Table: Target silage test results and advice on meal feeding rates
Winter feeding is now well underway on cattle farms in Ireland and farmers will be looking at their silage test results to see what level of additional feeding, if any, their different groups of cattle will need.
It is advisable to look through the results from the different cuts of silage and take note of the fields and management practices that yielded the best silage test results.
Farmers will know all to well the benefits of feeding good quality silage to their cattle over the winter versus poor quality silage.
The table below details the key information found in a silage analysis, what the values mean, and what the target values are:
| Result | Meaning | Low | High | Target |
|---|---|---|---|---|
| Dry matter (%) | Feedstuff less water content | 13-17 | 40-55 | 28-32 |
| pH | Measure of acidity | 3.4-3.7 | 4.5-5.5 | 3.8-4.5 |
| Ammonia – N (% N) | Indicator of grass N content at cutting | 4-7 | 15-25 | <10 |
| NDF (% DM) | Measure of forage fibre and intake potential | 42-47 | 55-65 | <44 |
| DMD (%) | Dry matter digestibility - Measure of quality | 55-65 | 76-80 | >72 |
| ME (MJ/kg DM) | Energy content (linked to DMD value) | 8-9 | 11-12 | >11 |
| UFV/UFL (unit/kg DM) | Energy content (linked to DMD value) | 0.6-0.7 | 0.89-0.96 | >0.89 |
| Crude protein (% DM) | Measures N as indicator of true protein content | 7-9 | 15+ | >13.5 |
| Ash (% DM) | Indicator of soil contamination | 5-6 | 12-15 | <8.6 |
Farmers will know themselves what good quality silage should look, feel, and smell like.
However, it can be hard to visually identify factors like the protein level and DMD% of good quality silage, which is where the silage test is beneficial.
The debate on silage quality often gets turned into a quantity versus quality debate but farmers in the business of regularly making good quality silage will know reasonably high yields can also be achieved in unison with making good quality silage.
The table below details guideline concentrate feeding rates based on silage DMD:
| Animal Type | Target ADG | 66DMD | 68DMD | 70DMD | 72DMD | 74DMD | 76DMD |
|---|---|---|---|---|---|---|---|
| Weanling/store | 0.6kg/day | 1.8kg | 1.5kg | 1.2kg | 0.9kg | 0.6kg | 0.4kg |
| Finishing Steer | 1kg/day | 7.0kg | 6.0kg | 5.5kg | 5.0kg | 4.0kg | 4.0kg |
| Finishing Heifer | 0.9kg/day | 7.0kg* | 6.0kg | 5.5kg | 5.0kg | 4.0kg | 4.0kg |
The higher the quality (and DMD) of silage, the less concentrate feed will be required for cattle to meet their target weight gain over the winter.
The Teagasc target is for steers and heifers to gain 0.6kg/day in their first winter and and 24-month steers to gain over 1kg/day in their second winter.
