FROM THE FARM REPORT: THREE THINGS I AM GOING TO MISS ABOUT CORTEVA BMR
- Allen Wilder
- Apr 14
- 3 min read
The recent decision by Corteva Agriscience™ to phase out brown midrib (BMR) corn by 2030 has some forage producers reeling. Indeed, I know several farms in close proximity to Miner that have grown BMR exclusively for their high-producing herds in past years. As you can imagine, they aren’t too excited about the news that BMR will be going away. And, for that matter - neither are we. BMR corn silage has been a mainstay in the Miner Institute forage program for many years and here are three reasons why:
Digestibility
The primary reason that BMR corn is grown is, of course, fiber digestibility. Over the years, we have found that a good BMR hybrid runs 8-12 percentage points higher in 30 hr. NDFD than a typical non-BMR dual purpose corn taken for silage. This digestibility increase comes along with a corresponding decrease in undigestible fiber that has the potential to cause gut fill limitations in high-producing cows.
Growing BMR not only increases the efficiency of the cow, but it also increases the use efficiency of harvest equipment as well. This is because the “extra” undigestible fractions in non-BMR corn still must flow through the harvester, get hauled to the farm, and be packed in the bunk - all at the farmer’s expense. Then this undigestible fiber is fed out to cows, it passes through the cow, and the farmer gets to pay to haul it again as manure. It is easy to make the argument that we would be much better off if we could eliminate some of this undigestible fiber to begin with. In other words, grow BMR.
Consistency and Dependability
Corn silage digestibility varies considerably from year to year, but the digestibility difference between BMR and non-BMR is consistently there. Since corn is a high-yielding crop that is direct chopped, it ends up being one of our most uniform forages from field to field and harvest day to harvest day. Alternative sources of highly digestible fiber include grasses and winter forage. However, these forages are much more difficult to get to a consistent moisture content and be harvested on time.
Particle Size
Those who follow Miner Institute research closely are sure to know that particle size is a big deal around here. It wouldn’t be, however, unless it was a big deal to the cow as well. Time spent at the bunk, for example, is greatly influenced by the particle size distribution of the TMR. When it comes to length of cut for a forage, we are looking for small and consistent. As long as most of the fiber particles stay on top of a 4 mm screen in a shaker box, we have not compromised the effective fiber of the forage.
What does this have to do with BMR, you say? Well, I have run a great deal of BMR plots through the research chopper at Miner and there is no doubt in my mind – BMR chops better. At the same chopper setting, the BMR particles were smaller and more uniform than the non-BMR corn samples. We could literally see the difference just by putting two samples side by side. Although people don’t often grow BMR because it chops well, I believe that the smaller particle size distribution is, in part, responsible for the excellent animal response that we see with BMR on the farm. Yes, we can adjust the chopper to achieve smaller particle size in conventional corn, but this increases chopping time and fuel consumption. From a practical standpoint, BMR always wins.
While Corteva appears to be committed to their decision to phase out BMR completely, it certainly wouldn’t hurt to tell Corteva why the dairy industry needs BMR to stay. There are, of course, downsides to growing BMR as well; standability, disease resistance, and lower yield for instance. But we have not found any of these to be a game stopper at our location in Chazy, NY. On heavier soils, we have found that BMR has similar or even greater digestible dry matter yields to conventional corn, and we plan to continue planting it as long as we can buy it.
— Allen Wilder