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Don’t go in circles: Four questions to consider when investing in a rotary

Steve Mattox for Progressive Dairyman Published on 04 November 2016

It’s hard to believe rotary parlors have only been with us since the Borden’s Dairy exhibit featured it in the 1939 World’s Fair. The Rotolactor, as it was called, was a truly amazing innovation that took time to catch on.

Fast-forward to the turn of the 21st century, and rotaries have taken the dairy world by storm. Now a common consideration for medium- to large-size farms, it should be on your list as an upcoming investment in the future.



As you start the purchasing process, be sure to ask four questions that will help steer you straight when you’ve decided to go circle.

How do I choose the right size?

One of the biggest mistakes a farmer should avoid is choosing the wrong-sized parlor. A rotary is a long-term investment with an average life span of more than 15 years if properly maintained. If you buy a rotary based on your current herd size, you limit future expansion. In contrast, buying too large of a rotary will impact overall efficiency and could be a waste of money.

One of the smallest rotaries is a 32-bail and the largest-to-date is a 106-bail for Jerseys (100-bail for Holsteins). Rotaries will milk 30 to 40 percent more cows per hour than conventional parlors on a per-stall basis.

We have seen customers that bought an 80-bail rotary when all they really needed was a 60-bail or, vice-versa, overestimating cows per hour or buying a deck that limits herd expansion. Make sure you talk to your dealer to discuss ways to optimize the equipment.

One way to ensure the proper optimization is to take a hard look at cow traffic at the entrance. If a cow can quickly step onto the deck, throughput is increased. Though the increase is slight, it is compounded by the number of cows and each second starts to add up. This added efficiency could reduce the number of bails needed, as the same amount of cows will be milked in a shorter time.


Equally important is cow traffic before they even reach the rotary. If it is constrained by too many twists and turns, or there are other infrastructure issues, there is no sense in building a larger deck if cows cannot be guided to and from it easily.

Too much disruption could cause the operator to stop the deck, and that is the worst thing you can do while it is running. You lose one of the biggest advantages of a rotary: speed. In static parlors, the operator controls the speed, but in a rotary parlor, the speed is controlled by the deck. A stopped deck for reasons other than safety, maintenance or repair is potentially wasted money.

How do I manage cow flow?

One of the most important considerations, alluded to in the prior section, is how cows will get on and off the deck. Cows enjoy the ride, and it is possible to achieve a very pleasant milking experience for them.

At times, I have seen farms that have a man pushing cows onto the deck. This is unsafe, disrupts cow flow and will slow down the process. Leave the cows alone and let them have the time and space to learn the equipment. Eventually, they get into a rhythm of their own, based on social hierarchy, which results in a less stressful milking experience.

Getting off the rotary is a different matter. Many cows enjoy riding so much you will have to use something to encourage them to get off. There are several different methods, such as compressed air, rubber mat and water, but none of these are 100 percent successful.

Some cows may ride as many as four or five times, regardless of the method used. Work with your dealer to design a safe protocol for encouraging the free riders to leave.


How about milking procedure?

Cow prep is more consistent on a rotary, but it is critical to have a great milk prep procedure to achieve proper letdown. Standard prep routines are used on the pre-milk side with a standard dip, strip, wipe and attach routine.

With a rotary, you can theoretically attach every cow with about 90 seconds of prep lag time, creating the proper oxytocin release in order to harvest as much milk as possible, as quickly as possible, with as little trauma to the teat ends as possible.

There is also a post-dipper stationed near the rotary’s exit. The post-dipper’s job is less strenuous than the other stations, yet it takes stamina to keep up with attaching the machines. Consider rotating staff with frequent breaks so one person does not continually perform the same function.

Speed is one of the most important features of a rotary. Therefore, be sure to invest in premium teat dip products with a fast kill speed. In static barns, the pre-dip likely sits longer on the teat, but the speed of the rotary makes quick disinfection a must. Any gains in speed may quickly be lost by lower milk quality if this important factor is not considered.

Finally, when evaluating your milking procedures, keep robotics in mind for the initial investment or at some point down the road. Robotics are designed to help ensure precision and potentially labor savings.

If these factors are a concern, evaluate a pre-spray or post-spray robot. There may also be future solutions on the horizon that could perform other functions of the milking procedure.

How will I keep my employees and animals safe?

The most important factor in a rotary parlor investment is the safety of your animals and employees. A moving machine as big as a rotary deck must be respected. No one but the cows should ever be allowed to ride on a deck if it is turning. Make sure all employees and technicians are properly trained and informed of potential risks before startup.

Religiously use all manufacturer recommended safety signs and devices to protect your workers and limit your liability risks. Make sure safety devices are in place and fully functional, and that all workers know how to use them.

Rotary parlors can be an intimidating investment, so getting all the basics right ahead of time is key. If you are seriously planning one, don’t go around in circles. Talk to a qualified dealer to find the right solution for you and your herd.  end mark


Steve Mattox is the marketing manager of project development for DeLaval.