Autumn preparation


3 min read

Pasture management Body condition score What to do when it rains

Late summer strategies in dairy farming involve continuous monitoring of feed demand and body condition score (BCS). This page discusses how managing pasture effectively, considering factors like over-grazing and dry periods, is crucial. It advises you to plan pasture renewal early and understand the effects of sowing dates on pasture performance. Evaluating BCS helps plan autumn actions, like adjusting feed. When it rains after a dry period, managing resources effectively, including the use of nitrogen and supplements, is critical. These strategies ensure healthy cows and quality pastures.

Summer strategies still apply in late summer. Continue to monitor and evaluate feed demand and have a BCS plan.

It’s important to consider the approaching change in season and have a plan for when it rains; reassess feed demand after January pregnancy testing, evaluate remaining summer crop yields, and think about autumn pasture renewal/or autumn feed crops where applicable.

Pasture management

Good grazing management is about maximising the pasture you grow and utilise balanced with allowing pastures to recover following any dry periods in the summer. If it’s still dry in late summer, manage for over-grazing. Frequent intense grazing before plants reach the three-leaf stage reduces recovery of tiller numbers and recovery time.

Pasture renewal

Start thinking about pasture renewal early so paddocks can be properly prepared.

  • Identify reasons for previous poor performance - such as fertility, drainages, and pests
  • Select pasture species - use the online Forage Value Index Cultivar Selector Tool
  • Sow early - sowing date affects pasture establishment, yield and persistence. Sowing early is particularly important in summer-dry areas as sowing early allows individual plants more time to develop and reach over twenty tillers in size prior to the following (potentially dry) summer. Later sowing in cooler autumn conditions means slower establishment due to cooler temperatures and greater potential to pug and damage new pastures in winter and spring. Sowing early (after 25 February) in dry conditions with treated seed is easier for contractors; it means faster establishment, more yield, and sets up better pasture persistence.

Body condition score

Assessing cows' BCS in mid-February to mid-March determines if actions are required and helps plan for autumn, e.g. drying off decisions, OAD and feeding

Have a BCS plan

A number of strategies will allow you to achieve BCS targets at calving. Drafting cows based on BCS, age and time of calving; milking OAD, and running more than one herd may be appropriate.

It's likely that a mix of the strategies will need to be implemented by autumn to ensure all cows achieve BCS targets.

With the decline in mid-season pasture quality (and possibly insufficient quantity), BCS gain slows down or cows lose BCS once more. In the North Island, in particular, cows lose BCS again in January and February. This loss of BCS is different to the loss in BCS post-calving and can be minimised by ensuring pasture quality is high or by providing the cow with high-quality supplementary feeds when there is insufficient pasture.

With milder autumn weather, pasture quality improves and cows gain BCS again. However, BCS gain is limited until the cows are dried off.

What to do when it rains - managing after the dry

How much rain does it take to break a drought?

After a long dry period significant rain is required. 50mm+ is sufficient to return soil moisture deficits to within 15% of field capacity.

It is better to apply nitrogen sooner rather than later – apply after 20-25mm of rain or more.

Feeding supplement after a very dry summer

Available pasture can halve after rain as can decay causing cows to be underfeed. Up to fifty percent of the pasture available before rain is lost as it quickly decays.

To avoid under feeding, it may be important to have supplement available to feed out after rain. If feeding out before the drought the amount required after rain will at least double in the first 7-10 days, reducing as pasture cover improves.

After autumn rain and very rapid pasture growth there is the opportunity 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.

Nitrogen (N)

Use of fertiliser N can result in pasture responses of up to 12kg DM/kg N. Autumn nitrogen responses vary considerably.

The only certainty to applying N fertiliser after the autumn rains is the grass will be greener. After a severe drought, nitrogen applications can be delayed for two weeks after it has rained as the soil has good reserves of mineralised nitrogen and pastures take time to recover. The response period to autumn applied N fertiliser is over three months and this has to be considered when making the final drying off decision i.e. the response of 12kg DM/kg N does not occur over a 2-3-week period.

Last updated: Sep 2023
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