Cooling and Cleaning Pose Problems

A common European practice is to rinse the milker unit with water after four or five cows have used it, and whenever it hasn't been used for 20 minutes. The entire system is washed with a full wash cycle three times daily.

We may need to adjust required cycles according to season. For example, rinsing may have to be more frequent during hotter months.

Some jurisdictions in Europe restrict the length of the milk line to the bulk tank to a maximum of 66 feet. This decreases the surface area exposed to warm milk. A plate cooler close to the stall with water flow regulated to coincide with milk flow is a good way to provide some initial cooling of milk.

Bacteria-free wash water and properly sloped lines for draining are musts on all dairy farms. These items may be even more critical on farms with robotic milkers because of the frequent equipment rinsing. If you're installing a robot on your farm, talk to your Dairy Farmers of Ontario field services representative before you put in the system.

Since milk is picked up while cows are milking and bulk tanks can't function at less than 10 per cent full, robotic milking requires additional equipment to resolve bulk storage issues.

Small bulk tanks have traditionally been used as buffer tanks that are filled while the main tank is emptied and washed. These small tanks can be a problem, although better solutions may be ahead. Several of the Dutch farms reported high bacteria resulting from inadequate cleaning of these small tanks, which sit empty and warm most of the time.

In a 60-cow herd, milk flow is about 75 litres per hour. If a buffer tank must be 10 per cent full before it can be turned on, a tank with a capacity of 500 gallons U.S. would sit for 2.7 hours before you could start to cool milk in it. This is too long a delay. It shows that small tanks with 10 to 20 per cent of the capacity of the main tank are best.

Elevating the buffer tank so gravity can empty it reduces milk pumping. Several newer European systems have 200 to 300-litre buffer vats to cool milk before it reaches the bulk tank. These vats provide enough capacity to allow automatic washing of the main tank. Ice bank tanks that don't require a 10 per cent fill are also used in combination with a brief shutdown of the robot while the tank is washed.

Of course, controls to these systems must be accessible in the milkhouse and labeled instructions must be posted for the transporter.