MANAGING THE COMMITMENT PEN IN GUIDED FLOW ROBOTIC MILKING

In fully guided flow robotic milking, cows receive access to the robot through a commitment pen, where they are held until a robot is available. A sort gate determines whether cows go to the commitment pen or the feed bunk. At the simplest level, cows with milking permission go through the commitment pen, to the robots, and cows without milking permission go to the feed bunk. It’s actually more complicated than that. Sort gate decisions in the software can also limit the number of cows that are allowed into the commitment pen. Cows with milking permission might be sent to the feed bunk if the commitment pen is full. Managing the commitment pen involves an interaction between gate decisions and milking permission.

Some farms do not limit the number of cows in the commitment pen. They rely on milking permission alone to determine which cows have access to the robots. If milking permission works perfectly, it will prioritize the right cows to be milked, as it does in a free flow barn. There are some limitations. The physical size of the commitment pen limits the number of cows it will hold. The number of robots and the milking duration determine how long cows might wait to be milked. People influence how cows flow to the sort gate. Feeding moves more cows to the sort gate – especially if they were out of feed. Downtime for maintenance and repairs will also cause inconsistent traffic to the gate. Inconsistent traffic can cause the commitment pen to get full, so limits are needed.

The first limit should be for cows with milking permission. The basic rule of thumb is to allow as many cows into the commitment pen as the system can milk in an hour. This avoids having cows wait too long in the holding area. For 2 robots, with a milking duration of 7 minutes, the rule of thumb would allow 17 cows. Reduce that number cautiously if the commitment pen is small. When in doubt round up, because setting the count too low will slow the flow of the barn by sending cows to feed that could be milked.

Some farms use a second decision that gives preference to cows that are overdue for milking. Using the example above, the basic decision might be reduced to 14, and the second decision would allow 4 more cows, only if they are overdue for milking, for a total of 18. Keep in mind that DelPro decisions are defined on hours after permission is received, not when cows are overdue. Be careful, the larger the difference between the base decision and the second decision, the longer it will take to milk the pen back down to the base decision.

A few farms have a no-pass decision that holds cows behind the gate if they have milking permission and the commitment pen is full. It’s tempting because it does avoid having to fetch those same cows later if they don’t come back. However, the no-pass decision will restrict access to the feed bunk, which limits dry matter intake. The no-pass decision can also result in a traffic jam behind the gate which discourages timid cows.

There are many more factors to consider, and many more ways to use gate decisions. They can keep problem cows away from the robot overnight, or sort cows for specific purposes at specific times of the day, and specific days of the week. Contact Cow Corner for help customizing gate decisions for your farm and your goals.