Green Crop Driers
Nutrition
The benefits of high temperature drying
Crops of grass and lucerne are grown and managed specially for high temperature drying. The main species of grass used are perennial ryegrass and tall fescue, but some high quality permanent swards are also used. They are cut at regular intervals throughout the year in order to produce a feed with a high and consistent nutritional value.
Lucerne is usually cropped for three years as part of an arable rotation. Unlike grass, it does not require nitrogenous fertilisers as it fixes its own nitrogen from the atmosphere.
After mowing, the swath is usually allowed to wilt for a few hours before being picked up with a forage harvester and hauled to the dryer.
The Drying Process
The harvested crop is dried in a rotary drum dryer (rather like an enormous tumble dryer). The fresh grass or lucerne is fed into one end of the dryer, through which is drawn hot air at around 800 degrees centigrade. As the material passes through the rotating drum, the majority of the water is rapidly evaporated from it so that when it emerges from the other end, the moisture content has been reduced to about 12 per cent. The process not only sterilises it, but also produces a feed that contains virtually all the nutritional value of the crop from which it was made.
The dried material is then usually milled and pelleted before being cooled to make it safe to store. Some producers leave it in its chopped form and then bale it to provide a source of long fibre - ideal for stimulating rumen function in high yielding dairy cows.
The nutritional value of British Dried Grass and Dried Lucerne
British Dried Grass and Dried Lucerne are high quality, natural feeds produced from crops grown and managed specially for high temperature drying. They are wholesome, healthy, safe, unadulterated and, above all, traceable feeds in which livestock farmers and nutritionists can have full confidence.
As well as being totally natural feeds for dairy cows and all other types of ruminant, Dried Grass and Dried Lucerne (referred to as 'Dehy' within the industry) offer a number of features that can make them invaluable in formulating a balanced diet.
Excellent supply of DUP
The high temperature drying process, with an air inlet temperature in the region of 800 degrees centigrade, protects some of the protein from breakdown in the rumen, so increasing the level of DUP. This can be important in helping to maintain milk yield and protein levels.
Good source of FME
Unlike the fermentation process during silage making which uses up most of the FME in the grass to feed the organisms that produce the acid needed to preserve the crop, the high temperature drying process preserves this naturally occurring FME, so important in helping to sustain the rumen micro-organisms.
Highly digestible fibre
Investigations have shown that Dehy produced from grass cut at frequent intervals contains highly digestible fibre, beneficial in helping to balance rumen VFA production. For this reason, most driers now aim to cut their grass at 35-day intervals as far as possible.
Valuable levels of NDF
Dried Grass and Dried Lucerne contain relatively high levels of NDF which can play an important role in buffering high starch and acidic feeds.
Excellent source of Beta-carotene
Dehy is an excellent source of Beta-carotene, which is particularly low in many other concentrates used for ruminants. The need for extra Beta-carotene is even greater when maize silage and other maize products are included in the diet.
Changes in ruminant production systems over the past few years - changes in milk markets, the effect of BSE, concerns about natural ingredients etc - have all made the attributes of high quality Dried Grass and Dried Lucerne more important than ever before. But, although for many years the advantages of using Dehy in ruminant diets has been acknowledged, a lack of information and a worry about variability has sometimes made it difficult for nutritionists to incorporate it in diets. In an effort to overcome these concerns, a comprehensive, independently operated monitoring programme has been undertaken by BAGCD to fully evaluate contemporary British Dehy.
As a result of this work - and earlier scientific analyses looking at the digestibility of the products - it is now possible to provide all the data needed for modern diet formulation. Click here for typical analysis