Autumn Grazing Management

The focus of autumn grazing management is to increase the number of days at grass and animal performance, but also to set the farm up during the final rotation to grow grass over winter and provide grass the following spring.

There are two key autumn periods:

• Period of autumn grass build-up
• Managing the final rotation

Generally, rotation length should be extended from 10 August. The focus of this period is to gradually build pre-grazing covers, targeting covers of 2,000kg to 2,200kg DM/ha in mid-September. Pre-grazing covers >2,500kg DM/ ha are difficult to utilise and should be harvested as surplus (round bales). Surplus paddocks should be removed in August.

Removing paddocks after the first week of September should be avoided if possible; a September harvest is too late as paddocks do not have enough time to re-grow to make any meaningful contribution in the last rotation. By achieving the right farm cover at the right time, decisions are easier to make. Many farmers fall into the trap of building cover too late and are pushed into harvesting excess grass in September.   

Targets for the end of September

• 2.5 cows/ha – 1000kg DM/ha
• 2.7 cows/ha – 1100kg DM/ha
• 3.0 cows/ha – 1200kg DM/ha

Carrying more than 3.0 cows/ha, it is not advisable to allow the peak farm cover to build higher than 1200kg DM/ha. Otherwise cows will be grazing covers in excess of 2000kg/ha which will have a negative effect on graze out of paddocks with a lot of dead material remaining in the sward

Aim: To build rotation length to 35 days by mid –September

• Be flexible – an autumn budget is a target for grass supply relative to growth and demand.
• Demand is in your control, however growth is mostly dependant on the weather conditions.
• If farm cover is below target at any stage, take quick action to bring it back on course, for example introduce a higher level of concentrate or remove surplus stock.
• During August/September and early October period it is important to measure grass supply weekly so that you know how much grass you have and how much you need to have.
• Once you know this, informed decisions can be made.
• Closing farm cover of 550-600kg DM/ha with covers ranging from 900kg DM/ha – first paddock closed to 200kg DM/ha – last paddock closed.
• It is important to graze down to a residual of 4 – 4.5 cm in the autumn to stimulate growth throughout the winter and avoid the carryover of dead material over the Winter and into the following Spring.
• The use of strip wires can become essential to allocate milking cows the correct amount of grass and also minimising damage to paddocks in unfavourable ground conditions.
• Start closing paddocks from the 10th October onwards (1-2 weeks earlier in wet areas).
• Aim to have 60% farm closed by the end of the first week of November (1-2 weeks earlier in wet areas). The paddocks grazed by this date will have an opportunity to grow grass before growth rates decline in November.
• Leave the grazing platform with an “adequate grass cover” when the cows are housed (farm cover of 550-600kg DM/ha).
• Do not re-graze fields that have been closed as Spring grass availability will be reduced. 1 kg DM of Spring grass is worth in the region of €0.16/kg DM while in the Summer 1 kg DM of grass is worth €0.04/kg DM.
• Feed supplements if there is insufficient grass in the daily allocation.
• Skip heavier paddocks if necessary – and graze paddocks with ideal covers – to meet 60% target if necessary.
• Use wet weather grazing techniques if ground conditions deteriorate (on-off grazing, strip wires).
• During the last rotation, you must focus on grazing residuals if you want to have top quality swards for your milking herd next spring.