The value of quality grass
Most farmers will agree that it’s not possible to produce high quality grazing and silage using inferior grasses. Output and profitability can vary significantly even when using varieties on the NI Recommended Lists.
Of course it’s vitally important to keep weed grasses to a minimum and eliminate all other weed species to maximise the value in the field or clamp, but, according to crop specialist Joseph Morton Ltd (Morton’s), a lot of profit potential comes down to the actual ryegrass varieties being grown.
The company’s technical advisor for the North West region William McCollum explains:
“There is sufficient variability, even within ryegrass varieties on the official NI Recommended Lists, to affect the profitability that can be achieved from the resulting silage or grazing. The argument for selecting the best available grass varieties is very strong even if you simply look at yield.
“If you then take into account quality criteria such as D-Value, the variance in crop value becomes even more pronounced.
“Looking at total grazing yields specifically, the highest yield of the perennial diploid ryegrasses comes from AberGreen (offering 1.8t DM/ha more than the lowest yielding on the list). The ‘top to bottom’ advantage from AberGreen, based on Kinghay’s grazing cost of £88/t DM, is therefore an astonishing £158/ha
“However, yield is only part of the story as there are stark variances in quality within the Recommended Lists.
“When we compare the high quality tetraploid perennial ryegrass AberBite (78.3D) with Delphin a lower D-value variety on the list (75.3D), we see a +3 unit difference in grass quality. According to calculations made in Northern Ireland, a 3 unit difference in silage digestibility is worth 1kg/cow/day in additional milk as well as increased protein content. This could make the difference between profit and loss in some circumstances and is far from a marginal gain.
“There are other quality criteria of the grass plant that can add value to the diet. Aber varieties have also been bred with increases in sugar content (water soluble carbohydrate WSC). There are good scientific reasons why this improves rumen efficiency and delivers better animal performance.
“It would appear, then, that the arguments for improving sward quality – and selecting the best available varieties when doing so – are very strong indeed. Soil analysis, pH adjustment and soil preparation are all important, but starting with the best possible raw material is vital.”
William concludes, “Grass is a crop like any other and variety selection is as important as it is when growing cereals for whole-crop, crimp or the combine. Farmers should check varieties in grass seed mixtures offered to them. At the very least they should ALL be on the Northern Ireland Recommended Lists.”
The Northern Ireland 2013/14 Recommended Lists are contained in the Morton’s 2014 Technical Guide. To get your copy please contact Morton’s on (tel) 028 4066 2521.