Lely

Overcrowding and robotic milking

In herds with robotic milking, herd dynamics change over time and differ from herds with tradional milking parlours. However, the often heard comment that, due to these different dynamics, it is no longer necessary to have one cubicle and one place at the feed bunk per cow is incorrect. Especially at night and during feeding, robot herds have more or less similar dynamics as tradional herds.

Feeding-lying behaviour
In herds with overcrowding, animals spend more time standing in alley ways and at the feed fence, and as a result spend less time lying and eating. To compensate for less time eating, cows will eat faster and larger meals. Such an eating behaviour increases the risk of ruminal acidosis. Together with increased standing times, this in turn augments the risk for claw disorders, such as laminitis (please refer to figure 1). Good claw health is essential for an optimal visiting behaviour to the robot.

Figure 1: Discoloration of the sole as a consequence of sub acute laminitis

Especially rank low cows, such as heifers and freshly calved cows, are the first to be affected by overcrowding. These animals are more frequently displaced at the feed bunk by dominant cows. In addition to that, free alley ways increase possibilities for lank row animals to visit the robot without disturbance by standing animals.

Since feed sorting is very hard to prevent, overcrowding will also resolve in dominant cows eating the most nutritious particles. Dominated cows (i.e. freshly calved) are then left to eat the more fibrous, less energetic particles which worsen their negative energy balance. Applying the PMR (Partly Mixed Ration) feeding strategy ensures that cows are fed according to their individual requirement. A well-balanced PMR prevent dominant cows from slug feeding.

Cow traffic
To have a good visiting behaviour to the robot, the robot has to be easily accessible. Firstly, this means that there should be plenty of free time on the robot so a cow can enter the robot and be milked. The free time of the robot should be at least 10%, however, it is better to have 15% free time on the robot to ensure labour-saving. Free time means the time that the robot is freely accessible. When there is less free time, especially dominated animals will not be milked enough, simply because they do not have the opportunity or they are afraid to do so (please refer to figure 2).

Animals that are not milked frequently (at least two times/day) have an increased risk of udder health problems. Overcrowding of a robot is not only dependent on the number of animals but also on the milk speed and treatment time in the robot. The robot performance report in the T4C management programme shows the machine results over the past period, including the number of milkings, the time spent on different activities and the overcapacity of the machine.

Figure 2: relation between % free time on the robot and the % of cows to collect Robot farms with poor management spend more time on collecting cows. To reduce labour and to improve farm performance, it is important to optimize feed management, space in front of the robot and in the barn, the farmers’ daily routine and animal health (f.e. claw health).

Secondly, space in front and around the robot is critical to achieve sufficient visits to the robot. This area is the busiest part of the barn, so any obstructions will disrupt cow traffic and reduce visits to the robot. For a good accessibility, the robot has to be visible and easy to reach from anywhere in the barn. As mentioned before, overcrowding causes more animals to just stand at the feed fence and in alley ways. This interferes with a good accessibility and visibility of the robot and hinders cow traffic.

Figure 3: Enough free space in front of the robot and in the barn

Overcrowding and animal health
Overcrowding increases the risk of disorders like acidosis and lameness. In fresh cows and heifers it will worsen negative energy balance and increase the risk of metabolic diseases. As a consequence, there is an indirect effect on fertility i.e. delayed 1^st ovulation and delayed conception.

Tips and tricks

• Prevent overcrowding: it will only cost money. At least one cubicle per cow, and preferably, one place at the feed bunk per cow
• Push feed regularly and check refusals (>5%) as an indication of sorting (are the dominant cows eating the best part of the food)
• Enough space in front of the robot(s) and robot(s) clearly visible
• Free time on the robot: at least 10% (preferably >15%)
• Wide passages every 15 cubicles for an easy access to the feed bunk/robots/water troughs