Careful calculations called for when looking to maximise forage production

Livestock producers are being asked to check their calculations carefully when looking to maximise their forage production this summer.

The results from two recent maize trials from NIAB and AFBI have highlighted the benefits of growing grass for silage rather than relying completely on maize.

Barenbrug’s agricultural product manager David Long says that now is the time to consider the options. "Many farmers who are currently struggling with a shortage of winter forage, and having to buy moist feed to make up the shortfall, are looking to increase their maize acreage this year. In many cases this is the right option, especially in areas where a hot dry summer is the norm and grass growth is limited by lack of water. But in areas that can grow good crops of grass farmers should consider not putting all their eggs in the maize basket."

Italian ryegrass can produce dry matter yields that are significantly higher than maize and have the advantage of filling the pit during the better summer weather rather than waiting for everything to come in October.

Results from the NIAB maize trials for favourable maize growing sites compared to the NIAB average Italian ryegrass dry matter yield show that maize achieved 17.4 tonnes per hectare with Italian ryegrass 16.3 tonnes per hectare.

David explains: "Over two years, maize has only two harvests, giving lower harvesting costs than with the two to three silage cuts of Italian ryegrass each year. So in this aspect maize is the most cost effective crop. However Italian ryegrass has only one establishment cost, whereas maize must be sown each year. With Italian seed being 25 per cent cheaper than maize and requiring one not two sowings, the cost advantage is clearly with Italian ryegrass. Growers also get the benefit of winter grazing the Italian sward rather than the problem of coping with run off from a maize stubble."

In more marginal maize areas the arithmetic looks slightly different with the Italians having distinct advantages in terms of the costs associated with producing a litre of milk. Maize and Italian ryegrass trials run by AFBI, near Belfast, in a good grass growing area with a climate that is typical of large parts of the western side of the UK produces the following results:

Dry matter yield (tonnes/hectare)

Maize 12.7

Maize under plastic 15.7

Italian ryegrass20.6

ME (MJ/kg dry matter)

Maize 10.5

Maize under plastic 11.0

Italian ryegrass 11.1@70D

Energy yield (GJ/hectare)

Maize 128

Maize under plastic 174

Italian ryegrass 228

David concludes: "To put the costs in perspective it takes around 5.75 MJ of energy to produce a litre of milk so farmers in this type of climate who choose to grow maize instead of High D Italian ryegrass can lose a potential production of 17,400 litre of milk per hectare. In addition if they opt to grow maize under plastic they will increase their costs by around £250 per hectare and still lose 9,400 litres of milk per hectare."