Have you enough silage on your suckler farm?

Winter feeding is well and truly underway and silage pits are starting to decrease in size. Due to the adverse weather conditions in certain parts of the country, some farmers were forced to house cattle in the early autumn.

Furthermore, weather conditions for harvesting silage during the summer months were far from ideal. Some farmers have ended up with poorer-quality silage than what was expected; this is also taking its toll on supplies.

Farmers who think they will be short silage should calculate how much silage they have left using the Teagasc guide.

Measuring pit silage on your farm

According to Teagasc, to calculate the amount of silage in a pit, farmers must first measure the length, breath and height of the clamp.

Once measurement is complete, farmers will have the area (m³) of silage available and can then estimate the quantity of fresh-weight silage available (tonnes) using a simple calculation.

This calculation depends on the dry matter (DM) level of silage and, as a rough guide, farmers with very wet silage (DM 18%) need to multiply the area available by 0.81.

Farmers with supplies of good-quality, drier silage need to multiply the total available area by either 0.77 (DM 20%) or 0.68 (DM 25%).

Calculating how much silage is in your pit:
  • Measure length, breath and height of your silage pit;
  • Multiple the length x breath x height = total silage area available;
  • Estimate the DM content of your silage;
  • Multiple the total available area by either 0.68, 0.77 or 0.81 (depending on silage DM);
  • Calculate how long the silage will last the animals on your farm.

For example, silage height (3.5m) x silage width (8m) x silage length (20m) = silage area (560m³). Assuming the silage has a DM content of 18%, the amount of silage available is: 560m³ x 0.81 = 453.6t (fresh weight).

Converting bales to tonnes

A lot of suckler farms will have both pit and baled silage. According to Aurivo, to calculate the tonnage of silage available from bales, farmers should multiply the number of bales by 600kg (normal) or 700kg (well-packed).

Therefore, assuming the bales were well-packed, 40 bales would be the equivalent of 28t of silage (fresh weight).


When both the pit and bales are considered, it means that there’s 481.6t of silage fresh weight available on this theoretical farm.

How long will the supplies last?

The requirement for silage on farms will vary depending on the system. Different types of animals – at various ages – require different amounts of silage. The table below outlines the amounts of silage required by animals.

Source: Aurivo

Example: How much silage is required for 50 suckler cows and 10 in-calf heifers?
  • Suckler cow requirement (per cow): 1.4t/month;
  • In-calf heifer requirement (per heifer): 1.3t/month;
  • Herd requirement ((1.4t x 50) + (1.3t x 10)): 83t/month.

Once the monthly requirement has been calculated, the farmer will then be able to judge how long it will last by dividing the total available by the monthly requirement.

481.6t (total silage available) / 83t (monthly requirement) = 5.8 months of silage.