Signal Grass (Brachiaria decumbens) Toxicity in Grazing Ruminants
Signal grass (Brachiaria decumbens) is a highly productive tropical grass that is widespread through South America, Australia, Indonesia, Vanuatu and Malaysia due to its adaptation to a wide range of soil types and environments. Animal production from these B. decumbens pastures is highly variable...
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doaj-98c5c930fbce4f5d921cbbcc779c626b2021-04-02T02:10:58ZengMDPI AGAgriculture2077-04722015-09-015497199010.3390/agriculture5040971agriculture5040971Signal Grass (Brachiaria decumbens) Toxicity in Grazing RuminantsSusan G. Low0Department of Environment and Agriculture, Bentley Campus, Curtin University, Bentley WA 6102, AustraliaSignal grass (Brachiaria decumbens) is a highly productive tropical grass that is widespread through South America, Australia, Indonesia, Vanuatu and Malaysia due to its adaptation to a wide range of soil types and environments. Animal production from these B. decumbens pastures is highly variable due to sporadic outbreaks of photosensitisation associated with low growth rates of young animals, anorexia and wasting. The identification of B. decumbens toxicity through clinical signs may grossly underestimate the impact and severity of the disease. Affected animals without clinical signs have elevated serum liver enzyme concentrations resulting from blockage of the bile ducts by birefringent crystals, identified as calcium salts of steroidal saponins found in leaves and stems. The concentrations of the steroidal saponins vary through the year and within the plant. Young, green leaves contain 5–10 times the saponin concentration of mature leaves indicating that B. decumbens pastures are likely to be more toxic during sprouting and early growth. Previous exposure, selective grazing, and avoiding toxic leaves may partly explain apparent resistance of some animals to B. decumbens toxicity. Further research is needed to define growing conditions that produce elevated saponin levels and to investigate the impact of B. decumbens on rumen function.http://www.mdpi.com/2077-0472/5/4/971Brachiaria decumbenssignal grasstoxicityphotosensitisationsteroidal saponinsruminants |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Susan G. Low |
spellingShingle |
Susan G. Low Signal Grass (Brachiaria decumbens) Toxicity in Grazing Ruminants Agriculture Brachiaria decumbens signal grass toxicity photosensitisation steroidal saponins ruminants |
author_facet |
Susan G. Low |
author_sort |
Susan G. Low |
title |
Signal Grass (Brachiaria decumbens) Toxicity in Grazing Ruminants |
title_short |
Signal Grass (Brachiaria decumbens) Toxicity in Grazing Ruminants |
title_full |
Signal Grass (Brachiaria decumbens) Toxicity in Grazing Ruminants |
title_fullStr |
Signal Grass (Brachiaria decumbens) Toxicity in Grazing Ruminants |
title_full_unstemmed |
Signal Grass (Brachiaria decumbens) Toxicity in Grazing Ruminants |
title_sort |
signal grass (brachiaria decumbens) toxicity in grazing ruminants |
publisher |
MDPI AG |
series |
Agriculture |
issn |
2077-0472 |
publishDate |
2015-09-01 |
description |
Signal grass (Brachiaria decumbens) is a highly productive tropical grass that is widespread through South America, Australia, Indonesia, Vanuatu and Malaysia due to its adaptation to a wide range of soil types and environments. Animal production from these B. decumbens pastures is highly variable due to sporadic outbreaks of photosensitisation associated with low growth rates of young animals, anorexia and wasting. The identification of B. decumbens toxicity through clinical signs may grossly underestimate the impact and severity of the disease. Affected animals without clinical signs have elevated serum liver enzyme concentrations resulting from blockage of the bile ducts by birefringent crystals, identified as calcium salts of steroidal saponins found in leaves and stems. The concentrations of the steroidal saponins vary through the year and within the plant. Young, green leaves contain 5–10 times the saponin concentration of mature leaves indicating that B. decumbens pastures are likely to be more toxic during sprouting and early growth. Previous exposure, selective grazing, and avoiding toxic leaves may partly explain apparent resistance of some animals to B. decumbens toxicity. Further research is needed to define growing conditions that produce elevated saponin levels and to investigate the impact of B. decumbens on rumen function. |
topic |
Brachiaria decumbens signal grass toxicity photosensitisation steroidal saponins ruminants |
url |
http://www.mdpi.com/2077-0472/5/4/971 |
work_keys_str_mv |
AT susanglow signalgrassbrachiariadecumbenstoxicityingrazingruminants |
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