Completing a forage budget
Meat & Livestock Australia April 15, 2024
Effective grazing management aims to maximise livestock production by matching the appropriate class of livestock with pasture biomass and quality that will allow livestock to achieve their daily intake requirements (i.e. a forage budget).
Forage budgeting involves assessing forage supply (kg DM/ha) and forage demand (kg Dry Matter intake). A forage budget can be used to determine stocking rate, grazing days available or identify pasture surpluses or deficits.
In northern Australia, a forage budget is most commonly performed at the end of the growing season (~April). It is a process that should be revisited every 2-3 months to ensure your forage budget is on track.
A forage budget can be performed on an individual paddock basis, or for the entire property.
Let’s work through a forage budget using the following scenario:
Jack is wanting to complete a forage budget for one of his paddocks. The forage budgeting period is between 1 April 2024 (end of the growing season) and 1 November 2024 (when Jack estimates the production point will occur).
This paddock is 1000 Ha and after performing multiple pasture cuts across the paddock, he has calculated an average of 3000 kg DM/Ha. He estimates 15% detachment, 10% unpalatable species, 10% unpalatable 3Ps and wants to leave a residual feed level of 1200 kg DM/Ha. He would like to calculate the forage supply (kg DM/ha) available for grazing (as per Forage Supply lesson):
He currently has 300 steers (aged between 1-2) with an average weight of 350kg. Jack lives in a low productivity zone. He would like to calculate the forage demand (kg DM/ha) of these animals between 1 April 2024 and 1 November 2024 (as per Forage Demand lesson).
Results
Will Jack’s current feed on offer get these steers through to the budget end date?
YES, the steers will consume 426 kg DM/ha out of the available 1095 kg DM/Ha – therefore leaving a residual of 1869 kg DM/Ha in the paddock.
THEREFORE
Jack could choose to:
- Run 772 steers (602 AE) in that paddock for the forage budgeting period instead of 300 steers (234 AE);
- OR he could graze the animals in that paddock until the 3rd October 2025 (551 days from 1 April 2024) before he reaches his residual of 1200kg DM/Ha.
EXPLANATION:
- 669 kg/ha available until we hit the residual of 1200 kg. 669 kg x 1000 ha = 669,000 kg TOTAL to graze in the paddock
- 234 AE x 8.5 kg/day = 1989 kg eaten by the steers per day
- 669,000 1989 = 336 days left for grazing.
To understand the calculations behind these results, please see the table below:
You can have a go at this process for one of your own paddocks using the Forage Budgeting Spreadsheet as provided by Col Paton.
When is the best time to complete a forage budget?
- The best time to complete a forage budget is at the end of the growing season, when no further growth is expected to occur.
- You may want to follow-up and re-do your forage budget in the middle of the dry season to reassess feed available and make further decisions around stocking/destocking.
- Know your green date and production point. The green date is the point at which the break in the dry season occurs.
- Budget out to 4-6 weeks after first expected rainfall.
- Budgeting only to the “green date” means cattle may not have enough grass when growth first starts after rain.
- Budgeting 4-6 weeks after this will ensure enough feed for a late start to the season and up to the point where there is enough feed for cattle to be at maintenance or putting on weight (production point).
- You can also budget to use the available feed in a paddock in a much shorter period of time. However, you must then be prepared to spell that paddock again until rainfall.
- Set the date you want in the forage budget, calculate the number of days and use this to calculate how many AE can be carried over that period with available pasture.