Harvesting high-quality milk as quickly and efficiently as possible is more important than ever for large dairy farms. For this reason, rotary parlors have become a popular option for farms looking to transition from milking cows in straight parlors. Much like the automotive industry, the large-scale sector of the dairy industry has been drawn to the efficiency of the continuous flow strategy used in rotary parlors.
When discussing milking procedures on rotary parlors, we first need to consider the farm’s management strategies. Milking more cows with moderate production versus milking fewer cows with higher production are two different management methods that can be successful depending on the economics of an individual farm’s enterprise. What works for one farm’s business model may not work at all for another operation.
However, most of the time, decisions on how cows will be milked on a rotary revolve around maximizing cow throughput, milk per stall and the optimal amount of time available for milk harvesting. For any management style, it is possible that a sacrifice will need to be made. Producers may need to accept either lower production per cow or fewer animals milked, depending on which route they choose. Understanding this thought process and what drives profit on any individual dairy ultimately leads us to how milking procedures are determined and executed on farm.
The tried-and-true steps for milking cows are as follows: pre-dip, forestrip, wipe, attach and adjust the milking unit, reattach if necessary and then post-dip. In many cases, forestripping, one of the best methods of tactile stimulation, is removed from the procedure. This leaves wiping as the first true contact with the teat to start the stimulation process. Biology dictates that to achieve maximum oxytocin response for maximum milk letdown, 60 to 90 seconds is needed between first touch on the teat to unit attachment.
Depending on size and speed of the rotary, cows may not have a unit attached until they’ve reached one quarter turn. If there is concern for lack of available milking time, cows may be attached before the 60 to 90 seconds. This can result in bimodal milk flow and longer milking durations. Severity of the bimodal flow can vary from slight to severe depending on milk production, milking frequency, stage of lactation, animal handling, adequacy of stimulation during teat wiping and other factors. When discussing excellent milking procedures, identifying the amount and type of tactile stimulation needed to maximize milk flow is imperative.
Poor stimulation can also negatively affect the number of milking incidents (such as kickoffs, forced unit detachments and second laps) per milking session. Keeping track of milking incidents with parlor automation software can be easy and efficient, depending on the program available. Milking incidents ultimately lead to decreased efficiency due to slowed cow throughput and increased milking durations.
Kickoffs can be elevated due to lack of proper stimulation. Bimodality of milk flow results in a rise of vacuum in the claw or on teat ends, which can cause discomfort and lead to more kickoffs. Increased kickoffs lead to more reattached units, meaning there is a risk of exceeding the maximum amount of time the cow has to milk out during the rotation.
In all scenarios, reattached units are less than ideal. If a farm’s management style is to milk fewer cows with higher yield per animal, then a cow would most likely become a second-lap cow to ensure her total yield is harvested despite the kickoff. Second-lap cows take up a stall in a second rotation, lowering throughput, and therefore efficiency, if there are many of them.
If a farm’s management style is to milk more animals with moderate production, then it’s likely the cow with a kickoff and late reattachment will exit the deck with milk left in her udder. According to studies, incomplete milkings, defined as 30% or more of total milk left in the udder on a twice a day milking frequency or three times a day milking frequency, can lead to both decreased production and increased somatic cell count, over time.
Although milking cows on a rotary has many advantages, it’s important to realize that it can be physically challenging for employees to work on a rotary due to the repetitive nature of their tasks. Unlike a straight parlor environment, employees stand in one position and cows come to them as the rotary turns. While this means less moving around for the milkers, it also means potentially less socialization with other workers, which could be considered a drawback.
A great way for an operation to minimize worker fatigue is to have employees rotate positions every so often to change the nature of the task they must do for every single cow. A good strategy for rotaries turning faster than five seconds per stall is to allocate two employees to attach simultaneously, giving them more time to complete the task and reducing their amount of physical stress.
Having a roamer position on a rotary can add value in several ways. Tasks the roamer may be responsible for are removing units milking in manual mode, reattaching kickoffs, loading the last few cows of each group, bringing the next group of cows to the holding pen, switching bulk tanks, changing milk filters, fixing small issues on individual milking stalls during milking, etc. Depending on management style and ability to source employees, anywhere from four to seven employees will milk cows per milking shift.
Farms that struggle with availability of a steady labor force could potentially replace one or more full-time employee(s) with teat-spraying robots because of their consistency and accuracy. Pre-dip and post-dip robots are the most common, and depending on rotary speed, two of each may be needed. There are some robots on the market that allow a farm to fully automate the pre-dip and wipe functions with a sprayer and scrubber, which could potentially eliminate both of those full-time employee positions.
When looking at robotic teat sprayer and scrubber options, it’s important to focus on the stimulation method used so that bimodality can be mitigated. Contact time with the scrub brush and ability to remove debris are also things to carefully consider when looking into a dual-function robot. A final consideration is how much milking time will be removed due to location of the robots and safety cages.
Farms that milk cows on a rotary should choose their milking procedures based upon their individual goals for cow throughput, rotary speed, milk-flow goals and labor availability. Ultimately, farms should aim to milk 80% of cows completely and correctly. On most commercial dairies, roughly 20% of the herd does not meet the average udder conformation, height and stature, or general milkability standards set by their herd mates.
The goal for these outlier cows should be for milkers to provide them with the most comfortable milking experience possible with their equipment. Any cow can be milked in a rotary parlor, but how they are milked specifically factors into the overall success and profitability of the farm.
References omitted but are available upon request by sending an email to the editor.
