If you’re going to graze the crop it is better to act sooner than later say scientists

NSW DPI researcher, John Piltz, said producers know that by making early decisions to graze or conserve crops, they can maximise the nutritional value of cereal crops that may not be harvestable for animal production.

“It’s worth remembering that dietary metabolisable energy (ME) is the key to animal production gains, but ME declines in the post-vegative growth stage,” Mr Piltz said.

“We advise producers to accurately evaluate all their on-farm and sale options for potential grain production, grazing, hay and silage or agistment opportunities.

“If crop yield is low, less than two tonnes of dry matter per hectare, hay and silage making losses will be high and grazing would be recommended.

“If you’re going to graze the crop it is better to act sooner than later, delaying cutting from early October to early November on the chance of rain would reduce ME levels with a negative impact on feed quality and potential animal production.”

To better inform management decisions Mr Piltz and NSW DPI analytical chemist, Richard Meyer, have predicted steer live weight change using Grazfeed and compared with data from wheat and canola samples tested by NSW DPI’s Feed Quality Service (FQS).

Samples from 2008-09 and 2017-18 had an average ME of 9.0 megajoules (MJ) per kilogram of dry matter, which would deliver a predicted daily live weight gain of 0.37 kilograms per day for a nine-month old, 280 kg British breed steer.

The more ME animals eat, the quicker they grow, as long as crude protein, vitamins and minerals are kept in balance. Increasing ME from 8.5 to 10.5 MJ for the same steer is predicted to increase live weight gain from 0.15 to 0.92 kg per day.

In the post-vegative stage crop ME declines an average 0.05 MJ per day as plants mature.

Results of the study are available through the Graham Centre for Agricultural Innovation, an alliance between NSW DPI and Charles Sturt University.