GETTING YOUR grazing rotation right is critical to maximise your pasture production.
A well-managed rotation will help not only to boost pasture intake per cow but enable a more effective use of supplements.
Establishing a rotation with newly sown pasture feedbase can be challenging. Planning ahead and managing sowing and grazing to fit into your feeding strategy sets a process for grazing that takes away the guesswork and makes it easy for you to manage, especially heading into spring.
The ideal strategy is to sow a few paddocks at a time to enable these to come into an established rotation.
This would be the perfect scenario but in reality most farms sow everything at once to fit in with contractor and other farm labour availability. So what do you do to manage this?
If all paddocks are sown at the same time, the first grazing will be the hardest to manage because you will head into some paddocks early (before canopy closure) and other paddocks at canopy closure.
Establishing a rotation is a compromise between coming in a little early to some paddocks and at the right stage for others. If you wait until all paddocks are at canopy closure then some paddocks will be past the best quality feed and milk production will be compromised.
Ideal grazing stage
The ideal grazing stage for a rye-grass plant is at two-and-a-half to three actively growing leaves or at canopy closure.
Prior to the first grazing in autumn, the rye-grass plant can sustain more than three actively growing leaves and does not require grazing to stimulate tillering (the production of more rye-grass plants).
Canopy closure is when the pasture canopy is thick to the point that you can’t see the ground beneath. At this stage there is no sunlight getting to the base of the plant or to the daughter tillers, where growth occurs and yellowing and death of leaves will occur.
Before grazing, new plants must pass the ‘pluck test’ to be sure cows won’t pull them out. Doing a ‘pluck test’ is as simple as pulling firmly at new plants to check whether or not they stay rooted in the ground.
If you can pull out the new plants, imagine what your whole herd will do to the new pasture!
After grazing, there needs to be a 4–6 cm residual between the clumps. This ensures the rye-grass plant can efficiently grow a new leaf, due to the plant having enough energy stores.
If the residual is less, then leaf size will be compromised; if the residual is greater than 6 cm, then you have wasted some top quality feed.
Cows will graze soft, palatable new rye-grass pastures hard. To prevent overgrazing at the start of the season, use on-off technique, giving the herd a limited time on the new pasture. Supplement the diet with hay and silage fed away from the new pastures.
Revising the rotation
Growth rates will slow through the autumn and winter as sunlight hours decline. You will need to lengthen the rotation to ensure pasture is grazed at the ideal stage (2.5–3 leaf or canopy closure).
This ensures pasture quality remains high and is able to be supplemented to ensure consistency for the cow’s rumen health and milk production.
This information comes from the Feeding Pastures for Profit program. The program, made up of seven sessions, teaches participants about grazing principles, how to establish a rotation and seasonal pasture management. If you are interested in participating, phone Murray Dairy on 5833 5312.