Dairy farming
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Dairy farming is a class of agricultural, or more properly, an animal husbandry enterprise, raising female cattle, goats, or certain other lactating livestock for long-term production of milk, which may be either processed on-site or transported to a dairy for processing and eventual retail sale. Most dairy farms sell the male calves borne by their cows, usually for veal production, rather than raising non-milk-producing stock. Many dairy farms also grow their own feed, typically including corn, alfalfa, and hay. This is fed directly to the cows, or stored as silage for use during the winter season. Additional dietary supplements are added to the feed to increase quality milk production.
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[edit] History of dairy farming
Before mechanization and the arrival of gasoline and steam engines, dairy farming was primarily a family affair intended to provide just enough milk for the peasants and homesteaders scratching out an existence of their own in the countryside [citation needed] . They might have just one or two cows and a bull, to provide milk for the family and to work as oxen moving wagons and plows.
Centralized dairy farming as we understand it primarily developed around villages and cities, where residents were unable to have cows of their own due to a lack of grazing lands. Near the town, peasants could make some extra money on the side by having additional animals and selling the milk in town. The dairy farmers would fill barrels with milk in the morning and bring it to market on a wagon. [citation needed]
Keeping milk cool helps preserve it. When windmills and well pumps were invented, one of its primary uses was for cooling milk, to extend its storage life before going to the town market. The naturally cold underground water would be continuously pumped into a tub and containers of milk set in the tub to cool after milking. This method of milk cooling was extremely popular before the arrival of electricity and refrigeration.
Before electrification most cows were still milked by hand, one after the other, each morning and night at milking time. This was feasible when a farm had up to about six cows but took too long as the herd size increased. Electrification brought the vacuum pump, and the automatic milking machine.
The first milking machines were an extension of the traditional milk pail. The early milker device fit on top of a regular milk pail and sat on the floor under the cow. Following each cow being milked, the bucket would be dumped into a holding tank.
This developed into the Surge () hanging milker. Prior to milking a cow, a large wide leather strap was put around the cow, across the cow's lower back. The milker device and collection tank hung underneath the cow from the strap. This innovation allowed the cow to move around naturally during the milking process rather than having to stand perfectly still over a bucket on the floor.
Surge later developed a vacuum milk-return system known as the Step-Saver, 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 hanging milk bucket would be dumped into the receiver cart, which filtered debris from the milk and allowed it to be slowly sucked through the long hose to the milkhouse. 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 hooks along the ceiling of the aisle.
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 final innovation in automatic milking was the milking parlor [citation needed], 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. Milking parlors allowed a large concentration of technical equipment to gather in one place, which permitted automatic milk take-off devices. Before this, milking was not entirely automatic, and each cow needed to be monitored so that the milker could be removed when the cows were almost done lactating. Leaving the milker on too long following lactation could lead to health problems such as mastitis.
[edit] The milking operation
[edit] Original hand milking processes
Until the late 1800s, the milking of the cow was done by hand. Several large dairy operations existed in some northeastern states and in the west that involved as many as several hundred cows, but an individual milker could not be expected to milk more than a dozen cows a day. Smaller operations predominated.
Milking took place indoors in a barn with the cattle tied by the neck with ropes or held in place by stantions. Feeding could occur simultaneously with milking in the barn, although most dairy cattle were pastured during the day between milkings. Such examples of this method of dairy farming are difficult to locate, but some are preserved as a historic site for a glimpse into the days gone by. One such instance that is open for public tours is at Point Reyes National Seashore.
With the availability of electric power and suction milking machines, the production levels that were possible in stantion barns increased but the scale of the operations continued to be limited by the labor intensive nature of the milking process. Attaching and removing milking machines involved repeated heavy lifting of the machinery and its contents several times per cow and the pouring of the milk into milk cans. As a result, it was rare to find single-farmer operations of more than 50 head of cattle.
[edit] Modern Milking Parlor Operations
A farmer with a modern milking installation such as a large herringbone or rotary parlor serving 16 or 24 cows at a time would be capable of milking around 300-500 cows per hour [citation needed]. Farmers in New Zealand aim to milk the whole herd in under two hours twice a day [citation needed] so that the animals get the maximum time in their pasture. Farmers in other countries usually have smaller plants and 150–300 per hour is more likely. Milking machines are held in place automatically by a vacuum system that draws the ambient air pressure down to 15 pounds of vacuum. The vacuum is also used to lift milk vertically through small diameter hoses, into collection pipes and, eventually, into a refrigerated bulk tank.
Milk is extracted from the cow's udder by flexible rubber sheaths known as liners or inflations that are surrounded by a rigid air chamber. A pulsating flow of ambient air and vacuum is applied to the inflation's air chamber during the milking process. When ambient air is allowed to enter the chamber, the vacuum inside the inflation causes the inflation to collapse around the cow's teat, squeezing the milk out of teat in a similar fashion as a baby calf's mouth massaging the teat. When the vacuum is reapplied in the chamber the flexible rubber inflation relaxes and opens up, preparing for the next squeezing cycle.
The extracted milk passes through a strainer and a plate heat exchangers before entering the tank, where it can be stored safely for a few days at approximately 3°C. At pre-arranged times, a milk truck arrives and pumps the milk from the tank for transport to a dairy where it will be pasteurized and processed into many products.
[edit] Super-Dairy Operations
In the Southern San Joaquin Valley of California a number of dairies have been established on a very large scale. These dairies consists of a series of modern milking parlor set-ups operated as a single enterprise. Each milking parlor is surrounded by a set of 3 or 4 loafing barns housing 1,500 or 2,000 cattle. Some of the larger dairies have planned 10 or more series of loafing barns and milking parlors in this arrangement, so that the total operation may include as many as 15,000 or 20,000 cows. The milking process for these dairies is similar to a smaller dairy with a single milking parlor but repeated several times. The size and concentration of cattle creates major environmental issues associated with manure handling and disposal, which requires substantial areas of cropland (a ratio of 5 or 6 cows to the acre, or several thousand acres for dairies of this size) for manure spreading and dispersion. Air pollution from methane gas associated with manure management also is a major concern. As a result, proposals to develop dairies of this size can be controversial and provoke substantial opposition from environmentalists including the Sierra Club and local activists. See http://villagenews.weblogger.com/kernDairies
[edit] Use of hormones and antibiotics
Many farms in the US provide cows with growth hormones (known as "BST" or "rBGH") to increase milk production. In Europe, use of BST is strictly forbidden [citation needed].
In no developed nation are farmers legally permitted to sell milk from animals who have been treated with antibiotics before the milk from the treated animal has been tested for residue and found to contain none [citation needed]. Current tests can detect dilutions as minute as five parts per billion, and it is illegal to use such "contaminated" milk for any purpose - it must by law be discarded as unfit for processing or consumption [citation needed]. Similarly, a withholding period after last treatment is required before slaughtering animals who have been treated with any medicines, and should residue be detected by testing at a slaughterhouse or dairy processing plant, severe fines (generally reserved for a first offense) and even criminal charges can result [citation needed].
[edit] Management of the dairy herd
Modern dairy farmers use milking machines and sophisticated plumbing systems to harvest and store the milk from the cows, which are usually milked twice or thrice daily. During the warm months, in the northern hemisphere, cows may be allowed to graze in their pastures, both day and night, and are brought into the barn only to be milked. During the winter months, especially in northern climates, the cows may spend the majority of their time inside the barn, which is warmed by their collective body heat. Even in winter, the heat produced by the cattle requires the barns to be ventilated for cooling purposes. Many modern facilities, and particularly those in tropical areas, keep all animals inside at all times to facilitate herd management. In the southern hemisphere milking animals are more likely to spend most of their lives outside on pasture.
The production of milk requires that the cow be in lactation, which is a result of the cow having given birth to a calf. The cycle of insemination, pregnancy, parturition, and lactation, followed by a "dry" period before insemination can recur, requires a period of 14 to 16 months for each cow. Dairy operations therefore included both the production of milk and the production of calves, or veal. As the size of herds has increased, the conditions in which large numbers of veal calves are raised, fed and marketed on larger dairies also have provoked controversy among animal rights activists.
[edit] Dairy farming in the world
In the United States, dairy farming is an important industry in Vermont, Pennsylvania, Wisconsin, Minnesota, Florida, Ohio, and New York but the largest state in dairy production is California [citation needed]. In Europe, Denmark, northern France, southern Ireland, United Kingdom, Switzerland, and especially the Netherlands, are particularly known as centers of dairy production [citation needed]. The world's largest exporter of dairy products is New Zealand which farms on a larger scale than Europe and the U.S.A. [citation needed]
[edit] Dairy competition
Most milk-consuming countries have a local dairy farming industry, and most producing countries maintain significant subsidies and trade barriers to protect domestic producers from foreign competition [citation needed]. In large countries, dairy farming tends to be geographically clustered in regions with abundant natural water supplies [citation needed] and relatively inexpensive land (even under the most generous subsidy regimes, dairy farms have poor return on capital). These too promote regional competition and laws to protect the regional production of milk. However, New Zealand, the fourth largest dairy producer in the world, does not apply any subsidies to dairy production [citation needed].
The milking of cows was traditionally a labor-intensive operation and still is in less sophisticated societies. Small farms need several people to milk and care for only a few dozen cows, though for many farms these employees have traditionally been the children of the farm family, giving rise to the term "family farm".
Advances in technology have mostly led to the radical redefinition "family farms" in industrialized countries such as the United States. With farms of hundreds of cows producing large volumes of milk, the larger and more efficient dairy farms are more able to weather severe changes in milk price and operate profitably, while "traditional" very small farms generally do not have the equity or cashflow to do so. The common public perception of large corporate farms supplanting smaller ones is generally a misconception, as many small family farms expand to take advantage of economies of scale, and incorporate the business to limit the legal liabilities of the owners and simplify such things as tax management.
Before large scale mechanization arrived in the 1950s, keeping a dozen milk cows for the sale of milk was profitable [citation needed]. Now most dairies must have more than one hundred cows being milked at a time in order to be profitable, with other cows and heifers waiting to be "freshened" to join the milking herd [citation needed]. In New Zealand the average herd size, depending on the region, is about 600 cows [citation needed]. Herd size in the US varies between 1,200 in the west coast and southwest, where large farms are commonplace, to 350 in the northeast, where land-base is a significant limiting factor to herd size [citation needed].
[edit] See also
- Animal husbandry
- Dairy
- Dairy products
- Factory farming
- Family farm
- Milk
- Managed intensive grazing
- Ubre Blanca
- Veal
