Archivos Latinoamericanos de Producción Animal, Vol 23, No 6 (2015)

Tamaño de la letra:  Pequeña  Mediana  Grande

The challenge of the genetic selection of animals that tolerate heat stress. The case of dairy cattle

Maria J. Carabaño

Resumen


The physiological stress produced by exposure to high thermal loads has negative effects on the productive and reproductive performance of livestock, as well as on the morbidity and mortality rate. The animals specialized in dairy production suffer to a greater extent the negative effects of heat than animals of meat breeds due to the high metabolic heat that is generated during the production of milk. In addition, the high selection pressure to increase milk production in cattle intensifies the vulnerability of these animals to heat stress (HS). Furthermore, predictions about the consequences of climate change are expected to exacerbate the problem of HS in dairy farms in the future. The negative impact of the HS can be mitigated in several ways, through improvements in livestock housing, through the genetic selection of heat-tolerant animals or the use of breeds adapted to heat and through the management of food. The path of genetic selection of tolerant animals represents a cumulative and permanent effect, with a relatively low associated cost if it is integrated into selection schemes already established for other characters. The selection of HS-tolerant animals, however, presents a series of challenges derived from the complexity of the mechanisms that determine this tolerance and the antagonism with the level of production. This paper summarizes the results of previous studies on the physiological response and genes associated with HS, as well as the possible approaches to the genetic improvement of heat tolerance, including the use of new genomic and transcriptomic information tools and the so-called fine phenotyping.

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