Silage

Three cuts of silage are taken each year. The first cut is taken in mid May. Second cut is taken at the end of June / beginning of July and the third cut is taken around the second week in August.

Management

Preparation for the all important first cut begins immediately after third cut the previous year. A compound fertiliser (26:4:4) is applied at a rate of 2 CWT/Acre which works out at about 65 kgN/Ha. After a 5-6 week rest young stock and beef cattle graze the silage ground until about 10th December. This gives the silage fields a tight graze which we find is essential for maintaining sward vitality. Slurry is applied mid-January (depending on ground conditions, it may be delayed for environmental reasons as it was in 1995 due to a wet spring) followed by an application of Urea (48:0:0) at a rate of about 75 Kg/Ha in late January / early February. A compound fertiliser (26:6:6) is then sown in late March 110 kgN/Ha. It is important that there is a six week period between the last application of fertiliser and harvesting to avoid high ammonia levels in the silage which can make it unpalatable. The silage area is then rolled around the start of April. The first cut of silage is usually taken around mid May it is cut harvested and ensiled by contractors. In order to reduce increase the dry matter of the silage the grass is tedded out. The target is to have a dry matter of between 25 - 35% dry matter. Effluent production represents a nutritive loss within the silage making system and also, due to its extremely high BOD value, a risk to the environment in term of its pollution potential. A new silo floor was laid in 1994. The silage innoculent Pioneer 11 88 (Powder form) is added to the silage to improve fermentation unless the silage is coming in very dry. After first cut, the silage then gets an application of 100 kgN/Ha of a 24:6:12 N:P:K fertiliser. Second cut generally takes place on the 28th June and the same area is cut and the same amount of fertiliser is sown unless organic manures are applied in which case rates are reduced accordingly. Third cut generally occurs around the 12th August. A smaller area is cut for third cut. this is because grass growth slows during this time of year and the beef stock and younger replacements need the extra ground. 100 acres are generally cut although this an vary depending on conditions at the time. Fertiliser and slurry application after third cut has already been detailed above.

Feeding

Over the winter the silage is fed through an easy feed system. The feed passages are 8ft wide and silage is fed by a Matbro TR200 with a shear grab attachment which helps to inhibit aerobic spoilage at the silo face. The feeding barriers drop down on bars which allows the cows to reach the centre of the passage and thus eliminates the need for graping. This barrier an also be dropped outwards. This is useful when filling the feed passage as it holds the cows heads back and stops them getting in the way of the loading shovel. Pins which hang down on chains from the top of the H-Irons can be slotted into holes in the bar that stop to cows from flipping the bar over when feeding. For further details see the page on our cubicle shed. First cut is fed to the dairy cows as it is the highest quality cut. The second and third cuts are fed to the beef cattle and replacements. The milking cows are offered silage ad-lib and are never asked to eat right down to the last. The leavings are scraped up with a bucket and fed to other cattle. This means that the cows never eat silage which is unpalatable to them. Dry cows are fed ad-lib straw and a limited amount of lesser quality silage. This is to prevent them from putting on too much condition. This means easier calving and recent research has shown that feeding straw to dry cows can improve the compositional quality of the milk in the subsequent lactation.

Silage Analysis

We analyse our silage using the Hillsborough Feeding Information System. First cut due to the weather was fairly wet this year. Second cut is analysed in two sections. The grass was cut down on Friday. Some of it was harvested on Saturday and the rest left until Monday by which time it had dried considerably.

1998 Analysis

1997 Analysis

1995/96 Silage Analysis

Explanation of terms

Intake Value
This indicates the likely intake potential of the silage. The figure is predicted via NIRRS and is widely recognised as the best system available for predicting the intake eo f grass silages. Range of Values: 45 - 110 Average: 70

Dry Matter (%)
This is the quantity of material remaining after all the water has been removed from the silage. The DM greatly influences the amount of nutrients available per unit weight of the silage consumed and hence its overall value as an animal feed. DM is quoted on an alcohol corrected toluene dry matter basis and takes account of the volatile constituents of the silage which are lost in oven drying. Consequently this true dry matter content is slightly higher than some of the volumes given in the past.

pH
Acidity of the silage is measured on the pH scale. Similar to the Ammonia N content of the silage, the pH will give a good indication of whether a silage has a good fermentation and is likely to store satisfactorily. the desirable pH range for a clamp silage is 3.8 - 4.2. Above pH 4.5, the risk of deterioration in store become increasingly apparent. However, high dry matter silages can be satisfactory at a higher pH. pH values at 3.6 and below are very acidic.

Ammonia N (% total N)

Ammonia N can thus be used as a partial guide to the success of the fermentation process. High ammonia levels (>20) may lead to reduced silage intakes and are normally associated with undesirable fermentations.

Crude Protein (%)
This value is indicative of the maturity of the grass at harvest but may be increased by late treatment with nitrogen fertiliser before cutting.

ME (MJ/kg DM)
Measure of the metabolisable energy content of the silage. It is derived from the D-value.

Lactic Acid (%DM)
In silage production grass is cut, harvested, stored in a silo and consolidated and sealed. The consolidation and sealing phases are vitally important as the removal of the air from grass allows fermentation rather than oxidation. The naturally occurring micro-organisms in the grass use grass sugar as an energy source and produce acids as the by-product. The major acid in a well preserved silage is lactic acid. Badly preserved silage contains large amounts of butyric, acetic and other acids from secondary fermentation with low levels of lactic acid. The level of lactic acid in the silage thus depends on the sugar level of the grass at cutting, the degree of wilting, the quality of sealing and the preservation. Silages with a restricted fermentation will tend to have lower levels. High levels reflect dominance of lactobacillus fermentation.

High dry matter silages may be well preserved and yet have a relatively low lactic acid content.

Lactic as a % total acids
In a well preserved silage, the lactic acid will dominate the fermentation process (see above). The average value is 60.

Neutral detergent fibre (%)
A measure of the total fibre in the plant, which gives a guide to plant maturity. (MADF + hemicellulose)

Acid detergent fibre (%)
A measure of the lignin and cellulose present. A high level indicates a more mature forage and lower digestibility.

D value
An abbreviation for the term digestible organic matter in the dry matter. It is stated as a percentage and is a useful measure of the energy an animal can obtain from the silage. Poor late cut silage will have a D value as low as 50% while excellent leafy silage will be >72%.

Protein degradability - a value (%)
This is a measure of the soluble protein as a proportion of the total protein. Values range from 50 - 80%. Average 68.

Protein degradability - b value (%)
This is a measure of the insoluble protein which can be digested by the animal as a proportion of the total protein. values range from 15 - 30%. Average 23.

Protein degradability - c value
This is the measure of the rate of breakdown of the 'b' fraction. Values range from 0.04 - 0.17. Average 0.07.

Fermentable metabolisable energy - FME (MJ/kg DM)
The metabolisable energy that can be utilised by the rumen microflora. This is the total ME minus the ME in the fermentation products and the ME in fat or oil. Average 8.0 MJ/kg DM. Range 7 - 10.

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Page last updated 28th August 1998