ASSOCIATION OF THE HSP70 LOCUS POLYMORPHISM WITH THERMOTOLERANCE AND PRESENCE OF CONDITIONS IN GULF CREOLE CATTLE IN INTENSIVE SYSTEMS

Abstract

Objective: To estimate thermotolerance through the analysis of physiological constants, as well as the conditions suffered by Gulf Creole (BCG) cattle and relate it to the hsp70 locus polymorphism under an intensive production system.

Design/methodology/approach: Leukocyte DNA from 60 BCG was genotyped using a 440 bp fragment by PCR-RFLP (Fok I). Physiological variables were estimated at 7-day intervals for 4 months during the hot season: respiratory rate (RF) and layer temperature (TC); likewise, the environmental variables temperature and humidity were recorded to determine thermal comfort. From the database of the production system, the conditions of the animals within the study period were quantified and categorized.

Results: The hsp70 gene was polymorphic in BCG. The frequency of the AB heterozygous genotype was 0.77 and for the AA homozygous genotype it was 0.23, with a predominance of the A allele (0.61). Data analysis allowed us to find differences in RF in BCG with AA and AB genotypes (p<0.05). CT showed no differences (p>0.05). The genotype and environmental discomfort did not show an effect on the presentation of conditions in BCG (p>0.05).

Limitations on study/implications: Due to the fact that the intensive system is changing and the BCG stay period is short, there are few animals that can be used for the study.

Findings/conclusions: BCG is polymorphic and thermotolerant and its performance in the presentation of conditions is favorable.