval. The time lapse between soaks should be reduced by 2 minutes for every 5 Celsius hotter (depending on your climate). With the help of a good climate computer, you can control each temperature stage with shorter time off between each shower and lengthen the soaking time.
Increasing milk production and feed intake
Research at several Universities proves that having 1.3-2L (0.5gal)/min sprinklers on your soaking line will increase your average milk production by 3.7kg (6.6lbs)/day-cow, depending on your climate. *
Feed intake has a considerable impact on milk production. With the help of soaking, cows tend to stay longer but less frequently on the feeding line when soaking is activated. * Making a positive impact on dry matter intake (DMI). Research by L. W. Turner from the University of Kentucky proved an increase of 9.2% of DMI on soaked cows. Cattle exposed to soaking and ventilation ate 17.7kg(84.1lbs)/day-cow of DMI vs 14.5 kg(77.0 lbs)/day-cow of DMI of cows not exposed to soaking and ventilation.
*(Cooling cows efficiently with water spray: Behavioral, physiological, and production responses to sprinklers at the feed bunk Jennifer M. Chen,* Karin E. Schütz,† and Cassandra B. Tucker*1)
The increase of laying downtime with high-velocity ventilation
Being well cooled and fed, your dairy cows can easily achieve a laying time of 12-14 hours/day to get the best milk production without any heat problems to occurs them. The only time they will stand up is to go to the milking parlor, the feed line and socialize a bit.*
*(Effects of Bedding Quality on Lying Behavior of Dairy Cows,J. A. Fregonesi, D. M. Veira, M. A. G. von Keyserlingk, and D. M. Weary)
Save water by using less
Saving water will always be important; research conducted at the University of California proved the efficiency of a 1.3L (0.3gal)/min sprinkler was as productive as a 4.9L(1.05gal)/min sprinkler. By having less water (73%) to manage, you avoid yourself from waste management issues and feet problems that can occur if your cows are always walking in a river.
(Cooling cows efficiently with water spray: Behavioral, physiological, and production responses to sprinklers at the feed bunk Jennifer M. Chen,* Karin E. Schütz,† and Cassandra B. Tucker*1)