Is the inclusion of sorghum in a forage plan a potential feed cost savings, or is it a big gamble?
During their annual meeting in Juneau last week, members of the Dodge County Forage Council weighed out the risks and benefits with help from Daniel Olson of Byron seeds.
Olson points out that not every establishment of sorghum and sorghum will turn out, but he said there are reasons why stands are poor and harvesting is challenging.
He began the discussion by offering suggestions for why the crop has a poor stand.
'Likely it is caused by planting when the soil is too cool,' Olson said.' These plants need soil that is at least 60 degrees to germinate. If soil is too wet, the stand will also likely not be good.'
While these plants require about two-thirds of the fertility necessary for raising traditional corn, he said they do still need some nutrients, and without any fertilization, the stand could be poor.
'If you plan to do more cuttings, you need to split your fertilizer application or you will have nitrates in the feed and nothing left for the second growth,' Olson said.
When harvesting, he recommended laying the material in wide rows. Tedding is helpful and merging is rarely needed.
Sorghum sudan can be made on the wet side (70 percent moisture) and can generally be harvested within 36 hours of cutting.
He suggested pulling off the shields in the back or raising them up completely to avoid compaction in the windrow.
Olson cautioned that prussic acid, common in these plants after freezing, can kill cows, but he it is only a problem when it is fed fresh (green chopping). Fermentation dissipates the prussic acid. Drying will not get rid of it.
The only time Olson knows of when cows died from it was when a farmer did not realize the crop had frozen in the low land and chopped it as fresh feed and another time when cows reached under a wire fence and ate enough of the crop on the other side to kill them.
According to Olson, another concern some farmers have is that their nutritionists don't like the silage in the ration.
'Nutritionists who do not understand digestible fiber will struggle with it,' he said. 'You can have almost twice as much digestible fiber as alfalfa in this crop.'
'The old mindset is that fiber reduces intake. That's partially true. It does limit intake.'
Olson said the average NDF, NDFd and soluble fiber for the undigestible part of the feed is almost identical between the sorghum silage and alfalfa.
'Because of soluble fiber, there is a lot of energy available in sorghum,' he said.
OIlson pointed to results of a study comparing the two and said it showed lower feed intake, the same milk production, weight gain and less manure with the sorghum as compared to the alfalfa silage.
'There is a limit to how much you can feed to the very high producing milk cows, but there are opportunities for those past peak and the lower producers in the herd,' he said.
Noting that it takes two-thirds of the amount of fertilizer and water to produce sorghum when compared with alfalfa and pointing out that it requires a shorter growing season, leaving opportunities for double-cropping, Olson sees an advantage in this crop.
'On your very best ground, you can probably still do better with corn,' he admitted. 'In the areas where there is deer pressure or the areas that are not as fertile, this crop will be a better investment.'
Three families of crop
He described the options, including forage sorghum, sorghum sudan and sudan x sudan hybrid.
Forage sorghum is the most like corn silage and is the cheapest to plant. Crude protein is the same or slightly higher than corn silage, and it can handle herbicides. It can be established with a corn planter or a drill. Ash content is lower, and it is intended for a single cutting.
Sorghum sudan has a crude protein three or four percentage points higher than corn silage, depending on how much nitrogen is put on it.
It can be planted with a drill and harvested 45 days after planting and then 30 thirty days.
The cutting height is 4-6 inches in order to encourage fast regrowth, but the last cutting can be lower.
The sudan x sudan hybrid is treated like haylage or pasture grass and is planted with a drill. The crude protein is six to eight percentage points higher than corn silage.
While it is possible to dry it in a day for hay, the best option is silage, Olson said.
It is too sensitive for herbicide usage, but because it is a dense crop, weeds are generally not an issue.
Multiple cuttings can be taken from this crop.
Olson recommends looking at the number of seeds per pound when figuring seeding rates since there is a great deal of variability. He also suggests getting seed that is treated with Concept in order to have options for herbicide use. Without it, herbicide cannot be applied.
Choose a sorghum that won't head out before harvest.
Sorghum needs rain to grow, but it is different than corn because if it goes through a dry period and slows down; as soon as it rains it will green up again and continue to grow. Corn, once it is dry, will not recover.