AUSTRALIA - A condition costing Tasmanian farmers over A$10 million each year could be linked to the island’s most widely used pasture grass.
Ill-thrift robs the state’s farmers of 3,300 tonnes of beef production every year, Meat and Livestock Australia study has calculated, dubbing it a ‘silent thief’.
Causing cattle to underperform despite having enough good feed, ill-thrift is widespread across temperate regions of the world, according to a consultant with Australian company Macquarie Franklin.
Researcher Basil Doonan has honed down the factors to three linked causes – mycotoxins, parasites and pasture quality.
Regarding mycotoxins, he explained that toxins produced by fungi in ryegrass could be behind the large cost to farmers.
Ryegrass is the most dominant pasture species used in Tasmania for finishing, and hosts a number of fungi and mycotoxins, he added.
“Mycotoxins can occur in both pasture and fodder crops and are secondary chemicals produced by a wide range of fungi that have toxic effects on animals, for example ryegrass staggers,” said Mr Doonan.
“Ryegrass staggers, photosensitisation and ill-thrift are all related to elevated levels of mycotoxins on pasture, particularly older, under-utilised pastures with more fallen dry feed.”
However, managing the condition has no easy answer, with Mr Doonan insisting more research is required before ‘practical solutions to ill-thrift could be recommended’.
A broad brush approach is through improved grazing management and changing feed, he suggested.
This would entail considering ryegrass quality in the autumn and winter months, a known time for ill-thrift to flare up.
Combatting its two main causes – parasites and pasture quality – are worthwhile, according to Beef and Lamb New Zealand advisers.
They recommend worm control and pasture renovation before tackling ‘more complex fungi issues’.
Furthermore, due to the different factors causing ill-thrift, testing is advised.
This could be faecal eggs counts for parasites, urine tests for endophyte toxins, pasture/faecal spore counts for facial eczema and liver assessments for trace elements.
Pneumonia and fusaria fungi are also linked to the disease.
Summarising a New Zealand study, Beef and Lamb New Zealand said: “The most common reason for stock growing slower than farmers expected over summer and autumn was poor pasture quality.
“However, when pasture quality was taken into consideration the next biggest cause of ill-thrift was parasitism.”
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