Cattle in northern Australia are failing to gain weight and the mystery might be solved by a tiny bacteria.
A beneficial bacteria is already used to inoculate the rumen of the cow, which gives them protection from toxicity when they eat the legume tree leucaena.
Researchers have found the current batch of bacteria is not as effective as it was, and they're seeking a better strain.
PhD student Michael Halliday, working with Associate Professor Max Shelton from the University of Queensland, says it's funded by the Australian Centre for International Agricultural Research.
He says the collaborators in Indonesia have helped identify cattle with the bacteria and those that aren't protected. They've begun transferring rumen fluid from the protected to the unprotected cow, with good results.
Leucaena is grown over 200,000 hectares for northern Australian cattle grazing, and was introduced in the 1960s. In the 1980s a bacteria inoculation helped cows digest the fodder easier.
"Since the break of the drought in 2004, many Queensland herds were found to be suffering sub-clinical toxicity as graziers reported reduced levels of performance on what is otherwise a productive leucaena pasture."
It prevents weight gain and affects the cow's ability to reproductive.
Mr Halliday says the bacteria may have mutated and "many graziers are re-inoculating on a yearly basis".
He says they are trying to find an improved strain of the bacteria, to multiply it in-vitro fermentation, for use as a new inoculation.