Neurological diseases of ruminant livestock in Australia. This was based on a number of reasons outlined in the paper such as the rate of action of the toxic antagonistic agent was too rapid for the dose administered of the prophylactic agent (Bourke et al 2003). The animals suffer from respiratory distress, their mucous membranes becoming cyanotic. Tolerates waterlogging and moderate salinity 7. This grass can be found as the main vegetation source in some regions so if you are a horse owner with an equine out on pasture, you must be cautious. Early detection of toxic fields enables farmers to mow the heads off grass or to allow grazing before the grass becomes too toxic. Continuously grazing or set-stocking pastures to keep new growth at a minimum especially during the autumn and winter months may assist. Deep root system helps dry soil profile and reduces rate of soil acidification No disturbance is needed to precipitate the clinical signs. Kangaroos that eat the grass can develop a condition known as the "phalaris staggers", which causes head tremors, a loss of co-ordination and collapse. They display incoordination and proprioceptive deficits with frequent falling over. However in certain circumstances, it does have the potential to become a toxic pasture plant, producing a variety of unrelated syndromes which manifest either as neurological or cardiac disturbances, presumably involving different toxins. Habitat Top of page. A perennial grass found mainly in lowland pasture on fertile soils. Cardiac disturbances include ventricular fibrillation and cardiac arrest, followed by syncope. Phalaris aquatica with its numerous cultivars is a much-valued perennial grass species widely used in improved pastures across south-eastern Australia. The perennial grass Phalaris is a valuable pasture species which features predominantly in Australian and North American grazing systems. Phalaris canariensis is commonly used for bird seed. The new cultivars such as Sirolan and Sirosa are lower alkaloid strains than older varieties such as Holdfast. “Sheep that start staggering may improve, but may be left with staggers for life,” she said. Phalaris staggers is an incoordination syndrome that is associated with the ingestion of phalaris (Phalaris aquatica) which contains dimethyltryptamine alkaloids (Finnie et al 2011). It is advised that two bullets are given to prevent a calcium carbonate coating building up around the bullet, which would decrease effective absorption of Co. Intraruminal grinders are also available for this purpose. Phalaris Toxicoses in Australian Livestock Production Systems: Prevalence, Aetiology and Toxicology. Phalaris toxicity can cause both a sudden death syndrome and a staggers syndrome. Few pests and diseases 8. Phalaris toxicity, or Phalaris staggers can affect sheep that are grazing on fresh breaks of phalaris. “If phalaris toxicity is suspected stock should be removed immediately, but slowly, from pasture.” To avoid phalaris toxicity it is best to avoid grazing phalaris during the first six weeks of new growth or to limit the intake of phalaris during the first two days of grazing to just a few hours per day. Some Phalaris species contain gramine, which, in sheep and to a lesser extent in cattle, is toxic and can cause brain damage, other organ damage, central nervous system damage, and death. Excellent drought survival ability. Responsive to increased soil fertility 4. It has also been noted that the incidence of this form of phalaris sudden death may be associated with seasonal increases of N-methyltryamine in P.aquatica (Bourke et al 2003). There is no treatment or consistent method of preventing outbreaks of ‘PE-like’ sudden death. Nitrate compounds have also been postulated as the causative agent as it has been documented that phalaris pastures can attain nitrate nitrogen concentrations >2920μg/g, with the potentially toxic concentration for sheep only 1000μg/g (Bourke & Carrigan 1988). With phalaris toxicity, effects to the spinal cord and brain lead to signs of central nervous system depression. With a flush of new growth across many grazing regions following recent rainfall after a prolonged dry period, there is currently an increased risk of livestock suffering from phalaris toxicity as a result of consuming young phalaris grass. Consideration of these risk factors suggests that producers should aim to avoid putting hungry stock on freshly-shooting phalaris dominant pastures, especially following periods of frosts or moisture stress. 4. “If phalaris toxicity is suspected stock should be removed immediately, but slowly, from pasture.”. “Cobalt supplementation may help prevent phalaris staggers, but not the sudden death syndrome.”. The compound accumulates in the CNS to directly interact with serotonergenic receptors in the motor and sensory nerve nuclei of the brain and spinal cord. 1. If no clinical cases have been seen within this time, the pasture is generally considered safe, and it is assumed that the animals can adequately adapt to the toxic challenge. Australian Veterinary Journal 67: 255-258, Finnie JW, Windsor PA, Kessell AE, 2011. Death or recovery can occur over the ensuing weeks or months, depending on the chronicity of ingestion and the severity of clinical signs. Elevated levels of ammonia levels in aqueous humor of these cases is similar to that seen in plasma in Citrullinaemia, suggesting compromise of the urea cycle in PE-like phalaris sudden death. Tolerates heavy grazing once established (particularly semi-winter dormant cultivars). Therefore it is advised that the phalaris pastures are continuously grazed or set-stocked to keep the new growth during autumn/winter to a minimum, and that hungry sheep should not be placed on previously spelled phalaris dominant pastures, especially not following periods of moisture stress or heavy frosts. 6. Knee-walking is frequently seen and the animals may ‘bunny hop’. “Signs include breathing difficulties and blue-coloured gums and the animal will usually die,” she said. It is very important you know what plants your horse has access to. 'Phalaris staggers' is an incoordination syndrome that is associated with the ingestion of phalaris at a time when it contains toxic alkaloids. The study in question failed to demonstrate any protective effect of these substances, however did not completely dismiss the possibility of their use for prophylaxis. However in areas prone to Phalaris poisoning, plants should be grazed cautiously in the autumn and early winter. It has been proven that the level of noxious alkaloids responsible for the chronic staggers syndrome are increased during certain periods, this being influenced by interacting plant, animal and environmental factors. Basaltic soils are high in cobalt and hence staggers is not common in areas where these soils dominate. 8. Burning annual ryegrass pastures in the fall destroys most of the galls colonized by bacteria and minimizes the risk of toxicity in the following season. Journal of Toxins 1:1. It prefers fertile, seasonally moist sites (Muyt 2001). The risk of stock developing phalaris staggers is a function of soil cobalt levels, levels of soil ingestion and levels of phalaris dominance and palatability. Australian Veterinary Journal 81:698-700, Healy PJ, Harper PAW & Dennis JA (1990) Bovine citrullinaemia: a clinical, pathological, biochemical and genetic study. Increased alkaloid content in the foliage of P.aquatica has been measured during periods of moisture stress, frost conditions and decreased light intensity, such as overcast weather or shading. ‘PE-like sudden death’ involves an acute onset of neurological signs and death that differ greatly from those of phalaris staggers. Some Phalaris species contain gramine, which can cause brain damage, other organ damage, central nervous system damage and death in sheep although Phalaris aquatica is said to be non-toxic. Annual Phalaris species usually grow in areas with a rainy, wet winter (subhumid) and in alluvial, sandy-clay or clay texture soils (Jauzien and Montegut, 1982).They are particularly well adapted to winter crops, and are difficult to control in cereal crops. Cardiorespiratory signs can be seen with the nervous forms of intoxication, probably due to the increased effort and strain on the cardiovascular system due to the nervous incoordination, rather than any direct effect of the toxin on myocardial function The affected animals remain conscious throughout, however if recumbent for a prolonged period, may become comatose and develop cerebral convulsions. New shoots are also more concentrated sources of the toxic alkaloid, with poisonous potential of the pasture rapidly declining after it has reached a certain height. However in certain circumstances, it does have the potential to become a toxic pasture plant, producing a variety of unrelated syndromes which manifest either as neurological or cardiac disturbances, presumably involving different toxins. Fresh regrowth can at times be dangerous to live stock due to the presence of toxic alkaloids. 1. Dr Gibney said sudden death syndrome usually develops 12 to 36 hours after the animal has been on pasture. A pyridoxine antagonist has also been suspected. Grass palm isn't toxic to humans but can be harmful when ingested by cats or dogs. The poisonous potential of Phalaris aquatica is dynamic and is a function of interacting plant, animal, environmental and management factors. In its early stages of growth (usually the first six weeks) phalaris grass contains toxic alkaloids, which if grazed, can lead to animals developing phalaris staggers. The greatest mortalities occur within 48 hours following the introduction to the pasture, with the highest incidence of disease seen during autumn through to late winter. Investigations into prevention have included prophylactic administration of thiamine and pyridoxine. Reed canarygrass (Phalaris arundinacea L.), a related plant and a widespread native grass found growing throughout most of the United States, is managed as forage for livestock and alleged to have alkaloid toxicity concerns. These lesions can usually only be detected in cases greater than several weeks duration (Bourke et al 1988). The noxious pasture is only poisonous for several weeks during this season though. Reed canarygrass (Phalaris arundinacea) is a stout, erect, perennial grass that is a major weed in winter crops and pastures worldwide. However more recently a mechanism involving hyperammonaemia due to the causative toxin interfering with the urea cycle has been proposed. Seasonal and weather patterns appear to affect alkaloid concentration, as most toxicity occurs in autumn and in times of drought. Habitat: Widely used as a pasture species where annual rainfall exceeds 450 mm (Muyt 2001). Again there is no treatment and stock should be removed immediately from the paddock with as little stress as possible to avoid eliciting further mortalities. Australian Veterinary Journal 69:165-167, Bourke CA, Carrigan MJ, & Dixon RJ (1998) Experimental evidence that tryptamine alkaloids do not cause Phalaris aquatica sudden death syndrome. Additional information is available in more recent reviews (Finnie et al 2011; Alden et al 2014), Blood DC, Gay CC, Hinchcliff KW & Radostits OM Veterinary Medicine: A Textbook of ththe Diseases of Cattle, Sheep, Pigs, Goats and Horses, 9 Ed, W. B. Saunders, London 2000 ‘Diseases caused by major phytoxins’ pg 1652-1653, Bourke CA & Carrigan MJ (1992) Mechanisms underlying Phalaris aquatica ‘sudden death’ syndrome in sheep. Agriculture Victoria District Veterinary Officer Rachel Gibney said phalaris staggers can develop between 10 days and four months after grazing pasture and animals can even show signs months after being removed from phalaris. Physical signs that an animal has phalaris staggers include staggering or stumbling, a bunny hop gait, head nodding, trouble standing or trouble eating and weight loss. Intraruminal cobalt bullets are also an effective measure to protect against Phalaris staggers, and allow potentially toxic pastures to be utilised and grazed. This neurological syndrome results from the repeated or protracted ingestion of methylated tryptamine alkaloids present in P.aquatica. But some farmers have moved away from the species because it causes phalaris toxicity, or staggers, a condition that can cause abrupt heart failure or a … Suggestions include agents known to produce thiamine-deficient PE in sheep such as thiamine antagonists (thiaminases) or amine co-substrates. Regrowth after grazing or mowing also shows a considerable increase in alkaloids. Phalaris staggers is sometimes a problem, particularly when rapid regrowth occurs after a cold or dry spell, but can be avoided by not grazing affected stands at that time or by dosing stock with cobalt. If the stock have been transported or yarded for a period of time without access to food, they should be fed before being placed on the pasture. Australian Veterinary Journal 89: 247-253, Alden R, Hackney B,  Weston LA, Quinn JC, 2014. Toxic levels of cyanide (20mg or greater/100g of hydrocyanic acid) have been measured in phalaris plants from toxic pastures (Bourke & Carrigan 1992), thus a cyanogenic poison has been investigated. As mentioned, no nervous signs are seen with this form of phalaris poisoning, nor are there any obvious gross or histopathological lesions. ‘PE-like’ sudden death outbreaks occur more commonly when hungry stock are put on phalaris dominant pastures that have been spelled or involved in rotational grazing where an abundance of new shoots has been available. 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