Grass quality monitoring for first cut silage 2018

Location of fields being monitoring (blue pins)
Location of fields being monitoring (blue pins)

The poor weather during the late summer/autumn 2017 had a major impact on the ability of farmers to get silage cut and/or autumn grass grazed off, writes Stephen Gilkinson, Dairy Technologist, CAFRE.

This has had an impact into the 2018 growing season, on both grass quality and quantity, with resulting implications for 1st cut silage.

A programme of grass quality monitoring across a range of 2017 field histories in different areas of Northern Ireland has been established by CAFRE, AFBI and Grassland Agro. This will provide real time information to farmers on the yield, quality and ensilability of standing crops of grass destined for silage making and may highlight any negative impacts of the wet autumn in 2017.

Grass destined for silage from seven fields is being sampled on a weekly basis from late April to the start of June. Samples are being analysed for quality and ensilability through the AFBI Hillsborough Feeding Information Service. On a weekly basis, harvestable yields of the standing grass crop are being estimated from three 0.25 m2 quadrants of grass cut in each field.

Grass quality results

To date, it is evident that there are big yield differences from field to field, with some of the variation related to autumn management. Grass quality (ME) has been less variable than yield, but is now declining with time across all the sites.

The field at Rasharkin where third cut silage was not taken, nor grazed off in the autumn has unsurprisingly the highest yield, but the lowest quality and is classed as difficult to ensile. Ease of ensiling is related to dry matter content, sugar content, nitrates concentration and buffering capacity. The higher the dry matter and sugar content and the lower the nitrate content and buffering capacity, the easier the crop will be to ensile. Rapid wilting will increase the dry matter content and encourage a good fermentation. If in doubt about ease of ensilability, grass samples can be quickly analysed through the AFBI laboratory. Further details of grass quality results and dry matter yields from this project are available on the CAFRE website:

There will also be opportunities to talk about this work with CAFRE technologists and AFBI scientists at the AFBI Dairy Open Day at Hillsborough on the 6 June. The theme is Dairy Innovation 2018 - Profiting from AFBI Research and CAFRE technologists will be contributing to the field demonstrations and in the main marquee.