Cuba's tropical climate is rather unfavourable to livestock breeding, especially cattle. The study of the adaptation processes of cattle breeds to tropical climates is therefore essential to improve management and production conditions. Normally, in this climate, the best adapted breeds are the zebus (Bos indicus) whereas the European cattle breeds (Bos taurus) suffer from heat stress and are very sensitive to diseases (parasites...). However, some European populations have successfully adapted to the Cuban climate. Among them, the "Charolais of Cuba". This breed of French origin is the result of French Charolais animals imported at the beginning of the 20th century. The breeding of Charolais animals spread throughout the island thanks to imports in 1919 and 1938 but, following the American embargo, imports and the resulting genetic mixing ceased. Since then, conservation and genetic improvement programmes have been developed in Cuba, particularly in the Manuel Fajardo genetic centre in Jiguani (Granma province). How these Charolais animals adapted was unknown. So far, no studies have been carried out to characterise their genetic diversity and their relationship with other bovine breeds.
A comparison of the genetic diversity of about forty Charolais animals from Cuba with animals of several dozen breeds of cattle, including French Charolais, revealed, as expected, a close relationship between Cuban and French Charolais animals (about 95%"genetic similarity"). However, it is precisely in these 5% differences, distributed over 104 different regions of the genome, that the genes linked to adaptation to tropical climate are located. For example, in these differentiated regions, genes involved in resistance to disease, physiological changes and tolerance to heat but also to muscle development are found. This work is not only the starting point for understanding how the Charolais adapted to tropical conditions, but also offers new opportunities to characterize the genetic diversity of other breeds economically important for cattle production in Cuba. As indicated, these studies are essential to improve and optimize strategies for the management, conservation and improvement of the main genetic resources of Cuba and more generally of tropical regions. The results of this work should also make it possible to select animals from other breeds that are more resistant to heat, an ability that is becoming increasingly important with global warming.
This study was carried out thanks to the support of the French Embassy in Cuba, the Cuban Ministry of Agriculture and the collaboration of researchers from the Institut National de Recherche Agronomique (INRA) de Jouy-en-Josas (GABI Unit), the Institut de Recherche et de Technologie Agroalimentaire de Catalne (IRTA), the Centre de Recherche en Agro-Génomique (CRAG) de Barcelona (Spain) and the Faculty of Veterinary Medicine of the University of Granma (Cuba).
Rodriguez-Valera Y., Renand G., Naves M., Fonseca-Jiménez Y., Moreno-Probance T.I., Ramos Onsins S., Rocha D., Ramayo-Caldas Y. (2018). Genetic diversity and selection signatures of the beef ‘Charolais de Cuba’ breed. Scientific Reports 8, 11005.
Unité Génétique Animale et Biologie Intégrative (UMR1313 GABI), Jouy-en-Josas