Read the Progressive Dairy Canada digital edition

Looking to tackle ventilation? Here’s where you should start

Mike Wolf for Progressive Dairy Published on 30 April 2021
Exhaust fans

If you’re looking for smart investments that leave a small financial footprint but have wide-ranging impacts throughout your dairy, consider ventilation and cooling.

Now it’s important to consider that ventilation upgrades and investments can be tackled in a tiered, financially sensitive way that can actually help dairies create smaller test scenarios in segments of their operation before fully investing in a comprehensive environmental system.



The following list takes you through five specific approaches to ventilation technology investments that can deliver positive results for your dairy in areas from productivity to reproduction to overall animal health and wellness.

1. Targeting the parlour and holding area

Before we go into detail here, it’s important to note that items one and two on this list are based completely on preference. Both represent great options for taking the first step into making a ventilation and cooling infrastructure investment.

Direct-drive fans push fresh, cool air into the parlour holding area, overhead recirculating fans direct that air down

For smaller herds, the parlour and holding area is definitely a great place to direct a ventilation infrastructure investment. Since the parlour is a consolidated area where most of your milking herd congregates and spends time during the course of the day, it’s the one spot on the operation where a ventilation upgrade can touch nearly every cow in your herd.

A basic, efficient ventilation strategy for a milking centre incorporates pressurizing fans in the parlour combined with natural ventilation, with the addition of some recirculating fans that include soakers and/or high-pressure fogging units to achieve evaporative cooling. It is essential an air exchange is inferred to remove the added humidity levels in the parlour and holding area. Without this, a sauna situation will develop. The goal of those recirculating fans is to achieve air speeds of 5 mph (8 km/h)at the cow level.


2. Dedication to cooling dry cows

The stigma of dry cows being a non-productive cost centre on dairies is one that is thankfully going by the wayside because investing in proper ventilation and cooling for your dry-cow pens can have significant positive upstream and downstream implications on your dairy.

Positive-pressure fans equipped with high-ressure fogging units over this rotary parlour

First, this is the lowest-cost investment you can make, due to the fact that about 10% to 15% of your overall herd is going to be in the dry-cow stage at any given time. And much like the parlour and holding area, the starting point is overhead recirculating fans combined with feedline soakers or equipped with high-pressure fogging units.

By improving ventilation and increasing overall comfort for your dry cows, research has found it’s possible to achieve higher productivity and milk quality when those animals begin lactation. Multiple studies conducted at the University of Florida indicate calves from heat-stressed dry cows are more likely to have health and wellness challenges, reduced growth, lower reproduction rates and lower first-lactation milk production.

When cows are comfortable, lying time increases. This results in increased blood flow to the udder, which is important in overall udder development and growth. Improved feed consumption and utilization is also a byproduct of dry cow comfort, tied to appropriate ventilation solutions.

3. Fans in the freestall barn

While the freestall barn will require a larger investment, it’s the best way to cover the vast majority of the herd with fresh air at the cow level for the longest period of time. Again, the first step in ventilating a freestall barn efficiently is adding recirculating fans, plus fence-line soakers. In more arid climates, optional high-pressure fogging capabilities are included.


If your budget is hospitable to additional equipment, our fourth recommendation is worth considering.

4. Consider a combination system

Recirculating fans are the foundation by which efficient and cost-effective ventilation is built. However, there’s much more to consider for maximizing overall ventilation effectiveness, especially in hotter, more humid climates.

The first element to consider is developing a negative-pressure living area where fresh air drawn through a properly sized inlet is directed to the cows’ living space by recirculation fans and then removed by exhaust fans. An additional design that is working successfully in tunnel-ventilated barns from 500 feet up to more than 1,000 feet long is using pressurizing fans to drive fresh, cool air into the structure, segmentally along its length, and then onto recirculating fans that force fresh air down to cow level. This ensures cows experience fresh air wherever they are along the barn’s entire length.

As cosw enter the parlour, overhead recirculating fans direct cool fresh air down to cow level

There are a number of different options for considering power-ventilation combinations, depending on the design of your barn or structure, but there are solutions that work great regardless of climate and geography.

5. Make the future comfortable

Finally, much like focusing on the dry-cow holding pen, another smaller demographic within the dairy is calves younger than 6 months old. Young calves benefit significantly from fresh air directed to their level and actively removed from their environments. Those benefits range from improved respiratory health, better feed intake and conversion, and in some instances, better coping ability with future exposure to hot, humid weather conditions and borderline heat stress.

If you already have ventilation and cooling components installed across your operation, one of the easiest investments you can make is the investment of time to ensure that all of your equipment is fully operational, clean and meeting current ventilation standards.

And regardless of which solution or investment level might be best for your dairy, it’s imperative to consult a professional dairy ventilation provider who can provide on-farm consultation and design services to help determine the right ventilation investment for your operation. end mark

PHOTO 1: Exhaust fans work in concert with inlet and recirculating fans to pull hot, humid air out of the parlour or living environment.

PHOTO 2: While direct-drive fans push fresh, cool air into the parlour holding area, overhead recirculating fans direct that air down to cow level and toward a bank of exhaust fans that pull warm, humid air out of the facility.

PHOTO 3: Positive-pressure fans equipped with high-pressure fogging units over this rotary parlour provide fresh, cool air and an evaporative cooling effect on cows while milking.

PHOTO 4: As cows enter the parlour, overhead recirculating fans direct cool, fresh air down to cow level. Courtesy photos.

Mike Wolf
  • Mike Wolf

  • Consulting Veterinarian
  • VES
  • Email Mike Wolf