During the second half of the nineteenth century, more than a hundred patents for milking machines were applied for in the United States alone. The proliferation of people trying to develop this device, as with any that sees development across countries, makes it difficult to attribute the modern product to one person or organization.
The problem with all kinds of automatic milking processes is that there is potential for damage to the cow's teats. A viable milking machine needs to strike a balance between producing a good yield of milk and safeguarding the cow, either from injury or infection caused by the equipment.
Many inventors made contributions to the field. Foremost is the DeLaval Company of Gustaf de Laval, famous for inventing a device for separating milk and cream through centrifugal force, which researched almost every type of automatic milker in existence, including ones that simulated the action of the human hand. Other key inventors included L. O. Colvin, who created one of the first viable vacuum milkers, and William Mehring, whose foot-powered vacuum milking machine also received notable popularity.
The closest ancestor of the modern milking machine is probably the "Thistle" machine of 1895, made by the Scottish Thistle company; its steam- driven pump resulted in a distinctive broken flow, called the pulsator. The regulation of the vacuum being applied to the cow's teat is essential to stop blood pooling in the teat, which can lead to injury; this key feature of modern machines is what links them back to the "Thistle."
