Automated Milking Systems

From the perspective of The Dairyland Initiative, we assume that the automated milking systems (AMS) from manufacturers such as AMS-Galaxy, BouMatic, DeLaval, GEA, and Lely function well in terms of harvesting milk. The choice between which unit to purchase will be the producer’s decision based upon the desired design features of the individual units and the availability of local service. The recommendations for AMS facility design outlined on this webpage can be applied no matter which manufacturer is chosen.

The Dairyland Initiative AMS Design Blueprint

Our experience with troubleshooting existing and designing new AMS facilities has led us to prioritize the following design criteria:

• Design for 55 cows per robot and a minimum 2 AMS units per pen
• Use deep loose bedding, specifically sand
• Provide a minimum of 24” (60 cm) of feed bunk space per cow in the main lactating cow pen with frequent feed push up
• Allow for unrestricted access to fresh feed in a free-flow or hybrid-flow traffic system
• Provide target air speeds in the resting area and adequate air exchange for sufficient ventilation of the barn
• Select cows to exit through a footbath when leaving the robot
• Allow fresh cows to have 24/7 access to the robot for 10-21 days after calving
• Have a separate first lactation heifer pen for herds with at least 3 robots where heifers have been introduced to robot gating prior to entering the milking pen
• Minimize labor time through functional gating and design

In a well-functioning facility that meets the above criteria, we can expect 2.8 milkings per cow per day with less than 5% of the group needing to be fetched, and a target of over 85 lb (39 kg) of milk per cow per day for the average mature Holstein cow.

Theoretical Robot Capacity

Robot manufacturers focus on theoretical robot capacity and defraying the cost of the robots over as many cows as possible by minimizing box time to maximize the number of milkings per day.

The calculation for theoretical robot capacity is as follows (assuming robot availability is 22 hours per day with two 1-hour wash cycles to clean the robot) and an average box time of 7 minutes per cow:

60 minutes per hour/7 minutes per cow = 8 cows milked per hour

22 hours x 8 cows milked per hour = 176 milkings per day

176 milkings per day/2.8 milkings per cow per day = 63 cows per robot

We commonly see ~60 cows per robot in the industry, but there is often a desire to ‘overstock the robot’ by decreasing box time. For example, at a 6-minute box time, the same calculation would result in 78 cows per robot. Such calculations fail to understand that cows are not robots and that there is a circadian rhythm to robot use throughout the day as shown for a free-flow robot in the figure below.

Milking and non-milking cow visits to the robot in a free-flow traffic system over a one-day period.

The desire to be milked is not constant throughout the day, with busy times around dawn and dusk, and quiet times early in the morning and around midday. Thus, it is highly unlikely that cows will ever maintain the constant throughput through the robot required to achieve the theoretical robot capacity. That is why in the literature, we see optimal cow performance at ~55 cows per robot, which is our recommendation for robot capacity.

We favor two to three robots per pen as this appears to yield more milk per robot, provides greater access and choices for cows, increases labor efficiency, and gives producers options for maintenance.

Sand Bedding

As with conventional parlor herds, sand bedding promotes ~40% less lameness and higher milk production per cow in AMS herds. Approximately 60% of Wisconsin AMS herds use sand bedding, and their average milk production is 3-6 lb (1.5-3 kg) more milk per cow per day than the AMS herds using mattresses for stall beds. Sand bedding continues to be best for cows!

Since cows never leave the pen in AMS facilities, many farms have turned towards V-shaped scrapers to remove sand laden manure from the pen. V-shaped scrapers that run frequently allow for easy bedding access. Manual manure removal is also an option, but functional gating and design is important to make manual manure removal labor efficient.

A V-shaped scraper that folds in and runs parallel to the stalls allows for easy machine access on bedding days.

Bunk Space

Multiple sources involved in the design of AMS units incorrectly state that cows behave differently in AMS facilities, and many 3- and 4-row pens have been constructed based on this false assumption resulting in very limited bunk space.

If intakes are to be optimized to maximize health and productivity, we recommend a minimum of 24” (60 cm) feed bunk space per cow in the main lactating cow pen with frequent feed push up and unrestricted access to fresh feed.

Because the crossover in front of the robot is recommended to be wider (20 ft or 6 m), this crossover space can be used to extend bunk space in AMS facilities, meaning that 3-row pens can be utilized in addition to 2-row pens. This is the case in tollbooth and L-shape layouts, making them the preferred robot layout for extending feed bunk space.

Tollbooth and L-shape layouts allow for extended bunk space in front of the robots because of the extra wide crossover (Veterinary Clinics of North American, 2019)

Frequent feed push up is essential in AMS facilities. We recommend automated feed pushers that run ~12 times per day to maximize feed access and milk production.

Cow Flow

Each traffic system (free-flow, semi-guided or hybrid flow, and milk-first guided-flow), has its pros and cons, and producers can succeed with any type of system.

Free-flow systems tend to be cheaper to build, have fewer gates, provide greater freedom for cow movement, and achieve slightly higher milk per cow per day on average than guided-flow systems. However, that higher milk yield is in part due to the increased feed rates observed using expensive robot feed (~3 lb (1.5 kg) more per cow per day), higher fetch rates (8% vs. 5%), more milkings per cow per day (2.9 vs. 2.6), and increased labor (~0.5 minutes per cow per day).

The variation within each traffic system is great, and the focus should be on optimal design and management for whichever system is chosen. However, we prefer that cows should have unrestricted access to the feed bunk when fresh feed is delivered to optimize feed intake. That means leaving crossovers open, even if there are guided-flow gates around the robots, which we refer to as semi-guided or hybrid flow.

A semi-flow or hybrid flow traffic system that has one-way gates around the robots, but no gates on the crossovers at the end of the pen, allowing for unrestricted access to the feed bunk and resting area.

Adequate Ventilation and Cooling

Adequate ventilation and cooling is essential to the success of AMS facilities. In a recent Canadian survey, ventilation was the single most important factor influencing milk production. The presence of robot rooms, which block inlets and air flow, and other electronics in the cow barn lead to a situation where mechanical ventilation and climate control is preferred over natural ventilation systems, especially in varied climates with hot summers and cold winters. When designing mechanical ventilation systems for AMS facilities, the robot room should be located closer to the exhaust end of the barn to limit windshadows downwind of the robot room.

Footbath Placement and Use

Lameness rates are higher in AMS herds than in conventional parlor herds. This is likely due to a combination of:

1. Use of mattress stalls rather than deep bedding
2. Use of slatted floors which injure the hoof wall, increasing the risk for white line lesions
3. Inadequate hoof care due to a lack of trimming facilities
4. Inadequate use of footbaths increasing the risk for infectious hoof disease

Footbaths are used less frequently in AMS herds than in conventional herds because it is difficult and time consuming. Often, footbaths are located in crossovers and cows are only foot bathed on bedding day – a practice we do not recommend.

Footbaths should be designed and located so that cows are automatically sorted through the footbath when exiting the robot and/or returning to the resting area, which is most easily done with a tollbooth robot layout.

Easy access to a trim chute for inspection of a lame cow’s foot is also a priority. Lame cows should be examined as soon as possible in all facilities, but this is especially important in AMS units where lame cows rapidly become fetch cows.

Tollbooth layout courtesy of 4dBarn where cows are sorted from the robot to the feed bunk, footbath, or chute.

Fresh Cow Management

We recommend fresh cow pens in AMS herds. It is not surprising that fresh cows, especially fresh heifers, perform poorly when they are immediately moved into a mixed age pen after calving.

AMS facilities should be designed to have a separate pen for early lactation cows and heifers with either their own robot stocked at under 50 cows per robot (this can be accomplished in herds of ~600 cows or more) or allowed free access to a shared robot with gates routing them back to their pen of origin.

With this robot placed perpendicular to the stalls, cows from a secondary milking group can access the robot as well as cows from the main milking group.

While conventional herds manage separate fresh pens for up to ~21-30 days in milk, the availability of data for cows in AMS herds makes the period of grouping more flexible. We recommend moving cows to the main lactating cow pens when herd targets are reached for health and milk production, which may be as early as 8-10 days or as long as 30-40 days, depending on the individual cow.

First Lactation Heifer Pens and Heifer Management

In many AMS herds, heifers perform poorly and are fetched at high rates in early lactation. We recommend training heifers during the rearing period to use swing gates to gain access to feed and water, and in some instances, walk in and out of dummy robot boxes. It is not intuitive to these animals to push on a swing gate, which appears closed, to get somewhere – they must learn to do this before calving.

While the desire to get the heifer milking in the robot quickly is understandable, we discourage over fetching heifers, preferring no more than 2 milkings per day, especially over the first 5 days in milk. Remember, heifers are fed when they enter the robot and overfeeding concentrate can have a negative impact on risk for ruminal acidosis and ketosis.

We also recommend AMS facility designs where the cows exiting the robot do so away from where other cows are waiting to enter the robots, and entry designs that protect the animal waiting to be milked from other cows trying to access the robot in order to avoid prolonged waiting times and reduced robot visits, especially for heifers and subordinate cows. A 4-foot (1.2 m) long barrier protects the shoulder of the waiting cow and facilitates her undisturbed entry into the robot as seen in the following photo:

Functional Gating

One of the main reasons for switching to AMS is labor efficiency. It is absolutely essential that AMS facilities be designed for one person to move cattle easily and efficiently around the robot with the least amount of stress.

Gating plans are an integral part of the AMS facility design process, and every AMS design should have a gate plan for:

1. Fetching a cow to be milked
2. Sorting a cow out for treatment or breeding
3. Moving a recently calved cow to the robot
4. Moving a cow to be dried off
5. Moving a cow to the trim chute

Movement in and around the robot is complicated, and sort gates can make life easy or hard depending on their design and location. Gate plans allow producers to imagine themselves moving cows in the barn, and time and money spent up front on gate design can save on hours of frustration in the future. Our sponsor, 4dBarn, specializes in gate design plans for AMS herds.

Cows’ unobstructed movement to and from the robot via alleys is extremely important. These are the highways to and from the milking center and they facilitate robot visits. For that reason, we recommend slightly wider alley dimensions in AMS herds than in conventional parlor herds, with the width of the cross alley in front of the robots being the most important in order to avoid congestion.

Robot Layouts

There are a variety of different ways to orient a robot within a pen. The six robot layouts commonly seen in practice include: side, island, tollbooth, crossway, L-shape, and the 4dBarn Herringbone®. Each layout has its pros and cons, with the common goal of facilitating cow access to the robot to promote milk production and labor efficiency.

The ideal robot placement will optimize visits to the robot by reducing traffic around the robot and providing plenty of space to minimize congestion and competition. Design should be used to promote robot visits – not feeding!

Some robot layouts are better suited for guided-flow traffic systems with a commitment pen while other layouts can only be used with free-flow traffic and allow for the placement of a fetch pen next to the entrance of the robot. Fetch pens should have a split entrance for cows to access the robot from either the fetch pen or the main milking group, and should be sized to provide 20 to 30 square feet per cow for 4 to 6 cows.

Labor is also affected by robot orientation. We want to minimize the amount of time spent fetching and moving cows, and minimize the alley area around the robot that needs to be manually manure scraped. When there are multiple robots per pen, it is best to locate them in the same area so that workers do not have to cross multiple points of cow traffic and repeat chores in multiple areas. This can be accomplished with perimeter feeding.

The table below outlines key considerations when choosing how to orient a robot within a pen:

Robot Orientation	Side	Island	Tollbooth	Crossway	L-Shape	4dBarn Herringbone®
Definition	Robots located on the side of the barn, parallel to the feed alley.	Robots located in an island in the center of the barn, parallel to the feed alley.	Robots located at the end of the pen, parallel to the feed alley. Cows enter parallel to the feed alley and exit perpendicular to the feed alley.	Robots located at the end of the pen, perpendicular to the feed alley.	Robots are located at the end of the pen, parallel and perpendicular to the feed alley. Robots can be placed facing each other (head-to-head), away from each other (tail-to-tail), or in the same direction (head-to-tail).	Robots are located at the end of the pen, slightly angled toward the feed alley.
Traffic system options	Free-, semi-, and guided-flow	Semi- and guided-flow	Free-, semi-, and guided-flow	Free-, semi-, and guided-flow	Free-flow	Free-flow
Cows exit separate from cows waiting to be milked	No if more than one robot	No if more than one robot	Yes	No if more than one robot	Depends on robot orientation	Yes
24/7 access for a secondary cow group	No	Yes	Yes	Yes	Yes, for robot perpendicular to the feed alley	Yes, for robot nearest secondary group
Extended bunk space in front of the robot	No	No	Yes	Yes	Yes, from robot perpendicular to the feed alley	Yes
Cows can be automatically sorted through a footbath	No if more than one robot	Yes	Yes	No if more than one robot	No	Yes