One of the tools to help farmers during this critical period is DairyNZ's Spring Rotation Planner, designed to help take the guesswork out of grazing management.
Why use the Spring Rotation Planner (SRP)?
- Provides guidelines for allocating pasture to cope with the growing milking herd and the shrinking dry herd.
- Helps avoid going too fast or too slow in the first grazing rotation after calving.
- Controls the rate of pasture cover decline on the farm so enough pasture remains to maximise pasture growth.
- Creates high pasture quality for the coming rotations
- Minimises pasture deficits during spring so that supplement use is kept within the financial budget.
Tips for using the SRP
- Allocate area accurately. Know the area of your paddocks and the daily breaks and how these relate to the rotation plan.
- Share the plan with staff and have regular updates (at least weekly, sometimes daily) on progress against the plan.
- Achieve target grazing residuals of 1400-1500 kg DM/ha (no clumps left) in the first rotation.
- Track actual rotation length versus target rotation length. Plot this on the graph each week.
- Track actual average pasture cover (APC) for the farm versus target farm pasture cover.
- Regularly tally the cow numbers in each mob.
What to avoid
- Going too fast too early - avoid over-allocating pasture to early calving cows
- Speeding up rotation to avoid pugging in wet weather, and not having a plan to get back on track.
- In a feed deficit, a slow rotation will help rectify the situation. A fast rotation will make the deficit worse and delay recovery.
- Feeding too much supplement and for too long - indicated by high grazing residuals or uneaten supplement.
- Not modifying the plan for an excellent spring - if pasture cover is above target then there is opportunity to offer more pasture area than planned.
Often feed budgets over estimate cow intakes at the start of calving. Cows reach peak milk production in as little as four weeks after calving but peak dry matter (DM) doesn’t happen until 7-10 weeks after calving. Therefore average herd intake requirements lag behind peak intake of early calving cows.
Quick table for calculating intake at a herd level
These intakes do not allow for wastage and need to be increased if conditions are wet or feeding supplements where wastage may be higher.
Note: This example is based on a 500kg cow with a peak intake of 18kg DM/day, 10 weeks after calving. This table shows herd intakes for the following calving spread: 20% 1 week before PSC, 60% by week 3, 87% by week 6 and 100% by week 10.
- Work out the total area being grazed using the SRP.
- Use the table below to work out the area allocation on a mob level.
Ready reckoner for m2 per cow
If the total area to be grazed using the table differs from your Spring Rotation Planner check:
- the line is starting at the correct point for PSC. The rotation length at the start of calving is normally about 100 days. Lower stocked farms may start at 80 days.
- the available DM figures used are correct (pre-grazing kg DM/ha minus residual kg DM/ha)
- feeding levels for different mobs are realistic and that you have allowed for any supplements being fed
- areas of paddocks and therefore m2 allocated are accurate
- the number of cows in each mob are tallied daily (appoint someone in the team)
Variations to the SRP for winter grazing
If bringing cows from winter grazing to the milking platform after PSC, then the starting point for the slope of the line from PSC to balance date will need to change.
If bringing the cows onto milking platform as they calve, start at PSC +7days. (i.e. stay on 100 day rotation for first 7 days after PSC and then draw slope of line down to balance date).
If bringing the cows onto milking platform in several calving groups, use PSC +5 days. (i.e. stay on 100 day rotation for first 5 days after PSC and then draw slope of line down to balance date).
For very wet farms, add 5 days onto the rotation length at PSC before drawing the line. This will allow more flexibility to speed up in the rotation in wet conditions to avoid pasture damage. You can slow the rotation down in drier conditions.
Every few days check that the area allocated is similar to the plan. Also track the proportion of the farm area that has been grazed since calving started.
Feeding cows in spring
Answers to the frequently asked questions about feeding dairy cows in spring.
Perennial Ryegrass Grazing Guide
An in-paddock pocket guide to assessing post-grazing residuals, pre-grazing yields and leaf stage of perennial ryegrass.
Spring Rotation Planner Poster
A laminated A2 poster for the shed/office wall to help communicate the SRP with the farm team and help you monitor the plan and allocate feed through the first rotation.
Spring Rotation Planner
Use the online Spring Rotation Planner to take the guess work out of grazing management. It will calculate: rotation length, area grazed per day and target average pasture cover.