Jürgen Döbereiner

Poisonous plants affecting livestock in Brazil

Plant poisoning, together with rabies and botulism, are the main causes of death in adult cattle in Brazil. Estimates indicate that about one million head of cattle die annually through plant poisoning in this country. There are approximately 75 plants of practical importance to animal husbandry that have had their toxicity confirmed by experiments with the animal species affected under natural conditions. The great majority of these plants only occur in Brazil and neighbouring countries. A few of them are forage plants that can become toxic under certain conditions. In this review the poisonous plants of interest to animal husbandry of Brazil are divided according to the clinical-pathological picture they cause in cattle; only cyanogenic plants, plants that cause nitrate/nitrite poisoning and the ones that cause oxalate poisoning, are grouped according to their toxic principles. Plants and their toxic principles, or of which possible toxic compounds have been isolated, are listed.

Macrocyclic trichothecenes: Cause of livestock poisoning by the Brazilian plant Baccharis coridifolia

Nine macrocyclic trichothecenes, thought to cause toxic effects in herbivors, were isolated from the Brazilian shrub Baccharis coridifolia. The structures of two new components, named miophytocene A and B, are described. Structure analysis was mainly accomplished by application of two-dimensional Fourier transform NMR techniques. The trichothecenes are most likely produced by the soil fungus Myrothecium verrucaria, which was isolated from soil samples around B. coridifolia. It is concluded that the plant is able to absorb and accumulate these mycotoxins. Histopathological studies on rabbits which received roridin E and A per os revealed mainly necrosis and hemorrhages of the mucosa of the colon and in the case of roridin A also of the caecum. Lethality in mice was generally low, intoxication proceeding slowly. It has to be considered, however, that all trichothecenes tested are practically insoluble in aqueous solutions and were applied as emulsions (i.p. and per os application). No trichothecenes or other toxic substances were detected from the Brazilian species Baccharis dracunculifolia, although slight toxic effects have been reported in cattle.

Surtos de botulismo em bovinos no Brasil associados à ingestão de água contaminada

Botulism in cattle occurs by ingestion of botulinum toxin C and/or D. Seven outbreaks of the poisoning in the states of Mato Grosso do Sul and Sao Paulo are reported. The clinical and pathological data, epidemiology and laboratory findings indicate a possible intake of the toxin through contaminated water. The average mortality rate was 20.1%, with 99.2% lethality and 31.62% morbidity. From about 9,000 cattle envolved in the outbreaks, 2,844 animals died, predominantly with a hyperacute and acute clinical picture. The high morbidity rates were observed within a short period and affected all categories of cattle, with a clinical and pathological picture characterized by paresis and paralysis of the muscles of locomotion, swallowing and mastigation, with abscence of gross lesions at post-mortem examination. The outbreaks were related to the presence of decomposed animal carcasses or vegetal material in the drinking water. Botulinum toxins C and/or D were detected in water samples, viscera and blood serum of a considerable number of materials examined.

Relação entre macrófagos espumosos ("foam cells") no fígado de bovinos e ingestão de Brachiaria spp no Brasil

To establish the etiological relationship and the appearance of foamy macrophages in the liver of cattle from tropical regions of Brazil, liver samples from the files of the Pathology Section of Embrapa-Projeto Sanidade Animal, Rio de Janeiro, were reviewed. A total of 55 liver samples of cattle which died from different causes between 1970 and 1991 were reexamined. Only samples of animals which grazed known pastures were reviewed. Foamy macrophages were not seen in the samples from 1970 to 1975, although 40 samples (72%) were from this period. Foamy macrophages were observed from 1976 on, coinciding with the introduction of Brachiaria decumbens from Australian seeds into Brazil. Some samples were from cattle with histories of photosensitization, which were at that time attributed to Pithomyces chartarum. The results of this study indicate that the liver changes are related to prolonged ingestion of Brachiaria spp.

Livestock poisoning in South America by species of the Senecio plant

The pyrrolizidine alkaloids retrorsine, senecionine, integerrimine, neosenkirkine and florosenine were isolated from different Senecio spp. common in southern Brazil, Uruguay and Paraguay. Structure elucidation of these compounds was mainly accomplished by two-dimensional FT NMR techniques. Detailed interpretations of 1H-1H and 1H-13C NMR correlation spectra are given. The alkaloids neosenkirkine, integerrimine and florosenine were found in Senecio leptolobus De Candolle, retrorsine accompanied by senecionine in Senecio selloi (Spreng.) DC and Senecio cisplatinus Cabrera. In Senecio heterotrichus DC. integerrimine is accompanied by retrorsine. Investigations on pathology and histopathology of Senecio envenomation in Brazil are summarized.

Equívocos arraigados no meio pecuário sobre deficiências e suplementação minerais em bovinos no Brasil

The economic importance of mineral deficiencies in cattle and their supplementation for animal health and production is well established. But in spite of the existing knowledge and conscience of professionals on this subject in Brazil, there are numerous erroneous interpretations and superstitions on mineral supplementation for cattle, together with indiscriminate commercialization of mineral mixtures; the latter, thoroughly accepted and applied in the rural area, causes considerable economic losses to the cattle industry. In this article of general interest we discuss, one by one, the most important misunderstandings and superstitions regarding this subject.

Pré-compostagem de cadáveres de bovinos acometidos pelo botulismo

Five carcasses of cattle that died from botulism were composted in individual isolated beds with the purpose of monitoring the effect on spores of Clostridium botulinum and of botulinum toxin. The diagnosis of botulinum poisoning was based on clinical and pathological, epidemic and/or laboratorial characteristics. Of the five bovines with clinical signs of chronic botulism, three were affected by the type D toxin, one by the CD complex, and one was negative for toxin and spores of C. botulinum in the viscera using a mouse bioassay. The composting process was carried out in beds with carcasses cut up and mixed with sawdust as a carbon source. They were kept anaerobic under a plastic sheet for 50 days. The temperature of the beds was monitored during the period and oscillated from 40.5 to 52.4oC. After this time, soft tissue had complete decomposed with a significant loss of weight (26.5-44.5%). The remaining bones no longer contained spores or botulinum toxin in the 5 samples taken from each carcass. Only 2 of the 200 samples of homogenized remaining (40 for each carcass) contained spores of C. botulinum type C. All samples were negative for botulinum toxin using the mouse bioassay. Composting carcasses of cattle that died from botulism eliminated botulinum spores and toxin from the remains.

Cara inchada of cattle, an infectious, apparently soil antibiotics-dependant periodontitis in Brazil

The objective of this review on the investigation of cara inchada in cattle (CI), pursued over the last 30 years, was to elucidate the pathogenicity of the disease and come to proper conclusions on its etiology. CI has been widely considered to be of nutritional origin, caused primarily by mineral deficiency or imbalance. However, the disease consists of a rapidly progressive periodontitis, affecting the periodontal tissues at the level of the premolars and molars during the period of tooth eruption generally starting in young calves. The disease led to great economic losses for farmers in central-western Brazil, after the occupation of new land for cattle raising in the 1960s and 1970s. The lateral enlargement of the maxillary bones of affected calves gave the disease the popular name of cara inchada, i.e., swollen or enlarged face. The enlargement was found to be due to a chronic ossifying periostitis resulting from the purulent alveolitis of CI. Black-pigmented non-saccharolytic Bacteroides melaninogenicus, always together with Actinomyces (Corynebacterium) pyogenes, were isolated in large numbers from the periodontal lesions. B. melaninogenicus could be isolated in small numbers also from the marginal gingiva of a few healthy calves maintained on CI-free farms. In vitro-assays showed that streptomycin and actinomycin, as well as the supernatants of cultivates of actinomycetes from soils of CI-prone farms, applied in subinhibitory concentrations to the bacteria tested, enhanced significantly (up to 10 times) the adherence of the black-pigmented B.melaninogenicus to epithelial cells of the bovine gingiva. The antibiotics are apparently produced in large quantities by the increased number of soil actinomycetes, including the genus Streptomyces, that develop when soil microflora are modified by cultivating virgin forest or Cerrado (tree-savanna) for the first time for cattle grazing. The epidemiology of CI now provides strong evidence that the ingestion with the forage of such antibiotics could possibly be an important determinant factor for the onset and development of this infectious periodontitis. The antibiotic enhanced adherence of B.melaninogenicus to the sulcus-epithelium of the marginal gingiva, is thought to allow it to colonize, form a plaque and become pathogenic. There is experimental evidence that this determinant factor for the development of the periodontitis is present also in the milk of the mothers of CI-diseased calves. It has been shown that the bacteria isolated from the periodontal CI-lesions produce enzymes and endotoxins capable of destroying the periodontal tissues. The epidemiology of CI, with its decline in incidence and its disappearance after several years, could be explained by the fact that the former equilibrium of the microflora of the once undisturbed virgin soil has been reached again and that the number of antibiotic producing actinomycetes has been anew reduced. By this reasoning and all the data available, CI should be considered as a multifactorial infectious disease, caused primarily by the anaerobic black-pigmented non-saccharolytic Bacteroides melaninogenicus, always together with the micro-anaerobic Actinomyces pyogenes. Accordingly, the onset and development of the infectious periodontitis is apparently determined by ingestion with the forage of subinhibitory concentrations of antibiotics produced in recently cultivated virgin soils. This hypothesis is supported by the recent observation of renewed outbreaks of CI-periodontitis in former CI-prone areas, following fresh cultivation after many years. The infectious nature of CI is confirmed by trials in which virginiamycin was used efficiently for the oral treatment of CI-diseased cattle. Previously it has been shown, that spiramycin and virginiamycin, used as additives in mineral supplements, prevented CI-periodontitis.

Esporos e toxinas de Clostridium botulinum dos tipos C e D em cacimbas no Vale do Araguaia, Goiás

The occurrence and distribution of Clostridium botulinum spores and toxins type C and D in 300 ponds, used by cattle for drinking on 130 farms located in 12 municipalities of the Rio Araguaia valley, State of Goias, Brazil, was evaluated. The presence of spores was determined indirectly by cultivation in culture medium, followed by inoculation and neutralization in mice of samples of the sediment from the bottom of the raining ponds, from superficial soil and from cattle feces collected to its circuit. The toxin presence was evaluated directly by inoculation in mice of the filtered sediment of the ponds, followed by the neutralization in mice with antitoxins C and D. The presence of C. botulinum spores was significantly more frequent (p<0,05) in the cattle feces (31%), when compared with the results of the superficial soil samples (19%) and the sediments (10%). Botulinum toxins of type C and D or classified as belonging to the CD compound were detected in 6 samples (2%) of the 300 ponds. Of the 130 worked farms, in 122 (93,85%) ponds Clostridium botulinum spores or toxins were found in at least one of the researched variables, whilst ponds on only 8 (6,15%) farms did not present any contamination. Age and depth of the ponds were associated with the frequency of detection of botulinum spores and toxins. The older and shallower the ponds were, the larger was the frequency of isolation of the spores and toxins. The contamination of the ponds in the Araguaia valley with Clostridium botulinum spores and toxins type C and D demonstrates the permanent and growing potential risk for the occurrence of botulism in cattle through drinking water.

Imunidade cruzada pelas sementes de Abrus precatorius e Ricinus communis em bovinos

Five bovines immunized against the toxicity of the seeds of Abrus precatorius L. (jequiriti bean) did not get poisoned or only slightly so when the seeds of Ricinus communis L. (castor bean) were given in amounts that in bovines, which never before ingested the seeds of A. precatorius or R. communis, caused moderate to severe poisoning or even death. A sixth bovine, which was not well immunized against the toxic action of the seeds of A. precatorius, was severely poisoned when given a high dose of the seeds of R. communis. On the other side, from five bovines immunized against the toxic action of the seeds of R. communis four were severely poisoned and the fifth one moderately when the seeds of A. precatorius were given in doses that in bovines, which never before ingested seeds of R. communis or A. precatorius, caused slight to severe poisoning. It is concluded that bovines immunized against the toxic action of the seeds of A. precatorius are resistant to the toxic action of the seeds of R. communis, but that the contrary is not the case; this is, bovines immunized against the toxic action of the seeds of R. communis were not protected against the poisoning by A. precatorius. Earlier studies by other authors had shown that the toxalbumins of the seeds of A. precatorius and R. communis, respectively abrin and ricin, are different as to their antigenic properties. A possible explanation for the difference in results can be.that in the present study polygastric animals were used which received the seeds orally, but in the earlier studies monogastric animals received the seeds or toxins by parenteral route. The administration of the fresh leaves or the pericarp of the fruits R. communis to bovines, which had been immunized against the action of the seeds of the plant, had the same toxic effect as to not immunized animals, showing that the immunity due to ricin does not give protection against the action of ricinin, the toxic principle of the leaves and the pericarp.