Treatment with potassium bromide mitigates ataxia and reduces tremor in lambs with perennial ryegrass toxicosis

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Abstract

AIMS: To assess the use of potassium bromide as a suitable therapeutic intervention for perennial ryegrass toxicosis (PRGT) by reducing the clinical effects of lolitrem B intoxication in sheep. METHODS: Neurological signs consistent with PRGT were induced in male lambs aged between 10–12 months by ingestion of a known dose of lolitrem B toxin in feed (0.16 mg/kg/day). Lambs were treated with the anti-epileptic drug bromide either daily from onset of trial (a loading dose of 540 mg/kg over three days then 20 mg/kg daily PO) or with bromide at a single dose of 300 mg/kg PO at a time-point based on clinical criteria. Ataxia, tremor and other physiological parameters including faecal cortisol metabolites, were monitored over time to evaluate efficacy of the treatment as compared to control groups. Serum and CSF bromide levels were assayed to assess therapeutic exposure in CNS and somatic tissues. RESULTS: Measurement of muscular tremor activity by average Root-Mean-Square (RMS) voltage from triceps electromyography (EMG) were decreased in bromide treated group (group 3) (0.0342 mV) compared to intoxicated animals not receiving bromide (group 2) (0.0608 mV, p=0.045). Degree of ataxia determined by mean composite gait score was also reduced in group 3 lambs (8.78) compared to group 2 lambs (21.71, p<0.001). General neurological signs improved to the extent that only two of nine lambs treated with bromide continued to drop into sternal or lateral recumbency on gait analysis despite while lambs in Group 2 lambs showed further deterioration of clinical signs. CONCLUSIONS: This trial suggests bromide can mitigate the neurological signs associated with PRGT in sheep. CLINICAL RELEVANCE: Alleviation of the neurological signs associated with ingestion of the neurotoxin lolitrem B during outbreaks of PRGT in livestock is of key importance to improving clinical outcomes, reducing mortality and improving productivity in both New Zealand and Australian production systems, and worldwide.
Original languageEnglish
JournalNew Zealand Veterinary Journal
DOIs
Publication statusE-pub ahead of print - 28 Jun 2019

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Anthoxanthum
potassium bromide
Lolium
Tremor
Ataxia
bromides
Bromides
Lolium perenne
poisoning
lambs
gait
Gait
Sheep
dosage
Eating
ingestion
anticonvulsants
sheep
therapeutics
electromyography

Grant Number

  • MLA B.AHE.0233

Cite this

@article{71bc72717ec942c29ec3e71a6d559120,
title = "Treatment with potassium bromide mitigates ataxia and reduces tremor in lambs with perennial ryegrass toxicosis",
abstract = "AIMS: To assess the use of potassium bromide as a suitable therapeutic intervention for perennial ryegrass toxicosis (PRGT) by reducing the clinical effects of lolitrem B intoxication in sheep. METHODS: Neurological signs consistent with PRGT were induced in male lambs aged between 10–12 months by ingestion of a known dose of lolitrem B toxin in feed (0.16 mg/kg/day). Lambs were treated with the anti-epileptic drug bromide either daily from onset of trial (a loading dose of 540 mg/kg over three days then 20 mg/kg daily PO) or with bromide at a single dose of 300 mg/kg PO at a time-point based on clinical criteria. Ataxia, tremor and other physiological parameters including faecal cortisol metabolites, were monitored over time to evaluate efficacy of the treatment as compared to control groups. Serum and CSF bromide levels were assayed to assess therapeutic exposure in CNS and somatic tissues. RESULTS: Measurement of muscular tremor activity by average Root-Mean-Square (RMS) voltage from triceps electromyography (EMG) were decreased in bromide treated group (group 3) (0.0342 mV) compared to intoxicated animals not receiving bromide (group 2) (0.0608 mV, p=0.045). Degree of ataxia determined by mean composite gait score was also reduced in group 3 lambs (8.78) compared to group 2 lambs (21.71, p<0.001). General neurological signs improved to the extent that only two of nine lambs treated with bromide continued to drop into sternal or lateral recumbency on gait analysis despite while lambs in Group 2 lambs showed further deterioration of clinical signs. CONCLUSIONS: This trial suggests bromide can mitigate the neurological signs associated with PRGT in sheep. CLINICAL RELEVANCE: Alleviation of the neurological signs associated with ingestion of the neurotoxin lolitrem B during outbreaks of PRGT in livestock is of key importance to improving clinical outcomes, reducing mortality and improving productivity in both New Zealand and Australian production systems, and worldwide.",
keywords = "Perennial ryegrass toxicosis, bromide, ataxia, sheep",
author = "Martin Combs and Scott Edwards and Josh Scherpenhuizen and Edward Narayan and Allan Kessell and Julie Ramsay and Shane Raidal and Jane Quinn",
year = "2019",
month = "6",
day = "28",
doi = "10.1080/00480169.2019.1637300",
language = "English",
journal = "New Zealand Veterinary Journal",
issn = "0048-0169",
publisher = "New Zealand Veterinary Association",

}

TY - JOUR

T1 - Treatment with potassium bromide mitigates ataxia and reduces tremor in lambs with perennial ryegrass toxicosis

AU - Combs, Martin

AU - Edwards, Scott

AU - Scherpenhuizen, Josh

AU - Narayan, Edward

AU - Kessell, Allan

AU - Ramsay, Julie

AU - Raidal, Shane

AU - Quinn, Jane

PY - 2019/6/28

Y1 - 2019/6/28

N2 - AIMS: To assess the use of potassium bromide as a suitable therapeutic intervention for perennial ryegrass toxicosis (PRGT) by reducing the clinical effects of lolitrem B intoxication in sheep. METHODS: Neurological signs consistent with PRGT were induced in male lambs aged between 10–12 months by ingestion of a known dose of lolitrem B toxin in feed (0.16 mg/kg/day). Lambs were treated with the anti-epileptic drug bromide either daily from onset of trial (a loading dose of 540 mg/kg over three days then 20 mg/kg daily PO) or with bromide at a single dose of 300 mg/kg PO at a time-point based on clinical criteria. Ataxia, tremor and other physiological parameters including faecal cortisol metabolites, were monitored over time to evaluate efficacy of the treatment as compared to control groups. Serum and CSF bromide levels were assayed to assess therapeutic exposure in CNS and somatic tissues. RESULTS: Measurement of muscular tremor activity by average Root-Mean-Square (RMS) voltage from triceps electromyography (EMG) were decreased in bromide treated group (group 3) (0.0342 mV) compared to intoxicated animals not receiving bromide (group 2) (0.0608 mV, p=0.045). Degree of ataxia determined by mean composite gait score was also reduced in group 3 lambs (8.78) compared to group 2 lambs (21.71, p<0.001). General neurological signs improved to the extent that only two of nine lambs treated with bromide continued to drop into sternal or lateral recumbency on gait analysis despite while lambs in Group 2 lambs showed further deterioration of clinical signs. CONCLUSIONS: This trial suggests bromide can mitigate the neurological signs associated with PRGT in sheep. CLINICAL RELEVANCE: Alleviation of the neurological signs associated with ingestion of the neurotoxin lolitrem B during outbreaks of PRGT in livestock is of key importance to improving clinical outcomes, reducing mortality and improving productivity in both New Zealand and Australian production systems, and worldwide.

AB - AIMS: To assess the use of potassium bromide as a suitable therapeutic intervention for perennial ryegrass toxicosis (PRGT) by reducing the clinical effects of lolitrem B intoxication in sheep. METHODS: Neurological signs consistent with PRGT were induced in male lambs aged between 10–12 months by ingestion of a known dose of lolitrem B toxin in feed (0.16 mg/kg/day). Lambs were treated with the anti-epileptic drug bromide either daily from onset of trial (a loading dose of 540 mg/kg over three days then 20 mg/kg daily PO) or with bromide at a single dose of 300 mg/kg PO at a time-point based on clinical criteria. Ataxia, tremor and other physiological parameters including faecal cortisol metabolites, were monitored over time to evaluate efficacy of the treatment as compared to control groups. Serum and CSF bromide levels were assayed to assess therapeutic exposure in CNS and somatic tissues. RESULTS: Measurement of muscular tremor activity by average Root-Mean-Square (RMS) voltage from triceps electromyography (EMG) were decreased in bromide treated group (group 3) (0.0342 mV) compared to intoxicated animals not receiving bromide (group 2) (0.0608 mV, p=0.045). Degree of ataxia determined by mean composite gait score was also reduced in group 3 lambs (8.78) compared to group 2 lambs (21.71, p<0.001). General neurological signs improved to the extent that only two of nine lambs treated with bromide continued to drop into sternal or lateral recumbency on gait analysis despite while lambs in Group 2 lambs showed further deterioration of clinical signs. CONCLUSIONS: This trial suggests bromide can mitigate the neurological signs associated with PRGT in sheep. CLINICAL RELEVANCE: Alleviation of the neurological signs associated with ingestion of the neurotoxin lolitrem B during outbreaks of PRGT in livestock is of key importance to improving clinical outcomes, reducing mortality and improving productivity in both New Zealand and Australian production systems, and worldwide.

KW - Perennial ryegrass toxicosis

KW - bromide

KW - ataxia

KW - sheep

U2 - 10.1080/00480169.2019.1637300

DO - 10.1080/00480169.2019.1637300

M3 - Article

C2 - 31248334

JO - New Zealand Veterinary Journal

JF - New Zealand Veterinary Journal

SN - 0048-0169

ER -