Revised rotations hold key to getting grass targets back on track this Spring

If covers are dropping rapidly, now is the time to ease demand by reducing daily area grazed and introducing supplementary feed. Photo: O'Gorman Photography.
If covers are dropping rapidly, now is the time to ease demand by reducing daily area grazed and introducing supplementary feed. Photo: O'Gorman Photography.
Joe Kelleher

Joe Kelleher

The weather has thrown everything at us this winter from storm Emma to "The Beast from East" all coupled with above normal rainfall and below normal temperatures.

The knock on effect for farmers is that silage pits are either empty in many yards or very close to it in most instances.

And with grass growth at less than half its normal level, there isn't a huge amount of feed outside in the paddocks either.

There is a huge difference between circumstances on farms this spring.

These range from farms that have grazed the entire grazing block to those that have yet to leave cattle out and from those that have 70 units of Nitrogen spread to those that yet to attach the fertiliser spreader to the tractor.

There are some that are staring at the back wall of the silage pit and those that have plenty of silage left.

With this huge variety in circumstances, there is no one size fits all solutions to the current challenge in front of us and it is up to every farmer to choose the appropriate strategy for his/her farm.

However, there are objectives that are common to all farmers this spring;

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  • Feed milking cows well to maintain good milk production, body condition and rumen health
  • Ensure youngstock and remaining dry cows are correctly fed
  • Manage grazing to protect ground conditions while utilising available grass
  • Maintain adequate grass cover on the farm by managing rotation length
  • Promote new grass growth by getting winter covers grazed and fertilizer applied
  • Managing average farm covers

Mean growth rates around the country were 8-10kg per ha last week. However growths of 12-18kg per day were reported in Ballyhaise, Moorepark and Johnstown, and commercial farms with early N applied, indicating some potential pick-up in growth rates. But corrective action will still be required in the short term on many farms.

Holding average farm cover above 500kg per ha in early April is very important to allow the farm respond quickly to improving growth conditions.

Farms with large areas grazed and/or little to no grass need to get daily demand below growth rate to prevent covers from falling too much. If covers are dropping rapidly, now is the time to ease demand by reducing daily area grazed and introducing supplementary feed. Cows must be adequately fed in this situation (discussed below). Housing a proportion of the herd can work well if cubicles and feed space are under pressure.

The aim is to have at least 1100kg DM per ha (ie enough grass for 80 cows for 24 hours on 1ha) back on the first paddock of the second round. With only 500-600kg recovery by April 1, a further 400-500kg total growth is needed before next grazing. It is difficult to project growth over the next few weeks, but at a reasonable estimate of 30kg per day on average, it will take until April 13-15 before there is adequate cover to start the second rotation. The plan at this stage should be to stretch end of the first rotation to this point (plus or minus 3-4 days). Review at the end of the first week of April and adjust if needed.

Ground conditions are slowly improving so farms with a low pc grazed and good grass covers on paddocks may have an opportunity to get area grazed now. This must be a priority, especially where silage stocks are running tight. Graze some lower covers to settle cows into grazing and then move to remove the heaviest covers if dry overhead. These paddocks will lie dormant until new growth is stimulated by grazing. Use on-off grazing if conditions are marginal and aim for two grazing bouts per day. Bring evening milking time forward to reduce labour impact.


N needs to be applied as a priority now. The aim was to have 70 units per acre out by the end of March, but this was not possible on many farms. For those that have no fertiliser out yet aim to spread 40-50 units as soon as possible.

For those that have some fertiliser out already, aim to get the 70 units out. It might also be time to consider getting some compound fertiliser out.

Silage stocks and feed options

Assess available silage stocks and likely feed demand immediately. Early action on feed deficits makes the problem easier to solve. Guideline figures for intake of fresh silage (22-24pc DM) are:

380-400kg per week for mature animals (dry/milking cows, bulls, in-calf heifers)

150-170kg per week for youngstock (yearling heifers)

This is based on full-time housing and can be reduced by 40-50pc if cows are grazed by day. Estimate total demand for the next four weeks, net of available grass on the farm, and compare to stocks in the yard.

Aim to have at least 1.5 weeks silage reserve on hand by late April. If this is unlikely it is best to take action now to stretch supplies. A 30pc deficit in silage can be managed by feeding extra concentrates. Deficits greater than this will increase risk of digestive problems through fibre shortages, so forage purchase may be needed.

Straight ingredients like hulls, beet pulp, and palm kernel are high in digestible fibre and work well to fill gaps of 2-3kg in daily feed budgets. They can be fed as a midday feed or along with a night-time silage allowance if grazing by day. They work much better for this purpose than cereals due to lower acidosis risk. They are also quite available and relatively cost-competitive per unit of feed energy and protein at present.

Exercise caution if introducing co-product feeds such as fodder beet or potatoes. These are excellent quality feeds but are very high in fermentable carbohydrate and low in fibre, and as such should be treated as wet concentrates rather than 'fodder-stretchers' per se. Consult your Teagasc adviser for detailed guidelines if considering such options for short-term feeding.

Good quality feed straw is an option to increase diet fibre (NDF) allowances but there are issues with cost and availability at present.

Joe Kelleher is a Teagasc dairy advisor based in Newcastle West, Co Limerick

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