Estudos genéticos e adaptativos de vacas de raça holandesa em condições semiárida

Abstract

The climate acts directly on farm animals, which when exposed to extreme conditions, such as those observed in semi-arid regions, become extremely susceptible to a permanent state of thermal stress and trigger physiological changes in adaptation that compromise the productive performance of the animal, as well as the profitability of the activity. The economic efficiency of dairy cattle is linked to the use of animals that have performance characteristics in terms of well-being, health and longevity. In such a way that the genetic evaluations are configured as modern tools of selection, that provide precise information on these characteristics. In this context, this study aimed to verify the influence of environmental conditions on the thermal adaptability, production, composition and milk quality of Holstein cows from the semi-arid region, in addition to identifying the genetic profile of the females through the values of GPTAs, examining the presence of haplotypes for genetic diseases of dairy cattle. Fifty Holstein cows belonging to the Agronomic Institute of Pernambuco (IPA) / São Bento do Una Experimental Station were used. The techniques used proved to be useful and allowed to establish the degree of influence of the thermal environment with respect to the characteristics evaluated, suggesting adaptation of the animals to the environment and demonstrating supremacy in the characteristics of production and quality of milk. The studied herd showed a genetic profile of great breeding potential for the productive characteristics, showing good correlations between the GPTAs of milk and solids production with the conformation and reproduction characteristics. Females carrying haplotypes for genetic diseases were identified, this information can be used as a selection criterion in order to reduce transmission to future generations. It is noticeable the need to adapt and develop technologies that provide significant improvements for dairy cattle, considering the welfare of the animals, the quality of the products and the profitability of the chain