Etologia de vacas F1 Holandês x Zebu em lactação durante o verão

Abstract

This work aimed to evaluate the ethology of five different genetic groups of F1 Holstein x Zebu cows in lactation during the summer. The evaluated groups were: Holstein x Gir, Holstein x Nelogir, Holstein x Guzonel, Holstein x Nellore and Holstein x Zebu. The experiment was conducted during the summer of 2015 at the Farm of the Agricultural Research Company of Minas Gerais (EPAMIG). The experimental design was completely randomized (CRD) with factorial arrangement 5 x 20, five cross breedings and 20 times of observation, totaling ten repetitions. Climate variables measurements were performed by means of dataloggers throughout the experimental period with collections scheduled for every 10 minutes. The observations regarding the behavior were carried out depending on the percentage of animals on grazing, idleness, rumination, urination, defecation, water intake and salt intake. Behavioral observations occurred during the day and at night every 30 minutes, being 7 days of adaptation and 10 days of experimental collections. The studied five genetic groups were similar statistically, therefore, were unified and the variables presented and discussed in terms of the environment and periods. The F1 animals used in this study did not change the grazing behavior due to high BGHI values. There was a higher frequency of rumination and idle period in the morning, showing a natural behavior of cattle. Defecation was more frequently during the day, coinciding with the period of greater movement of animals. Water consumption was higher during the periods after milking, and the salt consumption was higher in the afternoon. There was a positive statistical correlation between BGHI and grazing, and negative one between BGHI and idleness. Thus, it is concluded that the grazing behavior of F1 animals was not changed because of the high BGHI values, explaining the adaptability and resilience of five genetic groups.