With barley prices currently lower than wheat, many dairy farmers will be considering barley as a feed source for the herd.
Like all feeds, barley and wheat have different feed test values, test weights and screening percentages.
These differences need to be considered as they can impact on the practicalities of feeding and the true cost.
When buying grains, as with all other feeds, ensure you feed test. Within any feed type there is significant variability in quality.
All grain should be weighed and tested before it is delivered and have the appropriate grade assigned so you know what you are getting.
Grain Trading Australia standards provide a minimum standard for each grade at: www.graintrade.org.au
Each grade has a minimum criterion that needs to be met for metabolisable energy, protein, screenings, test weights, etc. These are minimum standards, so quality will vary and can impact the ration.
Feed tests from the 2018-19 season showed the average test results for barley to be slightly lower than wheat in protein and energy, with an average of 12.2 per cent crude protein (CP) verse 13.8 per cent CP in wheat and 13.3 megajoules of metabolisable energy (MJ ME) compared to 13.9 MJ ME respectively.
However, there is more variation within each type of grain than between the averages.
Screenings are small, cracked/broken grains, chaff or other impurities. The screenings contribute to the weight but may not be digestible in the rumen.
This is often due to the smaller grains going through the roller mill uncracked making them undigestible.
The maximum percentage of screenings allowable under each grade may be different. For Barley 1 the maximum screening percentage is 15 per cent while ASW1 wheat is 5 per cent.
Ensure you use feed test values to review the diet balance as the protein and energy content changes with different cereals and between loads.
Changes in the protein or energy content of the diet can impact on the level of milk production.
Cows in early lactation require a diet with a crude protein content of 16 to 18 per cent, while late lactation cows require 12 to 14 per cent.
As for energy, about one litre of milk will be lost for every 5-6 MJ ME lost from the diet.
When changing grains or grain source, check the calibration of your feeders to ensure the cows are receiving the desired amount of grain.
The test weights of barley are generally lower than wheat, meaning there are less kilograms of grain per hectolitre (kg/hl).
For barley of the grade Barley 1, the minimum test weight is 62.5 kg/hl, whereas for wheat of the grade ASW1, the minimum test weight is 76 kg/hl.
This means that if you were feeding 5 kg of wheat through your feeding system at 76 kg/hl and then changed to barley at 62.5 kg/hl, you would actually only be feeding 4.1 kg of barley if the system is not recalibrated.
Remember, get a feed test to ensure you know what you are getting.
When changing types of grain or grain sources complete a diet balance using the feed test results and re-calibrate your feeders.
For more information, phone Agriculture Victoria on 136 186.
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