There are some simple, short-term feed budgets you can calculate manually, without the need for a computer. Some examples are given below.
To fill in the budget template, you will need to:
- Measure the pasture mass (kg green DM/ha) in the paddock you have allocated to the stock to get your starting point (tool 8.6)
- Estimate pasture quality (tool 8.6 or tool 7.6 in Grow More Pasture)
- Determine the estimated intake of livestock from the table below
- Look up typical pasture growth rates for your pasture type and soil fertility (see tool 8.2)
- Define the minimum target pasture mass (kg green DM/ha) for the class of stock (see procedure 8.2 or the MLA Pasture ruler).
To convert pasture mass to Feed on Offer (FOO), add 300kg/ha..
Q1: How many lactating ewes with twins can I put in a 40ha paddock for a 42 day lambing, while ensuring the minimum to meet stock requirements is maintained?
Pasture available
|
Present pasture mass (tool 8.6): |
1,700 kg green DM/ha
|
Less required minimum pasture mass (kg green DM/ha)*: |
1,500 kg green DM/ha
|
Available pasture: |
200kg green DM/ha
|
Plus pasture growth (42 days lambing x 40 kg green DM/ha/day): |
1,680kg green DM/ha
|
Total Available Pasture: |
1,880kg green DM/ha
|
Livestock Requirements
|
Ewe intake 2.9 kg green DM/head/day x 42 days**+ spoilage of 15% |
140kg green DM/head
|
Less required minimum pasture mass*: |
Total available pasture
|
|
1,880
|
= 13.4 ewes/ha
|
|
Livestock requirements
|
|
140
|
|
Stocking rate |
13.4 ewes/ha x 40ha = approximately 536 ewes for the paddock |
* The minimum pasture mass is 1,500kg green DM/ha to ensure that nutrient needs of these lactating ewes with twins are met (see procedure 8.2).
** Intake estimate from the table (downloaded here (75 KB)) (pasture digestibility 70%).
Q2: How long will a 16ha paddock last stocked with 400 pregnant ewes ensuring pasture is kept above a minimum level to meet livestock requirements?
Pasture available
|
Present pasture mass: |
1,000 kg green DM/ha
|
Less required minimum pasture mass: |
700 kg green DM/ha
|
Available pasture: |
300kg green DM/ha
|
Daily growth rate of pasture*: |
27kg DM/ha/day
|
Total Available Pasture: |
|
Stocking density (400 ewes divided by 16ha): |
25 ewes/ha
|
Livestock requirements**
(1.2 kg green DM/head/day x 25 ewes/ha + spoilage of 15%): |
35kg DM/ha/day
|
Results
These calculations indicate a net pasture loss of 8kg green DM/ha/day (ewes are consuming 35kg green DM/ha/day which is 8kg greater than the pasture growth rate of 27kg green DM/ha/day).
Therefore, available pasture is declining at the rate of 8kg DM/ha/day.
How long will the paddock last (300kg DM/ha divided by 8kg green DM/ha/day)? |
About 38 days |
When calculating short term (1-5 days) feed budgets, except in spring, pasture growth may be ignored.
* From tool 8.2
** Intake estimate from the table (downloaded here (75KB)) (pasture digestibility 70%)
Stocking rate calculator
A stocking rate calculator can be downloaded from http://www.mla.com.au/News-and-resources/Tools-and-calculators/Stocking-rate-calculator using the search function. This calculator automates the process shown below.
Q3: Will I have enough pasture for my 50kg early pregnant Merino ewes to meet their nutritional requirements over 3 months given I have an average of 500 kg DM/ha (green) in my 40ha paddock now?
3 month feed budget
To fill in the budget template below, you will need to:
- Estimate pasture mass (kg green DM/ha) in the paddocks you have allocated to the stock to get your starting point
- Look up typical pasture growth rates for your pasture type and soil fertility (see tool 8.2)
- Estimate pasture quality (see tool 7.6 in Grow More Pasture)
- Look up the minimum pasture mass required (kg DM/ha) for the class of stock to meet their requirements (see tool 8.5)
- Determine the estimated intake of livestock for each month from the table (downloaded here (75KB))
- Look up the target condition/fat score for the class of stock in question (see tool 3.3 in Market Focused Lamb and Sheepmeat Production and tool 10.1 in Wean More Lambs)
- Account for a spoilage factor due to trampling, dung and urine. A figure of 15% is used here.
Step 1: Calculate available pasture as per step 1 above
Present pasture mass: |
500 kg green DM/ha |
(A) |
|
Less required minimum pasture mass: |
500 kg green DM/ha |
(B) |
|
Available pasture (A-B) |
0 kg green DM/ha |
(C) |
|
|
|
|
|
Plus growth for the period |
|
|
|
Growth rate per day* x number of days |
|
|
|
June: 17 kg DM/ha/day x 30 days |
510 kg green DM/ha + |
|
|
July: 16 kg DM/ha/day x 31 days |
496 kg green DM/ha + |
|
|
August: 26 kg DM/ha/day x 31 days |
806 kg green DM/ha = |
|
|
Growth for the period |
1,812 kg green DM/ha |
(G) |
|
Total available pasture for 92 days (C+G) |
1,812 kg green DM/ha |
(H) |
|
|
|
|
|
Step 2 Livestock requirements (from the table downloaded here (75 KB)) |
|
|
|
(Intake per day + 15% spoilage) x No. of days |
|
|
|
(0.9kg** + 0.3kg spoilage) x 92 days |
110 kg green DM/head |
(I) |
|
Stock density that will achieve desired outcome (H ÷ I) |
17 head/ha |
(J) |
|
|
|
|
|
Step 3: Number of stock in the paddock to achieve desired outcome |
|
|
|
J x paddock area (ha) |
|
|
|
17head/ha x 40 ha |
680 ewes in the paddock. |
|
|
In the above example 680 ewes in the 40 ha paddock would ensure that pasture requirements for the early pregnant ewes are always met during pregnancy.
* From Tool 8.2
** Intake estimate from the table (downloaded here (75 KB)) (pasture digestibility 70%)
|