Robotic systems, also known as voluntary milking systems or VMS, are becoming more widely used in North America. Dr. Trevor Devries, Department of Animal Biosciences, University of Guelph, said that with the rapid adoption of this technology, there should be benefits, including aspects that make robotic milking successful.

Those who have adopted VMS report benefits through greater milking frequency and subsequent higher milk yield, improved cow health and reproduction, potential for better herd management and data collection and less or more flexible use of labor, especially on small to medium size farms.

Cows also benefit from VMS, primarily through improved behavioral freedom, which results in better health and production. “It’s allowing the cow to be milked when she wants to,” said DeVries. “We’d like to see that happen at regular intervals but we’re providing the cow the autonomy to do that on her own schedule. That also matches other aspects of her time budget – eat, lie down and drink when she wants to.”

However, some aspects of VMS can be less than desirable. DeVries listed undesirable situations, such as cows that don’t want to go to the robot, udder health management and improper nutritional management.

“Cows may not get to the robot when they want to,” said DeVries, “or do so in a consistent manner. One of the keys to robotic milking is that cows voluntarily go for milking and go consistently with the opportunity to go at different times of the day to maximize efficiency of the system.”

The main factor in consistency for cows is the design and management of facilities. “There are a lot of ways to design robotic milking facilities,” said DeVries. “We can take existing facilities and retrofit them and be successful or build new facilities. We can set up robots within pens in different configurations.”

Most VMS are comfortable with 50 to 55 cows per unit, although some dairies stock 55 to 60. DeVries said with more animals per unit, it’s challenging to manage cows to optimize the number of milkings. If a farm pushes for more than 50 to 55 cows per unit, it’s critical to make sure everything else is managed well to avoid losing milking frequency and yield.

When cows don’t want to go to the robot, facilities might be the limiting factor, or cow mobility is reduced due to lameness and subsequent pain. “The pain restricts her mobility and restricts her desire to be milked voluntarily,” said DeVries. “In robotic herds, we still see a significant amount of lameness.”

Most lame cows are moderately or clinically lame, not three-legged lame. “They’re walking with some kind of gait abnormality, often the result of a hoof quality problem, infectious or non-infectious, causing low level pain that restricts her normal walking behavior,” said DeVries. He added that minor deviations in hooves can be enough to cause a difference in milking behavior, resulting in lower milk production.

Most risk factors for lameness are not specific to robotic farms, but research has identified lying environment of the cows, particularly free-stalls, as well as stall size and comfort, can limit the desire of cattle to spend time lying down or force them to stand on hard concrete for longer than desirable.

“We saw lower prevalence of lameness in barns with wider stalls, stalls with more lunge space, deep sand bedding and lower stocking density,” said DeVries, explaining research findings. “These are all things that affect how much time cows are willing to spend in stalls, as well as the amount of bunk space. When there’s sufficient bunk space, cows can eat when they want to and satisfy that behavior. That limits the time they have to stand and wait for access to feed, which can cut into lying time, which can impact hoof health.”

When robotic systems first came into use, DeVries said there was concern about increased mastitis and poor udder health. “The inefficiencies in technology are being worked out,” he said. “We don’t see any prolonged negative effects in udder health with robots.”

Some researchers have documented increases in cases of clinical mastitis immediately following the adoption of robotics (usually six to 12 months after adoption). However, there’s no true difference beyond that timeframe. DeVries said this proves that udder health changes have little to do with the robots and milking procedures and are more likely due to changes in housing and management as well as stress.

Milk quality issues tend to be more frequent in older, retrofitted facilities because beds and alleys are smaller, increasing the level of udder contamination. One significant difference in VMS vs. parlor milking is when a cow enters a robot with a dirty udder, the robot doesn’t differentiate between that udder and a cleaner one. In a milking parlor, a human worker will clean an excessively dirty udder prior to unit attachment. For this reason, it’s critical to make sure cows stay as clean as possible in a VMS.

With VMS, quarter level milking and quarter level take-offs decrease the risk of overmilking individual quarters. DeVries said the VMS allows for more effective drying off of cows because reducing milk production prior to dry-off is easier. There’s also less risk of udder engorgement immediately following dry-off.

Eating behavior of the bunk ration plays a big role in voluntary milking behavior in cows. “With a robot, we can manipulate feed to some degree by changing feed allowance in the robot,” said DeVries, “which also changes the cows’ desire to go to the robot, as well as milking permissions – how often they go to be milked.”

The most desirable situation is cows that don’t all eat or visit the robot at the same time. “Cows can spend hours per day waiting to be milked,” he said. “If we can get cows to spread out milking activity more evenly across 24 hours, we optimize the use of the robot and get more milkings and more milk.”

It’s critical in any system that when cows go to the feed bunk, there’s feed available, and that’s even more important with a VMS. “It doesn’t matter how we do that – manually with human-driven equipment or robot technology, as long as it’s done consistently,” DeVries said. “In many situations, automated technology pays for itself because it delivers feed more often and more consistently.”

by Sally Colby