The dairy sector in Brazil has started to explore an important market niche: the production of milk for people who have allergies to beta-caseins, which correspond to 30% of milk proteins. Breeding and genetic improvement studies developed by Embrapa Dairy Cattle (Juiz de Fora, MG) in partnership with dairy Gyr and Girolando breeders' associations are going to further stimulate this segment. Sire summaries of progeny tests with such breeds, which bring the genetic traits of the bulls whose semen will be used to fertilize cows, had already featured the trait for the production of the milk that has been called “A2”. Embrapa's researchers claim there is scientific evidence that A2 milk beta-casein does not cause reactions in people who have an allergy to this specific protein. The allergy to cow's milk protein, known as CMPA, is a problem more often observed in children. According to data from the Brazilian Association of Allergy and Immunology (Asbai), about 350,000 individuals in Brazil are allergic. Patients with the problem will have to eliminate cow's milk from their diet, ceasing to benefit from an important source of calcium and other nutrients at a moment in life where human beings need them the most. Although allergists posit that A2 milk is not recommended for all cases, the Embrapa Dairy Cattle researcher Marcos Antônio Sundfeld Gamma states that it can be beneficial for many people, as beta-casein is the main causer of CMPA. Allergy is different from intolerance It is important to stress that A2 milk is not recommended for lactose intolerance, which can be mistaken with cow's milk allergy. The allergist and immunologist Aristeu José de Oliveira asserts that CMPA and lactose intolerance are distinct problems. Lactose is milk's sugar and not a protein. Intolerance occurs in people who have a deficiency in the production of an enzyme called lactase, whose role is to break lactose molecules during the digestive process, transforming it into energy for human body cells. The symptoms of lactose intolerance are abdominal pains, diarrhea, flatulence and distended abdomen. CMPA unchains a series of reactions, some of which are similar to lactose intolerance, which can generate confusion between the two problems. However, in addition to gastrointestinal symptoms occurring more pronouncedly (diarrhea and vomits), CPMA can cause red wheals in the body, often accompanied by itching, swelling of the lips and the eyes, and, in the acutest reaction, anaphylaxis, which can lead to death. Unlike allergies to some foods like peanuts, chestnuts and seafood, which can last the patient's entire life, when CPLA starts in the early infancy, right after the child has their first contact with cow's milk, there is a great likelihood of the allergy going away in their adolescence. But until then, the most serious cases will have to be constantly monitored. “A2 milk can prevent such afflictions, as when it is digested by humans, it does not cause the formation of substance called beta-casomorphin-7 (BCM-7), responsible for triggering the allergic process”, explains the Embrapa Dairy Cattle researcher Marcos Vinicius G. Barbosa da Silva. Some scientific studies suggest that BCM-7, which stems from the digestion of beta-casein A1 (from common cow's milk), not only triggers CMPA but can also intensify neurological problems in individuals with autism and schizophrenia. The substance can even influence the cardiovascular system. “BCM-7 oxidates LDL, known as bad cholesterol, which is related to the buildup of arterial plaques, increasing the risk of heart disease”, Silva states. Genetic improvement Scientists concluded that up to eight thousand years ago cows only produced A2 milk. A genetic mutation in the bovine cattle led to the appearance of animals with the gene for the production of A1 milk. Such trait is more common in the breeds with European origin (taurus subspecies). The Dutch Friesian and Brown Swiss breeds have a 50% chance of producing A2 milk. The probability is higher for the Jersey breed: 75%. Out of the taurus subspecies, only Guernsey cattle, which is not very common in Brazil, shows 100% of their individuals capable of producing A2 milk. Meanwhile in the Zebu breeds (indicus subspecies), which predominate in Brazilian cattle farming and include dairy Gyr, 98% of individuals have positive genetics for A2 milk production. “The high frequency of allele A2 in Brazilian cattle farming is a competitive advantage so that our farmers can explore the upcoming market niche around the product”, Silva says. For another Embrapa researcher, João Cláudio do Carmo Panetto, the information available in the dairy gyr and girolando sire summaries is going to facilitate the process of genetically improving the herd if the breeder decides to produce A2 milk. But the information regarding the bull whose semen will be used in the fertilization is not enough. The cows of the herd should also be genotyped, that is, it is necessary to identify in an individual's genetic material if the animal is homozygotic (it has the two alleles) for A2 milk production. The ideal is that A2A2 cows are selected, so that when they are inseminated by an A2A2 bull, they will have 100% of their heifers with A2A2 alleles. Panetto explains: “If a cow has an A2A2 genotype, it will certainly pass on the A2 allele to its progeny. Similarly, an A1A1 cow will pass the A1 allele on. For an A1A2 cow, there is a 50% chance of passing on either allele to its progeny. A cow is genotyped by collecting the animal's biological tissue, which can be a blood or fur sample. The sample is submitted to a specialized laboratory that will determine one of the following types of results: A1A1, A1A2 and A2A2. After that, all it takes is the selection of the suitable semen, based on the information present in the dairy Gyr and Girolando sire summaries.” Embrapa's researchers advise that the selection process can be accelerated by culling A1A1 and A1A2 animals. Only heifers and calves with the A2A2 genotype should remain in the herd. The speed with which the herd will be converted for A2 milk production will depend on the strategy for the use of A2 sire semen, the investment in cow genotyping, the culling rates, and calf retention. “If farmers choose do perform all of the activities as a set, without drastically reducing the herd, the time required to have all the farm animals be A2A2 could vary between two and three generations, about 10 to 15 years”, Panetto reckons. Promising market It can seem complex and long, but those who have opted for A2 milk production say that it pays off. The cattle farmer Eduardo Falcão, owner of the Estância Silvânia ranch, in Caçapava (SP), says that the liter of A2 milk can be sold as dairy products that are up to four times more expensive than conventional milk. Estância Silvânia specializes in dairy Gyr genetic improvement, and Eduardo Falcão is a pioneer in the production and trade of A2 milk in Brazil. The production of Estância Silvânia is still small, about 700 liters of milk a day that are used to make cheeses, butter and ricotta, which are then sold in the Paraíba Valley and in São Paulo city. Some other farmers who have dairy gyr herds are following the same path. According to Silva, this is a way to add value to the milk deriving from dairy Gyr herds, whose breed's nature is to be less productive than Dutch Friesian or the synthetic breed Girolando, a result of the crossing of dairy Gyr with Holstein. The international market points to the success of the enterprise. New Zealand, the world's largest exporter of milk powder, has produced A2 milk since 2003. The country trademarked the name A2 Milk and certifies dairies and farms that exclusively produce A2 milk. Another major exporter, Australia, has also already entered this market. The curious thing is that the product has ceased to be exclusively for milk-protein allergic people and is conquering the general public. In Oceania it is possible to buy such milk and dairy products in several stores and cafés. The product is also already seen in the supermarket shelves in the UK and the United States. Translation: Mariana Medeiros