Doing a feed inventory establishes your current stock of various feed ingredients. Generally, the process involves determining the volume of each feed stored and then multiplying by the stored density to yield a weight of feed.
For example, silage in a bunker silo has a dimension of 30 feet by 10 feet by 50 feet. Its volume is 15,000 cubic feet. If the silage has a stored density of 40 pounds (as-fed) per cubic foot, the weight of feed in the bunker is:
15,000 cubic feet x 40 pounds AF per cubic foot = 600,000 pounds = 300 tons as-fed.
There are several ways to do a feed inventory: pencil and paper, computer spreadsheets or commercial software that integrates with your feed weighing system.
How long will my feed last?
With feed inventory management, you are predicting how long an ingredient will be available to feed and making adjustments accordingly. If the projected date to feed depletion occurs before a new crop comes in, you need to consider if you will reduce the rate of consumption to extend the feed ingredient, purchase more of that feed, substitute an existing feed ingredient into the ration or a combination of these choices.
The projected Time to Inventory Depletion = Feed Inventory (tons) / Consumption Rate (tons per day)
For example: 100 tons stored / 2 tons fed per day = 50 days to depletion
There are a number of publications and software tools that can help establish and manage your feed inventory.
Find a list here: www.progressivedairy.com/feed-inventory
Will feed need to be purchased?
The projected feed to purchase (tons as-fed) to meet feed needs at a given consumption rate is:
Feed Inventory (tons) – [Consumption Rate (tons per day) x Time ‘til harvest (days)]
For example: 100 tons – [2 tons per day x 70 days]= -40 tons (as-fed) to purchase
(negative value means feed to purchase, positive value means excess feed)
When is the best time to do a feed inventory?
There is no one best time to do an inventory. Doing an inventory at different times for different reasons may be beneficial. For example, doing an inventory in:
- October/November allows you to make a projection to see if purchased feed will be needed or if the consumption rate needs to be adjusted. This allows needed purchases when commodity prices are apt to be lower in winter and will allow purchases before Dec. 31, assisting in tax management.
- February/March allows you to make a mid-course correction prior to the harvest season. Estimates of density will be more accurate after having fed from a storage for a while, so estimates of quantity stored will be more accurate.
- June/July allows you an early warning of inadequacy of feed supplies for the upcoming feeding season. Purchases of standing crops remain an option if deficiencies are discovered.
- Any time you are required by a lender to provide a balance sheet, a feed inventory and the feed value is needed.
PHOTO: Tractor filling feed bunk. Staff photo.
Reprinted with permission from the University of Wisconsin Extension Team Forage