December 2022 Eoin O’Brien (Sales Manager)
Grass silage, made from fermented grass, is the most popular source of feed for livestock farmers during the winter months. Grasses and pasture crops, like maize or rye, are cut, fermented, compressed, and kept until they are needed to be fed to livestock. Once it is wrapped into bales or pit, it is easily stored in airtight conditions with no need to dry beforehand, making it a low-effort source of nutrition for cattle and sheep.
It is important that farmers know the nutritional value of their silage to enable them to calculate the amount of feed they require. Read on to find out more about the importance of silage analysis, what it includes, how to interpret silage results, and how IAS can help.
Why do farmers need silage analysis?
Animals need more calories in winter months to maintain body heat and upkeep body maintenance and growth. If they do not get the right nutrients, then farmers could see a significant decline in animal health, which would then impact productivity and profitability for their business.
During the winter months when most animals are housed, their nutritional requirements increase and have to be maintained from silage. In order to achieve this effectively, it is vital the farmer knows the nutritional value of their silage. IAS Laboratories carries out comprehensive analysis on the nutritional and mineral status of your winter feed.
Silage analysis gives farmers all the most important nutritional information they need to make informed decisions around winter feeding. It details the quality of feeding characteristics such as percentage digestibility and protein content, and will also identify any mineral deficiencies found including copper, iodine, selenium, and cobalt. This allows farmers to take rapid corrective action if necessary to avoid productivity loss.
Accurate silage analysis will allow farmers to supplement their animals with the appropriate rate of concentrates to meet the animal’s daily dietary requirements and to enhance and meet subsequent performance targets. Feeding concentrates is very costly, and so the level at which meal is fed to livestock should be determined by the quality of the silage to avoid unnecessary expenditure.
What does silage analysis include?
IAS Laboratories offers a range of silage testing services from pre-cut to post preservation grass analysis. We test for a broad spectrum of minerals and determine the nutritional value of the silage overall. Data is given on dry matter, pH, ammonia, protein, metabolisable energy (ME), and dry matter digestibility (DMD).
When providing a silage sample for analysis, it is important to follow the correct method of sampling to get the most accurate results. The nutrition levels of silage can then be confirmed through independent laboratory analysis.
IAS provides provide silage evaluations for farmers all over Ireland to help you save money and remain productive. To book your test now, visit our website.
How do I interpret my IAS silage results?
Understanding the silage results you receive from us will help you make crucial decisions around animal nutrition and winter feeding. Details on interpreting your results are given below.
Dry matter (DM %): the amount of silage material that remains after water has been removed. Generally, the higher the dry matter level, the higher the potential intake of silage. Low dry matter silages tend to be extensively fermented and will be high in acids and low in rumen structure, reducing intakes. High dry matter silages are more susceptible to spoilage (bacterial and fungal).
The expected target range is 25-35%. The mean average of silage we have tested this season so far is 28%, with a high of 60% and a low of 15%.
Crude protein: If high, additional protein tends to be rapidly degradable and may be poorly utilised, especially if there is inadequate rumen available energy in the diet. High milk and blood urea levels have been associated with high protein silage. High blood urea levels can have a direct and indirect impact on fertility.
The target range for protein is 7-20% dry matter. The mean average of silage we have tested this season so far is 14.4%, with a high of 21.2% and a low of 9.7%.
pH: a measure of the acidity or alkalinity of the silage. Where the pH of grass is above the target range, typically because of poor or secondary fermentation, undesirable VFAs may have been formed and production may be reduced. Feeding animals more acidic silages, on the other hand, may impair rumen performance, resulting in acidosis, lower intakes, and production.
The target range is 3.5-5 depending on dry matter levels. The mean average of silage we have tested this season so far is 4.22, with a high of 5.8 and a low of 3.5.
Dry matter digestibility (DMD): the content of digestible organic matter in the dry matter. This decreases progressively as the forage matures and becomes more “stemmy.” DMD is a good guide to overall nutritional value.
The target range is 55-75% depending on the type of stock. The mean average of silage we have tested this season so far is 73.7%, with a high of 83.4% and a low of 65.29%.
Metabolisable energy (ME): the most important measure of the energy content of silage when fed to ruminants. It represents the amount of energy available to the animal after accounting for losses in digestion, gases, and urine.
The target range for ME is 8.0-12.0 mj/kg of dry matter. The mean average of silage we have tested this season so far is 10.7 mj/kg, with a high of 11.5mj/kg and a low of 9.9mj/kg.
Ammonia: High values are indicative of butyric fermentation and may be associated with high blood and milk urea levels. High blood urea has been both directly and indirectly linked to infertility. Care should be taken in interpreting this term as it is a percentage of the total N, not a percentage of the dry matter.
The target range for ammonia is >15% of the total N. The mean average of silage we have tested this season so far is 5.34%, with a high of 11.87% and a low of 1.14%.