Hepatogenic photosensitization in lambs supplemented with different levels of extruded urea in Brachiaria spp. pastures in the Brazilian Cerrado: Case report

The aim was to report cases and risk factors for hepatogenous photosensitization in lambs kept on Brachiaria spp. pastures and supplemented with levels of extruded urea (EU). The herd consisted of 69 Texel crossbred lambs with known parentage (fathers and mothers adapted to the consumption of forage of the genus Brachiaria), randomly divided into 5 groups and distributed in individual paddocks for each group. The animals were supplemented with increasing levels of EU (Amireia® 200S): 0, 6, 12, 18, and 24 g of EU per 100 kg-1 of body weight (BW). The concentration of protodioscin was estimated in the mixed pastures of Brachiaria spp. (cv. Marandu and cv. Basilisk), structural components (leaf, stem, and dead material), samples of each cultivar, and in the months of December (2018), February, and April (2019). The animals were examined daily, and when behavioral changes were identified, they underwent clinical examinations and anamnesis. Weighing was performed every 14 days, followed by necropsy and serum biochemical analysis, including gamma-glutamyltransferase (GGT). The highest concentrations of protodioscin (p < 0.0001) were found in the pastures used by animals supplemented without extruded urea (7.07 ± 0.56), in the Basilisk cultivar (11.35 ± 0.06), in the leaf blade components (2.08 ± 0.05), and thatch (2.20 ± 0.00), and in the month of April (7.34 ± 0.29) (the month with the lowest rainfall), respectively. Fourteen (20.29%) cases of photosensitization were observed in lambs, of which six recovered, and eight died. Serum GGT levels ranged from 42.2 to 225 IU/L; however, in animals that died, values ranged from 209.4 to 225 IU/L. The use of levels 12 g and 18 g per 100 kg-1 of body weight of extruded urea may contribute to the lower occurrence of photosensitization, as the animals selected pastures with lower protodioscin content, presenting a smaller number of cases.

Photosensitisation and green egg yolks in laying hens caused by the feeding of ensiled alfalfa leaves

1. The present study was carried out to determine the effects of feeding ensiled alfalfa leaves (ALS) as an alternative protein source to laying hens under the terms of an organic diet. Due to the occurrence of unexpected negative health effects and undesirable egg yolk pigmentation in the test groups the trial was prematurely stopped and further analysis was conducted to evaluate the responsible substances.2. Body weights of the test groups decreased significantly already in week 2 of the trial. Performance variables dropped. Olive green pigmented egg yolks were found in groups fed diets containing ALS. Severe comb necrosis occurred in the experimental group receiving the highest level of ALS (20%) combined with the option of free-range access and therefore natural light exposure.3. The noxious agent found in ALS, blood serum and egg yolk was the photosensitising chlorophyll derivate pheophorbid a (PPBa), deriving from a strong depletion of chlorophyll contained in the alfalfa leaves. PPBa caused the olive-green pigmentation found in yolks and led to photosensitivity in groups with the highest level of ALS in the diet in combination with light exposure.4. By aiming for high protein and amino acid levels, harvesting and processing have, unintentionally and initially unnoticed, led to a strong accumulation of phototoxic PPBa. From these results it is strongly advised not to include ensiled alfalfa leaves as a protein source in organic laying hen diets.

Photosensitization by Brachiaria ruziziensis in a sheep herd

Some species of the genus Brachiaria are cultivated worldwide in tropical and subtropical climate regions as the main feed for ruminants. Several studies report photosensitization by Brachiaria decumbens, Brachiaria brizantha, and Brachiaria humidicola, but the poisoning by Brachiaria ruziziensis have been reported only twice. Cutaneous and hepatic lesions may be caused by the steroidal saponins present in the leaves or by the mycotoxin sporidesmin produced by the saprophyte fungus Pithomyces chartarum. The present report describes the clinical and pathological changes observed in an outbreak of hepatogenic photosensitization in sheep kept in B. ruziziensis pastures. In addition, the present study will provide a better understanding of the etiology of this photosensitization through the evaluation of the saponin protodioscin and the spore count of P. chartarum. Santa Inês and Lacaune mixed-breed sheep showed signs of photosensitization after feeding B. ruziziensis. Clinical signs included jaundice, apathy, dehydration, and photosensitization characterized by facial edema and cutaneous scars, especially in the ears. Pathological examination of the liver revealed diffuse infiltrates of foamy cells, rare multinucleated cells, and mild enlargement of hepatocytes (megalocytosis). The skin showed acute epidermal and dermal necrosis with occlusive thrombi. B. ruziziensis showed low levels of protodioscin (0.020 ± 0.024% in mature leaves and 0.065 ± 0.084% in sprouts) but high P. chartarum spore counts (mean of 479,844 ± 443,951 spores/g plant). Thus, sheep grazing B. ruziziensis pastures must be closely monitored because of the risk of photosensitization.

Experimental poisoning by Heterophyllaea pustulata Hook. f. (Rubiaceae) in goats. Clinical, biochemical and toxicological aspects

The aim of this study was to investigate the clinical, biochemical and toxicological findings of the experimentally poisoning induced by Heterophyllaea pustulata in goats. Ten healthy adult female Saanen breed goats were used in the experiment. The goats were randomly assigned to two groups of five individuals: control and experimental group (CG and EG). Both groups were kept in the same enclosure devoid of shade for 8 h daily. The EG received only H. pustulata samples (leaves and thin steam) and water ad libitum. The CG received lucerne hay. Blood samples were taken at different times after oral administration of vegetal samples, and level of hepatic enzymes, total bilirubin, conjugated and non-conjugated bilirubin was measured, together with the detection of anthraquinones (AQs) and phylloerythrin by High Performance Liquid Chromatography with Diode-Array Detector and Mass Spectrometry with Electron Spray Ionization and Quadrupole Time Of Fly analysis. At the same time, skin biopsy samples were collected for AQs determinations. For histopathological examination, hepatic biopsy samples were collected on day 8. Clinically, all goats of the EG revealed photophobia, dermatitis and photosensitization. None of these goats developed jaundice or died during the experiment (15 days). In addition, affected goats exhibited a significant elevation in the serum levels of glutamic oxaloacetic transaminase, direct bilirubin, and total bilirubin. Microscopic examination of the liver samples revealed slight degenerative lesions. Although phylloerythrin was not detected in sera, a high level of two predominant AQs in H. pustulata (rubiadin/soranjidiol) were noted between 24 and 72 h after plant consumption, which coincided with the period in which the clinical signs were more obvious. Since those AQs were not identified in skin samples, the clinical findings were supported by the presence of AQs in sera. Finally, toxicological studies of the AQs are important, since many current works suggest their potential use in the photodynamic therapy.

Impaired secondary oxidant deactivation capacity and enhanced oxidative stress in serum from alveld affected lambs

Alveld is a hepatogenous photosensitivity disorder in lambs. The aim of the study was to investigate if alveld affected lambs had a reduced capacity to handle oxidative stress induced from either endogenous and/or exogenous photosensitizers. Serum samples from alveld lambs (n=33) were compared to serum samples from control lambs (n=31) and exposed to a controlled amount of singlet oxygen ((1)O2). The sera from alveld lambs were found to have an impaired ability to deactivate reactive oxygen species (ROS) compared to control sera. A higher degree of initial hemolysis and a higher concentration of the exogenous photosensitizer phytoporphyrin (PP) were detected in alveld sera compared to the controls. The action spectrum for the formation of (1)O2 indicated that PP as well as the endogenous compound protoporphyrin IX (PP IX) may act as in vivo photosensitizers. A relatively high level of iron was detected in pooled serum from alveld lambs that showed a high degree of hemolysis. It was concluded that alveld photosensitivity is likely to be initiated by a photodynamic reaction involving PP and possibly also PP IX followed by a light-independent reaction involving hemoglobin-related products and catalysis by the Fenton reaction.

Photosensitisation induced by clofazimine in a cat

A pale ginger cat was treated with clofazimine for feline leprosy. During the course of treatment, photosensitisation by clofazimine led to a dermatological disease resembling actinic dermatitis. The mycobacterial disease was eventually cured with clofazimine and the photosensitisation was managed by regulating sunlight exposure. Upon review of the literature, this appears to be the first documented case of drug-induced photosensitisation in the cat.

Secondary hepatogenous photosensitization in a llama (Lama glama) bred in the state of Sáo Paulo, Brazil

Milk yield in lactating range beef cows was estimated by milking 42 cows four times at approximately monthly intervals during the lactation. Milking was by machine after oxytocin injection. Weights of calves, before and after suckling, over a 24-hour period were used to estimate calf consumption. Breed-age group averages for 24-hour milk yield varied from 3.7 to 8.4 kg, with an overall average of 6.4 kg. Breed of cow accounted for 82.5% of the variance in milk yield in these data. Milk yield declined on the average by 0.02 kg per day of lactation. The correlation between calf consumption and milk yield was 0.58. Butterfat was 3.9% on the average, protein 3.5%, solids-not-fat 9.1% and total solids 13.0%. Breed-age group or month of test did not significantly influence milk constituent percentages, although butterfat and total solids tended to rise as lactation progressed.A good estimate of milk yield was obtained by one test milking. Milk composition based on one test milking was not reliable. Milk yield as estimated in any month was highly related to calf average daily gain from birth to weaning. Use of two test milkings improved the relationship only slightly. Milk solid component percentages showed little relationship to calf gains.

Sapogenin levels in Narthecium ossifragum plants and Ovis aries lamb faeces during two alveld outbreaks in Møre og Romsdal, Norway, 2001

The proposal that saponins produced by the lily bog asphodel (Narthecium ossifragum) may be the direct cause of the hepatogenous photosensitization disease alveld seen in Norwegian lambs was investigated by comparing sapogenin levels in two control and two toxic pastures, and in faeces from lambs grazing the four pastures in the Halsa and Surnadal municipalities, Møre og Romsdal county, Norway. Generally similar levels of sapogenins, determined after hydrolysis of parent plant saponins, were found in Narthecium leaves collected in June/July 2001 from the two alveld outbreak areas and two nearby control areas. Differences in the median sapogenin levels determined for leaf samples in outbreak and control areas were not statistically significant. The total level of free and conjugated sapogenins in faeces recovered from the rectums of lambs grazing the outbreak and control pastures areas varied greatly. The results obtained do not support the hypothesis that a dose-response relationship exists between Narthecium saponin levels and the occurrence of alveld outbreaks.

[Case report: photosensitization followed by chronic exungulation in cattle]

Isolated cases of photosensitization in grazing cattle are observed in a greenland district of North West Germany close to the North Sea. With adequate treatment the disease usually takes a benign course. Sometimes, however, also the claws are involved in the disease process with the consequence that the photodermatitis later on is followed by chronic exungulation. Details of a respective case are described and documented by pictures: A non-pregnant heifer (age 2 years) was falling sick with acute photodermatitis and Pododermatitis/-dermatosis coronaria aseptica in late autumn (November). After treatment and housing of the patient the acute symptoms (dermatitis, lameness) subsided. About 3 months later deep horizontal circular fissures of the horn wall about 2 cm beneath the coronary band could be observed in all 8 claws - the beginning of chronic exungulation. Subsequently the distally growing "old" horn-capsulars became progressively smaller and movable. The patient, being again on pasture (on soft ground) in the next grazing season, showed recurring lameness. The lameness could be improved by repeated cutting of the horn-wall at the tip of the claws. The "new horn-shoes" had normal conformation and full weightbearing capacity. The heifer calved in September; her milkproduction was in the average of 3 years 9.428 kg. The cause of the photosensitization could not be identified.

Scalp EEG for the diagnosis of epilepsy and photosensitivity in the baboon

Spontaneous seizures have been observed in several baboon species housed at the Southwest National Primate Research Center (SNPRC), including Papio hamadryas anubis and cynocephalus/anubis, hamadryas/anubis, and papio/anubis hybrids. The goal of this study was to establish a noninvasive, reliable electroencephalographic technique to characterize epilepsy phenotypes and assess photosensitivity in these subspecies. Thirty baboons with witnessed seizures, and 15 asymptomatic baboons underwent scalp electroencephalograms (EEGs) with photic stimulation (PS). The sensitivity and specificity of surface EEG for identifying interictal epileptic discharges (IEDs) in baboons with witnessed seizures were examined. The morphology of IEDs, electroclinical features of seizures and responses to PS, reproducibility of EEG findings, and intrarater reliability were also evaluated. Twenty-three seizure baboons (77%) demonstrated IEDs, predominantly with frequencies of 4-6 Hz in 18 baboons and 2-3 Hz in six baboons. Two seizure animals had a mixture of 2-3-Hz and 4-6-Hz IEDs. All animals with 2-3-Hz IEDs were 3 years old or younger. Myoclonic seizures (MS) and generalized tonic-clonic seizures (GTCS) were recorded in 13 baboons (43%). PS activated IEDs in 15 baboons (50%) and seizures in nine baboons. The presence of IEDs or seizures was not associated with a particular gender or species (Fisher exact test, alpha=0.05). Seizures were more common in animals >3 years old, while PS-induced IEDs and seizures were more prevalent in P.h. anubis/cynocephalus crosses compared to P.h. anubis. In the asymptomatic controls, IEDs were recorded in five baboons (33%), and photoparoxysmal responses were observed in two (13%). Surface EEG is a sensitive and reliable instrument for characterizing the epilepsy encountered in Papio species. Electroclinically, the seizure animals had generalized epilepsy with photosensitivity. The variation in IED morphology may be age-related or it may reflect different epileptic phenotypes. Ketamine provoked IEDs and seizures in most seizure animals and only in a few asymptomatic baboons; therefore, it may enhance the sensitivity of surface EEG for detecting a predisposition to epilepsy.

Photosensitivity in feedlot calves apparently related to cocoa shells

Primary photosensitization was observed in 11/78 cross-breed calves. The skin lesions were diffuse dermatitis with thickening and wrinkling with areas of alopecia. The severe photosensitivity dermatitis was associated with cocoa shell ingestion. The lesions resolved after removal of the cocoa shells from the feed ration and prevention of exposure to sunlight. Cocoa shells may contain photodynamic agents that cause photosensitization in calves.

Experimental Tribulus terrestris poisoning in sheep: clinical, laboratory and pathological findings

Eleven native sheep, 1-2 years old, of both sexes were randomly divided into two groups, 6 sheep being allocated to the experimental group and 5 serving as controls. The sheep in the experimental group were fed 80% Tribulus terrestris and 20% alfalfa hay and wheat straw, while the control sheep were given a mixture of 40% alfalfa hay and 60% wheat straw. Clinical signs of hepatogenous photosensitivity were observed from day 11, including reddening and crust formation on the muzzle, nose, ears and eyelids, depression, weight loss, icterus, conjunctivitis, and yellow discoloration of the urine. Laboratory findings on weekly samples indicated significant differences (p < 0.05) in white blood cell count, total plasma protein and fibrinogen, total and direct bilirubin, blood urea nitrogen and creatinine concentrations, and aspartate aminotransferase and alkaline phosphatase activities. There were no significant differences in the packed cell volume, in the neutrophil, lymphocyte or eosinophil counts, or in the serum calcium, phosphorus, potassium, sodium or chloride concentrations. At necropsy of the experimental animals, there were various degrees of generalized icterus and the livers were swollen and discolored by bile pigment. Histopathological examination revealed varying amounts of crystalloid material in the bile ducts and renal tubules, hepatocellular degeneration, biliary fibrosis and proliferation, renal tubular necrosis and focal necrosis of cardiac muscle.

Induction of photosensitivity in sheep with Erodium moschatum (L.) L'Hérit

Erodium moschatum is an exotic weed in the southern and southwestern coastal areas of the Western Cape Province (WCP), South Africa. It has been suspected as the cause of photosensitivity in sheep. However, attempts to induce photosensitivity by dosing it to sheep have thus far been unsuccessful. During August 1999, 2 sheep suffering from severe photosensitivity were presented for clinical examination to the Western Cape Provincial Veterinary Laboratory (WCPVL). One sheep was sacrificed for autopsy. Except for skin lesions associated with photosensitivity, no icterus or other lesions were present. Histopathological examination of affected skin revealed epidermal necrosis while the liver had no microscopic lesions. It was therefore concluded that the sheep might have been suffering from primary photosensitivity. The farm from which the sheep came, situated in the Malmesbury district, WCP, was visited to determine the source of the photodynamic agent. The flock from which the sheep originated had been grazing in a camp where E. moschatum was growing abundantly and had been heavily grazed. Some remaining Erodium in the camp was collected, pulped and dosed over a period of 7 days to an adult sheep. Another sheep was dosed simultaneously with Erodium growing on the premises of the WCPVL. Both sheep developed mild photosensitivity, which was confirmed by histopathological examination of skin biopsies. It was concluded that E. moschatum can induce photosensitivity (probably the primary type) in sheep if ingested in large quantities.

Experimentally induced cholangiohepatopathy by dosing sheep with fractionated extracts from Brachiaria decumbens

Cholangiohepatopathy was induced in 5 lambs by oral administration of extracts from signal grass (Brachiaria decumbens) in Brazil. Grossly there were pale foci multifocally distributed throughout the hepatic parenchyma in 4 lambs. The microscopic changes, which were similar to those produced by other steroidal sapogenins-containing plants such as Tribulus terrestris and Panicum spp., included multifocal cholangitis, bile duct proliferation, and the presence of crystals in the biliary system.

Isolation of steroidal sapogenins implicated in experimentally induced cholangiopathy of sheep grazing Brachiaria decumbens in Brazil

As part of an experimental study, crystal-associated cholangiopathy was induced in 9 sheep by grazing pure pastures of Brachiaria decumbens in Brazil. One of these sheep showed characteristic lesions of photosensitization. The analysis of the B decumbens samples by acidic hydrolysis followed by TLC and infrared spectrum revealed diosgenin as the principal sapogenin present in the plant. In the rumen contents samples from the B decumbens-grazing group were identified by TLC, 1H and 13C NMR and EIMS as epismilagenin, episarsasapogenin, and a mixture of smilagenin and sarsasapogenin. In the bile samples from the B decumbens-grazing group, TLC analysis demonstrated 2 compounds similar to epismilagenin and episarsasapogenin. However, by this same method, those compounds were not observed in the rumen contents and bile from 2 sheep which served as control animals. The P chartarum spore counts remained very low during the experimental period.

Hepatotoxicity and secondary photosensitization in a red kangaroo (Megaleia rufus) due to ingestion of Lantana camara

Three red kangaroos (Megaleira rufus), an adult male, an adult female, and a yearling, were exposed in bedding and food to coastal bermuda hay that contained the toxic plant Lantana camara. The adult male exhibited signs of anorexia, depression, lethargy, and jaundice. The adult female was presented dead. After 1 wk, following exposure to sunlight, the adult male and a yearling joey developed exudative dermatitis of the ear margins, eyelids, muzzle, and scrotum and opacity of the corneas. The adult male had a leucocytosis, anemia, bilirubinemia, bilirubinuria, hyperproteinemia, and elevated alanine aminotransferase, gamma glutamyl transpeptidase, alkaline phosphatase, and bile acid serum levels. Postmortem examination of the adult male revealed jaundice, and the liver was swollen, mottled, and pale yellow to reddish yellow. The gall bladder was markedly distended. Histopathologically, there was hepatocellular enlargement with vesiculation of the nuclei and sporadic feathery degeneration of the cytoplasm. The yearling joey survived and was treated symptomatically with i.v. fluids and antibiotics. The history, clinical signs, diagnostic findings, necropsy findings, and exposure to the toxic plant Lantana camara support the diagnosis of secondary photosensitization and hepatoxicity.

Metabolism of saponins from Narthecium ossifragum--a plant implicated in the aetiology of alveld, a hepatogenous photosensitization of sheep

One sheep was dosed over 4 consecutive days with 2.1 kg of leaves and flower stems of Narthecium ossifragum before it was killed. Sarsasapogenin and smilagenin glycosides, in the ratio 9:1, were the dominant saponins present in the dosed plant material. GC-MS analyses of the free and conjugated sapogenin content of samples recovered from the sheep identified three distinct regions of metabolic activity. In the first metabolic region, in the rumen and omasum, the ingested plant saponins were hydrolysed to the parent sapogenins, before being oxidized at C-3 and reduced to give the epi analogues of the ingested sapogenins. The second metabolic region consisted of the duodenum, jejunum, the liver and associated ducts. Sapogenins appear to be absorbed in the jejunum and may be transported via the portal vein to the liver, where 3 alpha-OH-5 beta-H sapogenins (epismilagenin and episarsasapogenin), but not 3 beta-OH-5 alpha-H sapogenins (smilagenin and sarsasapogenin), are conjugated and excreted into the bile as episarsasapogenin and epismilagenin conjugates in the ratio 4:1. In the third metabolic region, in the caecum and the colon, the epi-sapogenin conjugates were hydrolysed to free epi-sapogenins. The absence of free and/or conjugated sapogenins in urine, collected 24 h after dosing commenced, indicates that saponins and their metabolites are not likely to be implicated in the kidney disease occurring in ruminants ingesting N. ossifragum.

Disease signs reported in south-eastern Australian dairy cattle while grazing Brassica species

OBJECTIVE

To estimate the relative frequency of various disease signs in dairy cattle fed brassicas in south-eastern Australia, to estimate the incidence of disease signs within affected groups and to identify risk factors for commonly reported signs in brassica-fed dairy cows.

DESIGN

A case series study and a case-control study.

PROCEDURES

Case data was collected using an incident reporting system. Herd managers and veterinarians recorded details about disease incidents in brassica-fed dairy cattle in summer and autumn 1995 using a standard questionnaire. Potential risk factors for photosensitisation were assessed using a case-control study.

RESULTS

Disease signs were reported in 66 groups of brassicated dairy cattle. Photosensitisation and bloat were the more frequently reported signs. While high incidences were reported in some groups, the incidence of disease signs was low within most affected groups. Photosensitisation occurred more frequently among groups of cows fed brassica crops treated with nitrogenous fertilisers or which were low yielding. Risks of other disease signs were greatest while the first one quarter of the crop was grazed.

CONCLUSIONS

In the study population, most disease outbreaks occurring in brassica-fed cattle were of low incidence. However, some high incidence outbreaks occurred. Results from this study suggest that important risk factors exist for disease signs in brassica-fed dairy cattle. Further studies are required if these risk factors are to be fully identified. This would allow the development of preventative strategies for high incidence disease outbreaks while feeding brassicas to dairy cattle.

Ergotism and photosensitization in swine produced by the combined ingestion of Claviceps purpurea sclerotia and Ammi majus seeds

Poisoning of domestic animals happens frequently in the southeast of Buenos Aires Province (Argentina). Intoxications are produced mainly by the ingestion of plants and mycotoxins, but animals are rarely affected simultaneously by both types of agents. One herd of pigs suffered simultaneous intoxications by ergot alkaloids from Claviceps purpurea sclerotia and furocoumarins from Ammi majus seeds. Pigs were fed a diet composed of wheat (poor quality) or corn and protein and vitamin supplements. This diet was completed with forage sorghum. Nervous signs were first observed 5-7 days after the initiation of feeding the suspect ration. These signs were followed by cutaneous irritation. Snout ulcers, eyelid edema, and conjunctivitis were observed in several piglets. Ten days after the start of feeding the incriminated ration, 8 abortions were observed. Many of the sows that were nursing piglets developed udder edema and teat cracking. Dermal lesions were observed in most of the animals with unpigmented areas in the skin but not in a Duroc-Jersey boar. Removal of the incriminated diet and feeding of another diet prepared with good-quality wheat allowed all the animals to recover in 15 days. The herd experienced normal pregnancies and parturitions, litter sizes, and piglet weights when fed a cleaned portion of the poor-quality wheat. No photosensitization lesions were observed. Examination of impurities in the suspected wheat indicated the presence of 2.2% of A. majus seeds and 0.14% of C. purpurea sclerotia. The quantitative analysis indicated the presence of 3.2 g xanthotoxin and 0.65 g bergaptene/100 g A. majus seeds and 0.73 g ergot alkaloids (expressed as ergonovine) per 100 g of C. purpurea sclerotia. Qualitative analysis demonstrated the presence of ergotamine, ergocristine, and ergonovine. These results indicate that clinical signs and lesions were caused by the ingestion of large quantities of these biologically active compounds.

Photosensitivity in South Africa. IX. Structure elucidation of a beta-glucosidase-treated saponin from Tribulus terrestris, and the identification of saponin chemotypes of South African T. terrestris

Saponin C, a beta-glucosidase-treated saponin isolated from ethanol-water extracts of a South African collection of Tribulus terrestris, was shown by one- and two-dimensional NMR spectroscopy to be ruscogenin 1-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-6)-acetylglucopyranoside++ +. GC-MS analysis of the hydrolysed ethanol-water (4:1) extracts of T.terrestris specimens from two of four sites, revealed high levels of ruscogenin and potentially lithogenic diosgenin saponins. Specimens from two other sites contained non-lithogenic saponins derived predominantly from tigogenin, neotigogenin, gitogenin and neo-gitogenin.

Recovery of hepatic function and latent mortalities in sheep exposed to the blue-green alga Microcystis aeruginosa

Seventeen sheep died, and many others showed signs of hepatogenous photosensitivity after being exposed to Microcystis aeruginosa at Lake Mokoan, Victoria, Australia. Two groups of sheep were observed, and their hepatic recovery was monitored by means of serum biochemical tests during the subsequent six months. During the first three weeks, their serum gamma-glutamyl transferase activity and bilirubin concentration declined rapidly to normal levels, and the signs of hepatogenous photosensitivity disappeared. Serum bile acid concentrations were above normal for almost three months. Thirty-four per cent of the sheep died during the observation period, and the serum biochemical tests provided no clear indication of the cause of these delayed mortalities. This study suggests that sublethal exposure to microcystins may cause prolonged morbidity and delayed mortality.

Liver disease in cattle induced by consumption of moldy hay

Normally innocuous forages are sporadically associated with hepatogenous photosensitization outbreaks at certain times of the year or when grown and harvested during unusual environmental conditions, such as periods of excessive rainfall. Allegations of livestock illness following consumption of such moldy hays are associated with clinical syndromes uncharacteristic of known forage-related diseases, suggesting that unidentified toxin(s) may be responsible. This study was instigated by field observations of hepatogenous photosensitization in cattle fed alfalfa-grass forage. To document the toxic nature of the hay, large bales of hay (450 kg) were fed, ad libitum, to 3 groups of 2 calves each. Elevated serum liver enzymes provided evidence of hepatobiliary disease. Gamma glutamyl transferase activities in serums of the calves sustained at least a 10-fold increase above baseline during the feeding trials. Histologic examination of liver biopsies and postmortem sections revealed mild periportal fibrosis and biliary hyperplasia. Culture material from 12 fungal isolates from the hay failed to induce liver disease in calves.

An overview of equine dermatoses characterized by scaling and crusting

Scaling and/or crusting are common clinical findings associated with equine skin diseases. Scaling and crusting may be associated with pruritic or nonpruritic dermatoses. This article focuses on those conditions that are usually nonpruritic in horses. They include the infectious dermatoses, the keratinization/seborrheic disorders, photosensitization, and the immunologic/inflammatory disorders, including pemphigus foliaceus, equine exfoliative eosinophilic dermatitis and stomatitis, and equine histiocytic dermatitis (sarcoidosis). Clinical signs that help differentiate the various disorders are given, and diagnostic and therapeutic options are discussed.

Narthecium ossifragum associated photosensitization in sheep in the Faroe Islands

Hepatogenous photosensitization in sheep is an important problem in various parts of the world. Most photosensitization diseases are associated with ingestion of plant or fungal toxins. The lily, Narthecium ossifragum, has long been associated with photosensitization in lambs in western Norway (Ender 1955, Flåøyen 1993) and in the northern regions of the British Isles (Ford 1964).

Photosensitivity in South Africa. VIII. Ovine metabolism of Tribulus terrestris saponins during experimentally induced geeldikkop

Geeldikkop was induced in a sheep by dosing it orally with a crude extract of the steroidal saponins from Tribulus terrestris. GC-MS analysis of the sheep's ruminal contents, bile, faeces and urine for free and conjugated sapogenins, revealed the general features of the metabolic pathway by which diosgenin and yamogenin glycosides were converted into the glucuronides of epismilagenin and episarsasapogenin, the major constituents of the biliary crystals that usually form during geeldikkop. Other steroidal saponins in the T. terrestris extract, including those derived from tigogenin, neotigogenin, gitogenin and neogitogenin appear to be non-lithogenic. The implications of these findings are discussed.

Photosensitivity in South Africa. VII. Chemical composition of biliary crystals from a sheep with experimentally induced geeldikkop

Geeldikkop was induced in a sheep by oral administration of crude saponins from Tribulus terrestris. Centrifugation of the bile from this sheep gave a pale green sediment of crystalloid material which was insoluble in common organic solvents, but soluble in acetic acid. Analysis of the crystalloid material by 1H and 13C NMR, EDXA, TLC, LSIMS, and by acidic hydrolysis followed by TLC and GC-MS, revealed it to be composed principally of a 6:1 mixture of the calcium salts of the beta-D-glucuronides of the steroidal sapogenins epismilagenin and episarsasapogenin. The administered saponin was found to contain glycosides of the steroidal sapogenins diosgenin, yamogenin, epismilagenin, tigogenin, neotigogenin, gitogenin and neogitogenin in the ratio 10:7:1:11:7:35:25. A metabolic pathway for the conversion of diosgenin and yamogenin saponins to the biliary glucuronides is proposed.

An outbreak of hepatogenous photosensitization in sheep grazing Tribulus terrestris in Argentina

An outbreak of hepatogenous photosensitization occurred in 40% of sheep grazing Tribulus terrestris in southern Buenos Aires province. Postmortem examinations revealed diffuse jaundice and ochre discoloration of the liver. Histopathological liver lesions consisted of fibroplasia, periductular lamellar fibrosis, hyperplasia of small bile ducts and diffuse swelling of hepatocytes. A crystalloid material was observed in some bile ducts. Aspartate aminotransferase and gamma glutamyltransferase serum activities were elevated in all tested animals while serum bilirubin content was elevated only in the most severely affected sheep. These findings are consistent with reports of geeldikkop, a photosensitivity of sheep which occurs in South Africa and Australia.

Llama dermatology

The purpose of this article is to add information to the many dermatologic topics initially discussed in the 1989 issue on llama medicine (normal anatomy; bacterial, fungal, ectoparasitic, immune-mediated, and zinc-responsive disease) and make mention of newly recognized diseases. Since 1989, it appears that one of the most common and perplexing groups of dermatoses seen at Colorado State University are hyperkeratotic/inflammatory dermatoses. These remain poorly understood. Idiopathic hyperkeratosis (zinc-responsive dermatosis) may be a true zinc deficiency or a keratinizing disorder responsive to supraphysiologic dosages of zinc supplementation. Idiopathic nasal/perioral hyperkeratotic/ inflammatory dermatosis (munge) and idiopathic necrolytic/neutrophilic/hyperkeratotic dermatosis bear clinical, histologic, and therapeutic similarities, and may be subsets of the same disease. Further studies (e.g., looking for metabolic derangements) are necessary to better answer these questions.

Photosensitization associated with exposure to Pithomyces chartarum in lambs

An epidemic of photosensitization was observed in a group of lambs on irrigated autumn pasture in western Oregon. Signs included crusting, necrosis, and sloughing of the skin over the nostrils, lips, and ears, and of the mucous membranes of the buccal regions. Microscopic examination of plant material from the pasture disclosed spores of Pithomyces chartarum. This fungus has been documented as a causal factor in photosensitization in sheep and cattle (facial eczema) in other parts of the world. An infective agent or other plant material that could have induced the clinical signs in the lambs was not evident. Weather and humidity conditions were ideal for fungal growth during the grazing period, and the fungus was detected in large numbers before and during the epidemic. Even though facial eczema has not been reported previously in northwestern United States, we feel the circumstances surrounding this epidemic warrant such a diagnosis.

Toxic hepatopathy and photosensitization in cattle fed moldy alfalfa hay

Cattle in 2 herds developed type-3 photosensitization after eating moldy alfalfa hay. Clinical signs included severe epidermal necrosis of unpigmented skin and marked decrease of milk production (herd 1). One herd had 18% mortality. Values for serum gamma-glutamyltransferase, lactate dehydrogenase, aspartate transaminase, and serum bilirubin were high in affected cows. Biliary epithelial degeneration and necrosis affecting the smaller bile ductules is the most consistent histologic lesion. Biliary hyperplasia, early portal fibroplasia, hepatocellular vacuolar degeneration and necrosis, and cholestasis were commonly seen. Mold growth on the alfalfa hay associated with prolonged wet weather prior to harvest was common to both herds. The cases reported here document hepatoxicosis and photosensitization associated with feeding moldy alfalfa hay grown in southeastern United States.

Parenchymal injury and biliary obstruction in relation to photosensitization in sporidesmin-intoxicated lambs

The hepatic changes were compared in lambs photosensitized or not photosensitized after exposure to sporidesmin. Injury to both the parenchyma and the biliary system was more severe in the photosensitized than in the non-photosensitized lambs. The activities of gamma-glutamyltransferase and glutamate dehydrogenase, and the total, conjugated and unconjugated bilirubin concentrations were significantly higher in sera from the photosensitized than from the non-photosensitized lambs. Hepatic glycogen levels were decreased in both the photosensitized and the non-photosensitized lambs, but were significantly lower in the former. Hence it is possible that lesions in hepatocytes contribute to retention of phylloerythrin and so to photosensitization.

Stratospheric ozone depletion and animal health

There is an increasing concern over ozone depletion and its effects on the environment and human health. However, the increase in ultraviolet-B radiation (UV-B) that would result from significant losses of ozone is also potentially harmful to animals. Any increase in disease in domestic species would not only have serious animal welfare implications but may also be economically important. The diseases which are likely to increase if ozone depletion continues include the squamous cell carcinomas of the exposed, non-pigmented areas of cats, cattle, sheep and horses. Uberreiter's syndrome in dogs is also associated with exposure to UV-B and may be expected to increase, as may the severity of conditions such as infectious keratoconjunctivitis (New Forest eye) in cattle. Aquaculture systems in which fish often have little or no protection by shading may also be at risk. Cataracts and skin lesions have been associated with the exposure of farmed fish to ultraviolet radiation and have resulted in significant losses.

Fungi on Narthecium ossifragum leaves and their possible involvement in alveld disease of Norwegian lambs

Spores of Pithomyces chartarum (Berk. & Curt.) M.B. Ellis were only rarely seen on leaves of Narthecium ossifragum (L.) Hudson collected in summer from five areas in western Norway in which alveld, a photosensitization disease of lambs, is endemic. Cladosporium magnusianum (Jaap) M.B. Ellis was found on all 118 leaf samples collected in the summers of 1990 and 1991. The hypothesis that P. chartarum contributes to the aetiology of alveld could not be supported, but it is possible that C. magnusianum may have a role in the causation of the disease.