Dairy farmers have a real opportunity to increase production from forage this winter according to Trouw Nutrition GB who reported the latest results for first and second cut grass silage and wholecrop at the UK Dairy Day (13th September).
The results show that the initial promise indicated when early first cuts were analysed has been maintained with improved milk potential. Second cuts are also higher quality, in part due to an earlier harvest, while wholecrops are analysing well.
Revealing the results, Trouw Ruminant Technical Development Manager Dr Liz Homer says the key will be to balance diets to exploit the potential in the silages. “Provided diets are carefully formulated to balance silages and to maintain good rumen health then there is a tremendous opportunity to increase milk from forage and improve margins.”
With over 3500 first cut samples now analysed, Dr Homer says that while there is the usual range in results, on average crops have a higher dry matter, crude protein content and energy levels than in 2016. NDF levels are lower reflecting the earlier cut crops and pH is slightly elevated which means clamp face management will be important once crops are open.
“On the traditional ME basis, first cuts are averaging 11ME, while on the more accurate Dynamic Energy approach they are coming in at 6.22MJ.”
Second cuts show an identical picture with better dry matter, energy and protein but reduced NDF. They will also need careful management once the clamp is opened to avoid wastage at the feed face. Wholecrop is generally less variable year on year and is analysing very close to previous years, once again providing a useful starch based forage.
Dr Homer says that looking at the milk production potential of grass silages, on an ME basis first cut would support M+6 litres from an intake of 10kgDM, while second cut will support M+5 litres.
“However, this underestimates the true potential. Using Dynamic Energy, a term developed in the NutriOpt Dairy system and which predicts the energy truly available to the cow, both first and second cuts should be expected to support M+8 litres provided the rumen is well balanced.
“Using the NutriOpt Dairy system it is possible to more precisely balance the rumen to ensure the optimum levels of rapidly and slowly fermented energy and protein to optimise rumen function. This year’s grass silages are generally higher in both fermentable carbohydrates and protein but it is the balance of these that will influence the types of supplementary feed that should be used.”
To illustrate the point, Dr Homer compared diets based on similar proportions of first and second cut grass and wholecrop and formulated to provide M+35 litres, but using 2016 and 2017 silage analyses.
“In 2016 diets needed bypass protein from sources such as bypass soya and slowly fermented carbohydrate so feeds like sugar beet pulp and soya hulls were a good choice. This year the need is for fermentable protein sources, possibly from a mix of soya, rape and possibly even urea while more bypass starch will be needed suggesting maize could replace some wheat. This will also help reduce the risk of high acid load and its negative effect on rumen health.
“By feeding the correct supplements it will be possible to capitalise on the value of forages and reduce overall feed costs this winter,” Dr Homer concludes.
