By default, animal enterprises are distributed evenly on the farm based on their energy (hence feed) requirements and the availability of food. This can be overridden by setting the location of enterprises (to blocks) and/or changing the relative productivity of blocks (how much feed they grow).
The following diagram depicts what parts of the model the animal distribution information entered in OverseerFM impacts. For a full interactive view of the scientific model in its entirety please click here
Changing where animals are, changes what animals eat, where they are and hence the nutrients and location of excreta.
The model places animals based on feed requirements
If enterprises graze different blocks, use “Based on animals present”. Only use “User defined” if there is a specific need to model animal grazing that is not based the animal’s feed requirements.
For relative yield, if you have no measurement of pasture yields, use no difference or yield based on soil and fertiliser, otherwise if you have measured averages for a period of time then can enter these to adjust pasture allocation
Enterprise allocation to blocks
There are three options for allocating enterprises (intake) to blocks. This option is only available if there are multiple enterprises and blocks.
Same as ratio of total animal intake
Model will allocate enterprises evenly across blocks based on their total energy requirements.
Use this when enterprises are not assigned to particular blocks on the farm. All enterprises graze all locations based on requirements and availability.
Based on animals present
Assign different enterprises to different blocks. The model will allocate ME intake for each enterprise based on the blocks that they have been assigned only.
Use this when enterprises graze specific blocks and they graze based on requirements and availability.
Can assign enterprises to blocks and set percentage of pasture grazed for each enterprise. The model will allocate intake to each enterprise based on these percentages.
Use this when enterprises graze specific areas but pasture is not allocated based on feed requirements of each enterprise.
Should only be used in rare situations where animals do not graze based on feed requirements. This is likely to be experimental.
The relative productivity of each block can be set to adjust how the model allocates intake. This allows you to adjust where animals get their feed based on farm management or pasture yields.
The model essentially allocates a percentage of intake to each block. Relative productivity allows this percentage to be adjusted based on differences in yield of animal management.
No difference: All blocks provide a similar yield and animals are rotated based on their feed requirements.
Relative pasture yield (from soil and fertiliser): Animals are rotated based on their feed requirements, but there is a difference in yield between blocks. The model calculates this difference in yield based on soil and fertiliser inputs.
Relative pasture yield: Provides an option to enter relative yields for each block if known. This is where the user wants to override the model estimations of yield.
Grazing days: Provides relative values for number of days animals are grazed. This is used when animals aren’t necessary allocated based on feed but rather some management practice or rotation.
Pasture assessment: Where an assessment of the pasture on each block has been taken, you can enter the results of that to describe the difference in relative yield.
Animal assessment: Where animals that have different intake are placed on different blocks then this can be used to adjust the relative intake applied to each block.
The last four options essentially do the same thing. They allocate different percentages to blocks based on some measurements entered by the user. The options are provided so that they make sense to the user.
It doesn’t matter whether actual numbers are entered, it is simply a relative value and so 2 is allocated twice as much as 1. This could equally be 2000 versus 1000.
Monthly allocation of enterprises to blocks can be overridden using grazing months. This should not be used to describe every movement of animals on a monthly basis based of feed requirements because the model already accounts for this movement.
It should only be used as a broad representation of animal movements where it is a conscious farm management practice (rather than feeding requirements) that you wish to model, for example, moving a class of animal off a particular block for a season such as winter.
If enterprises are restricted to small areas for short periods of time (month on, month off) the model will struggle to balance feed requirements across the farm and so not provide a reliable result or in some cases provide a feed allocation error. The model is trying to analyse the effect of larger system changes, not small changes to animal rotations.