How to adjust rations to incorporate BMR corn silage -

This article was #22 in PDmag's Top 25 most-well read articles in 2010. Summary: BMR corn silage has become a valuable tool in dairy rations for helping to increase milk production and improve herd health. When implementing the new ingredient, nutritionist John Brouillette recommends modifying the ration over several days to maximize success.

Click a link below to read other articles in the Top 25:
Time to reclaim animal well-being as our issue: http://bit.ly/PDTop25_23
3 open minutes with Doug Maddox and Gary Genske: http://bit.ly/PDTop25_24
3 open minutes with David Martosko of HumaneWatch: http://bit.ly/PDTop25_25

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Brouillette BMR

As forage levels increase in lactating cow diets, forage quality and feed management are becoming top priorities on today’s dairies. Over the past few years, highly digestible BMR corn silage has emerged as a valuable tool to help dairy producers increase production, bolster herd health and improve profitability while feeding high-forage rations.

BMR corn silage hybrids are evolving in agronomic performance and yield, while maintaining the high levels of digestibility that work well in lactating cow diets. Due to this continual improvement, more nutritionists and dairy producers are considering BMR corn silage to increase productivity and generate higher income-over-feed costs (IOFC).

Planning for a transition to BMR corn silage
Dairy producers often make ration changes to take advantage of the most cost-effective ingredients and manage inevitable changes in forage quality. Any ration change requires proper planning, timing and implementation to allow the rumen environment to gradually adjust. Dairy producers and nutritionists have discovered that slowly modifying the ration over several days can help maximize success.

The same guidelines hold true for dairy producers who are incorporating BMR corn silage in a dairy ration for the first time.

BMR corn silage has several nutrient parameters that are similar to conventional corn silage, including crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF) and starch levels. But there are unique attributes of BMR corn silage that dairy producers should consider before adding it to the diet or replacing conventional corn silage with BMR.

These compositional differences are responsible for the positive impact BMR corn silage makes in lactating cow diets:

• Lignin levels are 25 percent to 40 percent lower in BMR than in conventional corn silage.

• Thirty-hour neutral detergent fiber digestibility (NDFD) may be 10 percent to 14 percent higher in BMR than in conventional corn silage.

• The rate of digestibility (Kd) may be 25 percent to 35 percent higher in BMR than in conventional corn silage.

Incorporating BMR into lactating cow rations
To take full advantage of the value of BMR corn silage, work with your nutritionist and consider these feed management guidelines:

• Meet with your nutritionist well before you plant BMR to learn about its merits, characteristics and feeding guidelines. Consider how you will feed BMR for the highest return on investment. If you only are able to feed BMR to a portion of your herd, high-producing groups will generally show the most dramatic response.

• Determine where the BMR corn silage will be stored on your operation. Although BMR can be mixed with conventional silage in a ration, it is best to store the different types of silage in separate structures.

• Ask your herd nutritionist to create a sample diet with BMR corn silage and other ingredients on the farm to predict the impact it will have in dry matter intake, rumen efficiency, grain savings and milk production.

• Once harvested, test your forages at a lab that has experience analyzing BMR corn silage using both near infrared spectroscopy (NIR) and wet chemistry/in-vitro methods. When comparing the nutritional composition of conventional corn silage with BMR corn silage, the most notable differences will be seen in lignin levels, NDFD and rate of Kd. This analysis will help your nutritionist best balance your new ration.

• When planning to transition to BMR, take its high digestibility into account and formulate the diets using dynamic ration formulation software. This software will “utilize” the digestibility of forages to optimize health, productivity and profitability.

• The higher levels of digestible fiber will enhance rumen microbial efficiency and replace a portion of the energy from starch sources. This leads to higher dry matter intake (DMI) and the need to feed at least 15 pounds of dry matter BMR corn silage per cow.

• Visually evaluate the diet presented to make sure the diet is well-mixed, has adequate particle size and has the appeal of the group of cows that will be consuming the mix.

Monitor your herd and fine-tune your ration
Monitor herd performance while transitioning from conventional to BMR corn silage. The fiber in BMR corn silage is more digestible and may result in an increase in group DMI. Keep an eye on total ration starch, NDF and effective fiber levels. Additional sources of effective fiber may be needed to maintain optimal rumen function and control the feed’s rate of passage through the rumen. As with any ration change, you may see changes in manure consistency, milk components and milk urea nitrogen (MUN). Monitor these areas and work with your nutritionist to fine-tune the diet.

To evaluate BMR’s return on investment, consider evaluating ration costs, IOFC and milk production of fresh cows at zero to 40 days in milk (DIM). You also may monitor peak and summit milk production, non-esterified fatty acid (NEFA) levels of fresh cows and the incidence of metabolic disorders or other herd metrics over time. PD

References omitted due to space but are available upon request by emailing editor@progressivedairy.com .