No one is suggesting that rotaries are going to take over or that they are somehow better than conventional herringbone or parallel milking parlors. However,today's rotaries will remain a viable option for some producers and not fade away like they did in the 1970s.

If you were to look through a dairy magazine published 30 or 40 years ago, you'd be amazed at how much has changed in this industry. The technology, for one thing, has improved tremendously.

Yet, some of the same concepts that we hear about today were floating around then - they just weren't as fully developed. For example, several articles appeared in 1973 about rotary milking parlors. Interest in rotaries was growing - so much, in fact, that the February 1975 issue of Dairy Herd Management referred to their "rapid acceptance."

By 1977, rotaries had dropped out of sight - nary an article or an ad-vertisement to be found.

Today, rotaries are making a comeback. And, this time, they're here to stay.

What goes around comes around
Many of the same issues that swirled around rotaries in the 1970s are issues today. Rotaries appeal to people because of high implied throughput - which, in the case of a 60-stall rotary, can be as high as 450 cows per hour. With a rotary, you can keep a constant flow of cows moving through the system.

But, assembly-line approaches to milking can be both a curse and a blessing. Rotaries usually run at a fast enough pace that one cow after another will walk onto the milking platform a scant 8 to 12 seconds apart. With so little time to handle each cow, a worker will only be able to attach milking units and not much more - unless another milker is brought in, and then you lose some of the potential labor advantages.

With many rotaries, the pre-milking udder routine is minimal at best.
Certainly, if you are interested in buying a rotary, you need to ask yourself these questions: What kind of pre-milking udder prep procedure do I want to follow? How clean are the cows when they come into the parlor? How many milkers do I want working at one time?

Your management system will have a major bearing on whether a rotary is right for you.

And, so will your expansion plans. With conventional parlors, it's possible to expand the size simply by adding onto one end - provided, of course, the building will accommodate it. With a rotary, you can't do that. You're locked in, and the only option at that point is to add a second rotary. That's a definite disadvantage, unless you have planned well enough ahead of time to anticipate future growth.

More reliable
Rotaries didn't last long in the 1970s because the companies that distributed them in the U.S. didn't put much development effort into them. Glitches oc-curred, as might be expected with any parlor system first being introduced. Companies pulled out before the glitches could be corrected, and rotaries lost ground to herringbones and parallels.

But, a few diehards have kept their rotaries going since the 1970s.

Brent Palmer, herdsman at a 325-cow dairy near Salt Lake City, Utah, has been milking in a 17-stall rotary parlor for nearly eight years, and the rotary itself is close to 22 years old. Preventative maintenance has been the key to keeping it going all of these years, he says.

The worst thing that has happened yet was when the track beneath the milking platform broke and sprung open and the platform wouldn't move, Palmer says. Luckily, he was able to weld the track in place temporarily, and it only put the milking schedule one hour behind. The next morning, he was able to correct the problem more permanently.

"We have yet to miss a milking because of problems with the milking platform, or table," Palmer adds.

Dan Sheldon, owner of Woody Hill Farm in Salem, N.Y., is another long-term user of rotaries. He's milked in a 14-stall rotary since 1974 and a 28-stall rotary since 1995. In all that time, he recalls only two milkings where the parlor was not rotating - and that was from having to wait for specialized parts. He agrees that most mechanical problems can be avoided with preventative maintenance.

If a handful of parlors from the 1970s are still going strong, then the newer models - which are much sturdier and more reliable - should have an even longer-lasting legacy.

There's really no comparison between today's rotary parlors and those from the 1970s, notes Mike Pawlak, vice president of Westfalia Dairy Systems, a leading manufacturer of rotary parlors. The carriage system on today's rotaries, consisting of I-beams riding on high-impact nylon or steel rollers, makes it much easier for the platform to turn. And, the easier it is for the platform to move, the less wear and tear on the entire system, Pawlak adds.

"With today's technology and the built-in safeguards, down days are virtually eliminated," Pawlak says, except for unexpected problems like power failures.

Fixed routine
Those employees of Sheldon's who have worked in other types of parlors say they don't want to go anywhere else after having worked in a rotary. They like the constant flow of activity.

That's one of the advantages of a rotary: You gain a fixed routine. It forces you to address a cow every 10 seconds or so, depending on how fast the milking platform is turning.

We've been hearing a lot lately about Total Quality Management (TQM) and its application to the dairy business. TQM seeks to promote consistent quality by identifying key steps in the manufacturing process and then formulating those steps in a routine that's highly repeatable. A rotary conforms to this concept, because it requires a worker to stand in a particular area - much like an assembly-line worker - and perform the same task every time a cow passes by.

Two other observations:

  • No coaxing is needed to get cows onto the milking platform. In fact, there's a lot of jostling in the holding pen as cows eagerly await their turn on the "merry-go-round."
  • Rotary milking systems are amazing quiet

Added efficiency?
The jury's still out on whether the throughput and labor efficiencies gained by rotaries are superior to conventional in-line parlors. Dennis Armstrong, a parlor efficiency expert who recently retired from the University of Arizona, is currently gathering the numbers - and he says further study is needed.

Efficiencies from a rotary will depend, in large part, upon the pre-milking hygiene practiced by the dairy. If the dairy has a minimal routine, there may be a labor savings, Armstrong says. If the dairy has an extensive routine, those savings won't be as great.

At one of the dairies that Armstrong has studied - Joe Pires Dairy in Tipton, Calif. - the 48-stall rotary is handling approximately 280 cows per hour. Because six of the stalls are used by cows that are entering or exiting the platform (or cows that are about to be post-dipped or have milking units attached), that leaves 42 stalls for cows that are actively milking. Another cow enters the platform every 10 seconds.

Theoretically, Pires' rotary parlor should be able to milk 360 cows per hour, but the actual number drops to 280 because one of the milkers has to stop occasionally and bring in another group of cows from the outdoor corrals.

With two milkers handling all of the duties, Pires' rotary is achieving a throughput of 140 cows per worker per hour. That's an admirable number, but also within the realm of possibility for conventional parallel or herringbone parlor systems. An article in the September 1998 issue of Dairy Herd Management told about a double-24 herringbone in Michigan where one worker had milked up to 175 cows per hour.

Simple math
Larry Jones, farm management consultant with the FARME Institute in Homer, N.Y., says all parlors - rotaries, herringbones, parallels - must conform to the "3,600-second rule." In other words, there are only 3,600 seconds in an hour to accommodate the work routine. If you have a 30-second work routine (including pre-milking prep and unit attachment), then one person can only handle 120 cows an hour, regardless of how many cows the parlor is capable of handling. The solution is to either cut the length of the routine or add more milkers.

Streamlining the udder prep procedure can cause problems, however, be-cause you may be eliminating a vital component of udder health and cleanliness.

Jones does acknowledge one clear advantage held by the rotaries, and that is entry time. If one cow is allowed to come onto the platform every 10 seconds, it creates a steady flow of cows onto the platform. Entry time is practically zero. But, if the entry time is lengthened to 15 seconds, the cows have to stop for a few seconds and wait, which slows things down.

So, entry time becomes a crucial part of the efficiency formula.

And, because cows usually require several minutes for milkout, entry time has to be coordinated with the size of the parlor and the pre-milking cow prep procedure.

John Hayne, rotary systems product manager for Alfa Laval Agri, says one of the things he inquires about when installing a parlor is the herd's milkout time so he can adjust the speed of the milking platform accordingly.

After doing the math, it becomes obvious that the rotaries are particularly well suited to large dairies - those with enough cows to keep a rotary with 48 stalls or more moving continuously - one cow at least every 10 to 12 seconds.

In the 1970s, it was typical to see small rotaries, with perhaps 14 to 17 stalls. Those rotaries didn't have the potential to move very many cows. But, the average herd was smaller than it is today. Today's herds are large enough for a ro-tary to finally make sense.

A striking example is provided at the 3,100-cow A.J. Bos dairy near Bakersfield, Calif. With twin 54-stall rotaries standing side-by-side, the dairy is running a total of 700 to 750 cows per hour through the milking center. The equivalent in-line setup, consisting of two double-54 herringbone or parallel parlors, couldn't generate those type of numbers unless it was getting six and one-half to seven turns an hour, and everyone knows that seven turns is unrealistic.

Here to stay
Jones says he agrees that rotary parlors are here to stay for two reasons:

  • The technology is much better than it was in the 1970s.
  • They make sense on many of today's large dairies.

Hayne, of Alfa Laval Agri, says there is definite interest among the 2,000-cow dairies in California. Often, the dairies are undergoing expansion or relocating from one area to another.

Ray Middel, North American sales manager for Westfalia Dairy Systems, says the primary interest in rotaries has been among commercial dairy farms with 500 or more cows. These farms are interested in rotaries with 48 or more stalls.

And just last month, another equipment manufacturer - Bou-Matic - introduced its line of rotary parlors.

The fact that these companies are spending millions of dollars to develop and introduce new product lines is perhaps the most compelling evidence yet of the rotaries' increasing popularity. And, most observers don't see it as a fad or fleeting fancy, either. This time, rotaries are here to stay.