First cut silage samples are flowing into analytical laboratories as farmers wait to see the quality of feed they will be basing diets on this winter.
Trouw Nutrition has developed new terminology as part of this process – Dynamic Energy (DyNE). It is part of its NutriOpt Dairy rationing system and the company believes it will enable farmers to measure energy levels more accurately.
Dr Liz Homer, ruminant technical development manager with Trouw Nutrition GB, says: “DyNE assesses the energy available to the cows as opposed to previous systems which just assess the energy in the feed.” Dr Homer explains that all rations are predictions based on an understanding of the nutritional value of feeds and how those feeds are utilised in the cow.
She says rationing systems attempt to predict how feeds will be utilised and how closely they will match requirements. “It is important to understand that what a cow uses to maintain herself and produce milk is not the feed she actually eats but the end products of digestion that are absorbed after the feeds have been broken down.
This covers rumen fermentation by trillions of micro-organisms as well as digestion in the intestinal tract. “The end products of digestion a cow can use include volatile fatty acids from rumen fermentation, digested bypass starch absorbed in the small intestine and VFAs produced by fermentation in the large intestines.
“Following a major international research project, we now know how to calculate the end products of digestion for a particular feed and so have a far better assessment of the energy available. Unlike ME which is an estimate of the energy content in a feed with no facility to predict how the feed will be digested, DyNE is the sum of the total end products of a feed – it says how much energy will be there for the cow to use.”
Dr Homer says farmers using DyNE and NutriOpt Dairy will be able to increase the precision of feeding this winter.
“Using nearly 20,000 grass silage samples we analysed last year, we found, on average, a cow eating 10kg DM/day of grass silage would receive enough energy for M+5 litres/day when rationed using the ME system, but M+7 litres when using NutriOpt Dairy and DyNE.
“This suggests that rationing using DyNE could have been worth about 400 litres more from forage per cow over a 200-day winter, which will make a big difference to margins.
“We found that not all forages resulted in increased milk yield, some performing worse when assessed on DyNE, so it is important to know the exact analyses of your silages to improve the predictability of your ration’s performance.”