Piles should be built at no more than a 30-degree slope and care must be taken not to introduce dirt into the silage
Producing high quality silage leads to production of high quality cattle, says ruminant nutritionist Leland Fuhr.
Silage handling and storage are key to achieving that quality and they depend on storage type and design, crop staging and proper packing and protection, among other requirements.
Fuhr shared his assessments during a July 21 session at the Ag in Motion outdoor farm expo, this year held in a virtual format because of pandemic restrictions.
Silage is developed through the fermentation process in which anaerobic bacteria convert sugars into volatile fatty acids, mostly lactic acid. The low pH is inhospitable for bacterial longevity so feed value is preserved in storage.
Fuhr emphasized that proper storage is essential.
“No matter the situation, storage quality always trumps chemical quality,” he said.
Feed quality rarely improves in storage. Instead, quality is determined by:
- Harvest date (maturity) of the crop
- Crop species (grass vs. legume)
- Harvest and storage
- Soil fertility
- Choice of cultivar
If silaging alfalfa, ideally it should be cut before bloom and allowed to wilt but not dry down, to achieve 55 to 65 percent moisture. Sugars in the crop diminish as the crop sits after cutting and lower sugars result in poorer fermentation.
Corn, which is straight-cut, should be at 65 to 68 percent moisture for best results, Fuhr said. However, if early frost kills the crop it may have to be cut before that point to avoid mould and mycotoxin growth.
“Some will talk about using the milk line or black line to determine the maturity of your silage corn and when to cut it but the truth be told, the thing you have to have is the moisture content in order to get the proper fermentation so it’s best to go off of moisture and for all intents and purposes, don’t pay as much attention to the cob.”
When using barley for silage, ideally it should be straight cut at mid- to firm-dough stage. However, it is commonly swathed first and then chopped. It’s not necessary to allow wilt on barley unless the silage is going into a tower silo, Fuhr said.
If cut at the boot stage, wilt is advisable. At that point yield has already been sacrificed.
Particle length at harvest is also a consideration. Finer particles pack better but if they are too fine, its unhealthy for the animals that will consume the silage. Moisture content also affects particle length.
In general, drier material results in longer particles at chopping.
Storing silage in a pit or pile is common on the Prairies. Piles should be built at no more than a 30-degree slope and care must be taken not to introduce soil into the pile because it can contain micro-organisms that promote mould or toxin development.
The other major enemy of silage is oxygen. That’s where adequate packing enters the picture. High density and low porosity are the goals.
“I find that silage packing is one of the most overlooked areas,” said Fuhr.
Often the most inexperienced operator is assigned silage packing duties. That can backfire if the pile isn’t sufficiently packed or if an overzealous operator puts dirt into the pile.
Fuhr said packing with smaller tractors can be more effective as opposed to larger tractors with triple or flotation tires.
He also recommended covering the pile as it is built and packed, with adequate plastic and weights, usually old tires, to hold it down.
If using bags for silage, tarps can be used to cover them to eliminate the need to constantly check for holes and rips. If holes are discovered, they should be patched immediately to limit oxygen entry.
When feeding the silage, don’t leave loose piles overnight, said Fuhr, and do not feed any visibly mouldy or spoiled material. Remove as little cover as possible that still allows adequate access to the face.
Safety dictates that people not stand too close to a silage pile face. The material generally weighs about 45 pounds per cubic foot, and people can be killed from either weight or suffocation if a face collapses.
Fuhr’s key messages:
- Start with a silage plan.
- Take time to design storage method.
- Harvest at optimum maturity.
- Wilt crops quickly to preserve nutrition.
- Use recommended ensiling moisture content.
- Determine best particle size before harvesting.
- Pack to achieve maximum density.
- Seal with high quality plastic.
- Weigh down plastic edges and seams.
- Keep a smooth face at feed out.
- Consider that inoculants do not make bad silage better.