Ecosyl (MTD/1) Trials Summary

Dr SJE Heron and Dr TR Owen

Introduction

Silage additives are generally used for one of three reasons:

as insurance in poor weather

for improved animal performance

for reducing aerobic spoilage

There is a wide choice of inoculants to choose from, although many are identical, being sold under different names.   To ensure a positive effect on farm profitability it is important to choose the right one which means considering the trials evidence, ease of use, safety and cost effectiveness.  It is particularly important to ask for independent trials evidence as many claims will be found to be unsubstantiated.   

Some products claim animal performance benefits on the basis of improved fermentation only and, while this may well increase animal production, it is certainly not always the case; indeed, it is well known that animal performance benefits are found with some inoculants even when there is little apparent improvement in fermentation.  The general belief that all inoculants will give animal performance benefits is based on positive results with just a few as many inoculants have no dairy trials to support them.

Basic intake and digestibility studies using live animals (in vivo studies) will give some indication as to the likely effects on milk yield and/or milk quality, but the only true test is to carry out full-scale dairy trials.

An independent review of published animal performance trials (Kung and Muck, 1997) found that out of 36 dairy trials with inoculants, less than half (17) gave a positive milk production response.  They concluded that only three inoculants had significant numbers of animal trials and singled out one in particular, stating that ‘an impressive number of animal experiments has been conducted using a single silage inoculant containing Lactobacillus plantarum MTD/1.’  This is the specific strain found only in inoculants from Ecosyl Products.  They also stated that ‘all inoculants are not the same’ and that ‘products with organisms of the same name are not necessarily the same organism and may not have the same effectiveness.’

Differences between Inoculants

Inoculants contain living bacteria and the particular strains chosen, the numbers applied and how well they cope with handling and storage can make a big difference to the final outcome.

Bacterial strain: Most inoculants are based on Lactobacillus plantarum, but there are many strains of L. plantarum, each with their own specific characteristics.  Take the analogy of dairy cows – Holsteins and Jersey cows are both one species, Bos taurus, but have very different traits. The MTD/1 strain is unique and results of trials using ECOSYL cannot be extrapolated to other inoculants.

Many inoculants contain additional ‘helper’ bacteria to start fermentation as L. plantarum does not usually work well until the pH falls to below about 5. Ecosyl does not need them as MTD/1 is active over the whole pH range. 

Bacterial numbers: Many silage experts agree that it is necessary to apply at least 1 million bacteria per gram of grass or legume in European conditions to be sure of dominating the natural bacterial population.  If a product, when used on farm, does not apply the same number of bacteria used in trials, product claims based on such trials would be invalid.

Robust bacteria: Being living organisms, bacteria are very sensitive to their environment and are subject to many stresses during manufacturing and storage.  In order to be able to resuscitate quickly to start a rapid, efficient fermentation immediately after application, the inoculant bacteria must be protected from these stresses as much as possible.  Several independent studies have shown that many well-known products did not meet their claimed application rates, some failing very badly.  ECOSYL, however, passed all the tests for both storage and tank mix life.

Enzymes: Some inoculants contain enzymes claimed to break down plant structural carbohydrates, increasing fibre digestibility and releasing sugars for fermentation. However, there appears to be little published evidence to substantiate these claims, perhaps because enzymes are expensive and not enough are being added.

The Evidence Behind Ecosyl

Ecosyl is the most widely researched inoculant in the world, with a total of 15 dairy trials, 19 beef trials, at least 40 intake/digestibility/ME trials and well over 200 fermentation trials behind it, most of which have been published.   The large number of trials ensures it has been thoroughly tested over a wide range of crops, ensiling conditions, etc and that the positive results are repeatable, not one-off results.

Dairy Trials

To date, there have been 15 independent dairy cow trials worldwide, all carried out at recognised university and government research institutes in the UK, Eire, USA, Canada, Holland, Germany and Japan. On average, Ecosyl treatment increased DM intake by 0.4 kg/d and milk yield by 1.2 litres/day (Table 1).  Improvements were found with grass, maize and lucerne and across a wide range of DMs (15-44% DM). Significant improvements were also seen in milk constituent output and bodyweight change.

                                Table 1. Average results of 15 Ecosyl (MTD/1) dairy trials. 

                                * statistically significant difference

Regression analysis shows a consistently higher milk yield from Ecosyl treatment irrespective of DM content.

In all except two of these trials there were only small differences in the fermentation analysis, in general both treated and untreated silages having undergone good fermentations and any differences being of no nutritional significance.  Thus, it is obvious that the positive benefit on milk production seen with Ecosyl are not just the result of improved fermentation, although numerous experiments have shown Ecosyl can improve fermentation in a wide variety of conditions (see Fermentation Trials).

It is worth noting that in seven of these trials the forage DM was above 30%, yet, on average, DM intake increased by 0.7 kg/day DM intake and milk yield by 1.3 litres/cow/day, proving that it is worth treating high DM silages.

An independent assessment of the Ecosyl dairy trials was carried out by the Dairy Research & Consultancy at the University of Reading in 1998 when there were only 14 trials (before the Japanese trial) and concluded that:

“Ecosyl silage inoculant can improve the performance from your winter forage by increasing milk yield by over 1kg/cow/day.”

“In a 100 cow herd, housed for 180 days during winter, milk income can increase by between £27 and £36 per cow, at a milk price of 15 to 20ppl, if fed Ecosyl-treated forage. This equates to £2,700-£3,600 extra income for the herd.”

Beef Trials

There have been a total of 19 beef trials with Ecosyl.  Five of these were with growing cattle fed grass silage with Ecosyl treatment showing on average a significant 15.2% improvement in daily liveweight gain.  Both DM intake (+5.5%) and the feed to gain ratio (-11.3%) were numerically improved although the difference was not significant. (See Appendix 5 for individual trial results).

A further two growing trials have been carried out with maize and three with lucerne silages. Ecosyl treatment significantly increased both silage DM intake (+8.3%) and daily liveweight gain (+8.8%).

Table 2. Growing cattle trial results.

* statistically significant difference

In nine trials with fattening cattle fed grass silage, Ecosyl treatment led to a significant 9.1% improvement in daily carcass gain. There were also trends towards higher DM intake and feed to gain ratio but these were not significant.

Table 3. Finishing cattle trial results.

* statistically significant difference

The improved liveweight and carcass gains from Ecosyl treatment were concluded to result from a combination of higher DM intakes and improved digestibility of the treated silages.

Intake/Digestibility/ME

Ecosyl treatment has led to increased intakes in some, but not all trials, so that can only partially explain the improvements in animal performance.  Gordon (1992) suggested digestibility was an important factor in explaining inoculant effects and Keady (2001) stated that one unit increase in digestibility can be expected to increase DM intake by 1.5%, leading to an extra 0.37 kg milk/cow/day or 28g/day beef liveweight gain.  It is most likely that the answer lies in a combination of increased intake and higher digestibility as Ecosyl has been shown to increase both.

The only way to determine intake, digestibility and ME of silages accurately is by feeding them to animals and analysing everything in and out. Such in vivo (through the animal) experiments are used to calibrate all laboratory-based methods. 

Feeding trials with Ecosyl-treated silage have shown significant increases in all these parameters.  Silage DM intake was increased by an average 5%, while organic matter digestibility (OMD) was increased by an average of 3 ‘D’ units over the untreated silage. Nitrogen digestibility was also found to be significantly increased.

                        Table 4.  Intake, digestibility and ME improvements from Ecosyl treatment.

                        * statistically significant difference

Ecosyl has been shown to have a bigger effect on organic matter digestibility at low crop digestibilities.  Using Ecosyl, crops could either be harvested at the usual time with a higher digestibility or left to give a higher yield at usual digestibility

In 15 of these studies, ME values for the silages were also determined and Ecosyl treatment was found to increase ME by 0.7MJ/kgDM on average.

These effects of Ecosyl on intake, digestibility and ME go some way towards explaining the magnitude of the production responses seen with Ecosyl.

Nitrogen Utilisation

Better nitrogen utilisation is another factor that helps explain Ecosyl’s positive effect on animal performance.  The faster MTD/1 fermentation means less of the true protein will be broken down and, in 30 trials with Ecosyl, treatment has resulted in up to 42% (average 8%) higher true protein in the silage.  Diets with a higher level of true protein are used more efficiently by the rumen microorganisms resulting in increased nitrogen digestibility and retention.

          Table 5.  N digestibility and N retention improvements from Ecosyl treatment.

                        * statistically significant difference

Fermentation

There are now well over 200 fermentation trials on Ecosyl covering a wide range of crop types, DMs and ensiling conditions.   Whichever way you look at the results, Ecosyl has been shown to significantly improve fermentation. Three parameters that are often used to judge fermentation are silage pH, ammonia content and the ratio of lactic acid to volatile fatty acids.

         Table 6. Some examples of the effect of Ecosyl on fermentation under different conditions.

        $ untreated control had a poor fermentation as indicated by an ammonia-N above 10%TN.
          * all differences were significant

It is often said that you need a sugar (WSC) content of more than 3% for inoculants to be successful, but the results above show that this is clearly not true for Ecosyl.

Legumes are particularly difficult crops to ensile due to their low sugar content and high buffering capacity, usually requiring wilting to above 30% DM and an additive to achieve success. In 1997 a four-year EU-sponsored LEGSIL project (Wilkins, 2001) was set up to investigate the ensiling potential of a number of legumes in four northern European countries with IGER carrying out the UK trials. Ecosyl was chosen as the inoculant for the trials.

Fermentation of a number of legumes ensiled at 25 and 40% DM was compared and it was found that at 40% DM both formic acid and Ecosyl were equally effective. At 25% DM formic acid was only slightly better than Ecosyl.  Red clover, white clover and lucerne were also baled at about 30% DM after Ecosyl treatment and fed to dairy cows with or without grass silage. All fermented well and led to increased DM intake and milk yield when substituted partially or completely for grass silage.  Ecosyl is consistently able to improve fermentation with low sugar crops because the MTD/1 strain uses the sugars available very efficiently, ensuring that the maximum amount of acid is generated.

References

Gordon, FJ (1992) Improving the feeding value of silage through biological control.  In Biotechnology in the Feed Industry, Proceedings of Alltech’s Eighth Annual Symposium (TP Lyons, ed), Alltech Technical Publications, 87-97.

Kung, L Jr & RE Muck (1997) Animal responses to silage additives.  Proceedings from the Silage:Field to Feedbunk North American Conference, Hershey, Pennsylvania, USA, February 1997, 200-210.

Keady, TWJ (2001) Digestibility vital for performance.  Farmers Weekly, 9 March.

Wilkins, RJ (2001) Legume Silages for Animal Production.  Project Report