Pathologic and Immunohistochemical Evidence of Possible Francisellaceae among Aborted Ovine Fetuses, Uruguay.

The only genus of the Francisellaceae family known to contain species pathogenic to mammals is Francisella, for which reported cases in the Southern Hemisphere have been limited to Australia. We describe severe necrotizing and inflammatory lesions and intralesional immunohistochemical identification of Francisella sp. lipopolysaccharide among aborted ovine fetuses in Uruguay.

Poisoning by Nierembergia veitchii: Effects on vascular smooth muscle cells in the pathogenesis of enzootic calcinosis.

Vascular mineralization is a hallmark of enzootic calcinosis. Histopathological, ultrastructural, and immunohistochemical investigations were performed on the external carotid arteries of seven sheep naturally poisoned by Nierembergia veitchii. Histologically, moderate to marked hyperplasia of the tunica intima was observed without mineralization. The tunica media exhibited mild to severe mineralization and osteochondroid metaplasia. Sheep with enzootic calcinosis showed arterial overexpression of osteopontin and tissue-nonspecific alkaline phosphatase and immunolabeling for osteonectin and osteocalcin in both intima and media layers of the tested arteries. The main ultrastructural finding in the tunica media was a marked phenotypic change of vascular smooth muscle cells from a contractile phenotype (VSMC-C) into a synthetic phenotype (VSMC-S). In the tunica media, VSMC-S produced matrix and extracellular vesicles, forming mineralizable granules associated with arterial mineralization. VSMC-S were also present in the tunica intima, but matrix and extracellular vesicles and mineralization were not observed. The absence of matrix and extracellular vesicles in the intimal hyperplasia, even in the presence of noncollagenous bone proteins, tissue-nonspecific alkaline phosphatase, and vitamin D receptors, reinforces the hypothesis that the presence of matrix and extracellular vesicles are crucial for the development of vascular mineralization in enzootic calcinosis. It is proposed that the two different VSMC-S phenotypes in calcinosis are due to the expression of at least two genetically different types of these cells induced by the action of 1,25(OH)2D3.

Evaluation of the one-side tick counting technique and of the level of infestation of bovines with Rhipicephalus microplus.

Counting ticks on one side of a bovine has been widely used to estimate the overall number of ticks; however, the accuracy of this method has not been determined. This work aimed to evaluate the one-side technique for counting ticks, identify bovines with a higher level of infestation, and determine the prevalence of infestation of adults and calves. To evaluate the one-side technique, ticks were counted on both sides of 352 bovines from three farms in nine months, and total numbers were correlated with the numbers counted on the left sides. The intraclass correlation coefficients reached values >0.99 for all farms, independent of the season. These results demonstrated that counting ticks on one-side and multiplying by 2 is a reliable method for estimating the overall number of ticks. To evaluate the level of infestation of various bovines, ticks were counted monthly, for 12 months, on the same bovines from seven farms. An animal was considered highly infested if the Anscombe residuals from a negative binomial GLM were ≥4, at least 2×. The number of bovines with infestation levels higher than expected varied among farms from zero to 3. Using this method, it is possible to evaluate the most infested bovines in order to remove them from the herd. The prevalence of infestation in calves reached 100% in five of the seven farms and 3- to 15-month-old calves had significantly higher infestation than adults.

Molecular detection of coccidian Apicomplexa Parasites isolated from wild crab-eating and pampas foxes through novel TaqMan™ probes: a contribution to their molecular epidemiology.

Neospora caninum, Toxoplasma gondii and Hammondia spp. are coccidian parasites similar in morphology. Molecular techniques are necessary to detect parasite DNA isolated from stool samples in wild canids because they were reported as definitive hosts of N. caninum life cycle. The objective of this study was to develop a highly sensitive and accurate molecular method for the identification of coccidian Apicomplexa parasites in crab-eating fox (Cerdocyon thous) and pampas fox (Lycalopex gymnocercus). Tissue samples from road-killed animals (pampas fox = 46, crab-eating fox = 55) and feces (pampas fox = 84, crab-eating fox = 2) were collected, and species were diagnosed through molecular assay. PCR was used for the amplification of a fragment of the coccidian Apicomplexa nss-rRNA gene. Additionally, we developed a novel real-time PCR TaqMan™ probe approach to detect T. gondii- Hammondia spp. and N. caninum. This is the first report of N. caninum DNA in pampas fox feces (n = 1), thus it was also detected from pampas fox tissues (n = 1). Meanwhile, T. gondii was found in tissues of pampas (n = 1) and crab-eating (n = 1) foxes and H. triffittae in one crab-eating fox tissue. Despite the low percentage (2.5%) of positive samples, the molecular method developed in this study proved to be highly sensitive and accurate allowing to conduct an extensive monitoring analysis for these parasites in wildlife.

A survey of management practices that influence calf welfare and an estimation of the annual calf mortality risk in pastured dairy herds in Uruguay.

Despite the importance of dairy farming in Uruguay, little information on dairy systems in this country is available in the scientific literature, and management practices that influence calf welfare at the herd level have not been explored. The aims of this study were to (1) describe the prepartum and calf-rearing systems, as well as the management practices that may influence calf welfare in pastured dairy herds in Uruguay, (2) estimate the annual calf mortality risk from birth to weaning, and (3) identify the primary clinical disease syndromes shown by the calves before death. A survey comprising a farm visit and a questionnaire was conducted on 225 randomly selected dairies with >30 milking cows, in 3 strata (31-99, 100-299, and ≥300 milking cows) of 6 Uruguayan departments where dairies are concentrated. Retrospective information from July 2013 to June 2014 was collected. A descriptive analysis was performed and results were inferred into the national dairy cattle population. Several management practices that could contribute to poor calf welfare were identified in a large proportion of farms. The annual calf mortality risk (calves that died between birth and weaning/calves born death or alive × 100, n = 149 farms) was 15.2%. Age at weaning averaged 75 d. Farmers reported that the most common clinical syndromes were diarrhea and respiratory disease in 85.2% and 47.5% of the farms, respectively. There was no continuous veterinary advice in 61.3% of the farms, 20.0% lacked data records, 38.5% had poor drainage in the prepartum area with waterlogging after rainfall, 52.1% monitored the prepartum area ≤2 times per day during the calving season, 65.1% did not perform navel antisepsis on newborns, 62.3% separated the calves from their dams at >24 h postpartum, 95.2% did not have a colostrum management program, 72.4% did not rotate the calf-rearing areas, 59.0% did not disinfect the calf feeders, 85.7% did not have staff dedicated exclusively to calf rearing, and 39.8% did not separate sick from healthy calves. The average volume of milk or milk replacer offered per calf was 4.5 L/day. Several of the identified management practices that affect calf welfare in the prepartum and calf-rearing periods could explain the high mortality risk. An effort should be made to conduct extension work focusing on the dissemination of good management practices to improve calf welfare and reduce calf mortality in Uruguayan dairy farms.

Palicourea marcgravii (Rubiaceae) poisoning in cattle grazing in Brazil.

Palicourea marcgravii is the most important poisonous plant of cattle in Brazil. It contains monofluoroacetic acid and causes sudden death associated with exercise. Herein, we describe the temporal and spatial distribution of the toxic disease. The survey was based on the epidemiological, clinical, and pathological data of the Setor de Anatomia Patológica (SAP) of the Universidade Federal Rural do Rio de Janeiro (UFRuralRJ) to report outbreaks of poisoning by P. marcgravii, from 1953 to 2018. Clinical signs were peracute and included labored breathing, loss of balance, muscle tremors, lateral recumbency, and limb paddling. Gross lesions such as congestion of large vessels and edema and pulmonary congestion were observed. Multifocal areas of vacuolar hydropic degeneration of distal contorted tubule cells with nuclear pyknosis were observed in the kidneys. The plant is found in forests, and the poisoning occurs mainly after clearing forests for pasture, in areas of natural forest recovery called "capoeira," which provide a favorable environment for maintaining P. marcgravii growth. Outbreaks of P. marcgravii poisoning coincided with periods of creation of large deforested pastures in the Southeast and Midwest regions of Brazil, and the poisoning should be considered an additional risk after deforestation. The most effective prophylaxis is fencing off the forest areas that contain these plants.

[A comparative study of commercial ELISAs for antibody detection in the diagnostic investigation of Neospora caninum-associated abortion in dairy cattle herds in Uruguay]. / Comparación de ELISAs comerciales para la detección de anticuerpos en la investigación diagnóstica del aborto asociado a Neospora caninum en rodeos lecheros de Uruguay.

Bovine abortion causes considerable economic losses to the livestock industry worldwide and is of concern for public health and food safety, given that many abortigenic infectious agents of cattle are zoonotic. Despite its importance, the etiological diagnosis of abortion in cattle is challenging both for veterinary practitioners and laboratory technicians, partly due to the difficulty in recovering aborted fetuses under extensive field conditions for pathological and microbiological diagnostic investigation, and in the early identification of aborted dams. Neospora caninum is a cosmopolitan protozoon identified as one of the main abortigenic agents in cattle worldwide. In this study we propose a comparative seroepidemiological approach for the diagnosis of abortion by N. caninum in dairy cattle. Samples from 12 to 93 cows/heifers with and without recent history of abortion (cases and controls) in four commercial dairy farms were tested. The ratio of controls to cases tested varied from 1:1 to 4.6:1. All samples (n=230) were analyzed by three commercial ELISA kits for the detection of anti-N. caninum antibodies. In all four dairy farms, the proportion of seropositive cows and/or heifers per kit was significantly higher in the cases than in the controls (Odds Ratios=5.13 to 36, p=0.0002 to 0.0485). The agreement among the three kits varied from weak to strong (Cohens kappa coefficients=0.58 to 0.83). We conclude that, despite the imperfect agreement between these kits, all of them allowed to arrive at similar conclusions regarding the statistical association between N. caninum seropositivity and abortion, thus representing a useful tool for the diagnostic approach at the population level under field conditions.

Bovine coronavirus in Uruguay: genetic diversity, risk factors and transboundary introductions from neighboring countries.

Bovine coronavirus (BCoV) is a recognized cause of severe neonatal calf diarrhea, with a negative impact on animal welfare, leading to economic losses to the livestock industry. Cattle production is one of the most important economic sectors in Uruguay. The aim of this study was to determine the frequency of BCoV infections and their genetic diversity in Uruguayan calves and to describe the evolutionary history of the virus in South America. The overall detection rate of BCoV in Uruguay was 7.8% (64/824): 7.7% (60/782) in dairy cattle and 9.5% (4/42) in beef cattle. The detection rate of BCoV in samples from deceased and live calves was 10.0% (6/60) and 7.6% (58/763), respectively. Interestingly, there was a lower frequency of BCoV detection in calves born to vaccinated dams (3.3%, 8/240) than in calves born to unvaccinated dams (12.2%, 32/263) (OR: 4.02, 95%CI: 1.81-8.90; p = 0.00026). The frequency of BCoV detection was higher in colder months (11.8%, 44/373) than in warmer months (1.5%, 3/206) (OR: 9.05, 95%CI: 2.77-29.53, p = 0.000013). Uruguayan strains grouped together in two different lineages: one with Argentinean strains and the other with Brazilian strains. Both BCoV lineages were estimated to have entered Uruguay in 2013: one of them from Brazil (95%HPD interval: 2011-2014) and the other from Argentina (95%HPD interval: 2010-2014). The lineages differed by four amino acid changes, and both were divergent from the Mebus reference strain. Surveillance should be maintained to detect possible emerging strains that can clearly diverge at the antigenic level from vaccine strains.

Fetal Pathology in an Aborted Holstein Fetus Infected With Bovine Parainfluenza Virus-3 Genotype A.

Bovine parainfluenza virus-3 (BPIV-3) is a recognized respiratory pathogen of cattle, and it has also been identified in aborted fetuses. However, little is known of this agent as a reproductive pathogen and detailed descriptions of fetal pathology on natural cases are lacking in the scientific literature. This article describes and illustrates lesions in a fetus spontaneously aborted by a first-calving Holstein heifer, naturally infected with BPIV-3 genotype A, broadening the current knowledge on fetal pathology by this virus. Fetal autopsy revealed diffusely reddened, rubbery and unexpanded lungs. Histologically, there was necrotizing bronchiolitis/alveolitis with intraluminal fibrin exudate and syncytial cells in the bronchiolar/alveolar spaces, and non-suppurative peribronchiolitis and perivascular interstitial pneumonia. In the small intestine there was multifocal necrotizing cryptitis and occasional necrotic syncytial enterocytes. Intralesional and extralesional BPIV-3 antigen was detected by immunohistochemistry in the lung and small intestine, and BPIV-3a was identified in fetal tissues by RT-PCR and sequencing.

Isolation and molecular characterization of four novel Neospora caninum strains.

Neospora caninum causes neosporosis, a leading cause of bovine abortion worldwide. Uruguay is a developing economy in South America that produces milk to feed seven times its population annually. Naturally, dairy production is paramount to the country's economy, and bovine reproductive failure impacts it profoundly. Recent studies demonstrated that the vast majority of infectious abortions in dairy cows are caused by N. caninum. To delve into the local situation and contextualize it within the international standing, we set out to characterize the Uruguayan N. caninum strains. For this, we isolated four distinct strains and determined by microsatellite typing that these represent three unique genetic lineages, distinct from those reported previously in the region or elsewhere. An unbiased analysis of the current worldwide genetic diversity of N. caninum strains known, whereby six typing clusters can be resolved, revealed that three of the four Uruguayan strains group closely with regional strains from Argentina and Brazil. The remaining strain groups in an unrelated genetic cluster, suggesting multiple origins of the local strains. Microsatellite typing of N. caninum DNA from fetuses opportunistically collected from local dairy farms correlated more often with one of the isolates. Overall, our results contribute to further understanding of genetic diversity among strains of N. caninum both regionally and worldwide.

Rhipicephalus microplus, babesiosis and anaplasmosis in Uruguay: current situation and control or elimination programs on farms.

Rhipicephalus microplus causes high economic losses for Uruguay; the country is divided into a R. microplus-free area and an endemic area. The aim of this research was to evaluate the R. microplus and tick fever situation in Uruguay and the feasibility of implementing R. microplus control or elimination programs to reduce the number of infested farms. A representative survey was performed to determine the number of infested farms, the number of farms with outbreaks of tick fever and the control and preventive measures being used. Control or elimination programs using generational treatment were implemented on 30 farms. Previously, a situation diagnosis was performed by evaluating the background of each farm, identifying acaricide resistance, serologically evaluating the enzootic stability of tick fever, and analyzing the risk of R. microplus introduction to farms. According to the survey, R. microplus was present on 9544 (36%) farms, and 3436 (36%) of these farms experienced outbreaks of tick fever. Only 323 (9.4%) farmers used the tick fever vaccine. Of the 30 farms for which control or elimination programs were carried out, 18 reduced the number of treatments applied per year and six achieved the elimination of the cattle tick. It is concluded that by administering elimination or control programs, it is possible to reduce the number of infested farms and the number of treatments to maintain control. New surveys should be performed to measure the degree of technology adoption by farmers and to analyze the advances in tick control or elimination programs on farms.

Tremorgenic Indole Diterpenes from Ipomoea asarifolia and Ipomoea muelleri and the Identification of 6,7-Dehydro-11-hydroxy-12,13-epoxyterpendole A.

Indole diterpene alkaloids have been isolated from Ipomoea asarifolia and I. muelleri and are associated with a tremorgenic syndrome in livestock. To better characterize the tremorgenic activity of the major indole diterpene alkaloids in these two plants, terpendole K (1), 6,7-dehydroterpendole A (2), 11-hydroxy-12,13-epoxyterpendole K (3), terpendole C (5), paxilline (6), and a new compound, 6,7-dehydro-11-hydroxy-12,13-epoxyterpendole A (4), were isolated and evaluated for tremorgenic activity in a mouse model. Compounds 1, 2, 5, and 6 all showed similar and significant signs of tremorgenic activity. In contrast, the 11-hydroxy-12,13-epoxy compounds, 3 and 4, showed no significant tremorgenic activity.

A Case of Prototheca zopfii Genotype 1 Infection in a Dog (Canis lupus familiaris).

Protothecosis is a rare disease caused by environmental algae of the genus Prototheca. These are saprophytic, non-photosynthetic, aerobic, colorless algae that belong to the Chlorellaceae family. Seven different species have been described. Prototheca zopfii genotype 2 and P. wickerhamii are most commonly involved in pathogenic infections in humans and animals. The objective of this work is to describe, for the first time, a case of protothecosis caused by P. zopfii genotype 1 in a dog. The dog, a 4-year-old mix bred male, was presented to a veterinary clinic in Montevideo, Uruguay, with multiple skin nodules, one of which was excised by surgical biopsy. The sample was examined histologically and processed by PCR, DNA sequencing, and restriction fragments length polymorphisms for the detection and genotyping of P. zopfii. In addition, transmission electron microscopy and scanning electron microscopy were performed. Histology showed severe ulcerative granulomatous dermatitis and panniculitis with myriads of pleomorphic algae. Algal cells were 4-17 µm in size, with an amphophilic, 2-4-µm-thick wall frequently surrounded by a clear halo, contained flocculant material and a deeply basophilic nucleus, and internal septae with daughter cells (endospores) consistent with endosporulation. Ultrastructurally, algal cells/endospores at different stages of development were found within parasitophorous vacuoles in macrophages. Prototheca zopfii genotype 1 was identified by molecular testing, confirming the etiologic diagnosis of protothecosis.

A review of the history of research and control of Rhipicephalus (Boophilus) microplus, babesiosis and anaplasmosis in Uruguay.

In Uruguay, control of Rhipicephalus microplus began in 1910. In 1941 the eradication of R. micoplus throughout the country was declared mandatory, although this attempt was unsuccessful. Since 2008 the country was divided into two regions: the south-western region, which is free of ticks; and a region of tick control that includes all departments to the north of the Rio Negro and five departments in the eastern region. In Uruguay, investigations on R. microplus, babesiosis and anaplasmosis started in 1921, and in the 1970s, studies of the epidemiology of R. microplus determined that from 2 to 3.5 generations can be produced annually and that the country is in an area of enzootic instability for babesiosis and anaplasmosis. Knowledge of tick epidemiology and of tick resistance to different acaricides led to the development of efficient methods of control or eradication, including integrated control and generational treatment. Although research results have led to a legal framework regarding R. microplus control, these measures have had variable results. This can be attributed to several factors, such as the discontinuation of the control measures, variable financial resources, changes in the dynamics of livestock movement, failure to adopt available technology for tick control by farmers, climate change, environmental alterations such as forestation and the increasing resistance of ticks to acaricides, which led to the development of multiresistant ticks. This paper reviews the history of R. microplus, babesiosis and anaplasmosis in Uruguay and proposes alternatives for their control.

An outbreak of poisoning by Kalanchoe blossfeldiana in cattle in northeastern Brazil.

In the world, Kalanchoe species are primarily ornamentals and houseplants, but some have escaped cultivation and can be found in the field. In Latin America, there are no reports of spontaneous poisoning by Kalanchoe species in animals. This study aimed to describe the epidemiological, clinical, and pathological aspects of an outbreak of poisoning by Kalanchoe blossfeldiana in cattle in the semiarid region of Pernambuco, Brazil. Epidemiological and clinical data were obtained from the owner and veterinarian during technical visits. Prunings of this plant were disposed of in a pasture with a shortness of forage. Seventeen cattle had clinical signs, and thirteen died 4-5 days after the first clinical signs were observed. Clinical signs and gross and histological lesions include gastrointestinal, cardiovascular, and neuromuscular disorders. Kalanchoe spp. contain cardiotoxic glycosides, and the clinical signs and lesions in cattle of this outbreak were consistent with poisoning by plants that contain these toxins.

Acute toxoplasmosis in pigs in Brazil caused by Toxoplasma gondii genotype Chinese 1.

This study reports the clinicopathological, immunohistochemical, and molecular findings from two cases of systemic toxoplasmosis in pigs showing apathy and dyspnea. In the post-mortem examination, severe diffuse necrotizing bronchointerstitial pneumonia with numerous intralesional tachyzoites of Toxoplasma gondii was observed. The lungs had not collapsed but were diffusely reddened, and the parenchyma showed friable whitish subpleural nodules with multifocal to coalescent distribution and diameters of 0.5-1.0 cm. The histopathological findings comprised mononuclear inflammation and multifocal areas of necrosis in alveolar septa (cases 1 and 2). In addition, esophagitis and ulcerations in the mucosa of the stomach and the small and large intestines were observed (case 1). Immunohistochemical analysis using anti-T. gondii antibodies on lung tissue in both cases revealed strong immunolabeling of free tachyzoites and tachyzoites in the cytoplasm of histiocytes and in cysts. Nested PCR targeting a 155-bp fragment of the B1 gene of T. gondii was positive for the DNA extracted from lung fragments from the two pigs. Genotyping of the samples by means of PCR-RFLP (10 markers) and by means of microsatellites (15 of them) revealed that these animals were infected with T. gondii that was molecularly characterized as the non-archetypal genotype Chinese 1. This presents worldwide circulation, but it had not previously been described in Brazil. The microsatellite analysis showed that the animals were infected with the same T. gondii isolate circulating in the environment.

Epidermolysis bullosa in animals: a review.

Epidermolysis bullosa (EB) is a hereditary mechanobullous disease of animals and humans, characterized by an extreme fragility of the skin and mucous membranes. The main feature of EB in humans and animals is the formation of blisters and erosions in response to minor mechanical trauma. Epidermolysis bullosa is caused by mutations in the genes that code for structural proteins of the cytoskeleton of the basal keratinocytes or of the basement membrane zone. Based on the ultrastructural levels of tissue separation, EB is divided into the following three broad categories: epidermolysis bullosa simplex, junctional epidermolysis bullosa and dystrophic epidermolysis bullosa. Human types of EB are divided into several subtypes based on their ultrastructural changes and the mode of inheritance; subtypes are not fully established in animals. In humans, it is estimated that EB affects one in 17,000 live births; the frequency of EB in different animals species is not known. In all animal species, except in buffalo with epidermolysis bullosa simplex, multifocal ulcers are observed on the gums, hard and soft palates, mucosa of the lips, cheek mucosa and dorsum of the tongue. Dystrophic or absent nails, a frequent sign seen in human patients with EB, corresponds to the deformities and sloughing of the hooves in ungulates and to dystrophy or atrophy of the claws in dogs and cats. This review covers aspects of the molecular biology, diagnosis, classification, clinical signs and pathology of EB reported in animals.

Induction and transfer of resistance to poisoning by Amorimia (Mascagnia) septentrionalis in goats.

Amorimia septentrionalis contains sodium monofluoroactetate (MFA) and can cause acute heart failure in ruminants when ingested in toxic doses. In this study, we demonstrate that resistance to poisoning by A. septentrionalis can be improved in goats by the repeated administration of non-toxic doses of A. septentrionalis. We also show that increased resistance to poisoning by A. septentrionalis can also be achieved by the transfaunation of ruminal content from goats previously conditioned to be resistant to naïve goats. These methods of improving resistance require further study, but appear to provide potential management solutions to mitigate toxicity problems from A. septentrionalis, and perhaps other plant species containing MFA.

Performance of sheep grazing in pastures of Brachiaria decumbens, Brachiaria brizantha, Panicum maximum, and Andropogon gayanus with different protodioscin concentrations.

Brachiaria spp. are the most important grasses for ruminants in central-western Brazil. However, the use of these pastures is limited by their toxicity due to steroidal saponins. This experiment was conducted for 60 days to demonstrate the resistance of sheep raised on Brachiaria spp. pastures to steroidal saponin poisoning. The experiment was composed by 48 animals randomly divided into four groups (n = 12). Among them, 32 4- to 5-month-old castrated male crossbred Santa Inês sheep, originating from flocks that had been grazing on Brachiaria spp. for more than three consecutive years, and 16 were non-adapted (naïve) sheep from flocks that never had prior contact with pastures of Brachiaria spp. were randomly divided into four groups. Each of the four experimental groups was composed by eight adapted and four non-adapted animals. The four experimental groups were introduced into paddocks, each of which contained a single grass: either Brachiaria decumbens, Brachiaria brizantha, Panicum maximum, or Andropogon gayanus. The addition of the naïve sheep to the groups was designed to detect pastures' toxicity to naïve sheep and to adjust the stocking rate to optimize the use of forage. The weight gains of sheep grazing on B. decumbens, B. brizantha, and P. maximum were similar; however, the A. gayanus group showed lower weight gains compared with the other groups (P < 0.05). The mean serum activities of γ-glutamyltransferase in the sheep grazing on B. decumbens were higher than those in the sheep from the other groups. No significant differences among the groups were found in aspartate aminotransferase, creatinine, albumin, or total protein serum concentrations. No clinical signs were observed in the adapted sheep in any of the pastures. Of the four non-adapted sheep introduced into the B. decumbens pasture, two showed clinical signs of steroidal saponin poisoning, and one died. No clinical signs were observed in the non-adapted sheep in the other pastures. The saponin (protodioscin) concentrations in the pastures varied from 3.3 to 12.2 g/kg DM in B. decumbens, from 2.8 to 9.1 g/kg DM in B. brizantha, and from 1 to 1.5 g/kg DM in A. gayanus. No saponins were found in P. maximum. It is concluded that sheep from flocks reared in pastures of B. decumbens and B. brizantha were resistant to steroidal saponin poisoning and showed similar weight gains to those of sheep grazing in other tropical pastures.

Hepatic and renal lesions in sheep intoxicated with Urochloa hybrid Mulato II in Argentina.

A flock of 48 sheep in Argentina grazing on a pasture of hybrid Urochloa (formerly Brachiaria) Mulato II (Urochloa ruziziensis × Urochloa decumbens × Urochloa brizantha) developed facial dermatitis, severe jaundice, and weakness after brief physical activity. Blood biochemistry of 3 animals revealed azotemia, elevated aspartate aminotransferase activity, and increased direct, indirect, and total bilirubin concentrations. The urine was markedly turbid and contained large concentrations of bile pigments and protein. At autopsy of 2 animals, there was severe jaundice and subcutaneous submandibular edema. The livers were enlarged, intensely yellow, and had a marked acinar pattern. Gallbladders were distended, and the kidneys were diffusely dark in one animal and yellow-green in the other. Microscopically, there was lymphoplasmacytic and histiocytic cholangiohepatitis with abundant crystals in the lumen of bile ducts and in the cytoplasm of macrophages. The proximal and distal convoluted renal tubules had protein casts in their lumens, and crystals were observed in the lumen and epithelial cells. Lectin histochemistry showed strong affinity for Arachis hypogaea agglutinin in hepatic macrophages. In the one sheep that was tested for heavy metals, copper concentrations in the liver and kidney were within the RIs. Despite the immediate change of pasture, morbidity and mortality were 100% within 3 mo. The association between the consumption of this pasture, and the clinical, biochemical, pathology, and lectin histochemistry findings confirmed intoxication with Urochloa hybrid Mulato II. To our knowledge, intoxication by this hybrid of Urochloa has not been reported previously.