Grass growth across GB has increased this week, by an average of 6.1kg DM/ha/day with the North East and Scotland seeing increases >12kg DM/ha/day thanks to some rainfall. The West Midlands was the only region to see a decline in grass growth and consideration should be given towards meeting animal requirements. Grass growth rates over this month have remained significantly below those seen in 2020 and the 6-year average due to the unusually cold and dry conditions for springtime.
Milk Yield from Grazing (MYFG)
MYFG has increased to M+11 litres/day this week, meaning it is above the average seen in 2020 (M+7.1litres/day) and the 6-year average (M+7.4litres/day). Increases in MYFG are linked to higher potential dry matter intakes, which may be attributed to increased sward density where there has been some rainfall to support growth.
Grazing Animals Limited by Spring Grass
As the month ends, grazing shortages continue to be reported across GB. With the forecast showing limited rainfall going forward and a delayed return to milder weather until mid-May, grass growth may remain slow and behind the 6-year average.
Over the last month, Trouw Nutrition have seen a crude protein range of 15.1-35.4%, with the current average being 21.3%. Low crude protein levels can be attributed to reduced nitrate uptake in grass because of the dry weather, however with some rainfall forecast, protein levels are expected to rise. It is important to closely monitor protein levels in the overall ration with adjustments being made to supplementation.
The grazing season so far has seen a range in sugar levels of 5.8-19.9% DM. However, the current value of 15.6% DM is much higher when compared to the 2020 (12.6% DM) and 6-year averages (11.25% DM) for the same period. Recent weather conditions cause high levels of photosynthesis during the day, stimulating sugar production in the plant. When overnight temperatures then drop below 6˚C, the plant is unable to utilise these sugars causing them to accumulate in the grass leaf. With typical night-time temperatures not expected to return until mid-May, sugars levels are likely remain above average.
Low crude protein levels and higher than average sugars lead to an imbalance of fermentable energy and protein in the rumen. NutriOpt Fermentable Energy and Protein Balance (NFEPB) nutrient should be between 0 and 200g per day in the total diet for the rumen to function efficiently. This season has seen a much bigger range in NFEPB compared to previous seasons, ranging from 1804g/day to -109g/day. A negative figure indicates higher fermentable carbohydrates than fermentable protein and therefore supplementing with fermentable protein may be required.
Pre-Cut NDF Tracker 2021
The UK average NDF content has dropped slightly this week to 32.76% DM, which is below the optimum 38-40% DM. The North East and Yorkshire had the lowest average NDF content at 28.9% DM and the highest sugar content at 18.62% DM. The highest average NDF content was reported in the East at 33.9% DM.
With mostly dry and cold temperatures, conditions for grass growth have not been ideal. Those considering first cuts will need to ensure grass is analysed and careful consideration is given to grass growth rates, low NDF, sugars and nitrates.