If you’ve been involved at all with dairy nutrition over the past six months you’ve definitely heard terms like “feed utilization,” “improved efficiency” and “rumen microbial breakdown.”

With prices climbing to unprecedented heights, we’ve focused our attention on feed efficiency, rather than cost, to ensure each pound of feed is best utilized to maximize outputs.

Simply put, feed efficiency measures how many pounds of milk are produced by 1 pound of feed. A base goal for feed efficiency should be 1.5, which means 1.5 pounds of milk is produced for every pound of feed consumed. To achieve this standard a cow producing 80 pounds of milk should eat about 53 pounds of dry matter (DM).

To ramp up efficiency, we must focus our attention on two key elements: the ration and the rumen. What we feed cows will inevitability influence how well they can digest it, and, therefore, influence rumen microbial populations and rate of feedstuff breakdown.

Corn silage is the basis of digestibility
We continually see corn silage levels climb in dairy rations, and for good reason. Silage is a relatively inexpensive feedstuff that provides energy to the diet and can easily be grown, harvested and ensiled. The many positive qualities have led producers to feed rations with more than half the diet composed of corn silage. Because it’s such a large part of the ration, corn silage digestibility and efficiency are especially critical.

There can be huge variability in silage. If we’re feeding corn silage with high levels of indigestible fiber, much of the feed will pass through the rumen and be turned to waste, rather than being broken down by rumen microbes and turned into usable energy and nutrients. This underscores how important it is to feed highly digestible silage hybrids of excellent quality.

High-quality silage hybrids bring more to the table than the energy typically associated with diets made with corn silage from typical grain hybrids. These silage hybrids modify:

• Kernel strength
Softer kernels are more easily broken down by the rumen, which improves fermentation so your cows may absorb more key nutrients.

• Lignin levels
Lower lignin levels mean more digestible matter. Whether it’s more starch, protein or fiber, the rumen should be able to best utilize each pound of feed.

• Digestible fiber
Fiber is necessary for proper rumen function and health, which makes digestible fiber even more important. More digestible fiber results in more available energy for milk production, reducing the amount of corn needed to produce the same amount of milk.

• Starch levels
Starch is used as a key energy source, which means adequate levels are necessary for daily requirements and milk production. Some corn silage hybrids are 3.5 to 5 percent higher in net energy for lactation than conventional corn silage hybrids, improving efficiencies and reducing the amount of grain needed to achieve the same production.

A 2007 University of Missouri study confirms just how well cows utilize corn silage hybrids. In the study researchers divided 63 cows into one of two groups. The control group was fed yellow dent corn hybrids, while the experimental group was fed high-quality corn silage hybrids. Results showed cows in the experimental group produced the same amount of milk while eating 2 pounds less dry matter, resulting in a 6 percent improvement in feed efficiency.

Another study at the University of Kentucky found that when cows were fed corn silage from high-quality hybrids, 3.5 percent fat-corrected milk production jumped 3 pounds while intake remained the same. Feed efficiency also improved, moving from 1.38 to 1.43.

Rumen bugs reign supreme
The ration we feed the cow is at the mercy of rumen microbes, which are ultimately responsible for the breakdown and digestion of nutrients. When fed properly, rumen microbes have the ability to break down more feed and produce more energy for use by the cow, thus improving feed efficiency.

In high corn silage diets, we typically walk a fine line between overfeeding a high-energy feedstuff and not meeting the cow’s energy requirements. When energy levels rise above needed levels the rumen pH drops, killing microbial populations and resulting in rumen acidosis.

Another advantage to nutrient-dense corn silage hybrids is that the whole plant provides the high energy cows need to maintain productivity, while also providing more digestible fiber. The digestible fiber keeps the rumen microbes healthy.

In the University of Missouri study, research also measured the amount of volatile fatty acids (VFAs) in the rumen. VFAs are produced by rumen microbes during digestion and are a good measure of ration digestibility. Results demonstrated that cows fed high-quality corn silage hybrids produced 13 percent more VFAs, showing an improvement in digestibility while ensuring a healthy rumen environment.

Management influences efficiency, too
How well you manage cows plays a critical role in how well cows utilize feed, remembering your focus should always revolve around rumen health, energy expenditures and feed utilization. If one of these three areas is out of balance, feed efficiency rates can suffer.

• Minimize stress
The more energy cows spend fighting to get to the bunk and traveling back and forth from the milking facility leaves that much less energy available for milk production. As a manager you can improve efficiencies by minimizing the number of stressors your cows encounter every day, directing more energy to milk production and further improving feed efficiency.

• Account for weather changes
Under heat-stress conditions, cows spend more energy dissipating heat and less energy producing milk. Keep cows cool with proper heat abatement methods as well as by maintaining rumen health with a highly digestible corn silage variety. Ensure the ration is kept out of the weather to maintain palatability and high dry matter intake (DMI).

• Monitor change
Fluctuations in DMI and production can often be the result of ration or environmental changes. To ensure the ration is promoting optimized DMI and resulting production levels, monitor feed efficiency on a regular basis to identify major trend changes in feed efficiency. This can be done by knowing feeding levels and estimated DMI, as well as average daily milk production.

As feed, fuel and fertilizer costs continue to climb, so will our ration costs. To get the most for every dollar spent, it’s critical we get the most back in the form of milk. By improving feed efficiency, you can get more milk from each pound of feed, making high-quality corn silage hybrids a good investment. PD

Jerry Weigel
Nutrition Manager at BASF
gerald.weigel@basf.com