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Non-BMR sorghum or sorghum-Sudan can replace corn silage, but don’t plant early.

Tom Kilcer

February 12, 2020

4 Min Read
Close up of a hand examining proso millet green crop ears in field
SWITCH TO SORGHUM: The cost of raising replacement animals can be cut by simply substituting a non-BMR sorghum or sorghum-Sudan for corn silage. stevanovicigor/Getty Images

A significant cost on farms is raising replacement animals. Exacerbating those costs are low-forage rations and overcrowding that stress the mature cow and increase the culling rate. Thus, you need even more replacement animals, which are costlier.

High-forage diets (if you have enough quality forage), reduced crowding and good animal comfort can go a long way toward reducing this high culling cost and the animals to replace them. These changes take time, but there is a step you can take to grow better heifers at less cost.

A common complaint from both farmers and nutritionists is that heifers are little porkers. You are trying to grow them fast and instead they get fat and don’t milk well.

The main problem could be the corn silage forage that you are feeding them. In discussions with nutritionists, as well as looking at research from the University of Nebraska and actual on-farm experience, switching part of the diet from corn silage to non-BMR sorghum or sorghum-sudan is a good alternative. 

Researchers in Nebraska used non-BMR sorghum-sudan with lower dry matter and nutrient intakes to get average daily gain in the recommended range of 1.75 to 2.2 pounds a day in Holstein heifers. Keep in mind that we have multiple on-farm examples of BMR sorghum species getting heifers nearly as fat as if they were on corn silage.

The slow rate of passage allows an animal to extract a tremendous amount of nutrients from the highly digestible fiber of BMR sorghums, even if there is no grain starch in the forage. Switching to a regular, non-BMR type sorghum has less digestibility, but you can grow the animals at the optimum rate of gain.

Less cost, more tonnage

Non-BMR will cost about 10% less and yield 1-2 tons more than a BMR type. The seed cost is over $100 an acre less than most stacked corn.

Corn rootworm isn’t an issue with sorghum as the roots are toxic to anything that bites into it. It does not get corn diseases and does not need to be sprayed with fungicide. Sorghum does get some of its own diseases but genetic selection controls most of those.

All of this means a significant reduction in cost while getting equal or higher yields than corn silage. It enables you to grow a better animal for less cost.

Choose male, sterile variety

Our extensive and ongoing testing, supported by the New York Farm Viability Institute, has focused on what is best for northern U.S. dairy farms.

The research suggests that having a non-BMR sorghum that has dry stalk gene to increase dry matter at harvest is ideal for heifers. We suggest that you choose a male sterile variety. The major lodging problem with sorghum is that when a heavy maturing grain head is 11-feet tall on a stalk as thin as a fishing pole it will fall. Male sterile varieties have no seed and using them solves the problem of over-mature seed heads on delayed harvest. Eliminating the seed keeps the increased digestible energy stored in the forage plant cells.

Limit seeding rates

Sorghum needs to be planted at a limited seeding rate or they will lodge. For 30-inch rows, our research suggests 5 pounds of seed per acre. For 15-inch rows, 8 pounds is suggested. For narrow-row drilling, which in our trial gave 18% higher yields, 10 pounds of seed an acre are all that is needed.

Sorghum should be purchased with a safener on the seed. This allows for certain corn herbicides to be safely used to control weeds, yet they will not harm the sorghum. Don’t dawdle; get the herbicide on immediately after planting to stay ahead of the weeds and not injure the crop. For organic farms, the high-seeding-rate sorghum-sudan is a better choice.

Wait to plant

We suggest that you look for a variety that will mature in your climatic region. Keep in mind that it is critical to have the soil temperature at 60 degrees F. If you ignore this and plant too early, you will have a weedy pile of nothing.

Waiting to plant — especially drilling the stand — maximizes sunlight interception. For the Albany area we rarely plant before June 1, yet we get yields that equal or exceed corn silage on the same ground. If you want to get the crude protein up, you need to feed the crop with manure or nitrogen, plus sulfur at rates slightly higher than corn silage. Many farms short the crop, and subsequent yield and protein suffer.

This is a crop designed for pairing with winter triticale. It gets planted in the early summer right after winter forage and haylage harvest, which opens a June window for immediately incorporating manure to meet all the fertilizer needs.

Our replicated research suggests harvesting — at least in northern New York — by the beginning of September.  Our data show that decreasing day length and sunlight intensity will rapidly decrease feed value by decreasing the NDFd. This works out as the winter forage needs to be planted at that point for optimum yield.

Kilcer is a certified crop adviser in Kinderhook, N.Y.

About the Author(s)

Tom Kilcer

Tom Kilcer is a certified crop adviser in Kinderhook, N.Y.

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