Pasture and Forage Minute: Considerations for Corn Silage, Last Cutting Alfalfa and Forage Inventories
Corn Silage Keys: Pack and Cover
Making good silage includes many factors. Are you prepared for corn silage harvest this year?
One of the most difficult pieces of silage harvest is getting the correct packing density. A good density goal is to have 14 lb. of dry matter per cubic foot. Pack only a four- to six-inch layer at a time and have proper tractor weight. The 800 rule can be used to determine how fast a tractor can pack based on weight. Take the weight of the tractor and divide by 800. That will give a how many tons per hour a tractor can pack to have a good density. For example, if the tractor weighs 32,000, divide that by 800, and we estimate 40 tons per hour that tractor can pack.
Silage harvesters can put out impressive volumes of chop, often overwhelming the packer with too many loads before they can get a proper pack. Remember, the speed of chopping should be determined by the packing speed, not the silage chopper.
The next item to address is covering the pile. Even after the silage is packed correctly, air and water can penetrate the outer layers and severely damage the quality and quantity of silage. Additionally, molds, unwanted bacteria and fungi have a prime place to grow in uncovered silage.
Studies at Kansas State University have reported up to 40% losses in dry matter from the top three feet of silage in uncovered silage bunkers compared to covered. Covering with plastic will give about an 8:1 return on investment for the producer.
Silage should be covered as soon as possible. Whether using standard black and white 6mil plastic or adding an oxygen exclusion layer, make sure the edges are sealed and the top has plenty of weight on it. This helps hold the plastic as close to the pile as possible, even in high winds, to reduce oxygen exposure.
A solid pack and a good cover can reduce losses, increase profit and be safer when facing the pile.
Last Alfalfa Cutting
Best management practices, like cutting alfalfa in the morning to speed drying to preserve sugars and starch for higher quality hay, are followed by most producers. However, timing the last fall alfalfa cutting seems to vary among growers; since the forage quality does not change as rapidly in later cuttings compared to earlier cuttings.
Usually, the first week of October is the average first killing frost (28°F) for alfalfa, so targeting Sept. 1 as the last alfalfa cutting would allow plants six weeks to store root carbohydrates prior to the killing frost. Last cutting timing decisions will potentially impact your crop’s winter survival and vigor next spring. For example, in five-cutting irrigation system, research has shown that the next spring first cutting yield will be lowered by approximately the same amount as the yield from a late fall last cutting.
This year’s drought may have extended the traditional 35 days between cuttings for four-cutting growers, so some producers are just now harvesting their third cutting with possibly only about six weeks until the first fall frost.
What may be the risk if these producers seek yet another cutting during this growing season?
If the first fall frost occurs earlier than normal, then winter injury is a risk. However, conditions vary from year to year, and plant winterizing generally begins about three weeks before the first frost date with the “ideal” being six weeks of uninterrupted growth in the fall to become well winterized. Winter survival of later cuttings will improve with younger stands (except new stands, winterhardy varieties and disease-resistant varieties. For those needing extra cash or forage this fall, the higher dairy quality forage values may offset the financial risk of needing to re-establish alfalfa stands next year which winterkill.
For most producers, the best strategy is to avoid harvesting alfalfa (Sept. 1 to Oct. 15) during the critical fall period six weeks before the first killing frost. This allows plants to enter winter with higher root carbohydrates.
Fall Forage Inventory
Summer is flying by and fall is just around the corner. While it may seem like a weird question to ask already, do you know how much feed or hay you have for this fall or going into winter?
Last year’s winter didn’t do anyone’s bale yard a favor and a dry spring and early summer didn’t help alleviate pressure on forage resources. With tight supply and high costs, it’s worth asking if you have enough feed this fall or winter for your current cattle numbers.
Consider the “best case” and “worst case” scenarios. Count bales, measure silage, calculate remaining pasture and get a real idea of how many calves and feeders you may have. If more forage is needed, there is still a very short window to plant a fall grazing crop, find some extra acres to hay or decide to chop a bit more silage if the situation calls for it.
While temperatures are still warm, those wanting to plant some extra forage should skip the warm-season species and focus on cool-season crops that will really take off in the fall. Right now, your two best choices are oats for either hay or grazing and turnips for grazing. Winter small grains like cereal rye, wheat and triticale can be mixed with the oats and turnips. They won’t produce much fall growth, but they will provide some early grazing next spring.
If growing your own feed isn’t an option, another action plan to consider is buying feeds that are cheaper now and storing them through the winter. We know how to do this with hay and silage, but what about distillers grains? Mixing distillers with low quality feeds and packing in a bunker or in a bag can significantly reduce the cost of protein and energy supplements during the winter months. This is especially helpful if cows are coming of off grass thin and need to improve condition before calving.
Planning is indispensable. Having a feed inventory, adding needed forage when able, and checking prices and availability of purchased feeds now will go a long way to reducing the anxiety of what we will feed our cows this fall and winter.