Oats are oats are oats? not at all by Roger Nicoll
GroundCover™ Issue: 43
AS A quality feed grain suitable for increasing weight gain in cattle, it seems not all oats are equal.
Research conducted at Wagga Wagga Agricultural Institute, as part of the GRDC-supported Premium Grains for Livestock Program, shows great variations in the digestibility and suitability of common oat varieties as cost-effective feed grains.
"Some farmers are wasting large amounts of money feeding poor-quality grain that is unsuitable for increasing weight gain in cattle, " according to research leader and NSW Agriculture animal nutrition expert, Alan Kaiser.
This research revealed more than a 20 per cent variation in digestibility among eight oats tested in a cattle production trial, and is supported by results with a much larger number of samples in laboratory studies, Dr Kaiser reported.
"The research identified oat varieties that produce highly digestible grain — up to 81 per cent digestibility — and the varieties with poor digestibility — 60 per cent, " Dr Kaiser said. "A variation in digestibility up to 21 per cent can translate to at least a 30-60 per cent difference in animal productivity (weight gain). In fact, in our experiment the impact on weight gain was even greater, and ranged from 0. 41 to 1. 27 kg/day. "
Dr Kaiser said both the variety and environment (growing conditions) influence digestibility. The varietal effect is correlated with lignin (an indigestible carbohydrate) levels in the hulls of the grain — high lignin content results in low digestibility.
Dual-purpose oat varieties like Cooba have high digestibility and varieties grown strictly for milling score poorly, according to Dr Kaiser.
"Growers should be aware that commonly grown oat varieties, such as Echidna and Mortlock, have high hull lignin and low digestibility. "
Dr Kaiser and his team have used a rapid colour test to determine the lignin content of commonly grown oats. Seven of the current popular oat varieties have tested for low lignin, high digestibility content. He expects these to be the popular varieties to be sown for feed oats next year.
Dr Kaiser said the research should discourage farmers from tarring all oat varieties with the same brush and to be more selective in choosing oats for feed purposes.
"Some varieties are as good as, if not better than, other grains like barley and wheat for feeding to cattle and sheep, " he added.
"In the future oats breeders will be placing pressure on varieties for lignin content as part of their selection criteria. "
|Low lignin (1)||Medium lignin (2-3)||High lignin (4-5)|
Contact: Dr Alan Kaiser 02 6938 1852 Mr Rob Inglis 02 6938 1612