• Meg Simpson

Don't feed them more today than you're able to feed tomorrow

My lawnmower has pretty much been sent into its winter hibernation as the grass growth slows down, so what does that mean for our feed management heading into spring? Setting our farms up has already begun, with the aim to get us through to balance day. The spring rotation planner (SRP) is a key tool in managing our feed to achieve this.

There’s two key parts to making sure that pasture is managed through the winter and spring to get us through to balance day, the farm strategic (stocking rate and calving date) and the operational (autumn management to achieve target calving pasture cover, and area grazed per day over winter and spring). Fitting the strategic plan to fit the pasture curve is the first part of this, but as now this is probably pretty well set, so we will focus on what can be done from a farm operational perspective. The opening pasture cover target will be dependent on growth rates and feed demand over winter, but the main goal of a SRP is to get through to the “magic date” – balance day, when pasture supply equals pasture demand. This is done by allocating the animals a set area per day (or per week), starting with a very slow rotation, and gradually speeding up in line with cow demand, to eventually be at the fastest rotation by balance day. Remember that the cows demand will increase in the few weeks post calving before she achieves peak intake.

The use of SRP is all about optimising pasture management, rather than “controlled starvation”. All it is doing is restrict the available area available to cows per day – then it’s up to the farmer to add the required supplements. This is why a feed budget is important to be used in conjunction to ensure that cow demand is being met. Sticking to the SRP however, should minimise the feed deficit and minimise the amount of supplement required going forward.

In the mid 80s there was some work done which led to the development of the spring rotation planner. Bryant and L’Huillier compared an ideal scenario with low pasture cover heading into calving, and then looked at the effect of maintaining a slow rotation, compared to speeding up rotation by increasing the area that milking cows were allocated. In this example speeding up the round ate away at average cover, and it took almost four months to recover – that is the definition of short-term gain for long term pain.

An important factor in the success of a spring rotation planner is discipline and regular assessment of progress – there’s no point having a plan, if you start creeping ahead without knowing you are doing it. It’s vital to continue to monitor the feed position and growth rates, particularly in the weeks leading up to balance day. Are the first grazed paddocks on track to achieve the targets required in the second round? If the growth is behind target, consider options to slow the rotation down by adding supplement, and if conditions are suitable consider the use of nitrogen, and if the growth is ahead of budget, consider speeding up the rotation (with caution).

There are lots of different ways to allocate feed using a SRP, but one of the simplest is marking a point at the start of calving on the slowest round (say a 100 day round which is 1/100th of the farm area) on the day that calving is supposed to start, then another on balance day (say a 20 day round which is 1/20th of the farm area). By connecting these two points you will get the area that should be grazed each day. The beauty of a straight line SRP is in its simplicity – as cow demand and the number of cows calved increase, so too does the area available to feed per day. This effectively manages feed intakes and pasture use to ensure that the cows are on a rising plane of nutrition heading into mating, and hopefully avoid any potential feed deficits.

If you would like to discuss how to develop and implement a spring rotation plan on your farm, or how you can pull things back before the short term gain becomes long term pain, please give me a call.

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