Winter feeding is well underway and many farmers have long opened their silage pit to start using the reserves of grass saved earlier in the year.
But how much silage is available on your farm?
To make it easier for farmers to calculate how much silage they have, Teagasc has developed a guide to calculate the quantity of silage available.
To calculate the amount of silage in a pit, Teagasc says 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 (t) using a simple calculation.
This calculation depends on the Dry Matter level of silage, and as a rough guide farmers with very wet silage (DM 18%) need to multiple the area available by 0.81.
For drier silages, farmers will need to multiple the total available area by either 0.77 (DM 20%) or 0.68 (DM 25%).
Silage height (3m) x silage width (8m) x silage length (24m) = silage area (576m3)
If the silage has an estimated Dry Matter of 25%, the amount of silage available is: 1,890 x 0.68 = 391.7t.
Teagasc has also set a number of guidelines on the quantity of pit silage different cattle types will eat each month over the winter.
It says that dairy cows will need 1.6t of pit silage each month, so over a four month winter a dairy cow will eat 6.4t of silage.
Therefore, the example pit given above will provide enough silage for 61 cows for four months. A similar calculation can also be used to calculate how long the silage left in your pit will last suckler cows.
If the silage pit on the farm contains 397.1t of silage, a farmer can calculate how long it will last by:
Suckler cow silage requirement (1.4t/month) x Number of cows (60) = Monthly silage requirement (84t).
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.
Total pit silage available (397.1t) / Monthly requirement (84t) = Months of silage left (4.7 months).
Example: Calculating the quantity of silage available
How long will the silage last?
Example: How long silage will last a 60 cow suckler herd