The dairy industry continues to seek the ideal ventilation system for dairy barns. Producers are turning to power ventilation and automation to save labor and provide an environment that adapts to the cows’ needs at any time of the day or night, year-round.
Insulate to Automate
Some basic ventilation trends can be learned from other animal production agriculture, such as the poultry and swine industries. For instance, one common trait of other production barns is an insulated ceiling. Insulated ceilings are proven to reduce the inside barn temperature by a minimum of 15°F. Insulated barns don’t sweat in the winter, and they reduce radiant heat under the roof on hot summer days. They also give you more year-round control to adjust temperature and ventilation through automation.
Two Separate Ventilation Systems Needed
There are two very different ventilation systems in dairy barns. One system exchanges the air (cfm’s for ventilation) while the other provides directed airflow (airspeed) on the cows. Trying to achieve both with one fan system is difficult to impossible and always results in very high operating costs. Air has a natural tendency to take the path of least resistance and looks for places to escape. As cows lay in rows or stand at the feed bunk, the air looks for paths around them. Dairy barns are big buildings with many large openings for cows or equipment to move in and out, and air to sneak out. Engaging two systems solves these problems efficiently and delivers the ultimate climate for the cows.
Air Exchange System
Good air exchange is the first step of ventilating a barn. In dairy barns, air exchange can be achieved by either natural or mechanical ventilation. Naturally ventilated barns have open sides or curtain walls that can open to allow fresh air to enter. Mechanical or power ventilation is a combination of inlets and fans that control the amount of air moving in and out of the barn. Tunnel, cross or tunnel plus ventilation are examples of mechanical ventilation systems. The trend is for producers to have a solid sidewall to help maintain a more constant climate year-round and avoid cross winds. Dairymen want year-round control for higher per-cow income.
Total Power Ventilation Systems
Today you have large direct-drive fans with precise control, always keeping the barn environment comfortable.
Cow Bunching
Cow bunching generally disappears with a power-ventilated barn. Why? All areas of the barn are comfortable, and the flies don’t like moving air. The fly biting problem seems to stop. Many producers know this can be a big problem and cause milk production losses.
Airspeed Systems
Once sufficient air exchange is in place, an airspeed system must be added. Fans over the stall rows and feed bunk areas focus airspeed in the areas where cows are typically located.
BIGGER is NOT BETTER – Oversized Fans Over Stalls Are a Problem
It is important to keep fan size correct here. Many dairy producers are adjusting to medium-sized fans, spaced more frequently in the barn to give consistent airflow to every stall and Cool the Cow in the Stall.
Higher Air Speeds
When it comes to cooling: the higher the airspeed the better. Fans currently on the market generally provide 12 to 20 mph off the fan face, while the newer fans provide over 35 mph off the face.
One Speed Versus Variable Speed
Currently, many 1-speed fans are used and this only provides full on or off options. Then airspeed fans must be delayed to come on until higher temperatures, when heat stress is already causing production losses.
Variable Speed Fans Earn More
ZAplus variable speed fans are available to allow airspeed fan systems to be turned on at much lower temperatures. Variable speed fans open the door to air movement at much lower temperatures (20 to 25 degrees lower) and precise airflow at cow level, which allows cool air to be used for cow comfort and preventative cooling as heat stress begins. Significant production increases are now possible.
Also, variable speed fans are much more energy efficient.
Automatic Controllers
There are several controller options available. They constantly adapt the barn environment to the cows’ needs. These controllers take into account temperature, wind direction, rainfall and other factors to automatically adjust curtain openings, roof vents, fans, etc. Air curtains that operate with a simple air blower to open and close are growing in popularity and also add insulation to your side walls.
Automating your air exchange system provides more consistent delivery of fresh, clean air to every cow. They are also able to adjust for climate conditions such as storms, cross winds or sudden changes in temperature, which may have otherwise gone unnoticed.
New controllers allow infinite adjustability and more precise cow comfort. Thermostats can be used to stage fans on as temperatures increase. Variable frequency drive (VFD) motors and new Electronic Commutative (EC) variable speed motor fans are gaining in popularity. These controllers tie everything together and automatically (24/7) adjust systems to precise air quality and cooling based on the cows’ needs.
In addition to increasing cow comfort, new motor technology can reduce energy costs as much as 50%. Energy efficiency grants are available for these fans in most areas.
Water Cooling System
Adding water to your heat abatement program dramatically increases the effectiveness of ventilation and airspeed. Many options are available, each with their own level of success and improving over time.
One of the earliest forms of evaporative cooling in barns is a sprinkler along the feed bunk. This is effective at providing some heat stress relief; however, it results in massive amounts of water waste (40 gal/cow/day) and causes an unbalanced barn, with cows standing at the feed bunk or laying down in the aisle.
Fogging systems and evaporative cool cells focus on cooling the air temperature. While they work well in lower humidity, maintenance issues are a concern and fan power can be reduced when blocked inlets affect static pressure.
Low-Pressure Water Systems
Low-pressure delivers water into the fan’s airstream and is quite effective. They allow cooling over the stalls which leads to more lying time. Their low water usage makes them a good option for free stalls, feed bunks, tie stalls, bedded packs, holding pens and hospital areas. Keep in mind that fans and airspeed are an important first step before adding water.
As with ventilation and airspeed systems, automated controllers are now available to operate these water systems. Many take into account temperature and humidity (THI) and adjust the settings accordingly. These controls make cow cooling automated 24/7 by adding the right amount of water, exactly when needed.
Three Systems = Complete Solution
Building a dairy barn is a big investment that typically costs $3,000 to $5,000 per stall. Without proper ventilation and cooling, that investment is wasted while cows stand in aisles and lose production. A completely automated ventilation and cooling system represents 10% to 15% of the stall costs. These additional costs are small compared to the return on the investment.
Improvements in ventilation and cooling often pay for themselves in just a few years or less.
The dairy industry is using automation to increase comfort in every area of the barn. Technology continues to evolve and improve these systems, opening the door to high conception rates and higher levels of milk production per cow. A small investment today in automating your ventilation and cooling systems can ultimately result in the ideal environment for cow comfort and big payback return.
Gold Standard Investment Benchmark
Compare a new ventilation investment to virtually any other investment on your farm.
A ventilation system works for you 24/7/365 versus many other investments on your farm that are only used for brief periods. It’s a GOLD standard investment—and a no-brainer to add more ventilation for your dairy herd.
Brent Hershey,
Tunnel Plus™
4-Season Ventilation & Cooling Systems
