Vital nutrients can be lost if producers do not store their forages correctly, said Karla Hernandez, SDSU Extension Forages Field Specialist.
"They need to find ways to prevent shrink losses in their bunkers and storage systems," Hernandez said. "Stored forages provide the essential nutrients for livestock when pastures are inadequate and are consistent feed supplies for dairies, sheep flocks, cow/calf producers, and beef feedlots."
Interestingly, Hernandez said most nutrient loss occurs during storage for silage and harvest for hay.
"Hay storage losses are around 5 percent for hay harvested at 15 percent moisture and stored under dry conditions. Forage quality tends to decrease if hay is baled above 20 percent moisture," she said.
Types of Storage Losses
Losses of dry matter and nutrient tend to increase when hay moisture is above 20 percent (Figure 2).
"Each mechanism in forage-preservation process, such as mowing, ranking, chopping, baling, storing, and unloading will probably cause loss of a forage dry matter," Hernandez said. "Some losses are either mechanical or biological."
She says when it comes to hay-making, most of the losses come from mechanical or weather damage, whereas, for silage-making, most losses will occur at storage and feed out stages.
"In general, round bales are usually subject to greater losses than small rectangular bales, because they tend to remain outside with no protection between baling and feeding," she said.
Other aspects Hernandez encourages growers to take in consideration when determining the storage quality of the forage include: (1) the presence of respiration (aerobic conditions) and microbial activity, (2) maillard reactions (nonenzymatic browning), (3) inside storage, (4) outside storage, and (5) stack arrangement (Figure 2).
Minimizing Losses
This aspect can be summarized by using good management practices. A summary of good hay making practices will be shown below.
Good hay making practices and their benefits
Practice | Benefit |
Alfalfa cut at immature growth stages (pre-bud or early bud) | Higher forage quality but lower yield production. |
Alfalfa cut at bloom stage | Higher yielding but lower forage quality. |
Mow forage early in day | Allow full day to dry (less respiration loss & faster drop in moisture). |
Form into wide swath | Increase drying rate (higher quantity and quality of forage). |
Rake at 40-50% moisture content | Increase drying rate (less respiration loss, faster drop in moisture, less rain damage, less leaf shatter & higher quality and quantity of forage). |
Baling moisture levels | Hay in small bales should be at or below 20% moisture, hay in round bales at 18% moisture, and hay in large bales at 16% moisture when baled. |
Store hay under cover | Protect from rain and sun (Inhibits molds and browning). |
Suggestions for silage management include:
1) Harvest at correct maturity and moisture concentration.
2) Fill the bunker as rapidly as possible.
3) Pack well and seal the bunker to reduce oxygen infiltration for at least 14 days to allow the fermentation process.
4) Feed appropriate rate to reduce face exposure to oxygen.
5) Unload an average of 2-6 inches/day to keep the surface smooth.This will limit aerobic deterioration and will help to reduce any possible spoilage.
6) Discard deteriorated silage, which will help preventing livestock health problems.
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