Evolução das enfermidades tóxicas em bovinos na Região Sul do Rio Grande do Sul: revisão, distribuição espacial e tendência em 42 anos

Abstract

Among the main diseases that cause mortality in cattle In the Southern of Rio Grande do Sul are several toxic diseases. The aim of this thesis was to carry out a comparative study to determine the evolution of the main intoxications that occurred in cattle in the Southern of Rio Grande do Sul from 1979 to 1999 and from 2000 to 2020. It was also determined the spatial distribution and the tendency of occurrence of these intoxications in the 42 years of activities of the Laboratório Regional de Diagnóstico da Faculdade de Veterinária da Universidade Federal de Pelotas (LRD/UFPel), making it possible to predict their occurrence in the coming years. Between January 1979 and December 1999, 3,753 bovine materials were received for diagnosis at LRD/UFPel, and 3653 cases from 2000 to 2020. Of the total number of materials received, 397 were diagnosed as intoxications, with 141 cases between the years 1979 to 1999 and 256 cases from 2000 to 2020. Out of 141 cases diagnosed in the first 21 years of operation of the LRD/UFPel, 113 (80.1%) were poisoning by plants, 22 (15.6%) were poisoning by fungi and 6 (4.3%) were poisoning by chemical substances. Between 2000 and 2020, of the 256 diagnosed cases, 224 (87.5%) were caused by toxic plants, 10 (3.9%) by fungi, 16 (6.2%) by chemical substances and 6 (2.4%) were caused by insects. In the temporal trend analysis, a significant linear trend was observed with values of p=0.03 and annual percentage change (APC) of 2.5 in the growth of the number of diagnoses of poisoning in general over the 42 years of the study. When analyzing the temporal trend of poisoning by Senecio spp. there was an increase in the occurrence of the diagnosis, with different characteristics and inflection points over time, with an annual growth of 9% in diagnoses during the first 21 years. It is also concluded that there was a decrease in the occurrence of poisoning by Solanum fastigiatum, Echium plantagineum and Claviceps paspali. Furthermore that poisoning by Ramaria flavo-brunnescens and Baccharis coridifolia maintained a similar percentage throughout the period. In addition, it was concluded that toxic diseases will likely remain as important causes of death of cattle in the region. This thesis also includes a brief literature review that aimed to rescue the knowledge generated in South America about the evolution of intoxication by R. flavo-brunnescens in domestic animals since its first report in the 1950.