Grasstec: Prepare for spring grass now
COMMENT: Closing is now under way on some farms, with the latest closing date 15 October. The highest grass cover that can be carried through the winter is 1200kgs/ha (2700kgs total cover). Carrying over covers greater than this will lead to increased plant decay and death, owing to low levels of light getting through to the base of the sward.
There are four key areas for successful autumn closing:
Begin closing at the right date
Northerly farms or those with a heavier soil type/older swards will begin closing at the beginning of October, whereas more southerly, free draining farms or farms with a high proportion of reseeded paddocks will close slightly later (10-15 October). This is entirely down to typical growth rates for the farm in autumn
Calving intensity in spring will dictate grass demand prior to magic day and hence opening cover required in spring. The greater the demand, the higher the closing cover needs to be. For example, if a farm typically grows 3kgs/day over the winter, this will add 180kgs onto the AFC. Therefore, if opening cover target is 800, closing cover must be 620kgs/ha (opening cover in spring – winter growth = closing cover in autumn)
Decide which paddocks to close first
First closed paddocks will have the highest cover in early spring so choose paddocks that have good access to tracks and water. Although this paddock will have the greatest cover, it will not be the first paddock to graze.
Cows should be turned out in spring to paddocks with a low cover (circa 700kgs/ha), so they will easily clean this paddock off and get into ‘grazing mode’ again. They will graze this down to zero easily and can then move onto heavier covers, achieving a low residual there also. Too often we see cows turned out onto the highest covers on farms and residuals are high. This continues in subsequent paddocks. Second rotation quality will be poor, leading to lower energy feed pre breeding. Start as you mean to go on. Paddocks reseeded in 2013 should be grazed off last, this will optimise tillering over the winter period
The majority of farms have more than one soil type – Try and alternate closing paddocks of either soil type so as not to have all the dry paddocks grazed first/last; this way we can work around difficult weather in late autumn and/or early spring.
This is a key time on farm so try to plan it well. Measuring grass weekly is key as growth rates can very considerably with shorter days and cooler nights. Youngstock ground also needs to be closed similar to the milking platform to ensure early turnout for maiden heifers.
By Cathal Mc Aleer, consultant with Grasstec Dairy Solutions which provides a dairy consultancy, farm infrastructure design and livestock sale service in Ireland and UK. Cathal can be contacted on +44 (0)77495 31679 or [email protected]