Dairy

Adairyis a place wheremilkis stored and wherebutter,cheeseand otherdairy productsare made, or a place where those products are sold.It may be a room, a building or a larger establishment.In the United States, the word may also describe adairy farmor the part of amixed farmdedicated to milk for human consumption,whether fromcows,buffaloes,goats,yaks,sheep,horsesorcamels.
The attributivedairydescribes milk-based products, derivatives and processes, and the animals and workers involved in their production, for example dairyman, dairymaid,dairy cattleordairy goat. A dairy farm produces milk and a dairy factory processes it into a variety of dairy products. These establishments constitute the global dairy industry, part of thefood industry.
The worddairycomes from an Old English word forfemale servantas historically milking was done by dairymaids.
Terminology differs between countries. In theUnited States, for example, an entire dairy farm is commonly called a "dairy". The building or farm area where milk is harvested from the cow is often called a "milking parlor" or "parlor", except in the case of smaller dairies, where cows are often put on pasture, and usually milked in "stanchion barns". The farm area where milk is stored in bulk tanks is known as the farm's "milk house". Milk is then hauled (usually by truck) to a "dairy plant", also referred to as a "dairy", where raw milk is further processed and prepared for commercial sale ofdairy products.
In New Zealand, farm areas for milk harvesting are also called "milking parlours", and are historically known as "milking sheds".As in the United States, sometimes milking sheds are referred to by their type, such as "herring bone shed" or "pit parlour". Parlour design has evolved from simple barns or sheds to large rotary structures in which the workflow (throughput of cows) is very efficiently handled. In some countries, especially those with small numbers of animals being milked, the farm may perform the functions of a dairy plant, processing their own milk into saleable dairy products, such as butter, cheese, oryogurt. This on-site processing is a traditional method of producing specialist milk products, common in Europe.
In the United States adairycan also be a place that processes, distributes and sells dairy products, or a room, building or establishment where milk is stored and processed into milk products, such as butter or cheese. InNew Zealand Englishthe singular use of the worddairyalmost exclusively refers to a corner shop, orsuperette. This usage is historical as such shops were a common place for the public to buy milk products.
Milk producing animals have been domesticated for thousands of years. Initially, they were part of thesubsistence farmingthatnomadsengaged in. As the community moved about the country, their animals accompanied them. Protecting and feeding the animals were a major part of thesymbiotic relationshipbetween the animals and theherders.
In the more recent past, people inagricultural societiesowned dairy animals that they milked for domestic and local (village) consumption, a typical example of acottage industry. The animals might serve multiple purposes (for example, as a draught animal for pulling aplowas a youngster, and at the end of its useful life as meat). In this case, the animals were normally milked by hand and the herd size was quite small, so that all of the animals could be milked in less than an hour—about 10 per milker. These tasks were performed by adairymaid(dairywoman) ordairyman. The worddairyharkens back to Middle Englishdayerie,deyerie, fromdeye(female servant or dairymaid) and further back to Old Englishdæge(kneader of bread).
Withindustrialisationand urbanisation, the supply of milk became a commercial industry, with specialisedbreeds of cattlebeing developed for dairy, as distinct from beef ordraughtanimals. Initially, more people were employed as milkers, but it soon turned tomechanisationwith machines designed to do the milking.
Historically, themilkingand theprocessingtook place close together in space and time: on adairy farm. People milked the animals by hand; on farms where only small numbers are kept, hand-milking may still be practised. Hand-milking is accomplished by grasping theteats(often pronouncedtitortits) in the hand and expressing milk either by squeezing the fingers progressively, from theudderend to the tip, or by squeezing the teat between thumb and index finger, then moving the hand downward from udder towards the end of the teat. The action of the hand or fingers is designed to close off the milk duct at the udder (upper) end and, by the movement of the fingers, close the duct progressively to the tip to express the trapped milk. Each half or quarter of the udder is emptied one milk-duct capacity at a time.
Thestrippingaction is repeated, using both hands for speed. Both methods result in the milk that was trapped in themilk ductbeing squirted out the end into a bucket that is supported between the knees (or rests on the ground) of the milker, who usually sits on a low stool.
Traditionally the cow, or cows, would stand in thefieldor paddock while being milked. Young stock,heifers, would have to be trained to remain still to be milked. In many countries, the cows were tethered to a post and milked.
While most countries produce their own milk products, the structure of the dairy industry varies in different parts of the world. In major milk-producing countries most milk is distributed through whole sale markets. In Ireland and Australia, for example, farmers' co-operatives own many of the large-scale processors, while in the United States many farmers and processors do business through individual contracts. In the United States, the country's 196farmers' cooperativessold 86% of milk in the U.S. in 2002, with five cooperatives accounting for half that. This was down from 2,300 cooperatives in the 1940s.In developing countries, the past practice of farmers marketing milk in their own neighbourhoods is changing rapidly. Notable developments include considerable foreign investment in the dairy industry and a growing role for dairy cooperatives. Output of milk is growing rapidly in such countries and presents a major source of income growth for many farmers.
As in many other branches of the food industry, dairy processing in the major dairy producing countries has become increasingly concentrated, with fewer but larger and more efficient plants operated by fewer workers. This is notably the case in the United States, Europe, Australia and New Zealand. In 2009, charges ofantitrustviolations have been made against major dairy industry players in the United States, which critics call "Big Milk".Another round ofprice fixingcharges was settled in 2016.
Government interventionin milk markets was common in the 20th century. A limited antitrust exemption was created for U.S. dairy cooperatives by theCapper–Volstead Actof 1922. In the 1930s, some U.S. states adopted price controls, and Federal Milk Marketing Orders started under theAgricultural Marketing Agreement Actof 1937 and continue in the 2000s. The Federal Milk Price Support Program began in 1949.TheNortheast Dairy Compactregulated wholesale milk prices in New England from 1997 to 2001.
Plants producing liquid milk and products with shortshelf life, such asyogurts,creamsandsoft cheeses, tend to be located on the outskirts of urban centres close to consumer markets. Plants manufacturing items with longer shelf life, such as butter, milk powders, cheese and whey powders, tend to be situated in rural areas closer to the milk supply. Most large processing plants tend to specialise in a limited range of products. Exceptionally, however, large plants producing a wide range of products are still common in Eastern Europe, a holdover from the former centralised, supply-driven concept of the market under Communist governments.
As processing plants grow fewer and larger, they tend to acquire bigger, more automated and more efficient equipment. While this technological tendency keeps manufacturing costs lower, the need for long-distance transportation often increases theenvironmental impact.
Milk production is irregular, depending on cow biology. Producers must adjust the mix of milk which is sold in liquid form vs. processed foods (such as butter and cheese) depending on changing supply and demand.
In theEuropean Union, milk supply contracts are regulated by Article 148 ofRegulation1308/2013 –Establishing a common organisation of the markets in agricultural products and repealing Council Regulations (EEC) No 922/72, (EEC) No 234/79, (EC) No 1037/2001 and (EC) No 1234/2007, which permits member states to create a requirement for the supply of milk from a farmer to a raw milk processor to be backed by a written contract, or to ensure that the first purchaser of milk to make a written offer to the farmer, although in this case the farmer may not be required to enter into a contract.
Thirteen EUmember statesincludingFranceandSpainhave introduced laws on compulsory or mandatory written milk contracts (MWC's) between farmers and processors. TheScottish Governmentpublished an analysis of the dairy supply chain and the application of mandatory written contracts across the European Union in 2019, to evaluate the impact of the contracts where they have been adopted.In the UK, a voluntary code of best practice on contractual relationships in the dairy sector was agreed by industry during 2012: this set out minimum standards of good practice for contracts between producers and purchasers.During 2020 theUK governmenthas undertaken a consultation exercise to determine which contractual measures, if any, would improve the resilience of the dairy industry for the future.
TheAustralian governmenthas also introduced a mandatory dairy code of conduct.
When it became necessary to milk larger cows, the cows would be brought to ashedorbarnthat was set up with stalls (milking stalls) where the cows could be confined their whole life while they were milked. One person could milk more cows this way, as many as 20 for a skilled worker. But having cows standing about in the yard and shed waiting to be milked is not good for the cow, as she needs as much time in the paddock grazing as is possible. It is usual to restrict the twice-daily milking to a maximum of an hour and a half each time. It makes no difference whether one milks 10 or 1000 cows, the milking time should not exceed a total of about three hours each day for any cow as they should be in stalls and laying down as long as possible to increase comfort which will in turn aid in milk production.  A cow is physically milked for only about 10 minutes a day depending on her milk letdown time and the number of milkings per day.
Asherdsizes increased there was more need to have efficient milking machines, sheds, milk-storage facilities (vats), bulk-milk transport and shed cleaning capabilities and the means of getting cows from paddock to shed and back.
As herd numbers increased so did the problems ofanimal health. In New Zealand two approaches to this problem have been used. The first was improvedveterinary medicines(and the government regulation of the medicines) that the farmer could use. The other was the creation ofveterinary clubswhere groups of farmers would employ aveterinarian(vet) full-time and share those services throughout the year. It was in the vet's interest to keep the animals healthy and reduce the number of calls from farmers, rather than to ensure that the farmer needed to call for service and pay regularly.
This daily milking routine goes on for about 300 to 320 days per year that the cow stays in milk. Some small herds are milked once a day for about the last 20 days of the production cycle but this is not usual for large herds. If a cow is left unmilked just once she is likely to reduce milk-production almost immediately and the rest of the season may see herdried off(giving no milk) and still consuming feed. However, once-a-day milking is now being practised more widely in New Zealand for profit and lifestyle reasons. This is effective because the fall in milk yield is at least partially offset by labour and cost savings from milking once per day. This compares to some intensive farm systems in the United States that milk three or more times per day due to higher milk yields per cow and lower marginallabour costs.
Farmers who are contracted to supply liquid milk for human consumption (as opposed to milk for processing into butter, cheese, and so on—see milk) often have to manage theirherdso that the contracted number of cows are in milk the year round, or the required minimum milk output is maintained. This is done by mating cows outside their natural mating time so that the period when each cow in the herd is giving maximum production is in rotation throughout the year.
Northern hemisphere farmers who keep cows in barns almost all the year usually manage their herds to give continuous production of milk so that they get paid all year round. In the southern hemisphere thecooperativedairying systems allow for two months of no productivity because their systems are designed to take advantage of maximum grass and milk production in the spring and because the milk processing plants pay bonuses in the dry (winter) season to carry the farmers through the mid-winter break from milking. It also means that cows have a rest from milk production when they are most heavily pregnant. Some year-round milk farms are penalised financially foroverproductionat any time in the year by being unable to sell their overproduction at current prices.
Artificial insemination(AI) is common in all high-production herds in order to improve the genetics of the female offspring which will be raised for replacements. AI also reduces the need for keeping potentially dangerous bulls on the farm. Male calves are sold to be raised for beef or veal, or slaughtered due to lack of profitability.A cow will calve or freshen about once a year, until she is culled because of declining production, infertility or other health problems. Then the cow will be sold, most often going to slaughter.
Dairy plants process the raw milk they receive from farmers so as to extend its marketable life. Two main types of processes are employed: heat treatment to ensure the safety of milk for human consumption and to lengthen its shelf-life, and dehydrating dairy products such as butter, hard cheese and milk powders so that they can be stored.
Today, milk is separated by huge machines in bulk into cream and skim milk. The cream is processed to produce various consumer products, depending on its thickness, its suitability for culinary uses and consumer demand, which differs from place to place and country to country.
Some milk is dried and powdered, some is condensed (byevaporation) mixed with varying amounts of sugar and canned. Most cream from New Zealand and Australian factories is made into butter. This is done bychurningthe cream until the fat globules coagulate and form a monolithic mass. This butter mass is washed and, sometimes, salted to improve keeping qualities. The residualbuttermilkgoes on to further processing. The butter is packaged (25 to 50 kg boxes) and chilled for storage and sale. At a later stage these packages are broken down into home-consumption sized packs.
The product left after the cream is removed is called skim, or skimmed, milk. To make a consumable liquid a portion of cream is returned to theskim milkto makelow fatmilk(semi-skimmed) for human consumption. By varying the amount of cream returned, producers can make a variety of low-fat milks to suit their local market. Whole milk is also made by adding cream back to the skim to form a standardised product. Other products, such ascalcium,vitamin D, and flavouring, are also added to appeal to consumers.
Caseinis the predominantphosphoproteinfound in fresh milk.  It has a very wide range of uses from being a filler for human foods, such as inice cream, to the manufacture of products such asfabric,adhesives, and plastics.
Cheese is another product made from milk. Whole milk is reacted to formcurdsthat can be compressed, processed and stored to form cheese. In countries where milk is legally allowed to be processed withoutpasteurisation, a wide range of cheeses can be made using the bacteria found naturally in the milk. In most other countries, the range of cheeses is smaller and the use of artificial cheese curing is greater.Wheyis also the byproduct of this process. Some people withlactose intoleranceare able to eat certain types of cheese. This is because some traditionally made hard cheeses, and soft ripened cheeses may create less reaction than the equivalent amount of milk because of the processes involved.  Fermentation and higher fat content contribute to lesser amounts of lactose. Traditionally madeEmmentalorCheddarmight contain 10% of the lactose found in whole milk. In addition, the ageing methods of traditional cheeses (sometimes over two years) reduce their lactose content to practically nothing.Commercial cheeses, however, are often manufactured by processes that do not have the same lactose-reducing properties. Ageing of some cheeses is governed by regulations;in other cases there is no quantitative indication of degree of ageing and concomitant lactose reduction, and lactose content is not usually indicated on labels.
In earlier times,wheyormilk serumwas considered to be a waste product and it was, mostly, fed to pigs as a convenient means of disposal. Beginning about 1950, and mostly since about 1980,lactoseand many other products, mainly food additives, are made from both casein and cheese whey.
Makingyogurtis similar to making cheese, only the process is stopped before the curd becomes hard.
Milk is also processed by various drying processes into powders. Whole milk, skim milk, buttermilk, and whey products are dried into a powder form and used for human and animal consumption.  The main difference between production of powders for human or for animal consumption is in the protection of the process and the product from contamination. Some people drink milk reconstituted from powdered milk, because milk is about 88% water and it is much cheaper to transport the dried product.
Kumisis produced commercially in Central Asia.  Although traditionally made frommare's milk, modern industrial variants may use cow's milk.
In India, which produces 22% of global milk production (as at 2018), a range oftraditional milk-based productsare produced commercially.
Originally, milking and processing took place on the dairy farm itself. Later, cream was separated from the milk by machine on the farm, and transported to a factory to be made into butter. The skim milk was fed to pigs. This allowed for the high cost of transport (taking the smallest volume high-value product), primitive trucks and the poor quality of roads. Only farms close to factories could afford to take whole milk, which was essential for cheesemaking in industrial quantities, to them.
Originally milk was distributed in 'pails', a lidded bucket with a handle. These proved impractical for transport by road or rail, and so themilk churnwas introduced, based on the tall conical shape of thebutter churn. Later large railway containers, such as theBritish Railway Milk Tank Wagonwere introduced, enabling the transport of larger quantities of milk, and over longer distances.
The development ofrefrigerationand better road transport, in the late 1950s, has meant that most farmers milk their cows and only temporarily store the milk in large refrigeratedbulk tanks, from where it is later transported by truck to central processing facilities.
In many European countries, particularly the United Kingdom, milk is then delivered direct to customers' homes by amilk float.
In the United States, a dairy cow produced about 5,300 pounds (2,400 kg) of milk per year in 1950, while the averageHolstein cowin 2019 produces more than 23,000 pounds (10,000 kg) of milk per year.
Milking machines are used to harvest milk from cows when manual milking becomes inefficient or labour-intensive.  One early model was patented in 1907.The milking unit is the portion of a milking machine for removing milk from an udder.  It is made up of a claw, four teatcups, (Shells and rubber liners) long milk tube, long pulsation tube, and a pulsator.  The claw is an assembly that connects the short pulse tubes and short milk tubes from the teatcups to the long pulse tube and long milk tube. (Cluster assembly) Claws are commonly made of stainless steel or plastic or both. Teatcups are composed of a rigid outer shell (stainless steel or plastic) that holds a soft inner liner orinflation.  Transparent sections in the shell may allow viewing of liner collapse and milk flow.  The annular space between the shell and liner is called the pulse chamber.
Milking machines work in a way that is different from hand milking or calf suckling. Continuous vacuum is applied inside the soft liner to massage milk from the teat by creating a pressure difference across the teat canal (or opening at the end of the teat). Vacuum also helps keep the machine attached to the cow.  The vacuum applied to the teat causes congestion of teat tissues (accumulation of blood and other fluids). Atmospheric air is admitted into the pulsation chamber about once per second (the pulsation rate) to allow the liner to collapse around the end of teat and relieve congestion in the teat tissue. The ratio of the time that the liner is open (milking phase) and closed (rest phase) is called the pulsation ratio.
The four streams of milk from the teatcups are usually combined in the claw and transported to the milkline, or the collection bucket (usually sized to the output of one cow) in a single milk hose.  Milk is then transported (manually in buckets) or with a combination of airflow and mechanicalpumpto a central storagevatorbulk tank.  Milk is refrigerated on the farm in most countries either by passing through aheat-exchangeror in the bulk tank, or both.
The photo to the right shows a bucket milking system with the stainless steel bucket visible on the far side of the cow.  The two rigid stainless steel teatcup shells applied to the front two quarters of the udder are visible.  The top of the flexible liner is visible at the top of the shells as are the short milk tubes and short pulsation tubes extending from the bottom of the shells to the claw.  The bottom of the claw is transparent to allow observation of milk flow.  When milking is completed the vacuum to the milking unit is shut off and the teatcups are removed.
Milking machines keep the milk enclosed and safe from external contamination. The interior 'milk contact' surfaces of the machine are kept clean by a manual or automated washing procedures implemented after milking is completed.  Milk contact surfaces must comply with regulations requiring food-grade materials (typicallystainless steeland special plastics and rubber compounds) and are easily cleaned.
Most milking machines are powered byelectricitybut, in case of electrical failure, there can be an alternative means of motive power, often aninternal combustion engine, for the vacuum and milk pumps.
This type of milking facility was the first development, after open-paddock milking, for many farmers. The building was a long, narrow,lean-toshed that was open along one long side. The cows were held in a yard at the open side and when they were about to be milked, they were positioned in one of the bails (stalls). Usually, the cows were restrained in the bail with a breech chain and a rope to restrain the outer back leg. The cow could not move about excessively and the milker could expect not to be kicked or trampled while sitting on a (three-legged) stool and milking into a bucket. When each cow was finished, she backed out into the yard again. The UK bail, initially developed by Wiltshire dairy farmer Arthur Hosier, was a six standing mobile shed with steps that the cow mounted, so the herdsman did not have to bend so low. The milking equipment was much as today, a vacuum from a pump, pulsators, a claw-piece with pipes leading to the four shells and liners that stimulate and suck the milk from the teat. The milk went into churns, via a cooler.
As herd sizes increased a door was set into the front of each bail so that when the milking was done for any cow the milker could, after undoing the leg-rope and with a remote link, open the door and allow her to exit to the pasture. The door was closed, the next cow walked into the bail and was secured. When milking machines were introduced bails were set in pairs so that a cow was being milked in one paired bail while the other could be prepared for milking. When one was finished the machine's cups are swapped to the other cow. This is the same as forSwingover Milking Parloursas described below except that the cups are loaded on the udder from the side. As herd numbers increased it was easier to double-up the cup-sets and milk both cows simultaneously than to increase the number of bails. About 50 cows an hour can be milked in a shed with 8 bails by one person. Using the same teat cups for successive cows has the danger of transmitting infection, mastitis, from one cow to another. Some farmers have devised their own ways to disinfect the clusters between cows.
In herringbone milking sheds, or parlours, cows enter, in single file, and line up almost perpendicular to the central aisle of the milking parlour on both sides of a central pit in which the milker works (you can visualise a fishbone with the ribs representing the cows and the spine being the milker's working area; the cows face outward). After washing the udder and teats the cups of the milking machine are applied to the cows, from the rear of their hind legs, on both sides of the working area. Large herringbone sheds can milk up to 600 cows efficiently with two people.
Swingover parlours are the same as herringbone parlours except they have only one set of milking cups to be shared between the two rows of cows, as one side is being milked the cows on the other side are moved out and replaced with unmilked ones. The advantage of this system is that it is less costly to equip, however it operates at slightly better than half-speed and one would not normally try to milk more than about 100 cows with one person.
Rotary milking sheds (also known as Rotary milking parlor) consist of a turntable with about 12 to 100 individual stalls for cows around the outer edge. A "good" rotary will be operated with 24–32 (~48–50+) stalls by one (two) milkers.  The turntable is turned by an electric-motor drive at a rate that one turn is the time for a cow to be milked completely. As an empty stall passes the entrance a cow steps on, facing the center, and rotates with the turntable. The next cow moves into the next vacant stall and so on. The operator, or milker, cleans the teats, attaches the cups and does any other feeding or whatever husbanding operations that are necessary. Cows are milked as the platform rotates. The milker, or an automatic device, removes the milking machine cups and the cow backs out and leaves at an exit just before the entrance. The rotary system is capable of milking very large herds—over a thousand cows.
Automatic milkingor 'robotic milking' sheds can be seen in Australia, New Zealand, the U.S., Canada, and many European countries. Current automatic milking sheds use the voluntary milking (VM) method. These allow the cows to voluntarily present themselves for milking at any time of the day or night, although repeat visits may be limited by the farmer through computer software. Arobotarm is used to clean teats and apply milking equipment, while automated gates direct cow traffic, eliminating the need for the farmer to be present during the process.  The entire process is computer controlled.
Farmers soon realised that a milking shed was a good place to feed cows supplementary foods that overcame local dietary deficiencies or added to the cows' wellbeing and production. Each bail might have a box into which such feed is delivered as the cow arrives so that she is eating while being milked. A computer can read the eartag of each animal to ration the correct individual supplement. A close alternative is to use 'out-of-parlour-feeders', stalls that respond to a transponder around the cow's neck that is programmed to provide each cow with a supplementary feed, the quantity dependent on her production, stage in lactation, and the benefits of the main ration
The holding yard at the entrance of the shed is important as a means of keeping cows moving into the shed. Most yards have a powered gate that ensures that the cows are kept close to the shed.
Water is a vital commodity on a dairy farm: cows drink about 20 gallons (80 litres) a day, sheds need water to cool and clean them. Pumps and reservoirs are common at milking facilities. Water can be warmed by heat transfer with milk.
Milk from a cow is transported to a nearby storage vessel by the airflow leaking around the cups on the cow or by a special "air inlet" (5–10 L/min free air) in the claw. From there it is pumped by a mechanical pump and cooled by aheat exchanger. The milk is then stored in a large vat, orbulk tank, which is usually refrigerated until collection for processing.
In countries where cows are grazed outside year-round, waste disposal issues need to be dealt with. The most concentrated waste is at the milking shed, where the animal waste may be liquefied (during the water-washing process) or left in a more solid form, either to be returned to be used on farm ground as organic fertiliser.
In the associated milk processing factories, most of the waste is washing water that is treated, usually by composting, and spread on farm fields in either liquid or solid form. This is much different from half a century ago, when the main products were butter, cheese and casein, and the rest of the milk had to be disposed of as waste (sometimes as animal feed).
In the dairy industries, there are two main types of wastewater produced; dairy wastewater and cheese whey. Dairy wastewater consists of material losses from the dairy products, effluents from the washing of tanks and equipment and sanitary wastewater from toilets and sinks.The typical concentrations of BOD and total Kjeldahl nitrogen for dairy wastewater range from 1200 to 5000 mg/L and 30 to 200 mg/L, respectively.Cheese whey is the liquid remaining after the formation of curds. It contains important amounts of carbohydrates, proteins, lactic acid, fats, and salts and its BOD value can exceed 40,000 mg/L.Dairy wastewater management usually includes equalisation, neutralisation and physical separation followed by biological treatment, while cheese whey is treated in anaerobic digesters or passes through membranes for protein recovery.
In dairy-intensive areas, various methods have been proposed for disposing of large quantities of milk. Large application rates of milk on the land, or disposing in a hole, is problematic as the residue from the decomposing milk will block the soil pores and thereby reduce the water infiltration rate through the soil profile. As recovery of this effect can take time, any land-based application needs to be well managed and considered.Other waste milk disposal methods commonly employed include solidification and disposal at a solid waste landfill, disposal at a wastewater treatment plant, or discharge into a sanitary sewer.
Dairy products manufactured under unsanitary or unsuitable conditions have an increased chance of containing bacteria. Propersanitationpractices help to reduce the rate of bacterial contamination, andpasteurisationgreatly decreases the amount of contaminated milk that reaches the consumer. Many countries have required government oversight and regulations regarding dairy production, including requirements forpasteurisation.
A portion of the population,includingvegansand manyJains, object to dairy production as unethical,cruel to animals, and environmentally deleterious. They do not consume dairy products given these ethical concerns. They state that cattle suffer under conditions employed by the dairy industry and how they are eventually killed for meat once their milk production declines.
Animal rights scholars consider dairy as part of theanimal–industrial complex. According to Kathleen Stachowski, the animal–industrial complex "naturalizes the human as a consumer of other animals," whose enormity includes "its long reach into our lives, and how well it has done its job normalizing brutality toward the animals whose very existence is forgotten".She states that the corporate dairy industry, the government, and schools forms the animal–industrial complex troika of immense influence, which hides from the public's view theanimal rightsviolations andcrueltieshappening within the dairy industry.Stachowski also states that the troika "hijacks" schoolchildren by promoting milk in the K-12 nutrition education curriculum and making them "eat the products of industrial animal production".
In 1937, it was found thatbovine somatotropin(BST or bovine growth hormone) would increase the yield of milk. Several pharmaceutical companies developed commercial rBST products and they have been approved for use in the U.S., Mexico, Brazil, India, Russia, and at least ten others. The World Health Organization, and others have stated that dairy products and meat from BST-treated cows are safe for human consumption. However, based on negativeanimal welfareeffects,rBST has not been allowed in Canada, Australia, New Zealand, Japan, Israel, or the European Union since 2000 – and in the U.S. has lost popularity due to consumer demands for rBST-free cows,with only about 17% of all cows in America now receiving rBST.