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9 Tips to Achieve High Quality Corn Silage

Corn silage is the foundation of many winter feeding programs. It provides an excellent source of energy that can reduce the costs of providing energy in a cow’s diet while also serving as a digestible fiber source. The details outlined below can help ensure that high quality feed is preserved.

1. Spend time getting equipment ready before harvest

General maintenance, such as greasing equipment and sharpening knives, needs to be done well in advance of the anticipated chopping date. Advance planning is important for a timely harvest at the proper moisture content.

2. Harvest timing

Harvesting at the correct moisture promotes favorable fermentation in the silage crop and decreases storage losses, so moisture content should be the determining factor for when to harvest. For bunkers, silage should contain between 30% to 35% dry matter (65% to 70% moisture). Upright silos and bags should contain 35% to 40% dry matter (60% to 65% moisture).

3. Correct length of chop:

Silage needs to be chopped finely enough for good packing to quickly eliminate oxygen and establish a good fermentation process. The chop length needs to be long enough to promote cud chewing. Thus, the recommended theoretic length of chop (TLC) is a compromise between these two factors.

Alfalfa haylage or silage = 3/16″

Unprocessed corn silage = 3/8″ to 1/2″

Processed (kernel processor) corn silage = 3/4″.

4. Adjusting silage choppers with on-line kernel processors

The optimum moisture content of silage harvested with a chopper containing a kernel processor is 62% to 65% (35% to 38% dry matter) to capture additional starch accumulation in the corn kernels. Most of the corn kernels should be pulverized to a similar size. To optimize starch digestion and provide adequate effective fiber, the recommendation is to cut to .75″ theoretical length with an initial roller clearance of 0.12″.

5. Keep knives sharp and properly adjusted throughout the filling process

Sharp knives prevent the shredding of silage, resulting in a more uniform chop. This allows for maximum forage compaction, good fermentation and sufficient particle size to prevent health problems in the cow.

6. Fill silos rapidly

Silos should be filled quickly to help eliminate air from the feed. Silos should be filled within a week to prevent dark brown and black bands within the silo. Fill bunkers from the back to the front, adding forage on a wedge and not from the bottom to the top in layers.

7. Pack, pack, and pack some more

Tightly-packed silage ferments more quickly and contains fewer yeasts and molds than loosely packed silage. Packing silage helps decrease the size of oxygen pockets, resulting in fermentation end products the cow can use better to make milk.

8. Cover silos immediately after filing

Bunkers or piles of silage need to be covered with 6 mil plastic tarps and weighted with tires (tires should touch each other) immediately after filling. The sides of bunkers also should be lined with plastic. Upright silos should be leveled and capped with a silo cap immediately after completion of filling.

9. Let silage ferment 3 to 4 weeks before feeding

Unfermented feed is higher in fermentable sugars and can cause cows to go off-feed. Gradually transitioning cows over seven to 10 days to newly-fermented silage is recommended. Data suggests that fermentation and maximum percentage of available starch may not be achieved until four months after ensiling.

Is There a Genetic Limit to Milk Production?

Cow comfort and herd management, not genetics, is limiting production in most herds, say these geneticists.

With herd averages approaching 40,000 lb of milk per cow and the single lactation record nearly double that, it begs the question: Are we approaching the genetic limits of milk production.

In a word: No, say Kent Weigel, a geneticist with the University of Wisconsin and Chad Dechow, a geneticist with Pennsylvania State University.

“We really aren’t,” says Weigel. The same question was asked 40 years ago when Beecher Arlinda Ellen produced 55,561 lb of milk in a 365-day lactation. That record wasn’t broken for 19 years. But then, the record toppled—again and again and again. Last year, Ever-Green-View My Gold-ET, set a new single lactation milk production record with 77,480 lb in 365 days. In percentage terms, My Gold out-did Ellen by nearly 40%!

“I think we have a little way to go before we reach the limit,” says Dechow. “If you look at the Predicted Transmitting Ability for milk on these record cows, they’re just slightly above average.”

The other way to look at, says Weigel, is to consider feed intake as a multiple of the maintenance requirement. In the 1980 and 1990s, top cows were producing maybe five times their body maintenance levels. “We didn’t have any cows at 6 or 7X maintenance; now we do,” he says.

“So there’s no evidence we’re hitting a limit, but at some time, we might simply reach the physical capacity of the udder, I guess.”

At what cost?

“To me, it more a question of cost,” says Weigel. “Is the extra pound of milk worth the cost of producing it, and is it my best strategy for profitability? If I have to spend 99¢ to get $1 back, is it worth it? Is increasing production per cow the lowest hanging fruit on my farm?”

Selecting for larger cows, with bigger frames and more rumen capacity, is not the answer, say both Weigel and Dechow. “Larger is not more efficient; larger is actually less efficient,” says Dechow. “We actually need smaller cows to be more efficient at current levels of milk production.”

Look at Jerseys. Some Jerseys are making 40,000 lb of milk, and they don’t have nearly the size and scale of Holsteins.

Health traits are becoming a larger proportion of selection indexes, which is a good thing. Unhealthy cows simply burn through calories to power their immune system. “Healthy cows produce more,” says Weigel

A bigger issue might be that farmers are placing less urgency on reproduction than they were a decade ago, says Dechow. Many herds are now reliant on reproductive hormone protocols to get cows bred. But if those tools are ever lost, it could become a problem.

Inbreeding is also a concern, and it continues to increase. Bull studs are doing a good job of weeding out detrimental genetic recessives. The real issue, says Dechow, is that the industry is likely weeding out just the worst recessive genes with obvious problems. “The ones that we don’t see as major recessives may be causing more subtle problems,” he says.

Still, both Weigel and Dechow say industry selection indexes do a pretty good job of balancing production, health traits and conformation. While every herd doesn’t need a customized index, the geneticists say each dairy owner should think about what he or she is trying to accomplish with the genetics they buy. “If there are a diversity of goals, there will be diversity of selection and inbreeding won’t be as big of a concern,” says Weigel.

Genetics isn’t really the issue limiting production and efficiency, he says. “The limiting factors in most herds are cow comfort and herd management.

“Most herds are doing 70% to 80% of things right, and are getting good production. But if they can get 99% right, wow! That’s when you see production jump.”


What is the Effect of Rain Damage on Hay?

Hay that has been cut and then rained on can lose quality in four ways. These include: 1) leaching of soluble carbohydrates, vitamins and minerals, 2) increased and prolonged plant respiration, 3) leaf shattering, and 4) microbial breakdown of plant tissue.

Leaching of carbohydrates, vitamins and minerals is usually at its highest when the hay has dried somewhat and we then have a prolonged rain. Rainfall right after cutting usually results in less leaching of nutrients and a quick splash-and-dash shower normally doesn’t result in large losses of these nutrients on freshly cut hay.

Increased or prolonged respiration occurs when hay is not allowed to dry sufficiently to stop the plant’s metabolic processes. Hay must reach moisture content of less than 30 percent for respiration to be reduced to acceptable levels. Hay that is rained on when relatively green will continue to respire for longer periods of time, resulting in the loss of forage nutrients and dry matter yield.

Likewise, partially dried hay that is rained on can continue to respire for longer periods resulting in lower quality and yield of hay.

Increased leaf shatter is another problem associated with hay that has been rained on. Wet hay usually means more mechanical handling of the hay in order to dry it. Since leaves tend to dry quicker than stems, any increased raking or tedding tends to shatter leaves from stems. Since more of the soluble nutrients are in the leaf tissue, the loss of leaf blades while raking and baling can reduce hay quality substantially. Loss of leaf blades can also result in reduction of dry matter yields.

Microbial breakdown of plant tissue occurs when fungi, molds and other microorganisms begin to feed on the downed hay. These organisms develop rapidly in warm-moist conditions and feed on the dead plant material. Hay that is lying on the ground and remains wet for long time periods becomes a perfect environment for these organisms to live and breed. They can quickly consume plant nutrients and destroy plant cell structure resulting in loss of dry matter yield, nutrient content and given time, will completely rot the hay.

What are the consequences of hay being rained on? Research conducted at the University of Kentucky by Michael Collins indicated that we can lose up to 5 percent of the dry matter per inch of rain on cut hay. Digestibility can be reduced by 10 percent or more due to leaching of nutrients and leaf shatter. A similar study done at Iowa State University reported protein loses of 3 percent and total digestible nutrient reduction of 4.6 percent.

One fact seems to hold true, you still cannot tell what the actual quality of the hay is until you have it tested. Testing it is your best strategy for determining the nutrient quality you will get from the hay. Sampling rained-on hay will give you the information you need to design a supplementation program that will keep your animals in good shape during the winter feeding period. Your local county Extension Educator can help you with sampling techniques, hay probes, and testing. For a small investment of time and money, testing will pay off big in the health and nutrition of your herd.