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Tropentag, September 10 - 12, 2025, Bonn
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Genetic diversity of the beta-casein gene in brown swiss cows from the Central Andes of Peru
Lucy Ruth Remigio Lorenzo1, Cristina Rivera Romero1, Bueno Wilder 2, Eduardo Leuman Fuentes Navarro1, Joao De-Souza Pacheco1, Gustavo Augusto Gutiérrez Reynoso3,1
1Universidad Nacional Agraria La Molina, Facultad de Zootecnia, Peru
2Universidad Nacional Agraria La Molina, Facultad de Zootecnia, Peru
3Iowa State University, Dept. of Animal Science, United States
Abstract
Cow's milk and its derivatives are fundamental to human nutrition and overall dietary health. However, 80–90% of the world's population experience stomach upset and gastrointestinal discomfort from its consumption. Scientific studies indicate that the digestibility of cow's milk depends on its protein composition and the breed of cattle. Casein, which makes up approximately 80% of milk proteins, includes beta-casein; this protein has two genetic variants: A1 and A2. The A1 variant is associated with stomach upset and inflammation, while A2 facilitates digestion in humans. Additionally, the beta-casein gene has two alleles named according to the specific protein variant they express. Currently, some dairy farms separate the milk of homozygous cows for A2 allele to produce and market the called A2 milk. The objective of this study was to evaluate the genetic diversity of the beta-casein gene in Brown Swiss cows from the Central Andes of Peru (Junín, Ayacucho, Huánuco and Pasco). Blood samples were collected from 445 cows, DNA was extracted using a commercial kit, and samples were genotyped by using the Axiom Bovine v3 SNP array. The results showed that Junín, Ayacucho, Huánuco and Pasco had an average A2 allele frequency of 0.66 (0.60 to 0.73). In relation to the genotypic frequencies, A2A2 ranged 0.35 to 0.52, where Junín had the highest value, the A1A2 frequency was intermediate with a range of 0.41 - 0.50. It was concluded that the frequency of the A2 allele was high but the A2A2 frequency was intermediate in Brown Swiss cows from the Central Andes of Peru.
Keywords: Beta-casein, Brown Swiss, diversity, genetics, milk
Contact Address: Lucy Ruth Remigio Lorenzo, Universidad Nacional Agraria La Molina, Facultad de Zootecnia, La Molina - Calle molinero s/n, Lima, Peru, e-mail: luremi01
gmail.com
