Powel-Smith is a Wisconsin dairy/forage specialist with DuPont Pioneer, and Mahanna is the DuPont Pioneer global nutritional sciences manager.
STARCH CONTENT AND FIBER DIGESTIBILITY may be reduced when corn plants are slow to emerge. Agronomic and environmental conditions can limit hybrid performance.

Feed costs make up the largest expense on most dairy farms. Forage production and the affiliated cost to grow, harvest, and store forage is a significant portion of the feed costs.

Forage quality and quantity are the basis for building the diet and ultimately for how well cows perform. Milk production and ruminal health are governed first by forage quality and inclusion rates and secondly by the supplementation needed to balance around the forage base.

Given the monumental role corn silage plays today in the forage offering, it may merit exploring some of the common pitfalls associated with hybrid selection and understand how to improve that process.

Dairy cows are a finicky bunch. The subtleties of feeding and growing rumen microbes and maintaining a healthy rumen environment for the cow is a balancing act all nutritionists are expected to master. Yet, the demand for more milk and higher components with lower purchased input costs continues to challenge nutritionists. Once a particular ration formula works, nutritionists have been loath to stray from their methods and run the gauntlet of obstacles in search of higher performance and opportunities with new forages.

The entry of an expanded portfolio of brown midrib (BMR) corn silage hybrids in recent years has led many nutritionists to formulate diets around the higher fiber digestibility conferred with BMR plants. The results have been promising for the most part. Cows often respond to BMR-based diets with higher intakes, more milk, and comparable components.

It starts in the field

Understanding plant physiology and the myriad of agronomic factors affecting plant growth and development is fundamental to harvesting high-quality forages. Yet, agronomy, entomology, soil microbiology, and plant pathology are not typical strengths of most dairy farmers or their nutritional advisers.

Recent Pioneer field studies with Wisconsin dairy farms have focused on “field” factors that influence forage quality. Three key management factors have emerged that will require further attention and study and hold promise to positively influence starch content and fiber digestibility in corn silage:

  1. Plant emergence — plants that emerge from 12 to 72 hours later are significantly lower in starch and digestible fiber.
  2. Nitrogen deficiency — stalk cannibalization during ear fill can rob valuable digestible nutrients needed by the cow.
  3. Disease resistance — plant health deterioration due to disease pressure can reduce fiber digestibility by as much as one point of NDFD30 per day during the pre-harvest window.

Knowing how planter performance, emergence, nitrogen, and hybrid disease resistance along with other agronomic factors are interacting across the spectrum of hybrid choices, fields, soil types, and weather patterns takes expert insight.

Who is on your farm walking fields to monitor planter performance and evaluate stand emergence?

In the dairy farmer fields Pioneer looked at in 2016, 19 percent of plants were 12 to 72 hours late in emerging. The 2017 field studies showed similar values to the 2016 study. Individual plant analysis showed that starch levels could be as much as 50 percent lower in late-emerging plants. Fiber digestibility was also as much as 20 percent lower in late-emerging plants.

Late-emerging plants are the silent thieves robbing the corn silage of its true potential. Remember back in the 1980s and 1990s when Midwestern-housed cows didn’t lie in stalls until they were exhausted? Producers struggled with sore feet, low milk production, and poor reproduction. A similar crippling situation exists in many dairy farm cornfields with hybrids that struggle with poor seedbed preparation and planter performance.

Nutritionists and their dairy clients are often frustrated with corn silage quality, and hybrids are an easy target. However, just like with uncomfortable cows, hybrid selections alone might not deserve all the blame. Agronomic and environmental conditions that limit hybrid performance also deserve attention. The dairy industry could see big advantages in silage quality with a stronger focus on agronomic practices during the growing season rather than waiting until the bunker is sampled.

Have the right tools

Planter performance is as critical to forage quality as parlor equipment is to milk quality and udder health. It is easy to drive by a cornfield in spring and see it turn green as plants emerge, and yet be totally unaware that emergence issues could be the root cause of poor silage quality at the end of the season. Fall tillage, spring tillage, and soil conditions at planting dramatically affect planter performance.

Planter settings need to be adjusted to fit conditions, field by field, day by day, and hybrid by hybrid. Who on your farm is helping manage this phase of forage quality? How well do you understand tillage and seedbed preparation? Probably nowhere near as well as you understand cow comfort, air quality, and bunk management in your barns.

Nitrogen deficiency exists in cornfields on most dairy operations. Corn plants, genetically programmed to reproduce, will cannibalize nitrogen from their own stalks to deposit starch in the kernel. Nutrient management confounds nitrogen management on most dairy farms. Yet, within the limitations of nutrient management, dairies need to make critical decisions on how to use available nitrogen to supply plants at critical stages. Who is helping you understand the nitrogen needs across your acres as rain, sunshine, and plant growth interact with soil conditions?

Leaf and plant diseases can lower the potential of an elite BMR hybrid to that of a conventional, nonBMR hybrid within a week if disease hits hard. Hybrid genetic resistance becomes a vital part of hybrid selection. Fungicides cannot fully protect against disease situations that can cripple forage quality in the final days just before harvest.

Hybrid disease resistance is critical when disease hits during ear fill, weeks after the last fungicide application has lost its protective strength. Knowing how disease is playing out requires someone to be walking fields and correctly identifying disease pathogens. Hybrids with better disease resistance typically are harvested looking greener. They are higher in starch and possess more digestible fiber. These corn plants feed much differently than hybrids affected by disease.

Knowing a hybrid’s potential strengths and weaknesses is key to the end product available to your nutritionist for balancing economical diets. Diets and the potential income over feed cost will look very different based on a plant’s ability to maintain health and produce starch and digestible fiber.

Know crop people

Who is walking your fields and monitoring your plants’ needs through the newest version of crop modeling? Who is best qualified to advise you on hybrid selection and planting rates within the agronomic constraints that exist across your acres?

You don’t expect your nutritionist to make feeding and herd care decisions without walking the herd. The same standard should apply for selecting and caring for your corn silage crop. Be careful relying on input from someone who has not walked your fields nor understands your hybrids.

Knowing plant physiology and environmental interactions requires a field and forage expert. Diets are made from the bunker, but forage quality is made in the field. These two bookends, which influence cow performance, require very different skills and knowledge base, and you need both skill sets jointly advising your operation.

The person who is walking your fields, understanding your soils, and watching your crops all the way through harvest needs to have a place at the table when making hybrid decisions. Your forage expert can inform and support the nutritionist as they use the corn silage as the base for building and fine-tuning their rations.

Without key insights from your forage adviser, diets can fall short of hitting their mark through no fault of the nutritionist. Forage analysis comes after harvest and does not unveil the subtle clues that a trained agronomic eye can ferret out in the fields long before it ends up in the silage pile. Be sure to include your field experts in your hybrid selection.

Until we unlocked the secrets of cow comfort, many herds struggled to get rations to yield the milk they promised on paper. Finding a true forage expert to join your team is as crucial to cow performance as the professionals on your dairy team today who feed and care for your herd. Your forage management expert may need to be more than a crop consultant hired to scout fields. They need to understand soils, plant physiology, diseases, fertility, hybrid starch/NDFD potential, and chemicals, as well as tillage and planter equipment.

This level of expertise will be the next important member to join the inner circle of advisers to progressive dairies of the future. There is as much opportunity to improve cow productivity from intense field to feedbunk management of corn silage quality as the dairy industry has realized from improvements in cow comfort and barn design over the past 20 years.

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