Many are watching the weather, wondering if the corn crop will mature before a killing frost. We have had cool weather which slowed crop development and then some very hot weather but a lack of moisture. What will September bring?
Across the state, many acres of corn were planted late. Will it mature enough for dry corn, high moisture grain or should it be chopped for corn silage? If corn will not make corn grain, selling it as corn silage is a possible option if there are livestock producers in need of feed. But how do you price it?
No matter how much corn grain is in silage, the correct moisture for harvest is still around 65%. This is critical to good preservation and the digestibility of the forage and grain portions of the plant.
Pricing corn silage is not as easy as pricing grain alone. It is a feed with many variables such as moisture content, grain content, and NDF content and NDF digestibility. All of these factors affect the feeding value of corn silage. Research conducted in Wisconsin, Illinois and Ohio indicates that the average corn silage of 35% starch would have approximately seven bushels of corn in every wet ton of corn silage. This provides us a starting point. Optimal silage quality as determined by the milk per ton would be at the R5.5 stage (half milk line) and harvested at 65% moisture. Two critical points to agree on are:
- What price are we using for corn?
- How will we weight it or determine how much is harvested?
The price of corn agreed on this year is more important than in past years due to the wide basis between new and old crop corn. It is currently over $1.00/bu or more in most markets. In the past we might have used the average price for the week the corn was harvested. This year I would suggest something closer to the price of new crop corn as the starting point. For ease of calculations, let's use $4.50/bu for the price of corn. This would equal $31.50/wet ton of corn silage ($4.50 x 7 = $31.50). If we used $5.00/bu, it would equal $35.00/ton. But what if there are only 3 bushels of corn grain per wet ton of silage? Is it worth only half as much? The answer is most likely no. If the corn silage is harvested at 65% moisture, the vegetative portion is likely to be as digestible as regular corn silage. While it may not yield as many tons per acre, what is harvested will be only 10 to 15% lower in digestible energy and likely higher in protein. It will be important to work with your nutritionist to formulate your diets because this energy will be coming from digestible fiber and not starch.
How will you determine how many tons you bought or sold? Weighing some of the wagons or trucks is a good estimate but probably should be counter checked by doing a calculation of the amount in storage at the end. Silo charts and bag length by diameter are relatively easy and accurate if you know your moisture content of the silage. Bunker and especially piles are more difficult but can be done with some geometry. You need to determine volume in cubic feet of the structure or pile. As-fed corn silage will typically weigh approximately 40 to 44 lb/cu ft packed in a bunker at harvest moisture. Remember, you need to agree on price and how you will determine amount before you start harvest.
Another question is whether nitrates are a concern in the corn? The rule of thumb is that if the corn plant sets an ear, there is little risk of nitrate accumulation. If you suspect that it could be a problem, be sure to test it. Nitrates also tend to accumulate more in the lower portion of the plant. You could chop at a 15-inch height to help with nitrate levels in the silage. Also, fermentation of the silage will cut the nitrates in half. As a rule, if the nitrate level is over 1,000 ppm, you should take some action to minimize the use such as feeding only half as much of that silage. If levels are over 3,000 ppm, this is in the high concern level. Be sure to work with your nutrition consultant.
Is high moisture corn, snaplage or earlage an option for you? It is best to harvest snaplage or earlage at 35% moisture. The snaplage or earlage should be well processed with no visible cob pieces. High moisture corn is optimal at 28 to 30% moisture. At these moisture contents, they can be stored in any type of structure or bag. Make sure storage is sized accordingly for adequate daily feed out.
Again, follow good silage making guidelines, consider using an inoculant, and always KEEP SAFETY IN MIND!