While rotary parlors have become a predominant choice for milking large herds, rotaries are not a new idea. They date back to the unveiling of the Rotolactor at the 1930 World’s Fair. Many variations of rotary milking environments have been brought to market since then.
This article focuses on external or parallel rotary parlors, the most common type either in use or being considered by dairy producers around the world.
External rotary parlors of 30 to 106 stalls are commonplace throughout North America today, with the planning of larger rotaries well underway by a number of companies. As rotary parlor technology has improved over time, so has the management and operation, stretching the envelope of productivity and profitability.
Much of the development, engineering and products coming to market are related to external rotary milking environments, such as robotics, to complete tasks historically performed by people. But before discussing robots, we should first go back to basics, and this revolves around the cow.
Some have suggested, “Cows love to ride on a rotary.” While it may please someone to think in these terms, it’s likely more accurate to suggest cows thrive on consistency in low-stress environments. Consistency and reduced stress are the two primary drivers for the efficiency gains we see with well-managed rotaries.
Consistency, both for cows and people
For the cow, unlike a batch or in-line parlor such as a parallel or herringbone, every stall presents as the same. Yes, the rotary may be of clockwise or counter-clockwise rotation, but never both. A cow queueing for and loading the rotary platform experiences the same thing each milking throughout its entire lactation.
Further, within a herd or group of cows, there is a hierarchy or social order. With a properly designed entrance area to the platform, we see cows “sorting” themselves, which I believe illustrates their individual biases for who they stand beside or follow. This factor alone creates an environment of reduced stress for the cow, which may serve to aid the milk ejection reflex and reduce apprehension, nervousness and aggravation.
Those of us who’ve milked in batch parlors have witnessed the opposite: Cows are required to be on the left or right side of the parlor, perhaps as the first or last, perhaps as a timid animal standing beside “the boss.” We’ve also experienced the realities often exhibited by bottlenecks in entrance lanes, a cow balking at assuming a stall position, milking units being kicked or stepped off, slower milkings and so on.
Rotaries also provide consistency for the manager and operator. Cows come to the person at a steady rate, often expressed as “x” number of seconds per stall, catering to more effective and repeatable work routines. This predictability creates a more inviting and hygienic work environment. Predictability allows for standard operating procedures to not only be developed but to be adopted with a high compliance rate.
What routines become more efficient with external rotaries?
With a milking parlor, on a cow-by-cow basis, time is required for completion of each step in the process of milk harvest:
1. Cow entrance or loading: Little time is required by the operators of a well-designed external rotary for entering or loading acclimated cows onto the platform, so this is the first gain in efficiency we see with rotaries.
2. Preparation or pre-milking routines, involving teat disinfection, teat cleaning (removal of organic matter), forestripping and drying: These steps are a critical component of stimulation, or inducing the flow of oxytocin to the mammary gland.
There are products on the market which automatically (via robot) perform the teat disinfection, or in a semi-automatic manner combine a number of these preparation steps. The effectiveness of these combined steps depends on the level of care and attention from the operator.
3. Lag time, the time between the stimulation phase and attach of the milking unit: Allowing for more lag time (waiting upward of 60 to 90 seconds from first touch of teats) usually converts to less time required for milking.
If you’re able to monitor with a herd management system including automatic milk meters, a valid benchmark is to harvest, on average, 50 percent of milk during the first two minutes of unit attach time. Achieving or exceeding this benchmark will identify a desired prep routine and stimulation, translating to faster milking and potential for enhanced udder health/teat condition.
4. Attach milking unit: Here, too, we see advancements in technology to automate.
5. Adjust for unit alignment: When attached to teats, the milking unit or teat cups should hang centered or in line with the rear median suspensory ligament of the udder. This is an easy and visual analysis when milking between the rear legs of the cow, as is the case with an external rotary.
6. Milking time: Should be hand- and issue-free.
7. Unit detach: Includes proper vacuum shut-off and retract once a low milk flow threshold is achieved. Today, milking units are detached automatically, often referred to as a takeoff or detacher. Using properly functioning detachers is another important step for consistency.
8. Re-attach as required: There should be little need for reattaching milking units if your milking system settings are correct, and you’ve followed the steps above. High incidences of reattaching is a symptom of an issue requiring your attention.
9. Post-milking teat hygiene (spray or dip): Another task more frequently being automated in some way.
10. Milking area (stall) cleaning: A key component of proper hygiene. As the cow platform/milking area is moving, clusters, stalls and the floor can be easily cleaned with a stationary sprayer, eliminating the demand for manual labor.
11. Cow exit: Like humans, cows are physically designed to walk forward; walking backward is not as natural. Special attention must be taken to ensure a safe and predictable exit area, leading to uniform cow flow. For a cow to effectively turn herself 180 degrees, she needs room for a complete shift of her facing direction as she is steered toward the return lane.
This, too, represents a gain in efficiency, both from a facility and management standpoint. All cows exit the milking area at same point in rotaries, passing a single and optional sort/separation area, streamlining the flow of cows returning to the barn, lot, shed or pasture.
Assuming these 11 steps are present in all types of milking parlors, external rotaries are allowing for marked gains in efficiency, depending on the size and operation. A number of sources point toward an average of 85 cows milked per labor hour (operators only) invested in parlors.
In highly efficient external rotaries with some form of added automation (pre- and post-teat spraying), upward of 200 to 300 cows are milked per labor hour invested. Possible productivity gains are directly proportional to rotary size. The smaller the rotary, the slower it turns to allow adequate milking time, compared to a larger rotary with a larger circumference turning at speeds in as little as four seconds per stall.
Where is automation headed?
We’ve noted how robotics or other forms of automation are quickly becoming an option, whether currently operating an external rotary or making an investment in one. As technology continues to evolve in the form of features and potential benefits, it should translate to a positive return on investment.
However, more often than not, there is a lack of alignment between the needs, wants and desires of an individual and the functionality of automation like a robot. Let’s look at an automatic teat sprayer (pre- or post-) as an example.
We often assume a person operates at a level of 100 percent hour after hour. In reality, we know this is not sustained for long periods. With robotics, it’s human nature, in lieu of the capital investment if for no other reason, to place extreme demands on the technology – “Mr. or Mrs. Teat Spray Robot, when I hire you, I expect you to:
- Never miss a teat
- Operate at an extremely fast pace
- Use very little product (teat dip).”
When we take the time to reflect on the three points (a, b, c) above, it’s clear to see how each conflicts with the other. For instance, it may be possible to “never miss a teat,” but we’d likely operate at an extremely slow pace or, alternately, use an excessive amount of product. So, as with all technologies, development and productivity gains are a process with a beginning but no end.
External rotary parlors may not be the right solution for any and all scenarios, but they can provide consistency for those who desire to maximize the efficiencies and possible economies of scale.
Consider an external rotary parlor if you aspire to milk more cows in less time, increase your herd size, leverage future technologies, provide a higher level of consistency and predictability for your cows and people in a reduced stress environment, and create a calm and inviting atmosphere.
The more you explore, visit and discuss, the fewer mistakes you’re destined to repeat, and that alone will make for increased efficiency. 
PHOTO: Cows milking with a rotary. Photo courtesy of DeLaval.
Mark Futcher is a manager – project coordination and technical sales support for the North America market area with DeLaval Inc. Email Mark Futcher.
