By Dianne Shoemaker, Mark Sulc and Bill Weiss
One thing you can say about dairy farming is that there is never a dull moment, and 2019 is no exception.
Many farms are facing or will be facing a shortage of forages for animals of all ages.
What are the realistic forage options for acres that have either not been planted, or have had planted crops damaged by too much rain?
With July 1 just around the corner, Mark Sulc, OSU Extension forage agronomist, and Bill Weiss, OSU Extension dairy nutritionist, help address the forage dilemma.
So, what are your best options for quality and quantity?
– Corn plant silage — Still has the highest potential yield but harvesting at the right moisture is the biggest risk;
– Forage sorghum — BMR best for lactating cows, conventional varieties okay if BMR not available;
– Sorghum Sudan — BMR best for lactating cows, conventional varieties okay if BMR not available;
– Sudan grass — BMR best for lactating cows, conventional varieties if BMR not available;
– Oat silage — Safer option if feed inventories not critical, can mow and wilt to correct harvest moisture;
– Oat and winter rye mix silage — Has the advantages of oat silage with a slightly higher yield in the fall and the potential for rye silage harvest in the spring; and
– Italian ryegrass silage — Small fall harvest with three cuttings next year starting in April.
Corn plant silage
The biggest risk with late-planted corn is getting moisture down to a reasonable level at harvest.
With current soil moisture conditions, it will be a crapshoot when many farms will be able to plant.
Corn planted into July will not make corn silage as we know it because it won’t have much ear and will be low in starch.
This silage will primarily be a source of fiber with potential yields about half of normal.
Harvesting at the proper moisture will be critical to a successful fermentation (drier than 30% DM up to about 40% DM).
Before a frost, many of these plants will be about 20% DM. Some late-planted corn may require a frost to allow the plant to dry down.
Because leaves die after frost, plants look drier than they are, so measuring dry matter regularly is essential.
When a plant is frosted, the window of opportunity to harvest as silage, before the plant is too dry, may be limited depending on local weather conditions.
It is critical to regularly monitor plant moisture post-frost and be ready to harvest. This high fiber feed will probably contain about 60% NDF.
Substantial diet changes must be made (work with your nutritionist) that are likely to include increased feeding of corn grain.
With higher corn prices looming, this is not an attractive option, but the tradeoff is feeding more expensive hay.
Forage sorghum and Sudan grasses
BMR varieties are most desirable, but seed may not be available.
If this is the case in your area, conventional varieties are your next best choice. Plant by July 15 and plan for one cutting.
A mid-September cutting will optimize quality for milking cows.
An early October cutting will have a much higher yield, but the higher-fiber forage will be more suited for heifers, dry cows or beef cattle.
Sudan grass harvested at 50 days of growth is an okay feed for dairy cattle. At 60 days, it is more challenging to feed to dairy cows for good milk production.
If the sorghums are frosted, prussic acid formation in the plant is an issue. It can be mitigated by ensiling, but avoiding frost is the best option.
Do not plant oats for silage before the last week of July or yield will suffer.
Overall potential yield is the lowest of the forage options. Yields of 1.5 to 2 tons of DM per acre (about 5 to 5.5 tons at 30 to 35% DM) of chopped oat silage are possible if planted in early August.
Harvesting between late boot, or early heading, will optimize quality. Potential feed value will be similar to mid-bloom alfalfa.
As a grass, inclusion rates in a lactating cow diet would have to go down, but it is a very acceptable feed. Potential challenges include rust infection in damp conditions.
How this could impact yield and feed quality depends on when the infection occurs.
Oats and winter rye silage
Planting this mix would allow a fall harvest and a potential spring harvest, understanding that the window for harvesting rye silage in the spring to optimize feed quality is usually very short.
The rye harvested in early spring can yield 2.5 to 3 tons of DM per acre of dairy-quality forage (boot stage).
The oat/rye mix should yield slightly more than oats alone in the fall cutting, with the potential for the spring rye harvest.
Italian ryegrass silage
This crop emerges as fast as oats and could produce up to a ton of dry matter per acre in the fall if planted in August, and less if planted as late as mid-September.
This crop would also be available for a first cutting in late April or early May.
Plot work with three cuttings has yielded between 3 to 5 tons of dry matter from improved varieties with good winter survival and adequate moisture.
Do not let a lot of growth go into the winter to avoid mold growth, so make a late fall harvest mechanically or graze to a height of 3 inches.
This crop will shut down by the end of the summer following establishment. As a grass, harvesting earlier optimizes quality.
If planted in September and harvested in late fall, the quality will be superb (NDF 48% and NDFD about 80%).
August plantings harvested in late fall will not be quite as high in quality. It will probably have protein in the mid-teens and NDF in the mid-50s.
It is a medium quality forage, but with proper diet formulation can work for lactating cows.
Seed cost will be higher than oats with a higher feed value similar to early mid-bloom alfalfa.
These forage options all require adequate nitrogen fertilization to maximize yield potential. Check any potential herbicide restrictions from the previously planted crop.
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