Brazil is famous for corn and soybeans, but in the country’s toughest, driest regions, farmers are starting to look more seriously at sorghum for silage.
Arthur Behling Neto, professor at the Federal University of Mato Grosso, says sorghum is becoming an important forage option for livestock producers who need reliability under tough growing conditions — without the high input costs associated with corn.
“Here in Brazil, as I believe it is in the U.S., corn is the main plant for ensiling because it has very good nutritional quality and characteristics for ensiling,” Neto explained during a recent episode of the “Dairy Nutrition Blackbelt Podcast.” “Sorghum is usually an alternative for areas that corn does not grow very well, especially because of the lack of proper rain.”
This is particularly true in eastern Brazil and drier parts of Mato Grosso where sorghum’s drought tolerance gives it an advantage. Economics also play a role.
“Compared to corn, the seed is cheaper and we use fewer pesticides. We also don’t need as much fertilizer, so it’s cheaper than corn for our farmers,” Neto adds.
As input prices keep rising, sorghum’s durability and lower price tag are catching more farmers’ attention.
Different Types of Sorghum
Sorghum in Brazil serves several purposes. Neto describes five main types:
- Grain sorghum
- Forage sorghum
- Sorghum for cutting and grazing
- Broom sorghum
- Energy-focused sorghum, such as sweet sorghum and biomass sorghum
Grain sorghum remains the most widely grown overall. But when it comes to silage, forage sorghum and biomass sorghum are gaining traction.
“For silage, we use more forage sorghum,” Neto says. “However, we are also increasing the use of biomass sorghum because of its very high productivity.”
His research team is working to identify varieties that maintain good nutritional value while improving yield.
“What we are doing here is looking for different varieties that can produce more but still keep the quality that forage sorghum usually provides for the animals,” he says.
Match Sorghum to Beef and Dairy
In Central Brazil, sorghum silage is used primarily in beef cattle systems.
Forage and biomass sorghum provide the volume and fiber needed for cost-effective beef diets. Dairy producers, however, often prioritize energy density and may turn to grain sorghum silage.
“When we talk about dairy cattle, some farmers look for grain sorghum because it has higher energy content and lower fiber,” Neto explains. “It is close enough to corn.”
Although grain sorghum produces less tonnage than forage types, its nutritional profile can better match the needs of dairy cows.
The Yield and Quality Trade-Off
One of the main challenges with sorghum silage is balancing yield and nutritional quality. Grain sorghum plants are relatively short and produce lower yields, but they deliver higher energy concentrations.
“Grain sorghum usually grows about 3.5' to 5' tall and produces around 10 to 14 tons per acre,” Neto says. “The yield is not very high, but the energy content is.”
Forage sorghum grows much taller and delivers substantially more tonnage.
“Our forage sorghum can reach 8' to 12' in height and produce between 18 and 32 tons per acre,” he explains.
Biomass sorghum pushes yields even further. Neto’s research team is evaluating varieties capable of producing 35 to 55 tons per acre.
However, extremely high yields often come with reduced feed quality.
“When we reach these very high yields, fiber content can go up to 70%,” Neto says. “Crude protein can drop to about 5% to 6%, and lignin can reach 8% to 10%.”
Because of this, his team is searching for hybrids that maintain nutritional value while still delivering strong yields.
Managing Tall Crops
Biomass sorghum can grow exceptionally tall, sometimes reaching 14' to 20'. To manage these large plants, producers typically harvest them in two cuttings rather than waiting for full maturity.
“Our biomass sorghum has a cycle of about 180 days,” Neto says. “We plant at the beginning of the rainy season in October. The first cut is usually in December or January, and the second cut happens around April.”
Plants are typically cut about 8" above the soil surface.
For silage, Neto generally targets 28% to 30% dry matter. While the traditional recommendation is 30% to 35%, slightly earlier harvest can help prevent grain from becoming too hard for animals to digest.
Sugar Content and Fermentation
Sorghum also contains significant levels of natural sugars, which can aid fermentation.
“For forage sorghum, we usually have between 15% to 18% water-soluble carbohydrates,” Neto says. “That’s very good for ensiling.”
Biomass sorghum tends to fall slightly lower, around 12% to 15%. Sweet sorghum, however, can contain dramatically higher sugar levels.
“Sweet sorghum can reach 30% to 35% water-soluble carbohydrates.”
While these sugars help drive fermentation, they can also lead to ethanol production, similar to what occurs with sugarcane silage.
“We sometimes have problems with ethanol fermentation,” Neto explains. “But with proper additives, we can still produce very good sweet sorghum silage.”
A Complement to Corn
Despite its growing role, Neto emphasizes sorghum is not meant to replace corn silage entirely.
“Sorghum silage is increasing in Brazil because it is a cheaper alternative for some farmers,” he says. “However, I do not believe it will reach the same levels as corn silage.”
Instead, he sees sorghum as a complementary crop that provides flexibility when corn production becomes difficult.
“We don’t want it to substitute corn,” Neto says. “We only want to use it when corn cannot produce very well.”
For farmers working in hotter, drier regions with limited inputs, that flexibility may be exactly where sorghum silage delivers the most value.
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