Sorghum is making a resurgence in both the grain and forage markets. Farmers have begun switching acres away from corn to sorghum this year because it costs less to produce, pays more at current prices and is competitive in nutritional quality for feeding purposes.

For dairymen, forage sorghum can provide an efficient, economical alternative to corn. The savings potential of forage sorghum starts with the seed. Most traited corn will usually cost an extra $100 per bag or more compared to forage sorghum. Cash input costs are also generally lower for sorghum in comparison to corn on a per-acre basis, as less fertilizer and water is needed.

Independent studies have shown that forage sorghum can save an average of $215 per acre in total production costs compared to corn silage.

One of the ways forage sorghum can save growers money is through reduced irrigation costs. Water efficiency is an area where forage sorghum really shines. Sorghum can grow on roughly 40 percent less water than corn requires and still achieve yields comparable to corn. This is possible because sorghum is much more efficient with the water it receives.

According to research from Texas A&M University, irrigated forage sorghum will yield 1.76 to 2.5 tons of biomass per inch of irrigated water, while corn produces only 0.84 tons per inch of water applied. Because of its high water-use efficiency and tolerance to prolonged periods without rain or irrigation, sorghum is a great option for dairymen in areas with limited rainfall or water availability.

A dependable crop

Adaptability is another advantage forage sorghum can offer to growers. Sorghum has the ability to tolerate dry spells and resume growth following drought-induced dormancy. Sorghum will also generate more roots in dry conditions. These extensive root systems are capable of reaching soil depths of 5 feet or more, allowing sorghum to find water when other crops cannot.

While forage sorghum is reliable in low-water situations, it will also flourish in wetter weather. The versatility to produce a crop in both wet and dry scenarios provides growers with a dependable forage option. Knowing what to expect from a consistent forage crop like sorghum can also make planning easier.

High-quality feed

When choosing a sorghum hybrid for silage production, both yield and nutritive value should be considered. There is wide variability in yield and nutritive value among forage sorghum hybrids. One of the primary differentiations will be whether the hybrid has the BMR trait.

The midrib of most grass leaves is white to off-white in color. Sorghums containing the BMR gene have midrib and sometimes stalks that have a brown to reddish-brown color which is very distinct when compared to non-BMR types. More importantly, hybrids with BMR genetics contain less lignin than non-BMR hybrids.

Lowering the lignin content of the plant increases the overall digestibility of the fiber component of the forage, improving ruminant stability and enhancing the overall feed value.

Texas AgriLife Extension specialist Ted McCollum has been studying BMR forage sorghums for years and has seen enough data to recommend forage sorghum with the BMR trait. “If I’m looking for energy value in my forage, I’m going to go to a BMR,” McCollum says. “Pick a variety based on the desired fiber, tonnage, quality and starch. Use fiber quality as the primary criteria.”

McCollum cautions that the BMR genotype alone is not a guarantee of better quality. His research shows variations in digestibility fluctuate from hybrid to hybrid, underscoring the need to review hybrid performance trials.

Managing for success

Forage sorghum silage performs best when it is managed properly. The standard methods include harvesting at the correct moisture level, maintaining a uniform chop, storing the silage in a timely manner and packing it properly.

While forage sorghum is generally managed similarly to corn silage, there are a few key differences growers need to take into consideration. Sorghum yield and forage quality perform best when moisture content levels fall between 63 and 68 percent.

Harvesting when the crop is too wet may cause problems during the ensiling process and decrease cattle intake. Cutting when forage sorghum is too dry may reduce energy and protein components of the silage.

The timing of harvest is also important to maximize the value of the grain if the hybrid planted produces a grain head. If the crop is left in the field past the soft dough stage, the sorghum kernels will harden to the point where they will pass through cattle without being digested.

To avoid this potential problem, harvest forage sorghum when 80 percent or more of grain heading has occurred and 50 percent of the kernels reach the soft dough stage. Swathing the sorghum may be needed as the plant is frequently too wet when the grain is ideal for ensiling.

Chop length recommendations vary depending upon the characteristics of the variety or hybrid planted. A half-inch chop is typical for standard forage sorghum varieties while a 1-inch to 1¼-inch chop length is recommended for BMR hybrids to achieve the proper rate of passage for cattle. The longer chop length allows cows to make proper use of the higher nutritive values of BMR forages within the rumen.

Proper storage and packing of silage are crucial to maximizing quality. Packing is necessary not only to get air out but, more importantly, to keep it out. Minimizing air infiltration during ensiling is essential for making good-quality silage. Any air that enters the silage mass causes respiration and the depletion of sugars essential for fermentation. Adequate packing and a good seal will minimize air exposure, preventing spoilage and shrinkage.

Providing value and versatility

Whether dairymen are seeking a crop with lower inputs, higher water-use efficiency or a high-quality feed option, forage sorghum is becoming an attractive alternative to corn. Its excellent tolerance to drought and heat provide peace of mind during the season and the ability to produce feed in years when other crops can’t.

The versatility of forage sorghum, combined with its cost efficiencies on a per-acre basis, make it a valuable option for dairymen to consider in place of corn silage.  PD

PHOTO: Forage sorghum with brown midrib genetics have a distinctive brown or reddish brown streak. The brown midrib trait reduces lignin in the plant for improved digestibility and higher nutritional quality. Photo provided by Travis Kidd.

• Travis Kidd

• Technical Development Manager
• Advanta Seeds and Alta Seeds
• Email Travis Kidd