**Session III -- Industry/Consumer Perspective and Non-food/Feed
Products -- Poster III-3**

**Characterisation of Grazing Oat Cultivars for Forage Quality**

Bruce Winter\*, Glen Fox and Richard Uebergang

Leslie Research Centre, PO Box 2282, Toowoomba, Queensland, 4350,
Australia

\*Corresponding author: bruce.winter@dpi.qld.gov.au

# Abstract

Forage varieties of cultivated oat (*Avena sativa* L.) are widely grown
in sub-tropical areas of eastern Australia during the autumn and winter
months, providing high quality forage for grazing animals. The
Department of Primary Industries and Fisheries in Queensland operates a
breeding program to develop high-yielding, crown rust-resistant
commercial cultivars of forage oat for farmers in Australia. However,
little information is available on forage quality attributes of these
cultivars. The effect of long term selection for high forage yield on
forage quality is unknown. The relative forage quality of the
fine-leaved prostrate plant type and the broad-leafed erect plant type
has not been quantified.

In conjunction with multi-cut replicated plot trials for the breeding
program, samples of cut forage were taken from a set of 12 advanced
selections and commercial cultivars for three selected cuts at three
locations over three years. Samples were dried at 60^o^C for four days,
ground and analysed using an NIR spectrophotometer at Leslie Research
Centre. A representative set of these samples was sent to SGS Agritech
Pty Ltd, Toowoomba, for wet chemistry analysis to determine protein,
digestible protein, acid detergent fibre, neutral detergent fibre,
digestible dry matter and soluble carbohydrate content. Using the wet
chemistry data, predictive data were generated for all samples from the
NIR analysis. For a preliminary data analysis, a subset of data was
selected using six varieties over two years, two sites and two cuts.

There were no significant differences between any of the genotypes for
any of the traits measured. However, site, year and time of cutting
effects were significant for most of the traits measured. Differences
for site, year and cutting time were so large in most instances, that
any small differences between genotypes were not statistically
significant. Samples from low yielding sites had a higher level of
soluble carbohydrate content than samples from high yielding sites.
Protein content was also much higher at the low yielding sites than at
high yielding sites and the protein content of the early cut was higher
than the late cut. There were no differences for protein content among
genotypes. Acid detergent fibre levels were higher in the late cut
compared with the early cut, and no difference between varieties, or
between sites were apparent. Similarly, neutral detergent fibre content
was higher in the late cut compared with the early cut, and there were
no differences between varieties or sites.

It appears that site, year and time of cutting have a much greater
effect on the measured forage quality traits than genotype selection.
While genetic effects may exist for these traits within the range of
genotypes tested, they are likely to be small and difficult to measure
in these trials. Selection for forage quality traits per se within this
breeding program is unlikely to be successful. It appears that selection
for high yield does not significantly affect forage quality within the
range of parameters in these trials, since higher yielding lines had
similar forage quality to lower yielding lines. It also appears there is
no significant forage quality advantage in varieties with a fine-leafed
prostrate plant type. Variety selection within the grazing oat cultivars
tested by this study is unlikely to produce a significant difference in
live weight gain in cattle.