Step-Saver milk transport
Freehand paper drawings of how a complete Step Saver system was installed in a typical dairy barn, also including other common barn structures.
As barns began to increase in size from perhaps 6 to 12 cows to 30 or 40 cows, the bucket milker became a very laborious milking system. As the barn length increased, the farmer had to walk an increasing distance from the cow to the milk bulk tank to dump the collected milk. An early vacuum milk-transport system known as the Step-Saver was developed to save the farmer the trouble of carrying the heavy steel buckets of milk all the way back to the storage tank in the milkhouse. The system used a very long vacuum hose coiled around a receiver cart, and connected to a vacuum-breaker device in the milkhouse.
Following milking each cow, the bucket milker would be dumped into the receiver cart. A foot pedal on the base of the cart lifted the cover, which kept contaminating dust and debris out of the cart, and allowed the farmer to hold the heavy bucket milker with both hands while pouring. A diffuser plate in the top of the cart prevented milk from splashing out while rapidly pouring the milk, and a large filter disk under the diffuser removed any debris from the milk.
Milk collected in a chamber below the filter, and was slowly sucked through the long hose to the milkhouse. When empty, a large float ball in the bottom of the cart would settle down over the drain hole to seal the line and retain system vacuum. When milk was poured into the cart, the ball would float up, unsealing the drain.
An automatic vacuum breaker in the milkhouse cyclically pulled milk from the cart into a glass jar using system vacuum, followed by a release of vacuum to atmospheric pressure, allowing the milk to flow into the bulk tank by gravity flow. When the float level in the jar dropped to setpoint, system vacuum was reapplied to restart the process. Check valves on the vacuum breaker milk hose prevented milk from flowing backwards to the cart when the jar vacuum was released.
As the farmer milked the cows in series, the cart would be rolled further down the center aisle, the long milk hose unwrapped from the cart, and hung on open hooks along the ceiling of the aisle.
Milking pipeline
Main article: milking pipeline
The next innovation in automatic milking was the milk pipeline. This uses a permanent milk-return pipe and a second vacuum pipe that encircles the barn or milking parlor above the rows of cows, with quick-seal entry ports above each cow. By eliminating the need for the milk container, the milking device shrank in size and weight to the point where it could hang under the cow, held up only by the sucking force of the milker nipples on the cow's udder. The milk is pulled up into the milk-return pipe by the vacuum system, and then flows by gravity to the milkhouse vacuum-breaker that puts the milk in the storage tank. The pipeline system greatly reduced the physical labor of milking since the farmer no longer needed to carry around huge heavy buckets of milk from each cow.
The pipeline allowed barn length to keep increasing and expanding, but after a point farmers started to milk the cows in large groups, filling the barn with one-half to one-third of the herd, milking the animals, and then emptying and refilling the barn. As herd sizes continued to increase, this evolved into the more efficient milking parlor.
Milking parlors
Innovation in milking focused on mechanising the milking parlour to maximise throughput of cows per operator, which streamlined the milking process to permit cows to be milked as if on an assembly line, and to reduce physical stresses on the farmer by putting the cows on a platform slightly above the person milking the cows to eliminate having to constantly bend over. Many older and smaller farms still have tie-stall or stanchion barns, but worldwide a majority of commercial farms have parlours.
The milking parlor allowed a concentration of money into a small area, so that more technical monitoring and measuring equipment could be devoted to each milking station in the parlor. Rather than simply milking into a common pipeline for example, the parlor can be equipped with fixed measurement systems that monitor milk volume and record milking statistics for each animal. Tags on the animals allow the parlor system to automatically identify each animal as it enters the parlor.
Recessed parlors
More modern farms use recessed parlors, where the milker stands in a recess such that his arms are at the level of the cow's udder. Recessed parlors can be herringbone, where the cows stand in two angled rows either side of the recess and the milker accesses the udder from the side, parallel, where the cows stand side-by-side and the milker accesses the udder from the rear or, more recently, rotary (or carousel), where the cows are on a raised circular platform, facing the center of the circle, and the platform rotates while the milker stands in one place and accesses the udder from the rear. There are many other styles of milking parlors which are less common.
Herringbone and parallel parlors
In herringbone and parallel parlors, the milker generally milks one row at a time. The milker will move a row of cows from the holding yard into the milking parlor, and milk each cow in that row. Once all or most of the milking machines have been removed from the milked row, the milker releases the cows to their feed. A new group of cows is then loaded into the now vacant side and the process repeats until all cows are milked. Depending on the size of the milking parlor, which normally is the bottleneck, these rows of cows can range from four to sixty at a time.
Rotary parlors
In rotary parlors, The cows are loaded one at a time onto the platform as it slowly rotates. The milker stands near the entry to the parlor and puts the cups on the cows as they move past. By the time the platform has completed almost a full rotation, another milker or a machine removes the cups and the cow steps backwards off the platform and then walks to her feed.
Automatic milker take-off
It can be harmful to an animal for it to be over-milked past the point where the udder has stopped releasing milk. Consequently the milking process involves not just applying the milker, but also monitoring the process to determine when the animal has been milked out and the milker should be removed. While parlor operations allowed a farmer to milk many more animals much more quickly, it also increased the number of animals to be monitored simultaneously by the farmer. The automatic take-off system was developed to remove the milker from the cow when the milk flow reaches a preset level, relieving the farmer of the duties of carefully watching over 20 or more animals being milked at the same time.
Fully Automated robotic milking
In the 1980s and 1990s, robotic milking systems were developed and introduced (principally in the EU). Thousands of these systems are now in routine operation. In these systems the cow has a high degree of autonomy to choose her time of milking within pre-defined windows. These systems are generally limited to intensively managed systems although research continues to match them to the requirements of grazing cattle and to develop sensors to detect animal health and fertility automatically.
Freehand paper drawings of how a complete Step Saver system was installed in a typical dairy barn, also including other common barn structures.
As barns began to increase in size from perhaps 6 to 12 cows to 30 or 40 cows, the bucket milker became a very laborious milking system. As the barn length increased, the farmer had to walk an increasing distance from the cow to the milk bulk tank to dump the collected milk. An early vacuum milk-transport system known as the Step-Saver was developed to save the farmer the trouble of carrying the heavy steel buckets of milk all the way back to the storage tank in the milkhouse. The system used a very long vacuum hose coiled around a receiver cart, and connected to a vacuum-breaker device in the milkhouse.
Following milking each cow, the bucket milker would be dumped into the receiver cart. A foot pedal on the base of the cart lifted the cover, which kept contaminating dust and debris out of the cart, and allowed the farmer to hold the heavy bucket milker with both hands while pouring. A diffuser plate in the top of the cart prevented milk from splashing out while rapidly pouring the milk, and a large filter disk under the diffuser removed any debris from the milk.
Milk collected in a chamber below the filter, and was slowly sucked through the long hose to the milkhouse. When empty, a large float ball in the bottom of the cart would settle down over the drain hole to seal the line and retain system vacuum. When milk was poured into the cart, the ball would float up, unsealing the drain.
An automatic vacuum breaker in the milkhouse cyclically pulled milk from the cart into a glass jar using system vacuum, followed by a release of vacuum to atmospheric pressure, allowing the milk to flow into the bulk tank by gravity flow. When the float level in the jar dropped to setpoint, system vacuum was reapplied to restart the process. Check valves on the vacuum breaker milk hose prevented milk from flowing backwards to the cart when the jar vacuum was released.
As the farmer milked the cows in series, the cart would be rolled further down the center aisle, the long milk hose unwrapped from the cart, and hung on open hooks along the ceiling of the aisle.
Milking pipeline
Main article: milking pipeline
The next innovation in automatic milking was the milk pipeline. This uses a permanent milk-return pipe and a second vacuum pipe that encircles the barn or milking parlor above the rows of cows, with quick-seal entry ports above each cow. By eliminating the need for the milk container, the milking device shrank in size and weight to the point where it could hang under the cow, held up only by the sucking force of the milker nipples on the cow's udder. The milk is pulled up into the milk-return pipe by the vacuum system, and then flows by gravity to the milkhouse vacuum-breaker that puts the milk in the storage tank. The pipeline system greatly reduced the physical labor of milking since the farmer no longer needed to carry around huge heavy buckets of milk from each cow.
The pipeline allowed barn length to keep increasing and expanding, but after a point farmers started to milk the cows in large groups, filling the barn with one-half to one-third of the herd, milking the animals, and then emptying and refilling the barn. As herd sizes continued to increase, this evolved into the more efficient milking parlor.
Milking parlors
Innovation in milking focused on mechanising the milking parlour to maximise throughput of cows per operator, which streamlined the milking process to permit cows to be milked as if on an assembly line, and to reduce physical stresses on the farmer by putting the cows on a platform slightly above the person milking the cows to eliminate having to constantly bend over. Many older and smaller farms still have tie-stall or stanchion barns, but worldwide a majority of commercial farms have parlours.
The milking parlor allowed a concentration of money into a small area, so that more technical monitoring and measuring equipment could be devoted to each milking station in the parlor. Rather than simply milking into a common pipeline for example, the parlor can be equipped with fixed measurement systems that monitor milk volume and record milking statistics for each animal. Tags on the animals allow the parlor system to automatically identify each animal as it enters the parlor.
Recessed parlors
More modern farms use recessed parlors, where the milker stands in a recess such that his arms are at the level of the cow's udder. Recessed parlors can be herringbone, where the cows stand in two angled rows either side of the recess and the milker accesses the udder from the side, parallel, where the cows stand side-by-side and the milker accesses the udder from the rear or, more recently, rotary (or carousel), where the cows are on a raised circular platform, facing the center of the circle, and the platform rotates while the milker stands in one place and accesses the udder from the rear. There are many other styles of milking parlors which are less common.
Herringbone and parallel parlors
In herringbone and parallel parlors, the milker generally milks one row at a time. The milker will move a row of cows from the holding yard into the milking parlor, and milk each cow in that row. Once all or most of the milking machines have been removed from the milked row, the milker releases the cows to their feed. A new group of cows is then loaded into the now vacant side and the process repeats until all cows are milked. Depending on the size of the milking parlor, which normally is the bottleneck, these rows of cows can range from four to sixty at a time.
Rotary parlors
In rotary parlors, The cows are loaded one at a time onto the platform as it slowly rotates. The milker stands near the entry to the parlor and puts the cups on the cows as they move past. By the time the platform has completed almost a full rotation, another milker or a machine removes the cups and the cow steps backwards off the platform and then walks to her feed.
Automatic milker take-off
It can be harmful to an animal for it to be over-milked past the point where the udder has stopped releasing milk. Consequently the milking process involves not just applying the milker, but also monitoring the process to determine when the animal has been milked out and the milker should be removed. While parlor operations allowed a farmer to milk many more animals much more quickly, it also increased the number of animals to be monitored simultaneously by the farmer. The automatic take-off system was developed to remove the milker from the cow when the milk flow reaches a preset level, relieving the farmer of the duties of carefully watching over 20 or more animals being milked at the same time.
Fully Automated robotic milking
In the 1980s and 1990s, robotic milking systems were developed and introduced (principally in the EU). Thousands of these systems are now in routine operation. In these systems the cow has a high degree of autonomy to choose her time of milking within pre-defined windows. These systems are generally limited to intensively managed systems although research continues to match them to the requirements of grazing cattle and to develop sensors to detect animal health and fertility automatically.
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