Australia
July 29, 2019
National sales and marketing manager, Tim Wilmshurst, said this strong philosophy on measuring forage quality has always been key for the company.
Tim Wilmshurst
“Livestock producers know that feed quality makes a huge difference to animal performance, not just yield,” he said. “From the outset, we chose to measure forage quality as a key criteria for our varieties, instead of only looking at forage yield.”
Over the past decade Seed Force has evaluated forage sorghum types by measuring yield and quality under different grazing or cutting regimes.
The company launched grass EBVs, developed by inputting its research data into a livestock production model, resulting in the patented Animal Performance Calculator.
“The information gathered from this work shows some clear decision pathways for farmers as well as dispelling some of the myths prevalent in the industry,” Tim said.
“We want to make sure that farmers have the full suite of information they need and the options available that will help them best achieve optimum results for their operation.
Addressing some common misconceptions
Taking on some of the misconceptions in the industry, Seed Force’s research shows that many of these are not always true.
“One common ideal is that sudangrass makes the best hay. However, hay is usually made at greater heights than where it has an advantage over other types,” said David Leah, Seed Force technical manager.
David Leah
“Cut short for silage, sudangrass offers the best fodder conservation option, but once hay is considered, sorghum x sudan or sweet sorghum may offer better value.”
There is also opinion that BMR types have higher qualit y than other sorghums, which David says depends on the BMR gene in the variety and the stage of grazing.
“Nutritive value data shows that varieties with finer stems and more leaf to the base can have higher feed value than BMR types.”
Another belief is that sorghum quality deteriorates rapidly as it runs to head too quickly when conditions are not favourable for harvest or grazing. To avoid this, David recommends the selection of a photo-period sensitive variety.
“PPS varieties will not run to head until the day length drops to 12 hours and 20 minutes, giving you cover when dry weather or wet conditions delay grazing or harvesting,” he explained.
Seed Force also challenges the assumption that millet is a lower cost, better quality option with lower grazing risk when compared with forage sorghum.
“Feed analysis has shown that millet, which is a shorter species, is inferior to forage sorghum at the same height. And while millet does not contain prussic acid, this is only a threat for forage sorghum under stress, such as under dry conditions, frost affected or where the stand is short.
“Millet consistently produces 40-45% of the yield of forage sorghum, and in almost all trial comparisons, the cost per tonne of millet is higher and its quality is lower.
Farmer decision pathways
As part of its holistic approach, Seed Force researches for different farming scenarios when assessing varieties.
“This is so we can provide reliable crop management recommendations for growers, based on their specific needs,” David explained. “Farmers want specific advice about the best varietal options to suit the way they want or need to farm. It is why the work we do to make sure we understand the characteristics of each variety is so important.”
For short grazing needs up to 0.8m high, David says sudangrass will grow faster than other options under these conditions, but first grazing needs to be early to encourage tillering.
“The increased tillers compared to sorghum x sudan and sweet sorghum gives sudangrass faster recovery over the first 14-21 days, after this though the others will catch up and pass it. The feed quality of sudangrass managed at this height makes it perfect for intensively manager rotational grazing.”
Once you choose to graze or cut beyond 0.8m in height the advantage of sudangrass is lost.
“Sorghum x sudangrass will grow faster to first grazing as the seed size is greater and it has more energy to establish. It is important though to select varieties with fine stems and high leaf content.
“As grazing or cutting gets to the higher end of the range, BMR types can maintain quality through lower lignin, meaning lower fibre levels for increased animal intake. They are ideal for multiple cuts or grazings where the stand can’t be managed intensively or where yield may be more important than quality.”
When only one big cut is desired, sweet sorghum types will usually provide the highest yields.
“These are the best option for conserving maximum fodder when only a single cut is likely,” David said. “They are typically the slowest types to produce feed when measured under 1.2m in height. But as cutting is delayed, they continue to produce more leaf growth and will out-grow other types.”
Selecting varieties that have ultra-late flowering (PPS) will ensure quality is maintained as the plants continue to grow and if weather conditions delay harvest.
“If good soil moisture or follow-up rain allows, sweet sorghums can provide a smaller second cut or late grazing option. As they have the highest prussic acid levels, be careful not to graze when it is too short or under stress.”
Contact Seed Force for more information.
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