Farmers realise the value of reseeding, but the amount of ground reseeded any year largely depends on the weather and the financial position on farms.
On average, only about 2.5% of grassland is reseeded annually; it should be at least four times this level to bring our national grass production up to what is required for reaching the 2020 dairy and beef production targets.
Together with lime and fertiliser, reseeding delivers the fastest return on investment.
Teagasc surveys indicate that many Irish pastures produce 50% less than their potential.
There is up to 50% difference in grass dry matter production between farms, and 60% within farms.
The key factor is the level of perennial ryegrass in pastures, and most of the production shortfall in poorer pasture occurs up to May and in late autumn.
Pastures with low ryegrass content are 25% less responsive to nutrients.
Reseeding pastures with a low level of perennial ryegrass has become more important with the end of milk quotas.
More feed is required, and , farmers cannot afford to be buying unnecessarily large amounts of concentrates to supplement poor quality grass and silage, or applying fertiliser on poor pastures that give a poor response.
The target for most dairy farmers in future will be 2.5 cows per ha (1 cow/ac).
For efficient milk production, this stocking rate requires grass production of around 14 tonnes of dry matter per hectare which is 40% higher than the average production on Irish dairy farms at present.
Advantages of reseeding poor pastures
* Potential 35% increase in yields of grass and silage (depending on adequate lime and fertiliser, how bad the old pasture is, and how well the reseeding is carried out).
* Better response to fertilisers (25% better response to nitrogen fertilisers).
* 20% higher digestibility
* Better seasonal growth
* Better quality silage (by 10 DMD digestibility units), easier to preserve.
* Big savings in concentrate requirements, worth 60 cent per animal per day.
* Better animal performance; higher milk yields (5L/cow/day better), higher milk protein (+0.2%) and live weight gain.
Costs and benefits
Excluding fertiliser and lime (used on old and new pastures) the extra cost associated with reseeding varies from €200 to €250 per acre.
An extra 1.5 tonnes of dry matter (7.5t of grass) per acre, per year, is worth €300.
And the reseeded pasture is much higher quality and grows earlier. If you maintain the reseeded pasture in a highly productive state for eight to 10 years, reseeding is the best investment.
But if reseeds revert to poor weedy pastures in a few years, reseeding is not worthwhile. The job must be done right, with proper follow-up, or not done at all. In order to justify the cost of reseeding many different factors should be considered.
The botanical composition of the existing swards and the management of the grassland after reseeding should be the main influencing factors. The demand for extra feed on your farm is another factor to be considered.
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