Toxic Agents in Ruminants Diagnosed in the Pathological Anatomy Service of the UFRRJ, Rio de Janeiro - Brazil

Background: Toxic agents are chemical substances or physical agents that, when interacting with living organisms, cause harmful effects. For animals, toxic products include those intended to combat endo and ectoparasites, rodenticide products, and heavy metals. Minerals and dietary additives, even if essential to the animal, can become toxic agents, among which sodium chloride, copper, urea, and ionophore antibiotics stand out. This study aimed to survey the diagnoses of accidental poisoning in ruminants over 65 years as recorded in the files of the Pathological Anatomy Sector of the Federal Rural University of Rio de Janeiro.Materials, Methods & Results: The diagnoses of poisoning by ticks, rodenticides, heavy metals, macro and micronutrients, and dietary additives in ruminants were made based on the association of epidemiological, clinical, and anatomopathological findings and, in some cases, by histochemical (rubeanic acid and Masson trichrome) and toxicological examinations. A review of data recorded over 65 years identified 372 poisonings in ruminants. Of these, 85.5% (318/372) were in bovine species and 14.5% (54/372) in goats, sheep, and buffaloes. The outbreak of poisoning by organophosphates resulted in the death of 16 cattle that ingested contaminated broken rice and corn. The spraying of this product on the bags was intended to control insects. Intoxication due to excessive administration of abamectin resulted in the intoxication of 16 calves, in two distinct farms. Toxicosis caused by coumarin derivatives resulted in the death of six cattle after accidental ingestion of these rodenticides near the pens. Arsenic poisoning occurred due to ingestion of ant poison, available in bone meal and a mineral salt, through baths with arsenic-based ticks, or in cases later confirmed by toxicological analysis, resulting in the death of 109 cattle. Sodium chloride toxicosis resulted in the death of 10 sheep that became ill in two farms after excessive consumption of salt and private access to water. The diagnosed copper poisoning resulted in the death of 165 ruminants (154 cattle, 10 sheep, and 1 goat). Urea poisoning occurred due to excessive ingestion by 13 cattle and 4 buffaloes, without prior adaptation. Cases of poisoning by ionophore antibiotics occurred in 11 sheep, 18 buffaloes, and 4 cattle. In all cases, the source of exposure was mineral salt and/or feed with an excess of ionophores. The results of the laboratory tests varied according to the type of intoxication.Discussion: Among the means of diagnosing poisoning by toxic agents, minerals, and dietary additives, anamnesis should be detailed and highlighted to present all relevant information. It is the basis for toxicological diagnosis, because it generates information that helps in the definitive elucidation of cases and establishing control and prophylaxis plans, facilitates the prediction of prognosis, and directs the application of appropriate therapy, when possible. In the intoxication diagnoses reported here, the toxicological examination was important in elucidating the toxicosis caused by organophosphates, coumarin derivatives, arsenic, and copper, but the referral for toxicological analysis was previously indicated by a hypothesis generated during the anamnesis. Therefore, anamnesis becomes important yet elusive as toxicological examination leading to diagnosing intoxication.Keywords: toxicology, diagnosis, chemical substance, farm animals.Descritores: toxicologia, diagnóstico, substância química, animais de fazenda.

Lasalocid Poisoning in Buffalo Calves in the State of Pará, Brazil

Background: Ionophore antibiotics are food additives with coccidiostatic or antimicrobial action; they are also used as growth promoters, ruminal pH regulators, volatile fatty acid molar modifiers, and methanogenesis reducers. However, these compounds have the potential to cause microbial resistance, in addition to the risk of intoxication. Ionophore poisoning may be caused by excessive intake, sensitivity of certain animal species, and concomitant use with other drugs. In Brazil, cases of ionophore poisoning in buffalos are rare. This study aims to describe the epidemiological, clinical, and pathological findings of lasalocid poisoning in buffalo calves.Case: A visit was made to a farm in the municipality of Mojú, Pará state to care for Murrah buffalo calves. After weaning, the buffalos were grazed in paddocks with Panicum spp., and received a supplement of mineral, protein, and vitamin. This supplement contained, per kg, 250 g PB, 50 g Ca, 20 g P, 8 g S, 39 g Na, 20 mg Co, 557 mg Cu, 200 mg Fe, 12.4 mg Se, 2040 mg Zn, 0.19 mg biotin, 26750 IU of vitamin A, 4175 IU of vitamin D, 155 IU of vitamin E and 300 mg/kg of lasalocid. The product was made available to all calves, at 1-2 g/kg body weight (BW), according to the manufacturer's recommendations. Older calves were raised together with those less than 30 days old; as a result, the older calves tended to eat more, which could lead to a supplementation consumption of more than 1 kg body weight per animal per day. It was reported that between 40 and 60 days after the introduction of this supplement, 16 calves fell ill and died due to apathy, motor instability, tremors, and distended neck. The herd had a mortality rate of 33.3%. Two calves underwent a necroscopic examination at the Pathology Section of the Veterinary Institute of the Federal University of Pará. Macroscopic examination revealed extensive pale areas in the skeletal muscles, myocardium, and tongue. Fragments of these muscles and various organs were collected, fixed in 10% buffered formalin, processed according to the routine histological technique, and stained with hematoxylin-eosin and Masson's trichrome stain. Microscopic examination of the histologic samples revealed foci of muscle atrophy and necrosis characterized by an increase in cytoplasmic eosinophilia associated with the loss of stretch marks, and hyperchromatic nuclei that were displaced to the periphery. The necrosis of the muscle fibers was highlighted by Masson's trichrome staining.Discussion: The diagnosis of lasalocid poisoning in buffalo calves was based on epidemiological data, clinical findings, results of macroscopic and histopathological examination, and based on the estimated ionophore intake, obtained directly from the supplement label and by the calf's handler. Based on the absence of stratification of the calves by similarity of age and because the buffalo calves older than 30 days could eat more than 1 kg of the supplement (containing 300 mg/kg of lasalocid), it was possible to estimate the intake of lasalocid per kg CP (body weight). Therefore, the intake of lasalocid by a 70-kg buffalo calf in approximately 90 days and daily supplement consumption between 1 and 1.5 kg would be between 4.2 and 6.4 mg/kg of body weight. This report reinforces that notion that buffalo calves should never ingest ionophores; however, if necessary, strict protocols must be followed to avoid poisoning in these animals. This study highlighted the fact that stratification of buffaloes by different age groups during feeding became a risk factor that allowed greater consumption by older animals; this led to the estimated consumption of 4.2-6.4 mg/kg of lasalocid.Keywords: ionophores, ruminants, buffalo calves, muscle necrosis.Descritores: ionóforos, ruminantes, bezerros búfalos, necrose muscular.Título:  Intoxicação por lasalocida em bezerros búfalos no Estado do Pará, Brasil 

Ruptura Bilateral do Músculo Fibular Terceiro em Bovino

Background: The peroneus tertius muscle is responsible for tarsal flexion and coordinate extension of the stifle joint. The most common causes of rupture are excessive effort when trying to rise on a slippery surface, mounting, or being mounted. Rupture of the peroneus tertius muscle is characterized by an inability to flex the hock. Most cases are not curable, presenting an unfavorable to poor prognosis, and the animal has to be euthanized. This study aimed to report the clinical picture and treatment of a bilateral rupture of the peroneus tertius muscle in a cow from the municipality of Castanhal, state of Pará (Amazonian biome). Case: We report the clinical picture and treatment of a bilateral rupture of the peroneus tertius muscle in a 4-year-old cow, mixed breed, weighing approximately 400 kg, calved 3 months ago, belonging to a batch of 40 cattle kept on extensive breeding system in a pasture of Urochloa (Brachiaria) brizantha. The clinical signs appeared after the cow was mounted by a 1,100 kg bull and consisted of lameness, falling into sternal decubitus with hind limbs extended backward, hyperextension of the hocks with flexed stifle, with the tibia and metatarsus in a straight line, which lead to a 90-degree position of the femur and knee. Abrasions in the dorsal region of the fetlocks reinforce evidence of dragging hooves. Diagnosis of bilateral rupture of the peroneus tertius muscle was performed by a clinical examination and semiological test. Non-steroidal anti-inflammatory drugs (flunixin meglumine, 2,2 mg/kg, every 24 h for 4 days) were prescribed for treatment, in addition to resting in a paddock with good availability of pasture, water, and mineral salt. After 3 months, we observed an improvement of the clinical signs, and after 6 months, an almost complete recovery. Only a slight difficulty in flexing the hock when moving remained. Discussion: In the present report, bull mounting was the probable cause of the hyperextension of both hocks and the bilateral rupture of the peroneus tertius muscle. According to the handler, these clinical signs were only evidenced after the animal was mounted. As stated in the literature, accidents such as falls, slips, mounting or being mounted, as well as excessive traction and over-elevation of the limb are considered predisposing factors for the onset of the disease. Rupture of the peroneus tertius muscle is unusual in production animals; therefore, the low occurrence of reports on this kind of rupture in the literature makes this case even more unique. The bilateral injury differs from cases described in the literature, in which the reported injuries were always unilateral. Our findings reinforce the hypothesis that the act of mounting was the triggering factor for the bilateral rupture of the animal peroneus tertius muscle. The breeding system also differs from the cases diagnosed by the same authors, since they describe the disease in bovines kept on intensive or semi-intensive breeding. In the present case, the cattle were kept on an extensive breeding system. The extension and flexion tests used in the clinical examination allowed for the diagnosis of rupture of the peroneus tertius muscle in both limbs, similarly to what has been reported by other authors. Anamnesis, clinical findings, and exclusion of different diagnoses were decisive for establishing the diagnosis. The treatment chosen was efficient, even though the case was severe, as the injury occurred in both hind limbs. Keywords: cattle disease, muscle injury, lameness, rupture. Título: Ruptura bilateral do músculo fibular terceiro em bovino Descritores: doença do gado, lesão muscular, claudicação, ruptura.Background: O músculo fibular terceiro é responsável pela flexão do tarso e extensão coordenada da articulação fêmuro-tíbio-patelar. As causas mais comuns da ruptura são o esforço excessivo ao se levantar em piso escorregadio, montar ou ser montado por outros animais, entre outras causas. A ruptura do músculo fibular terceiro é caracterizada pela incapacidade de flexão do jarrete e, na maioria dos casos, não há recuperação, o prognóstico geralmente é desfavorável a ruim e o animal é destinado à eutanásia. O objetivo deste estudo foi relatar o quadro clínico e o tratamento empregado na ruptura bilateral do músculo fibular terceiro em uma vaca do município de Castanhal, estado do Pará (bioma amazônico). Case: Descreve-se o quadro clínico e o tratamento empregado na ruptura bilateral do músculo fibular terceiro em uma vaca, com quatro anos de idade, sem raça definida, com aproximadamente 400kg, parida há três meses, pertencente a um lote de 40 bovinos mantidos em sistema de criação extensiva em pastagem de Urochloa (Brachiaria) brizantha. Os sinais clínicos surgiram após ser coberta por um touro de 1.100Kg e consistiram em claudicação, queda em decúbito esternal com os membros posteriores estendidos para trás, hiperextensão dos jarretes com a soldra flexionada, ficando a tíbia e o metatarso em linha reta, levando a formação de um ângulo de 90º entre o fêmur e o joelho. As escoriações na região dorsal dos boletos pélvicos reforçam a evidência do arrastar das pinças. O diagnóstico da ruptura bilateral do músculo fibular terceiro foi realizado por meio do exame clínico semiológico. No tratamento foi prescrito anti-inflamatório não-esteroidal (flunixin meglumine, 2,2 mg/kg, a cada 24h, durante quatro dias) e repouso em um piquete com boa disponibilidade de pastagem, água e sal mineral. Após três meses observou-se a melhora dos sinais clínicos e após seis meses uma recuperação quase completa, permanecendo apenas uma leve dificuldade de flexionar o jarrete no momento da locomoção. Discussion: No presente relato, a monta do touro foi a provável causa da hiperextensão de ambos os jarretes e a ruptura bilateral dos músculos fibulares terceiros. A lesão bilateral difere de casos descritos em livros e artigos em que as lesões relatadas foram sempre unilaterais, reforçando a hipótese de o ato da monta ter sido o fator desencadeante da ruptura bilateral do músculo fibular terceiro do animal. Conclui-se que a anamnese, achados clínicos e exclusão de diagnósticos direfencias foram decisivos para instituição do diagnóstico. O tratamento instituído foi eficiente, mesmo se tratando de um caso grave, no qual a lesão ocorreu em ambos os membros posteriores