Desempenho de bovinos de diferentes composições raciais quanto a produtividade e susceptibilidade ao carrapato Rhipicephalus microplus no Centro Oeste do Brasil

Abstract

The present thesis was based on research to evaluate the reproductive and productive performance of cattle of different racial compositions and their susceptibility to helminths and ticks, as well as to evidence alternatives for the control of Rhipicephalus microplus in the Brazilian Midwest. In chapter 1, the reproductive performance of multiparous and primiparous Brangus and Nellore sows submitted to fixed-time artificial insemination (FTAI) with bulls of five different breeds was evaluated, correlating with the body condition score (BCS) and later the performance was compared. productive of their progenies from birth to weaning. There were statistical differences in the pregnancy rates of the different categories (multiparous and primiparous) as well as in the correlation between the ECC. In chapter 2, the performance of purebred zebu, ¾ european x zebu ½ european x zebu cattle in the rearing phase was evaluated regarding average daily weight gain (ADG) and susceptibility to infestations by helminths and R. microplus. It was identified that ½ blood animals are more susceptible to parasitic infestations, and although they presented 100g more in the ADG when compared to the other racial compositions, statically they did not differ. Chapter 3 is placed as the closure of the problem presented, aiming to compare four control strategies of R. microplus, pointing out which one presented the best cost benefit. The percentage reduction of ticks of two pour-on formulations was evaluated, one injectable and one contact acaricide via spraying with the use of an atomizing chamber (veterinary shower), as well as the performance of in-vitro tests with different acaricides for the identification of resistant strains. In summary, the contact acaricide formulation can be indicated as the best tick control strategy, in addition to being more cost-effective in medium and large herds.