A congenital periocular leiomyosarcoma in a dairy calf.

A mass was removed surgically from the right orbit of a 1-d-old Holstein calf. Grossly, the mass filled the rostral part of an enlarged orbit and compressed the globe toward the caudal pole of the orbit. The brown, 6-cm tumor had central yellow and brown areas, and a smooth, glistening cut surface. Microscopically, the neoplasm was highly cellular and composed of spindle cells arranged in irregular, broad, interlacing streams and bundles, forming a herringbone pattern and supported by a sparse collagenous matrix. Neoplastic cells infiltrated surrounding soft tissues and compressed the globe. The neoplastic cells had positive immunolabeling for α-smooth muscle actin, desmin, and vimentin, and negative immunolabeling for factor VIII, myoglobin, cytokeratin, and skeletal muscle actin. Histopathology and immunohistochemistry results confirmed a diagnosis of leiomyosarcoma. To our knowledge, congenital periocular leiomyosarcoma has not been reported in cattle previously. This rare tumor could be included as a differential diagnosis in newborn calves with periocular masses.

Acute atrazine intoxication in heifers: Case report and toxicological studies.

Atrazine is a triazine organochloride herbicide, frequently used in different agricultural activities. Rare acute intoxication with atrazine is reported in production animals, and its metabolism in mammals is unknown. We report a spontaneous case of atrazine acute intoxication in 16.1% animals of a 168-beef heifer herd exposed to the herbicide at a farm located in Buenos Aires province, Argentina. Affected heifers showed different neurological signs and died suddenly, similar to the previous natural atrazine intoxication report. During autopsy, no gross lesions were observed. Different body fluids and tissues samples were collected during postmortem examination. No relevant histopathological findings were observed. High levels of atrazine and its metabolites were detected in different fluids and tissues by ultra-liquid chromatography high performance coupled to triple quadrupole mass spectrometry. These findings suggest ruminal or hepatic metabolization of atrazine in the exposed cattle. This is the first report of quantification and distribution of atrazine and its metabolites in intoxicated mammals providing relevant information for diagnostic purposes.

Infectious sporadic bovine abortions: retrospective analysis.

Infectious sporadic abortions in cattle are mainly caused by opportunistic bacteria and fungi usually present in environmental or gastrointestinal and reproductive microbiota of healthy animals. A retrospective analysis was carried out to evaluate the main opportunistic microorganisms involved in bovine abortions recorded at INTA Balcarce (Argentina) from 1997 to 2023, accounting for 2.2% of the total diagnosed etiologies of bovine abortion. The opportunistic agents identified as the cause of abortion in 29 fetuses were bacteria (90%) and fungi (10%). Escherichia coli (n = 8), Trueperella pyogenes (n = 5), and Histophilus somni (n = 4) were the bacterial species most often identified as causing infectious abortions, whereas Aspergillus spp. (n = 3) was implicated in all fungal abortions identified. Pure culture of bacteria or fungus was achieved from abomasal content and/or lung essential. Main microscopic findings were bronchopneumonia, myo- and epicarditis, meningitis, and portal hepatitis. Herein, we highlight the importance of detecting potential infectious bacteria in cultures to improve etiological diagnosis of bovine abortions associated with compatible microscopic findings to confirm the etiology.

Bovine campylobacteriosis in heifer: pathogenesis study and insights in the conventional and molecular diagnosis in an experimental bovine model and field cases.

Campylobacter fetus spp. is a bacterium associated to reproductive losses in cattle worldwide. It is a venereal infectious disease known as bovine campilobacteriosis, with high impact mainly in countries with extensive production systems. Here, we show pathogenesis and diagnostic methods for Campylobacter fetus detection in cervico-vaginal mucus (CVM) samples from heifers experimentally infected and field cases from herds with low reproductive performance by campylobacteriosis infection. Bacterial culture, direct immunofluorescence test and qPCR were used as diagnostic methods to evaluate detection of C. fetus. In the experimental model 30 Aberdeen Angus and crossbred heifers and 4 Aberdeen Angus bulls for natural mating were assigned to 3 groups experimentally challenged with C. fetus subsp. fetus (Cff), C. fetus subsps venerealis (Cfv) and C. fetus subsp venerealis biovar intermedius (Cfvi), respectively, and a negative control group, all followed for 9 months. Also, field samples of CVM and aborted fetuses were recollected from seven beef cattle farms. Bacteriological culture had the higher C. fetus detection rate in CVM being the most appropriate, followed by qPCR (with commercial extraction DNA kit), direct immunofluorescence test and qPCR (with in-house extraction DNA method), in both, experimental model and field cases. From experimental model after natural mating, 62.5% and 25% heifers got pregnant from Cff and Cfvi groups, respectively, while from Cfv no pregnancy was detected. The strain more frequently detected was Cfvi, followed by Cff and Cfv. Colonization of Cff in female genital tract with high number of carriers and presence in aborted fetuses was evidenced, suggesting a high risk to bovine reproductive health. Bacteriemia was not detected after genital infection. Given the low detection rate of either test, we suggest the use of both, PCR based methods and bacterial culture could result in higher detection rate in farms with endemic campylobacteriosis.

Pollen beetle (Astylus atromaculatus)-associated gastroenteric disease in cattle: report of 6 natural outbreaks.

Astylus atromaculatus is a pollen beetle native to South America, commonly found in crop flowers. Experimental intoxication of sheep and guinea pigs by this beetle resulting in fibrinonecrotizing enteritis has been reported. We describe here 6 natural outbreaks of intoxication in cattle associated with consumption of alfalfa (5 of 6) and mixed native (1 of 6) pastures heavily contaminated with A. atromaculatus. The outbreaks occurred during the summer (January-February) of 2023 in Argentina (n = 4) and Uruguay (n = 2), in beef cattle under extensive or semi-extensive rearing systems, with overall cumulative incidence and mortality of 22.3% and 17.8%, respectively. The main clinical signs included acute onset of anorexia, lethargy, hyperthermia, hindlimb weakness, reluctance to move, and diarrhea, for up to 15 d. In 2 outbreaks, sudden death was observed. Eight Hereford, Angus, and/or crossbreed heifers, cows, steers, and/or calves were autopsied. Gross and microscopic findings included multifocal necrosis with fibrinous pseudomembranes in the forestomachs and/or small and large intestines. Fragments or whole specimens of A. atromaculatus were identified in the ruminal content of all animals. Testing for multiple gastroenteric pathogens was negative as was testing of A. atromaculatus for cantharidin and batrachotoxin. GC-MS and LC-MS/MS performed on the beetles did not identify any known toxic compounds. Based on the exposure to A. atromaculatus-contaminated pasture, gross and microscopic lesions, and negative results of all testing for multiple gastroenteric pathogens, a diagnosis of intoxication by A. atromaculatus is proposed. Disease caused by A. atromaculatus consumption has not been reported previously in cattle, to our knowledge.

Bovine campylobacteriosis in bulls: insights in the conventional and molecular diagnosis.

Campylobacter fetus is a gram-negative motile bacterium, with two subspecies relevant to cattle health: C. fetus subsp. venerealis (Cfv) and C. fetus subsp. fetus (Cff). Both subspecies are associated with reproductive losses in cattle. In this study, we evaluated the identification of C. fetus for the diagnosis of bovine campylobacteriosis through bacteriological culture, direct immunofluorescence (DIF) and molecular tests in preputial smegma (PS) samples of three Angus bulls challenged with Cfv, Cfv biovar intermedius (Cfvi) or Cff, respectively, in an experiment imitating the natural infection. Two DNA extraction protocols were tested (in-house thermal extraction and commercial kit). Aspiration and scraping collection for PS were compared by conventional tests. Additionally, bacteremia was also evaluated in blood samples. Bulls were challenged by natural mating with heifers that had been experimentally infected with C. fetus subspecies; which led to infection. The Cfv- and Cfvi-bulls were positive for at least 9 months. Although Cff is not considered a venereal strain, in this study it was transmissible to bull from heifers experimentally infected, as evidenced by its colonization and persistence in the preputial cavity for 5 to 6 months. This finding suggests a potential risk of dissemination within herds. The results obtained by bacteriological culture or direct immunofluorescence (DIF) showed no significant differences, regardless the sampling device used (aspiration with Cassou pipette, metal and plastic scraper). C. fetus qPCR, on the other hand, yielded better results with an in-house DNA extraction method than with a commercial kit (75% vs 66.6%). Furthermore, qPCR diagnosis was more efficient than culture (66.6%) or DIF (56%). Bacteremia in whole blood samples was negative by qPCR and bacteriological culture in all samples. Altogether, this study demonstrated the transmission of Cff from heifers to bull and also showed that PCR-based methods are promising for the diagnosis of Bovine Genital Campylobacteriosis from clinical samples of PS.

Spatial-temporal trends and economic losses associated with bovine abortifacients in central Argentina.

The aims of this work are, firstly, to provide the geolocalization of cases of bovine abortion with definitive diagnosis and, secondly, to estimate the economic losses due to the most frequent abortifacients diagnosed agents in cattle in Buenos Aires province, Argentina. The total beef and dairy cattle population at risk of abortion is 8,358,186 and 538,076, respectively. In beef cattle, the overall risk of abortion was estimated at 4.5% for all pregnancies, where 27.9% are due to Campylobacter fetus, Neospora caninum, Leptospira spp., Brucella abortus, and bovine viral diarrhea virus with economic losses of US$ 440 per abortion, being the annual loss to the beef industry of US$ 50,144,101. In dairy cattle, there was an 8.0% risk of suffering abortion, 26.1% produced by the same abortigenic agents. The economic losses were estimated at US$ 1,415 per abortion, which equals a total loss of US$ 17,298,498 for the dairy industry in the region. The results of this study show that infectious causes are highly prevalent in Buenos Aires province, and they caused severe economic impacts in the dairy and beef industries. Furthermore, changes in temporal trends of infectious abortion occurrence were detected, probably related to the inclusion of molecular diagnostic techniques with more sensitivity or different epidemiological or husbandry conditions in the region analyzed.

Strongyloidiasis (Strongyloides papillosus) in lambs in Uruguay.

Here, we describe a spontaneous outbreak of strongyloidiasis (Strongyloides papillosus) in sheep in Uruguay. In a flock of 150 lambs, 60 animals became ill and 12 died within 3 weeks. Affected animals showed weakness, weight loss, enophthalmos and, in some cases, sudden death. Postmortem examination revealed muscle atrophy, dehydration, and small intestines with a foamy and liquid content. Histological examination of the duodenum and the jejunum showed a thick mucosa with severe villous atrophy, mononuclear mixed infiltrate in the lamina propria, and a large number of nematodes embedded in the mucosa, with numerous granulomas in the lamina propia. Small intestinal content analysis showed a total of 13,200 female nematodes in the duodenum and 2000 in the jejunum, identified as Strongyloides papillosus (Strongyloididae). This parasite has long been considered to behave as a commensal parasite or at least to cause significant disease only when present in large numbers. This report shows that Strongyloides papillosus can be highly pathogenic in sheep.

Clostridium piliforme infection (Tyzzer disease) in horses: retrospective study of 25 cases and literature review.

Tyzzer disease (TD) is caused by Clostridium piliforme, a gram-negative and obligate intracellular bacterium. The disease occurs in multiple species. A triad of lesions, namely colitis, hepatitis, and myocarditis, is described in cases of TD in some species, such as rats and mice. We carried out a retrospective analysis of 25 equine cases with a diagnosis of TD; 24 of 25 cases occurred in foals <45 d old; the remaining foal was 90 d old. There were 12 males and 12 females; no sex information was available for one foal. The affected breeds were Quarter Horse, Thoroughbred, Arabian, Paint, and Hanoverian. Most of the cases (19 of 25) occurred in the spring. There were 9 cases of sudden death; the remaining animals had diarrhea, fever, distended abdomen, depression, weakness, non-responsiveness, and/or recumbency. Gross findings included icterus, hepatomegaly with acinar pattern, serosal hemorrhages, pulmonary edema, and/or fluid content in small and large intestine. Microscopically, all foals had severe, multifocal, necrotizing hepatitis. Necrotizing lymphohistiocytic colitis was observed in 10 of 25 foals, and multifocal necrotizing myocarditis was found in 8 of 25. Gram-negative, Steiner-positive, intracytoplasmic filamentous bacteria were observed in hepatocytes, enterocytes, and myocardiocytes, respectively. PCR detected C. piliforme DNA in the liver (24 of 24), colon (20 of 24), and heart (5 of 25). Our results indicate that necrotic hepatitis is the hallmark of TD in horses; the so-called triad of lesions is not a consistent characteristic of the disease in this species.

Isolation of Campylobacter fetus subsp. venerealis from seminal vesicle of a naturally challenged bull.

Campylobacter fetus is a well-recognized pathogen that affects reproductive rate in cattle. In the present study, two Angus bulls were kept (39 days) separately with a group of heifers experimentally infected with Campylobacter fetus subsp. venerealis (Cfv) and Campylobacter fetus subsp. venerealis biovar intermedius (Cfvi), respectively. Each bull resulted infected post-mating by its respective strain (Cfv and Cfvi). Semen samples collected from each bull at days 39, 82, 132 and 269 resulted positive for C. fetus by bacteriological culture and/or direct immunofluorescence (DIF) test, and confirmed by polymerase chain reaction (PCR) from colonies isolated. Diagnosis resulted better with bacteriological culture (100%) compared to DIF (37,5%). Campylobacter fetus was isolated from seminal vesicle and preputial mucosa by bacteriological culture and confirmed by PCR and DIF test from colonies previously isolated from these tissues (day 276). Microscopic lesions detected in both bulls showed moderate diffuse subepithelial lymphoplasmacytic postitis. None of the seminal vesicle presented relevant microscopic lesions. To our knowledge this is the first report of isolation of C. fetus from seminal vesicles in a bull. The experimental model herein described, mimicks the natural infection and constitutes a promising alternative for future studies of campylobacteriosis in cattle.

Spongiform leukoencephalopathy in an adult mixed breed female dog

Leukoencephalomyelopathy is a nonspecific lesion characterized by widespread vacuolation of central nervous system white matter. It is mainly of genetic basis, occurring in young pure breed dogs. This report describes a neurodegenerative disease associated to demyelination in an adult mixed breed female dog. After 20 days in a kennel with12 other dogs, the dog showed progressive nervous signs with ataxia and inability to maintain balance. No other dog was affected. After 15 days, the animal was euthanized in extremis and necropsied. No macroscopic lesions of diagnostic relevance were present. Microscopically, status espongiosus was observed in white matter throughout the length of theneuroaxis, from frontal brain lobe to lumbar spinal cord. Specific stains of Kluver Barrera and immunohistochemistry for the detection of phosphorylated and non-phosphorylated neurofilaments, microglia, astrocytosis, oligodendrocytosis and myelin proteins in brain and spinal cord sections showed demyelination, axonal fragmentation and degeneration, microgliosis and decrease of oligodendrocytes. The anatomopathological study and epidemiological data suggests a primary demyelination due to decrease in number and function of oligodendrocytes, which is probably of genetic basis with lateonset.(AU)

Spongiform leukoencephalopathy in an adult mixed breed female dog

Leukoencephalomyelopathy is a nonspecific lesion characterized by widespread vacuolation of central nervous system white matter. It is mainly of genetic basis, occurring in young pure breed dogs. This report describes a neurodegenerative disease associated to demyelination in an adult mixed breed female dog. After 20 days in a kennel with12 other dogs, the dog showed progressive nervous signs with ataxia and inability to maintain balance. No other dog was affected. After 15 days, the animal was euthanized in extremis and necropsied. No macroscopic lesions of diagnostic relevance were present. Microscopically, status espongiosus was observed in white matter throughout the length of theneuroaxis, from frontal brain lobe to lumbar spinal cord. Specific stains of Kluver Barrera and immunohistochemistry for the detection of phosphorylated and non-phosphorylated neurofilaments, microglia, astrocytosis, oligodendrocytosis and myelin proteins in brain and spinal cord sections showed demyelination, axonal fragmentation and degeneration, microgliosis and decrease of oligodendrocytes. The anatomopathological study and epidemiological data suggests a primary demyelination due to decrease in number and function of oligodendrocytes, which is probably of genetic basis with lateonset.

Analysis of the structure and factorial invariance of the Multidimensional Environmental Concern Scale (MECS).

BACKGROUND: Most studies focused on measuring environmental attitudes consider a one-dimension measure of pro/anti-environmentalism, such as NEP scale. Nevertheless, more recent research has shown that it seems more adequate to use a multidimensional approach when assessing complex relations among people and the natural environment, particularly on cultural basis. This paper aims to test the psychometric properties of the Multidimensional Environmental Concern Scale (MECS) and, in particular, its factorial invariance. METHOD: Two studies were conducted. The first one assessed factorial invariance using two different approaches (multiple group confirmatory factor analysis - MGCFA, and alignment method) in a sample of 907 undergraduate students from Argentina, India, and Spain. A second study was conducted with 557 adults from Mexico and Spain, which also evaluated the criterion validity of the MECS' scores. RESULTS: The results obtained allowed to assure an acceptable degree of invariance of the MECS among all countries, and in terms of gender (Studies 1 and 2), age and education level (Study 2). CONCLUSIONS: Results provide support for a multidimensional approach when studying the environmental concern, showing that the environmentalism presents different associations depending on the analysed country. A deep analysis on different conceptualization of environmentalism will be promoted.

Senecio spp. transboundary introduction and expansion affecting cattle in Uruguay: Clinico-pathological, epidemiological and genetic survey, and experimental intoxication with Senecio oxyphyllus.

The genus Senecio is distributed worldwide, being responsible of poisoning in livestock and humans. Many species of Senecio have high invasion and expansion capacity, highly competitive with agricultural and native plant species, causing ecological damage. Particularly in Uruguay, poisoning by Senecio have grown exponentially to reach epidemic proportions. Herein we describe Seneciosis as a re-emerging and expanding epidemic disease affecting cattle, by describing clinico-pathological, epidemiological and genetic variation of species involved, as well as an experimental intoxication with Senecio oxyphyllus. For this, a study was carried out on 28 cattle farms in Eastern Uruguay, with history of seneciosis from 2010 to 2016. Plants of fifty populations of Senecio were sampled, in 2015 and 2016, for identification, analysis of alkaloids and study of genetic variation. In turn, post-mortem examination was performed in cattle of natural and an experimental case to confirm the intoxication, showing microscopic characteristic lesions (hepatomegalocytosis, diffuse fibrosis and ductal reaction). Four species of Senecio were identified: S. oxyphyllus, S. madagascariensis, S. selloi and S. brasiliensis. In the genetic study, 489 molecular markers of amplified sequence-related polymorphisms (SRAP), associated with species and pasture, were used for genetic variation analysis. There was no statistically significant association between genetic variation determined by molecular markers and population (specimens of same species collected from the same farm), botanically determined species, or geographical origin. The increase of seneciosis in cattle in the last years, the presence of species not identified to the moment with implication in the poisoning outbreaks and expansion of these plants shows that the disease is in an epidemic growing active stage. In turn, the experimental poisoning with S. oxyphyllus confirms its chronic hepatotoxic effect, being an emergent species for the region, of high distribution and toxic risk. This latter turned out the main Senecio species involved. This case of expansion of harmful plant for animal production and desirable plant species, can be useful as a model of ecopathological characterization, which is likely to occur with other toxic plants in different geographical ranges globally.

Solar-induced dorsal skin necrosis in sheep.

BACKGROUND: Solar-induced thermal burns of dark skin over the dorsum have been reported in dogs, sheep and a pig. OBJECTIVES: This report describes an outbreak of solar-induced thermal burns over the dorsal skin of criollo and Texel sheep in Uruguay. ANIMALS AND METHODS: Cross-bred criollo and pure-bred Texel adult ewes from a flock of 80 animals presented with severe skin lesions. Eight animals were evaluated clinically and skin biopsy specimens were collected from three ewes for histopathology. Epidemiological data were collected. RESULTS: Black/brown criollo sheep presented with extensive, wide, linear dorsal skin necrosis extending from the interscapular to the lumbosacral area. Necrotic skin was firm, dry and largely detached from the underlying subcutis. Nonpigmented Texel sheep showed milder lesions with rapid re-epithelialization and healing. Histological features were consistent with third-degree burns, characterized by full-thickness coagulative necrosis of epidermis and dermis, including blood vessels and adnexa. The cumulative incidence of the disease was 21% during the 30 days post-shearing, affecting 50% of criollo and 7.4% of Texel sheep (P < 0.001). CONCLUSIONS: The findings are consistent with post-shearing, sun-induced thermal burns leading to dorsal skin necrosis. Risk factors include sunlight exposure during hot months after shearing, dark skin and obesity.

Perinatal mortality in cattle associated with goitre

The role of iodine in ruminant reproductive function is well known. However, studies about the impact of this deficiency in reproductive performance of cattle are scarce. This paper describes stillbirth episodes in three beef cow herds in northwest Argentina. The stillbirth losses ranged between 15.8 and 25%. Grossly, the thyroid glands presented diffuse, bilateral and symmetric enlargement. Microscopically, follicular epithelium showed severe hyperplasia and hypertrophy, forming multiple stratified layers of large cuboidal cells, with papillary projections into the follicular lumen. Free thyroxine (T4f) mean levels in serum from aborted cows and heifers was 0.63±0.05 ng/dl. A diagnosis of congenital goiter was performed based on these findings. Following the diagnosis, the herds were supplemented orally and parentally with iodine. Mean T4f level post-treatment was 0.80±0.05 ng/dl and the stillbirth rate dropped sharply.

Perinatal mortality in cattle associated with goitre

The role of iodine in ruminant reproductive function is well known. However, studies about the impact of this deficiency in reproductive performance of cattle are scarce. This paper describes stillbirth episodes in three beef cow herds in northwest Argentina. The stillbirth losses ranged between 15.8 and 25%. Grossly, the thyroid glands presented diffuse, bilateral and symmetric enlargement. Microscopically, follicular epithelium showed severe hyperplasia and hypertrophy, forming multiple stratified layers of large cuboidal cells, with papillary projections into the follicular lumen. Free thyroxine (T4f) mean levels in serum from aborted cows and heifers was 0.63±0.05 ng/dl. A diagnosis of congenital goiter was performed based on these findings. Following the diagnosis, the herds were supplemented orally and parentally with iodine. Mean T4f level post-treatment was 0.80±0.05 ng/dl and the stillbirth rate dropped sharply.(AU)

Pathology of cattle experimentally intoxicated with ground Ricinus communis seeds

Five Aberdeen Angus calves were inoculated intra-ruminally with ground seeds of Ricinus communis at doses of 1, 1.5, 2 or 3 gr per kg of body weight, or with saline solution (control), respectively. Grossly, all intoxicated animals showed hemorrhages in abdominal serosas, epicardium, endocardium, spleen, pre-stomachs, abomasum, and small and large intestine, and diffuse edema of the ruminal mucosa. Microscopically, in all animals inoculated with R. communis seeds, the main feature was the presence of pyknotic and karyorrhectic nuclei in the endothelium of central nervous system, hepatic, ruminal, intestinal, glomerular and alveolar capillaries, and in lymphoid cells of multiple organs. Apoptosis, confirmed by activated caspase-3 immunohistochemistry, was observed in these cells. No gross or microscopic lesions were observed in the control animal. The results of this study suggest that apoptosis is the main mechanism of cell death in cattle intoxicated with R. communis seeds.

Pathology of cattle experimentally intoxicated with ground Ricinus communis seeds

Five Aberdeen Angus calves were inoculated intra-ruminally with ground seeds of Ricinus communis at doses of 1, 1.5, 2 or 3 gr per kg of body weight, or with saline solution (control), respectively. Grossly, all intoxicated animals showed hemorrhages in abdominal serosas, epicardium, endocardium, spleen, pre-stomachs, abomasum, and small and large intestine, and diffuse edema of the ruminal mucosa. Microscopically, in all animals inoculated with R. communis seeds, the main feature was the presence of pyknotic and karyorrhectic nuclei in the endothelium of central nervous system, hepatic, ruminal, intestinal, glomerular and alveolar capillaries, and in lymphoid cells of multiple organs. Apoptosis, confirmed by activated caspase-3 immunohistochemistry, was observed in these cells. No gross or microscopic lesions were observed in the control animal. The results of this study suggest that apoptosis is the main mechanism of cell death in cattle intoxicated with R. communis seeds.(AU)

Retrospective analysis of cattle poisoning in Argentina (2000-2013)

A retrospective analysis (2000 to 2013) of cattle poisoning caused by toxic plants and other compounds was carried out in the Pampas region of Argentina by the Animal Health Group of INTA-EEA, Balcarce. During this period, 1263 reports of diseases of different etiologies (infectious, parasitic, toxic, metabolic and miscellaneous) were recorded in cattle, by collecting anamnestic, clinical and pathological information. A toxic etiology was diagnosed in 21.1% of these reports. Iatrogenic poisoning caused by ionophores was the most frequently recorded etiology. Consumption of toxic plants (Wedelia glauca, Solanum glaucophyllum, among others), mycotoxins (Claviceps purpurea, Claviceps paspali, Epichloë coenophiala, among others), and plants producing cyanide and nitrates/nitrites were also commonly diagnosed. The high frequency of toxic episodes and the difficulties in their diagnosis by practitioners in our livestock production systems emphasizes the importance of this report.(AU)