Did you notice the title: “forage” program, not field crops? That is deliberate, because this article concerns the use of field crops harvested as forage and fed to ruminants – mainly dairy cows but other livestock as well. You can get plenty of information on grain corn, soybeans and cereal grains from other sources, but among the FARMING magazine readership the focus is on forage crops. For example, in the U.S. only about 7 percent of the corn crop is harvested for silage each year but in the Northeast it’s at least 50 percent. It may be even higher in 2017 because wet spring conditions delayed corn planting in much of the region, and then worries about Hurricane Irma caused some farmers in Pennsylvania and the Delmarva area to chop their corn for silage instead of waiting for grain harvest and running the risk of severe damage.
Determine forage crop inventories
Now is a great time to check (or recheck) your forage inventories, including your various silage crops and dry hay as well. Use silo tables available online and in various farming handbooks to estimate the amounts in each silo. This may take some figuring because if you have already fed some of the silage from a top-unloading tower silo the remaining silage will weigh more per foot of height. An example, using the University of Wisconsin silo capacity table, is available online at (http://cdp.wisc.edu/pdf/Feed%20charts.pdf.)
The estimated dry matter capacity of silage in a 20- by 60-foot tower silo is 152 tons. You filled the silo to the top and have fed off 20 feet so there is 40 feet of silage remaining. Do not use the silo table values for the silo capacity in 40 feet of silage; first, determine the dry weight of silage in the top 20 feet of height (33 tons) and subtract this from the 152 tons the silo held when full. The approximate tons of dry matter in the remaining 40 feet of silage is 152 minus 33 or 119 tons. Divide this figure by the percent dry matter of the silage (determined by forage analysis or on-farm testing) to arrive at total tons. For instance, if the silage is 35 percent dry matter, then the amount of as-fed silage in the example is 340 tons. Do not make any inventory calculations until at least a few weeks after silo filling to account for settling and fermentation losses. There will be some additional feeding losses, but with good management these losses should not be great.
The next step
By now you are probably well into your winter feeding program and should know how much of each type of forage you are feeding. Therefore you can determine how long current inventories will last, assuming no significant change in rations. If you do not plan on a significant change in the number of animals you will be feeding between now and next year’s forage harvest then use your current feed program to calculate how much of each feedstuff you will need. If you will increase herd size, calculate current forage fed per head and use this to estimate your farm’s forage needs in the coming year. For hay crop silage you may decide to estimate how much forage you’ll need only until mid-summer since the new feeding season often begins a month or so after you harvest first cut.
The situation is somewhat different for corn silage than it is for hay crop silage. After legume and grass forages are ensiled they undergo little change between full fermentation and feedout. With hay crop silage stored in bunkers and drive-over piles this assumes that the silage was chopped at the correct moisture content (little or no silo effluent) and then was well-packed and covered with a plastic tarp that’s securely weighted down. But corn silage has high starch content, and the starch continues to increase in digestibility for several months after ensiling. Therefore, a ton of corn silage has greater milk-producing potential four months after ensiling than it does one month after silo filling. That is why a good goal is to begin feeding corn silage no sooner than around the beginning of the new year. If you cannot accomplish this goal right away, every week you delay feeding “new crop” corn silage will increase its potential value to your livestock.
I mention the goal of delaying feeding new crop corn silage at this time because if you have already been feeding 2017 corn silage you may want to plan on planting enough corn for silage in 2018 that you have enough for a 14-month supply. Does this mean planting more corn next spring than you did in 2017? Probably, but this depends somewhat on the corn yield you had this year. Although 2017 was a generally poor year for corn in much of the Northeastern U.S. and the adjoining areas of Canada, prior experience should give you a good idea of what normal corn yields are on your farm.
Forage crop trends
The trend on many progressive dairy farms has been an increase in the amount of corn silage relative to hay crops. That is in part because corn silage is more labor-efficient: only one harvest per season instead of three or more. Another reason is yield: On average corn harvested as whole-plant silage yields more dry matter per acre than do most hay crops. For instance, 18 tons of corn silage harvested at 35 percent DM will yield 6.3 tons of dry matter per acre whereas few fields of alfalfa or grass will yield this much per acre even if cut four or five times. If you rotate one of your older hay fields to corn harvested for silage you may find that on a yield basis you can replace two acres of worn-out hay crop with one acre of corn for silage. This will have an impact on your forage rations, so any large changes should first be reviewed and discussed with your dairy nutrition consultant.
Changes that result in considerably more corn silage will probably mean the need for additional storage. If planting more corn for silage will be a one-year deal, options include silage bags or a drive-over pile. A drive-over pile may be cheaper than putting up silage bags but you will need a “high and dry” site or you will be playing in the mud. We have used silage bags and drive-over piles at Miner Institute and have been pleased with both. However, if more corn silage will be a long-term change, you should consider other permanent storage options in addition to bags and drive-over piles, including bunker silos. Plan ahead for where you will store the various types of silage. Avoid covering the previous year’s silage with new crop forage; this is more of an issue with bunker silos than with other types of storage. Speaking of silo covers, if you have not tried one of the high-density, low oxygen permeability silo covers, you might consider it. Research has shown that even with their moderately higher cost, the low permeability covers are economical because of reduced spoilage losses and improved silage quality.
Seed orders for 2018
By now many farmers have most of their seed corn ordered and for good reason since early ordering results in the best selection of hybrids, especially new releases where seed supply may be limited. An option with early ordering is early payment, either at the time you place the order or a month or two later. Check with your tax advisor in deciding whether it’s better to pay for the seed in 2017 or in 2018, but in general early-pay programs for farm seeds have enough of a discount to make them a good deal. When I managed the Miner Institute crop operation I did not have a strong preference for the various seed sizes or shapes (rounds vs. flats) of seed corn because research has shown that this variable has little impact on germination or growth – with one exception. What I did avoid were very small rounds since our finger pickup corn planter would overplant this seed unless we operated it at a somewhat slower ground speed. And who wants to go slow during corn planting?
Look before you leap: Read the herbicide label
Make sure that the herbicides you use in one year do not prevent your rotating to a different crop the following year. Most of the problems involve rotating from corn to establishing a forage crop such as alfalfa. Even though some postemergence corn herbicides are used at very low rates they can still be very persistent in the soil. In the old days it was not unusual to see atrazine toxicity to alfalfa seedlings when too much of this herbicide was used the year prior to seeding. We seldom encounter this particular problem anymore because the maximum legal application rates of atrazine have been considerably reduced, but there are other herbicides that can pose a threat. Always read the label – and the time to do so is before you apply the herbicide, not when trying to figure out what went wrong!