With research showing that a minimum of 5 per cent ration sugars is needed to fully support rumen function, choosing the right feeds to supply those sugars is critical.
Charlotte Ward, KW nutritionist, says: “Feeding additional sugars has been established as having a significant effect on fibre digestion and the ability of rumen microbes to convert rumen degradable protein, such as that predominantly found in grass and grass silages, into protein available to the cow.
“Getting the supply of sugars right is therefore critical to getting the most out of conserved forages this winter and to feed efficiency overall.”
Ms Ward warns that even a 3 per cent drop in rumen efficiency through incorrect energy balance can increase feed costs for a typical 200-cow herd by £500-600/month.
Research from the United States shows early to mid-lactation dairy rations should contain 5-7 per cent fermentable sugars on a dry matter basis to fully support microbial breakdown of forage fibre in the rumen.
These sugars will also increase utilisation of high levels of effective rumen degradable protein in grass silages, improving efficiency and reducing potential waste and losses to the environment.
As Ms Ward points out, both are highly relevant to the 2019 grass silages being seen across the country.
The latest Trouw Nutrition data shows grass silages are more lignified this year due to the greater maturity of many swards when first cut, with good levels of crude protein, particularly on those farms using a multi-cut system.
She says: “If they are going to realise their full potential, these silages are going to need more sugars in the ration to ‘fuel’ the breakdown of that extra fibre.
“The same applies to capturing the higher levels of crude protein in many silages and avoiding additional nitrogen losses.
“Unfortunately, large numbers of the forage-based rations fed in the UK contain only 3-4 per cent sugars. Not only that, but many of these are residual sugars in preserved forages, which are not particularly accessible to rumen microbes.
“Including feeds in the ration that supply additional sugars is therefore extremely important.”
Ms Ward says it is possible to increase ration sugar levels by replacing cereals with a confectionary or breakfast cereal blend, by using a molassed sugar beef feed or one of the many cane molasses blends available.
She adds it is important to introduce additional sugars slowly, allowing time for the rumen to adapt.
“Aim to maintain a balance in the rumen by keeping the starch-to-sugars ratio at about 3:1.”