Seasonal Pasture Quality Under Scrutiny

AUSTRALIA - Cattle on Queensland's Central Coast are making maximum use of the current high quality, highly digestible pasture thanks to optimum dry matter content, crude protein and energy levels following the prolonged extreme summer wet season.

3 June 2011

2 minute read

Oceania

Department of Employment, Economic Development and Innovation (DEEDI) industry development officer Jim Fletcher, Mackay, who has set up a series of coastal monitoring sites to measure pasture nutrition levels throughout the year, said with the onset of cooler weather, a downturn in pasture quality can be expected.

Mr Fletcher said the pasture monitoring initiative funded through Reef Catchments is a part of the Mackay Sustainable Grazing Project plan to collect Near-Infrared Spectroscopy (NIRS) faecal samples on a regular basis.

"By collating NIRS data on pasture digestibility, dry matter, crude protein, energy and phosphorus content, we will be able to develop a better picture of the seasonal fluctuations of pasture quality throughout the year," Mr Fletcher said.

"The project objective is to be able to provide coastal cattle producers with timely advice to undertake cost-effective seasonal supplementation programmes.

"We have established improved pasture monitoring sites at Proserpine, Habana, Sarina and Pleystowe where the principal grass species are pangola, signal, Tully humidicola, Callide Rhodes and Kazungula setaria.

"By collecting random faecal samples from the cattle grazing these sites, NIRS technology can provide information for proper assessment of metabolisable energy, digestibility and protein levels giving an accurate overall picture of the productive ability of the pasture," Mr Fletcher said.

Sample test results from May showed digestibility was around 55-60 per cent, which is considered mid to high range for central coast pasture. This equates to an estimated 2.1 to 2.3 per cent dry matter intake as a percentage of animal liveweight.

"With dry matter levels currently around 40-45 per cent, 4.5 kg drymatter intake of pasture is probable whereas during the extreme wet weather early this year, high moisture content prevented cattle from achieving the desired dry matter intake.

Mr Fletcher said crude protein levels at the monitoring sites ranged from nine -13 per cent, which is well above the animal's maintenance level of around six per cent.

"Provided pastures are appropriately stocked to allow selection of leaf material and not stem, the district's pastures could be expected to be producing daily liveweight gains of up to 0.5 kg/head/day during May. Where intake is less than 4.5 kg as in an overgrazed situation, growth would possibly be just above or near maintenance," Mr Fletcher said.

"Our regional pastures are now moving into a critical time of the year where the plant nutrients are migrating from the leaves into the seed and root systems to remain dormant during the colder months," Mr Fletcher concluded.

Mr Fletcher said the next set of data may show a downturn in grass quality.