Background to Rotation

 is a simulation program that produces management reports allocating each paddock to the best matched herds or mobs on a rotationally grazing livestock farm.

The original idea of was developed by Roy McCallum from the use of an early computer spread sheet program adapted to record pasture growth rates on a continuous basis and used on his dairy farm located near Pahiatua New Zealand

 is a web version of a CP/m Basic program written in 1980 by Dr Ian Boag, then a Massey University Industrial Management and Engineering Lecturer and systems engineer.

It was Ian Boag's advice to use the concept of an active paddock and herd simulation model rather than a static global feed budget. This concept gave its unique characteristics and usefulness in comparison with other feed budgeting techniques.

In addition the program is based on knowledge that grew out of a profitable association with the research work on pasture assessment and allocation by B J Ridler, then Senior Lecturer in Agricultural Systems Management at Massey University Palmerston North, New Zealand.

 has been rewritten and adapted to the web in 2002 by Rhys Williams of NZ Internet Services Ltd. The web version has enabled advances in computing technology to be applied to an original inflexible program that had stretched the capabilities of a 28k 1980's micro computer.

Practical Farmer's Response to a Need

 proved to be a useful, large herd management tool at a time when pasture budgeting and feed planning focused on the late winter and early spring feeding of dairy cows.

This computerised rotation planning program is a practical farmer’s response to a need to simplify the complex tradeoffs required by farm mangers when managing the year round growth and consumption patterns of their farms. 

The basic input required by is the regular updating of the cover in kilos of dry matter per hectare for every paddock to be included in the rotation simulation.

Photos were taken on David Clegg's dairy farm at Rongotea.

All other inputs are the known variables of: numbers of herds, stock numbers, paddocks and sizes, daily expected feeding levels and the expected average growth rate for that farm for that period.

Rotation Has Limits Too

An important reminder that is a mathematical simulation program using your inputs which, if all things are equal, can match actual outcomes.

However the program does not have the capacity to  fortell the exact future nor guarantee that your predicted growth or consumption rates will be matched every time by the pasture growth or livestock consumption on your farm.

Your judgement as a practical farmer is still required to get the best from the program!

It should be remembered that the grazing animal has the capacity to be selective in what it chooses to graze.

Also the grazing threshold will not be respected by under-fed stock, which will readily eat today what you may have been planning to save for tomorrow.

 does not change the fundamental rules of rotational grazing management but it does structure, simplify and plan how those management rules should be applied

A pastoral farmer's wish for fast growing, dense, weed free, evenly grazed pasture, glowing under sunny skies and grazed by happy and content livestock could occur as a  result of using and good management.

 However, as desirable as such a bucolic picture may be, the primary benefit from the use of is the structured involvement of stock managers and staff in the critical process of optimising the growth and allocation of quality pasture with supplements as necessary for a productive and profitable farming result.

Roy McCallum
Retired Dairy Farmer
Palmerston North
New Zealand