Spring pasture choices for your farm
Getting the best out of your spring pasture can be a risky business, but with the right strategy in place it
can pay great dividends.
Let us firstly look at the facts for vegetative ryegrass.
1. Ryegrass dominant pasture between two and half and three leaves produces a better balanced feed
than ryegrass less than two leaves. Ryegrass with less than two leaves can be much higher in
nitrates and potassium (K), and lower in calcium (Ca) and magnesium (Mg), when compared to
the three leaf plant. Pasture at the three leaf stage has ryegrass plants that satisfy cow requirement
for Ca and Mg on a pasture only diet, and can be lower in nitrates and potassium (K).
2. Dry matter production can be up to 50% more ryegrass at three leaves compared to two leaves.
3. Post grazing residual is very important, the ryegrass plant stores water soluble carbohydrates (plant
sugars) in the bottom 5 cm of the plant, if eaten below 5 cm this impacts on regrowth due to less
stored sugar available for regrowth. If post grazing residual is too high (greater than 9 cm
between clumps) this impacts on pasture density through restricting light to the base of the plant,
fibre build up, reduced leaf size/less growth, stem elongation and aerial tillering.
4. At greater than two leaves, root growth has now continued and water soluble carbohydrate stores
within the plant are building again.
Spring issues are as follows:
 In spring the majority of ryegrass tillers change from vegetative tillers (producing leaf only) into
reproductive tillers (producing rapid elongation of the stem and seed head production) before
senescence (tiller death) in early summer.
 When ryegrass tillers have changed to reproductive tillers (seeding) they will have more than three
“green” leaves and have a quicker leaf emergence
 Ryegrass stems elongate and the seed heads emerge. This puts pressure on management due to
increased fibre levels in late spring. This may compromise cow efficiency (per cow production)
 At maximum rotation for ryegrass (up to three leaves), other pasture species may no longer be
palatable (ie fog grass, prairie grass).
 Fodder conservation is a tool used to manage spring surplus, build fodder reserves and maintain
pasture quality on the next rotation.
 Topping can be used as a recovery tool when post-grazing height is above 6 cm and there is a high
proportion of clumps.
Using the above information you should make a choice on a leaf emergence rotation that suits your
farm.
If you choose a spring rotation close to three leaves
Your reward is:
 Maximum amounts of high quality ryegrass grown per hectare for the cows’ consumption and
fodder conservation.
Your burden:
 A need to check the pasture regularly (3-4 days a week), for seed head emergence and stem.
elongation. Defer these paddocks for fodder conservation if they are more than 3 leaves.
 Adjusting cow allocation and fodder conservation area (rotation length stays the same).
 Doubting yourself about nitrogen applications: “I didn’t need more pasture.”
 Fodder conservation cost. Cash flow impact of fodder cost in spring rather than purchasing the
feed later in the season.
 Weather restricting fodder conservation opportunities.
If you choose a spring rotation between 2 – 2.5 leaves
Your reward is:
 It is easier to maintain pasture quality because growth rate is depressed and cows keep up with
growth.
Your burden:
 You could have grown more high quality pasture.
 You still have to top paddocks.
If you choose a spring rotation less than two leaves
Your reward:
 Able to leave staff/relief milkers for a week and the pasture will not be widely out of control.
 From the roadside, not as many weeds (lot less feed).
 Tractor time less than above as you will have less area to top.
Your burden
 Not growing as much pasture, at least 50% less ryegrass.
 Smaller, weaker ryegrass tillers.
 Weaker root system. The plant is not accessing as much nutrients and water. You may see more
root pull in early autumn, which again impacts on density through winter.
 Pasture maybe higher in nitrates and K and lower in Ca and Mg.
 If using high levels of concentrates, you may have lower level of pasture in the total diet and
require a fibre source to be balance the diet.
Contact
Jason McAinch
DPI Maffra
Tel: 5147 0800