Doenças do sistema nervoso central que afetam bezerros até 12 meses de idade no Sul do Rio Grande do Sul: estudo retrospectivo

Abstract

The present study aimed to determine the frequency of central nervous system diseases that occur in calves under 12 months old in southern Rio Grande do Sul. For this, it was used the database of the Regional Diagnostic Laboratory of the Veterinary School, Federal University of Pelotas. This work is part of a project to identify and determine the frequency of diseases that occur in farm animals in this region through retrospective studies. It was also described a rare congenital disease of the central nervous system undiagnosed in cattle, establishing its importance for the differential diagnosis of other neurological diseases that occur in calves under 12 months old. It was reviewed all the necropsy protocols and materials sent to the laboratory between January 1978 and December 2014 in order to separate bovines under 12 months of age who had neurological signs. Epidemiological data on the origin of the animals, type of breeding, race, age and time of occurrence and frequency of the diseases were rescued. It was identified 578 cases of cattle with neurological signs, of which 147 (25.4%) had up to 12 months of age. The diagnoses were grouped by etiology, with viral diseases accounting for 42.2% of the cases; bacterial diseases for 20.4%, and parasitic diseases for 14.9%. Birth defects and hereditary diseases accounted for 6.8% of the cases, followed by poisoning / mycotoxicoses with 5.44%. Nutritional deficiency and multifactorial diseases, both, accounted for 2.7% of cases, and trauma, degenerative diseases and neoplasia, together, accounted for 0.68% of the diagnoses. Inconclusive cases represented 1.36% of the total. In calves from birth until 90 days of age, the main diseases observed were congenital defects, meningitis and encephalitis by bacteria, and abscesses of the central nervous system. In calves between four and nine months of age the diseases observed had a lower frequency, highlighting just rabies as the main diagnose. From 10 to 12 months of age, babesiosis, rabies and encephalitis by herpes viruses were the most important cause of death. The rare congenital defect described was classified as type I lissencephaly (classical) that occurs in humans. It was demonstrated the importance to perform differential diagnosis of diseases of the central nervous system occurring in cattle at 90 days of age, since the clinical signs observed here are similar to various other diseases of the central nervous system that occurs in calves with this age group.