Determining the Optimum Quality Harvest Stage of Male-Sterile BMR Forage Sorghum

Final report for ONE20-367

Project Type: Partnership
Funds awarded in 2020: $13,351.00
Projected End Date: 07/31/2021
Grant Recipient: Advanced Ag Systems LLC
Region: Northeast
State: New York
Project Leader:
Thomas Kilcer
Advanced Ag Systems LLC
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Project Information


Short season BMR sorghum has been tested and produces high yields and quality to replace corn silage (1,10). It has many advantages over corn silage, especially for organic farms. In balanced rations, BMR sorghum sp. can produce the same milk as corn silage but with higher components and greater feed conversion efficiency (1). Sorghum sp. stalks will lodge as the grain head fills – a major limit to farmer adoption. Male sterile – either sorghum or sorghum-Sudan – gave some of the highest yields in PI’s trials and had the best standability with no maturing seed to bring the plant down and had higher digestibility than their seeded counterparts. Photosynthetic energy in male-sterile continues to build in the plant cells and is not translocated to the seed sink. A BMR male-sterile sorghum was harvested from the boot stage and continuing each week for 7 weeks post heading.  Ensiled replicate samples each week were wet chemistry analyze for quality components.  Over the harvest period, dry matter increased 53%.  The hypothesis of this project was clearly proven as quality components increased significantly as Non-Fiber Carbohydrate (NFC) increased 71%; Non-Structural Carbohydrates (NSC) increased 185%; Water Soluble Sugar (WSCS) increased 500% to 18.85% of the dry matter.  Protein only decreased slightly and NDFd 30 NDF from emerged head to the last harvest decreased 2.5%.  With the increase in digestible components, the NDF went down.  Utilizing the CNCPS model rebalanced for sorghum, the data indicated that waiting at least 6 weeks after heading increased the feed value to the point that the same milk was produced as with corn silage, but with only 0.9 lb. more of corn grain and 1.1 lb. less of SoyPlus.  On 100 cows this is a direct savings of over $5000 at January 2021 prices. Outreach is on-going with newsletters and farmer presentations.  In 2021, a complete repeat of this study will validate the findings of this SARE project.

Project Objectives:

The project seeks to both quantify and qualify the forage nutritional quality component changes of a male sterile bmr sorghum from boot stage to 35% dry matter silage stage to determine the optimum harvest window. Lyons et al 2019 Dairy Science(10), clearly determined the components for a fertile seeded BMR brachytic dwarf sorghum. Because there is no pollination in the male-sterile, there is no carbohydrate sink to pull photosynthetic nutrients from the cells in the rest of the plant and convert them to starch in the seed. This has the potential to dramatically shift both the amounts and the components of the digestible portion of the plant. This could have a significant impact on the makeup and profitability of utilizing the forage as a major component of the dairy ration. The analysis of changing forage quality components over time will tell us when is the optimum time to harvest; how big the harvest window is for dairy forage; and if there is any stoppage or loss of nutrients past a certain point in the fall with this crop. As farms, especially organic farms, increasingly switch to male-sterile genetics, this project will significantly increase their success in utilizing the forage.


Winter forage acres, needs to be planted early for high yield and soil protection, but directly reduces the corn season (8,9). There is no short-season BMR (Brown Mid Rib = high digestibility) corn. Short season BMR sorghum has been tested and produces high yields and quality to replace corn silage (10). Work by the PI and documented by Dr. Chase (Professor Emeritus, Dairy Nutrition, Cornell) is that with proper balancing, BMR sorghum sp. can produce the same milk as corn silage. Work at Miner Institute on BMR sorghum-Sudan also documented the same milk production as corn silage but with higher components and greater feed conversion efficiency (1).
Dairy/livestock farmers are turning to BMR forage sorghum species for benefits superior to corn. Corn seed is increasingly expensive to grow. Genetic rootworm resistance is failing, and disease controls require expensive fungicides. Sorghum is $100/acre cheaper to grow on just seed cost. Sorghum species eliminates corn rootworm for following corn crops, and is deer-proof. Organic corn silage requires multiple cultivations which leave the soil vulnerable to erosion. Cultivation, critical for organic corn silage success, is at the same time that organic haylage needs to be made. Thus, the haylage is often late, severely limiting the profit potential of the organic farm. Optimum sorghum planting is in drilled narrow rows (PI’s replicated research found 18% higher yield compared 30-inch row) quickly canopies to prevent erosion, shade out weeds, and maximize sunlight interception in our short season. Based on our work, sorghum-Sudan’s rapid emergence and dense stands utilizing a stale seedbed is replacing corn silage on organic farms without cultivation to control weeds. Thus, more organic farms are switching to BMR sorghum-Sudan as their energy forage.
The PI’s research has found that most sorghum and especially sorghum-Sudan stalks, even the Brachytic dwarf type, will lodge as the grain fills – a major limit to farmer adoption. The research found that of the BMR, the male-sterile – either sorghum or sorghum-Sudan - without a seed head, gave some of the highest yields and had the best standability with no maturing seed weight to bring the plant down. In paired comparisons, the male-sterile had higher digestibility than their seeded counterparts. Photosynthetic energy continues to build in the plant cells and was not translocated to the seed sink. Unfortunately, with no grain we have no indicator for the optimum time to harvest male-sterile types. Sorghum breeders cannot tell farmers the optimum harvest time for a crop without seeds. This knowledge is critical to determine varietal season length for our farms and for the farmers to harvest at the optimum time to support profitable milk production.
The solution is to plant a BMR male-sterile sorghum on the Dutch Hollow farm. Beginning at boot stage in August, and continuing for 6 weeks; six replicate samples will be taken, chopped, inoculated and vacuum sealed for fermentation. Samples will be sent to Cumberland Valley Analytical Lab for analysis of quality components. The data will determine the optimum harvest date.


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  • Brian Chittenden - Producer


Materials and methods:

On May 25, when soil temperatures were over 60 F, a field of male-sterile bmr sorghum (Richardson Seed: donated seed) was drilled at 14 lbs. seed/a in 8-inch row spacing on the Dutch Hollow farm. The site was chosen to be away from any random source of sorghum pollen that would compromise the research project. The seed was treated with a herbicide safener and atrazine and Dual were applied immediately after planting to control weeds. A one-harvest system was used. For this proposal, when the plants reach the boot stage, once each week after, for 6 weeks, randomized 6 plants will be selected and each chopped at 1-inch length of cut. Each sample was treated with an inoculant (Chr. Hansen Silo Solve MC) and vacuum sealed for fermentation. After 3 weeks of fermentation, the samples for that week were shipped to Cumberland Valley Analytical Laboratory. This sequential shipping was to eliminate the difference in the amount of fermentation between the first week’s samples taken and the final week's samples. The forage analysis components were NIR+ which will give Dry Matter, Moisture, Crude Protein, ADFCP, NDFCP, Soluble Protein, ADF, NDF, Lignin, Starch, Sugar, Fat, Ash, Calcium (Ca), Phosphorus (P), Magnesium (Mg), and Potassium (K) and pH on ensiled forage. Calculated values were provided for Available Protein, Adjusted Protein, Degradable Protein, NEl, NEm, NEg (OARDC Summative Energy Equation), NSC, and NFC. It provided a 30 hr NDF Digestibility with Kd rate, a NIR evaluation of fermentation acids, as well as a uNDF at 30 hrs, a uNDF at 120 hrs, and 240 hrs, total fatty acids, and soluble fiber. This option also included a soil contamination probability index of low, medium, or high for forages. For corn silage comparison samples, the NIR Plus Option provides 12 hr NDF digestibility and 7 hr (4mm) starch digestibility. The normal NIR with the sorghum may give erroneous numbers for sugar and cellular starch. As the male-sterile plant is not mobilizing cellular starch and sugar and sending it to a fertile seed sink, it accumulates in the plant forage cells the longer the plant is growing past flower emergence. Because the sugar and starch amounts are far outside the norm of regular forage crops, the algorithm results for the NIR analysis would not be accurate so a wet chemistry analysis was used to accurately capture what is going on in the plant as it approaches harvest. Ethanol Washed Starch was used to remove the free sugars and then measure the glucose that remains in the starch fraction to get an accurate measure. Without the ethanol wash, the lab may end up double-counting the sugar that would appear as starch.

Yield checks were taken for the first three weeks but it was obvious that the wet yield was not changing after the head emerged. The resulting data was statistically analyzed (6 reps/harvest date x 6 harvest dates) utilizing Statgraphics software to determine both mean and statistically significant differences of the components at each date and again across dates. The averages of each component of each harvest date were entered into the CNCPS model to determine the impact on the potential milk-producing ability of that forage over harvest dates. This gave us the optimum harvest time.

Research results and discussion:

With the help of Brian Chittenden of Dutch Hollow Farm and support by Northeast SARE grant and Richardson's Seed, we established a four-acre field in the Hudson Valley, just south of Albany NY.  We would like to report an outstanding crop – the reality is that it was the worst crop of sorghum I had grown in 40 years.  Extreme dry weather limited initial emergence and prevented most of the herbicides from being activated.  An error in tillage left most of the roots in the top two inches of soil.  30% of the stand was foxtail. The variety was a low-yielding in-bred we deliberately selected to achieve heading by the beginning of August and enough weeks post heading before frost.  Plant physiology, rather than the total yield. affects the forage quality by harvest date. Our yield from the normal parts of the field was about 12 tons of 35% DM silage.  We are rerunning this experiment in 2021 with a normal high-yielding hybrid seed that is presently being grown in South America. Fortunately, we had several blocks in the field that emerged normal and had good weed control which allowed realistic sampling. We sampled starting at the boot stage on August 10 and continued weekly until a killing frost on September 21.  This last harvest was one week later than the SARE proposal.  It was made possible by funding from Texas sorghum seed company Richardson’s seed.  This was fortuitous in that the extra week showed a continuing major increase in the quality components we were studying in this project.

For each harvest date, six whole stalks were chopped at a 1-inch length of cut and then treated with SiloSolve MC inoculant (designed for wet, high sugar forage).  There were 6 reps for each date. Fermentation was effective with a silage pH of 3.67 on average.  All harvest dates' pHs were below 3.8. with lactic the predominate acid (88.9%) produced.  Note that despite silage dry matters from 18 to 27%, no butyric was detected in any of the 42 samples.  This shows the critical importance of using a proper inoculant.

Our theory of waiting after heading to increase the forage quality proved out.  The immediate benefit was higher dry matter forage for more efficient harvest and fermentation. The dry matter increased 56% during that 7 weeks which means farmers are hauling more feedable forage and less water for the same ton of feed.  It also increased the success of fermentation and decreases or eliminates leachate which was historically a problem with sorghum sp. crops.  

The key result from this research is that the digestible components continued to increase for the seven weeks after heading.  This increase was all in cell constituents.  Dr. Ferraretto of the University of Florida has researched increasing the digestibility of sorghum grain contained in sorghum silage. For processing corn grain in corn silage, the standard is a 4.75 mm processor gap.  Dr. Ferraretto found that a much smaller processor gap was necessary to adequately break the sorghum berries for digestion along with a shorter length of cut.  Both of these factors greatly slow the harvest and increase the wear on the processors and fuel use – ultimately increasing the cost of the forage at the mouth of the cow.  Our finding avoided this entire problem by not having any grain to process (no processor needed) but store the same nutrients in the forage plant cells. It also allows for a longer length of cut which the PI’s research has found, along with no processing, is critical to eliminating the leachate from the potentially wetter forage. The longer length of cut produces a more effective fiber in the rumen to retain the sorghum forage for a greater extent of digestion – releasing the increased nutrients this SARE research found was stored in the forage cells.

An addition to this project is that the Chr Hansen company wanted to test two of their inoculants on this crop and so we ran a parallel study (funded by Chr Hansen) on their inoculants.  This was beneficial in that we were able to use the SiloSolve MC results of their samples in addition to our own SARE results which were also treated with the MC.  They used the same analysis as we did, so it gave us 12 reps per harvest date instead of the original 6, greatly strengthening the statistical reliability of our analysis at no cost to SARE.

The results of the forage analysis were compiled for each harvest date.  Dr. Larry Chase inputted them into the Cornell Net Carbohydrate and Protein Systems model to determine the pounds of milk supported by metabolizable energy and metabolizable protein.  Because of the extreme weather conditions, the corn silage from the same farm tested considerably outside the norms.  The forage analysis and their nutritionist said it was very, very high quality but when they fed it the cows did not milk.  This indicates that the weather produced very abnormal corn silage components outside the algorithms that can accurately predict the energy and milk producing ability.  Dr. Chase’s analysis switched to using the mean of normal corn silage analysis that is in the DairyOne database. 

Because of the abnormality of the corn silage, we are concerned that perhaps the BMR sorghum had also changed.  This is highly unlikely as sorghum is a crop that normally grows in the hot, dry conditions that we had much of the growing season. To be sure, we have applied for and secured funding for an exact repeat of this study in 2021.



Research conclusions:

Multiple clear results came from this project. 

The first advantage we found in delaying the male-sterile sorghum harvest for seven weeks after heading, is that the photosynthesis kept adding nutrients to the forage which significantly increased the dry matter of the crop harvested. At heading (formerly recommended harvest stage) the silage was only 17.6% dry matter.  This is a challenge to ferment properly and uses a lot of farm resources to simply haul water from the field.  At the end of seven weeks, the dry matter was 56% higher (27.6% DM) which meant the farmers were hauling more nutrition and less water, and the crop is easier to ferment properly with an inoculant.

The second result is that the quality components increased tremendously the longer that we waited after heading. This proved our fundamental hypothesis for this project. From boot stage to the 7th week after, the cellular (forage) sugar increased 500% to 18.85% of the dry matter of the forage. This is an accurate number that was determined by wet chemistry.  Rumen available sugar is critical to high milk protein levels.  Higher protein milk gives a greater return on milk price for the farm.  Utilizing sorghum forage with its slow-release cellular sugar will avoid subclinical acidosis that happens when other sugar sources are dumped into the rumen.  In addition, the digestible component Non-Structural Carbohydrate increased 185% and the Non-Fiber Carbohydrate increased 71%.  These components, making up increasing amounts of the dry matter, drove the NDF (fiber) levels down on a dry matter basis which allowed for 2.6 more pounds of sorghum to be incorporated into the diet from the 6th and 7th harvest dates, reducing the cost of the ration even further.  Without nutrients in the seed head, the expense of processing the forage is eliminated. 

The most important finding is that this male-sterile bmr sorghum without grain, in a properly balanced ration, will support the same milk as corn silage.  It can do this with less protein supplementation, and only slightly more corn grain supplementation.  Dr. Larry Chase’s analysis showed that sorghum silage is NOT corn silage and the nutritionists need to rebalance the rations for higher digestible fiber feeding. In the initial ration Dr. Chase constructed, we simply swapped corn silage for sorghum silage.  The 85 pounds of Metabolizable Energy (ME) milk supported by corn silage dropped to 79.4 ME milk with the sorghum silage.  Sorghum is slightly lower in energy than well-eared corn silage but is higher in crude protein.   Rebalancing the ration for sorghum, the ME milk supported was the same as corn silage and the Metabolizable Protein (MP) was higher than the corn silage (see table below).  The key is to increase the NDF being fed as it is higher digestibility than the corn silage.  Note: a direct finding of this research is that as we decreased the forage NDF levels (increasing quality) by delaying harvest 7 weeks, we were able to feed 2.6 more pounds of BMR sorghum dry matter to the cows. If you look at the table below, you can see that compared to corn silage, the earlier harvested sorghum required 3.5 more pounds of cornmeal to maintain milk production.  It did it though with 1.2 fewer pounds of SoyPlus/cow/day.  By allowing the crop to increase quality components with increasing time after heading – the hypothesis of this study - the energy accumulating in the plant increased until only 0.9 lb of extra cornmeal (27% reduction) was needed to match the corn silage potential milk production and 1.1 fewer pounds of SoyPlus.  Inputing the grain cost of early January 2021 the sorghum cost 100 cows over a 305-day lactation, $3,294 more in corn grain, and $8,388 LESS in SoyPlus from feeding the harvest delayed male-sterile sorghum.  An over $5,000 direct savings for the farm.

Harvest Date

Sorghum, lbs. DM

Alfalfa, lbs. DM

ME Milk, lbs.

MP Milk, lbs.

Corn grain, lbs. DM

Soy Plus, lbs. DM

Corn Silage Base

20 Corn



































Sept. 7







Sept. 14







Sept. 21








Another benefit for non-milking livestock emerged from this research project results.  Our experience on farms has been that a non-BMR type sorghum sp. is a better forage for growing replacement animals.  Seed cost alone is $100/a less.  Yields in our variety trials, at a separate location, exceed that of corn silage.  There is a major problem on a large number of farms where corn silage is fed to heifers and they get too fat.  The excess fat laid down in the developing mammary glands inhibits the maximization of milk production.  BMR sorghum sp will get them as fat as on corn silage.  Non-BMR sorghum will grow them properly with a large body and rumen size yet limited excess fat deposits.  By utilizing the male-sterile gene in a non-BMR sorghum, and the results of this SARE research, we found that the farmers can adjust their harvest date after heading to account for more or less energy depending on what they had for additional forage to feed the heifers.  Thus, this SARE study found that we can target the exact harvest to the quality needs of the group being fed.

The finding of this project is ready to be applied to grass-fed beef production (presented to grass-fed beef farmers at a meeting in Indiana).  Utilizing the BMR gene coupled with the male sterile gene in a sorghum-Sudan planted into a stale seedbed at a slightly higher seed rate; we can produce an organic crop (all gene changes were with conventional breeding) that utilizes all the energy without reproductive grain starch which meets the requirements for the grass-fed system. This allows the beef to grow to size and marbling in nearly the same time as conventional grain-fed finishing.  This quick turnover is critical to maintaining a profitable return in beef production.  It will also directly meet the energy forage needs of organic grass-fed dairy production.  Several farmers have requested more information on following this process for grass-fed dairy.


Because the quality changes we were able to document were so outside the formerly understood parameters of BMR sorghum, we opted to repeat this study using a hybrid instead of an inbred for the trial (inbred was the only type available for this SARE research that was short enough season to match our climate growing season limitations).  A sorghum research funding group has announced that they will fund our repeat trial due to the very high interest in the outcomes of this SARE study.  The participating sorghum breeding company that supplied the inbred seed for the SARE trial has made a special cross to match our growing season with a hybrid and the associated plant vigor that comes with hybridization.  This cross and seed were produced in Argentina and shipped to us in May of 2021.  Again, because of the outstanding results of this SARE study and finding that the SiloSolve MC inoculant was superior to inoculants designed for drier, lower sugar forages the question arose whether this was a one-time occurrence or a solid finding.  The Chs Hansen inoculant company had committed to repeating their study alongside our above BMR male-sterile study. This will both answer the question of the inoculant choice while again simultaneously doubling the treatments for the harvest date study for stronger statistical analysis. 




Participation Summary
1 Farmers participating in research

Education & Outreach Activities and Participation Summary

4 Consultations
3 Curricula, factsheets or educational tools
1 Online trainings
2 Published press articles, newsletters
5 Webinars / talks / presentations

Participation Summary:

1,350 Farmers participated
425 Number of agricultural educator or service providers reached through education and outreach activities
Education/outreach description:

Jan 2021 Sorghum alternative

Feb 2021 Sorghum Mgt 2

Newsletters on the results were sent out in January and February to over 1,100 agribusinesses, consultants, and farmers.  This generated a large number of phone consultations that were held with farms wanting to add this crop to their rotations. These have continued throughout the spring.  Multiple discussions were held with sorghum breeders and sorghum seed suppliers to develop the best varieties for the northern US farms.  Based on the results of this SARE study, sorghum breeders are rapidly developing male-sterile varieties that will fit the growing season of northern US farmers. 

The results of this research were presented and discussed directly with farmers at Feb 3, 35 NY farmers, Feb 4, 65 NY farmers; Feb 10, webinar for 110 Wisconsin farmers; Mar 20 Grass-Fed Beef Conference, 40 farmers, Indiana; 3 one-hour phone group consultations Feb. 24, Mar 3, and 9.

The request has been made and the presentation developed for the Certified Crop Advisors training in NY in early December.  This will have a huge multiplier effect as it reaches more than 150 consultants, agronomists, and university personnel.

A short YouTube presentation ( )was uploaded that focuses on why using sorghum, and the key critical forage quality findings of this SARE grant.  This enables farmers and agribusiness consultants to view the information and findings on their own time.

Outreach will continue well after the end of the SARE project with the addition of the second year of research data validating our findings. 

Learning Outcomes

250 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Key areas in which farmers reported changes in knowledge, attitude, skills and/or awareness:

The project is just beginning to hit its stride in outreach with the January and February newsletter in 2021.  Multiple farmers have contacted me for further information.  The results of this research were presented and discussed directly with farmers at Feb 3, 35 NY farmers, Feb 4, 65 NY farmers; Feb 10, webinar for 110 Wisconsin farmers; Mar 20 Grass-Fed Beef Conference, 40 farmers, Indiana; 3 one-hour phone group consultations Feb. 24, Mar 3, and 9.  Reports back from farmers at the Grass-Fed Beef Conference indicates that a significant number of the farmers are considering or will be trying the male sterile bmr sorghum this year.   Dozens of farmers have called for more detailed information of the growing of the crop.   Seed suppliers have reported that they are out of or nearly out of male sterile varieties.  Formerly only a small amount of seed was sold to be used as a cover crop after vegetables.  The information generated in this report as to the quality of the forage produced has been a game changer for both farmers and seed suppliers. 

The request has been made and the presentation developed for the Certified Crop Advisors training in NY in early December.  This will have a huge multiplier effect as it reaches more than 150 consultants, agronomists, and university personnel.

Project Outcomes

2 Grants applied for that built upon this project
2 Grants received that built upon this project
$17,752.00 Dollar amount of grants received that built upon this project
2 New working collaborations
Project outcomes:

This project's results were only compiled at the end of last year and outreach was in January and February of this year.  The only feedback so far are a number of farmers and agribusiness consultants who contacted me to determine what companies had the varieties that they needed to try this new crop.

As this project was based on an inbred, the yield was not a typical commercial yield and the farmer recognized that the results were his donation to improving forage production for all farmers.  Thus the crop on this small field was not harvested.  The farmer is closely following our repeat trial this year.

Assessment of Project Approach and Areas of Further Study:

The project was a clear success in that it proved delay harvest with a male sterile bmr sorghum will increase feed quality significantly.  It clearly showed that waiting at least 7 weeks after heading will optimize feed value.   The increase in feed value allows it to directly compete on cost and quality, with corn silage in the ration.  The grass fed beef and grass fed dairy producers are already asking questions to incorporate this new crop into their farm system as an energy source similar to corn silage but meet the grass fed criteria.  The non bmr version of male sterile will fit the needs of replacement heifers and dry cows without the problems of over condition that corn silage with its high starch, brings to the ration. Several farmers and consultants are already using this information to utilize the crop.  A follow up research, based on requests we already are getting, is to test the non bmr male sterile for replacement animal forage and develop a data base of changing feed quality so farmers know when to harvest for growing heifers' without having excess energy that would get them to fat. 

The challenge for sorghum breeders is to produce varieties for northern US that will head in time to allow 7 weeks before a killing frost.

Because the results were so far outside the norm ( on the good side) we are repeating the study utilizing funding from the Sorghum Check Off program. 

The results of this project are applicable to most of the US as sorghum is widely grown as a forage source.   It would be valuable and useable by diary and livestock producers.

Information Products

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.