Fermented wholecrop can have a range of harvest dates. It can be harvested strategically to react to the season as it unfolds. This flexibility allows farmers to more consistently achieve the yields of quality silage required for their livestock. Depending on the maturity of the wholecrop cereal at harvest and what type of cereal it is the analysis received can be vary.
Below are a general set of analysis based on a cereal crop harvested for the best energy and digestibility levels, which is normally between 35-45% DM.
| Parameter | Unit | Value/range |
|---|---|---|
| Dry matter (DM) | % DM | 38-42 |
| Crude Protein | % DM | 6-10 |
| D Value | % | >65 |
| ME | MJ/kg DM | 9.5-10.5 |
| pH | 4 | |
| Ammonia | % DM | <5 |
| Ash | % DM | <8 |
| Starch | % DM | 25-30 |
| NDF | % DM | 40-45 |
| ADF | % DM | 20-25 |
| Lignin | g/kg DM | 40-50 |
| Lactic Acid | g/kg DM | 45-100 |
| Acetic | % DM | 1.5-3.0% |
| Butyric | g/kg DM | <2 |
What it means for silage quality and feed value if these parameters aren’t ideal:
Dry matter.
This is one of the indicators for crop maturity, if it’s too low the plant most likely will not have developed much starch and will have a lower overall energy value. However, the fiber digestibility of the silage will be increased. If the DM is too high it poses significant challenges to the ensiling of the cereal because of the development of a waxy cuticle and the hollow stems seen in cereals, making the crop challenging to compact. This makes wholecrop cereal silage prone to instability during feeding which will reduce the energy available from the silage during feeding.
Crude Protein
Wholecrop cereals aren’t generally grown as a protein source to the animal. If the protein is extremely low this could indicate inadequate growth conditions for the plant and other parameters of nutritional importance may be influenced as well.
pH
The pH of the silage needs to be lowered quickly to inhibit the activity of spoilage organisms. pH also needs to to remain stable when the silage is opened, otherwise it’s possible to lose excessive amounts of DM through heating and spoiled silage due to undesirable yeast and mold growth. Using condition specific forage inoculants such as the MAGNIVA forage range quickly preserves and improves feedout stability of wholecrop silages.
Ammonia
High levels of ammonia are a sure sign that protein is being broken breakdown in the silage due to the action of undesirable microbes that are known as Enterobacteria and Clostridia, this reduces the quality feed value and palatability of the silage. High ammonia levels can also be due to excessive soil contamination although this is rare with regards to wholecrop cereal silages.
Ash
Higher levels of ash are a sure sign of excessive levels of soil contamination, . Soil contains large numbers of differing bacteria some good other very much undesirable when trying to produce good silage. If excessive levels of undesirable bacteria are introduced during the silage making process it tends to lead to poor quality silage of low palatability and feed value.
Starch
Because cereals are mostly grown to provide an energy source to the animal the starch content should be as high as possible. If this is too low the crop will have a lower feedout value and because wholecrop cereal silage is so dry it may even reduce the energy density of the diet.
ADF and Lignin
These are the fiber fractions and give an indication of plant maturity. If too low this means the plant probably didn’t develop as much starch as possible, making it less valuable as an energy source in the ration. If too high this means the crop will be more challenging to ensile due to the physical characteristic of the cereal (waxy hollow stem) and the fiber fractions will be less digestible. High levels of Lignin indicate a very mature crop, which again will difficult to ensiling and have low fiber digestibility.
Lactic, Acetic, Butyric acids
Lactic Acid is normally produced by Lactobacillus bacteria (LAB) through the ensiling process. The acid reduces the pH of the silage inhibiting of undesirable bacteria. This helps maintain the quality of the silage for feed out. The quicker the ensiling process occurs the more likely that silage quality will be maintained and why condition specific forage inoculants such as MAGNIVA are recommended when making silage. Such products contain high levels of LAB and ensure the pH of the silage is lowered quickly. Acetic Acid is an important acid especially in high energy crops which can unstable and heat extensively when opened due to yeast and mold growth. Acetic acid actively inhibits the growth of yeast and molds ensuring the silage stays stable through the feedout period. Acetic acid is mainly produced by specialized LAB called heterofermentative LAB. Through the ensiling process these bacteria utilize some of the Lactic and convert it to acetic acid.
If ensiling higher energy crops or even crops at higher dry matters always look for inoculants containing Lentilactobacillus buchneri 40788 and or Lentilactobacillus hilgardii CNCM I-4785 to maintain feedout stability
Butyric acid is produced by undesirable clostridial bacterial strains. Clostridia can only grow through the ensiling period if the pH of the silage remains high for an extended period. Butyric acid is pungent and weaker acid than lactic acid meaning the pH of the silage does not reach a stable and safe point. This tends to result in low quality silage with reduced energy, nutrient and palatability levels
Crude Protein, Starch, Ash, NDF, ADF and Lignin are the parameters that tell you about the quality of the plant that was ensiled.
pH, ammonia, lactic-, acetic-, and butyric acid are the parameters that tell you about the quality of the fermentation and what type of fermentation occurred to preserve the plant that was brought into the silo.
