Maximise Home Grown Feed Supply
After the break there is a need to increase pasture cover by keeping on a slow rotation. Do not
speed up the rotation to fully feed the herd, as this will not allow pasture covers to increase. Use
supplements to help protect and build pasture covers, and to avoid underfeeding cows to an extent
that there is a large carry over impact on milk production or animal welfare.
It can be tempting to start grazing as soon as some growth is observed but this normally leads to low
pasture covers during winter and reduced potential for growth in the following spring. If possible it is
best to delay grazing until the pre-grazing cover reached 2,400 kg DM/ha, and only if the predicted
growth rate was enough to sustain a rotation (i.e. enough paddocks are likely to become eligible for
grazing over the next period of time). The aim is to maintain the target rotation length from that
point in time onwards, with paddocks to be grazed consistently at the 3rd leaf stage through winter.
Manage pasture wisely. Until early spring at least, quantity is more limiting than quality. Set your
rotation to graze paddocks between the 2nd and 3rd leaf stage for ryegrass. Grazing before this will
slow pasture growth and provide cows with less NDF and effective fibre which could lead to
problems with acidosis. In the 3030 farmlets this meant being able to reach an average rotation
length of 45–48 days throughout early to mid-winter.
Place cows in a sacrifice paddock to feed grain/concentrates and other supplements, in order to
slow the paddock rotation and build a pasture feed wedge.
Once grazing starts, don’t graze below 4–6 cm between pasture clumps [equivalent to 1,500–1,600
kg dry matter (DM) per ha]. Pastures that are grazed too hard will take longer to recover from
grazing and grow less feed.
Strategic Nitrogen Use.
Nitrogen applications should be delayed for at least 2 weeks after the break, particularly after a dry
summer as the soil will have good reserves of mineralised nitrogen and the pastures will take time to
recover.
A good approach after the break is to assess pasture cover and density across the farm and identify
one third of the area as the first paddocks to be grazed. Apply nitrogen fertiliser at 40-60kgN/ha to
the other two-thirds of the area to boost growth rates and get these paddocks into the grazing
rotation as soon as possible. Follow the cows with the same rate of nitrogen across the first
paddocks to be grazed until the whole farm has been covered.
What influences the response rate to nitrogen?
The amount of pasture grown from applied nitrogen is dependent on:
1. The amount of nitrogen available in the soil – the less nitrogen in the soil, the higher the
response.
2. Soil temperature –warmer soil will result in a greater increase in pasture growth. Nitrogen
should be applied before soil temperature drops below 7°C to ensure plant uptake occurs.
3. Plant growth – the faster a pasture is growing, the greater the growth response.
4. Soil moisture – too much or too little water will reduce the response.
5. Application rate – applying too little nitrogen will be ineffective while applying too much will
result in a lower response per unit applied.
Gibberellic acid
Gibberellic acid is a plant growth regulator that is widely used in horticulture and has also been
trialled on pastures. It can stimulate pasture growth through reserve mobilisation and leaf and stem
elongation in grasses, clovers and weeds. The greatest benefits from are likely to be achieved when:
1. It is applied along with nitrogen. Generally, the responses from gibberellic acid and nitrogen
are additive
2. It is used in autumn to fill a feed deficit and build pasture cover for winter.
3. It is used in spring when feed shortages are forecast and pastures are grazed between 3-4
weeks after application
Apply gibberellic acid after grazing to actively growing pasture (soil temperature above 7 oC) with
adequate soil moisture and fertility. Pastures should be grazed within 3-4 weeks after application for
maximum however there is evidence that yield responses are available through to 5-6 weeks.
Develop an action plan for damaged paddocks
Paddock by paddock, assess the productive potential of each paddock e.g. How dense is the
pasture? Have weeds taken over? Does the paddock need oversowing? Rank paddocks in order of
priority (e.g. badly damaged pasture on productive flats will have a high priority).
For paddocks with reasonable density, make sure they have adequate fertility, particularly N, K and
S and consider extra fertiliser in early spring to boost growth.
For the rest, decide what to sow in them and when, what fertiliser is needed, and the costs
involved.
Oversowing or direct drilling with short-term ryegrass may boost feed supply early and provide good
spring growth for fodder conservation.
From a late break a forage cereal such as barley, triticale or rye can provide strong early feed and
good yields for spring silage, however silage quality will generally be lower than for ryegrass.
Be sure to not graze newly sown pastures and crops too before they are ready. If plants pull out of
the ground when the leaves are ‘plucked’ grazing will result in a loss of plants and reduced yields.