The labour-intensive element of existing milking techniques is cleaning and inspecting the cows' udders and fixing the milking cups to the teats, which takes about one minute for each animal.
The robot system measures the length of the cow to get a fix on the position of the udder and then uses two ultrasound detectors to locate the front right teat and fix the cup to it and move the other three cups into place. The sensors tell the system's computer when the milking cluster is attached.
The cow's teats are washed inside the cups, and the milk is then automatically tested for mastitis. The waste water and any rejected milk is sent to the dump tank. The rest of the milk goes to a cooler, and on to a bulk tank to await collection. At the end of the milking cycle the cluster is removed by the robot, which moves automatically between the stalls.
The machine is designed to deal with 'standard' cows, but a cow's udder changes shape depending on the age of the animal and the stage of lactation. The robotic milkmaid has five attempts to find the teats and if it fails, the cow is urged out of the milking stall into a separate area, allowing the farmer to check for damage to the udder.
The other problem is that cows do not keep still. 'The milking cluster, once positioned, is fully floating in all directions and copes with the restlessness of the cow, and even controlled kicking,' Mr Smith says.
Each cow is tagged with a transponder and as it enters the stall the personal computer coupled to the system checks its identity, and when it was last milked. If the animal is not due to be milked it is nudged out again. If the system detects any problems such as mastitis, the cow is directed into a separate pen. The farmer is then paged, and can choose whether to attend to the cow immediately. The farmer is also alerted if any cows are not present for milking. The computer is programmed to dump milk from a cow with mastitis, and provides reports of each cow's yield.
The robot milker, which has taken eight years to develop, is now in use on about 15 farms in Holland, Belgium, France and Germany, and Mr Smith expects the first UK robot milker to be installed early in 1994. Dutch dairy farms tend to be smaller than UK farms, and Mr Smith acknowledges that the robot system may not be so convenient when the cows are grazing in distant fields during the summer. A two-station system costs pounds 122,000, and installation will cost from pounds 3,000 to pounds 5,000.
Mr Smith says that although this is 20 per cent more than existing systems, farmers can increase their yields or, if they are already producing to quota, can cut costs by reducing the size of the herd. 'And there are also huge time benefits for farmers. The whole dairy farm is geared around milking time. Now everything happens automatically, and the farmer is alerted only if there is a problem with his herd,' Mr Smith says.
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