FEEDING FOCUS April 2016 • Issue 14
Making the most of your silage In the continuing climate of low milk prices, maximising milk production from forage will be a key focus for many dairy farmers in the coming months.
Harvest 2013
Harvest 2014
Harvest 2015
Dry Matter (%)
32.9
31.9
32.8
With every additional 1,000 litres of milk obtained from forage reducing production costs by as much as two pence per litre, and with the grass silage harvest just around the corner, now is the time to asses your grass silage strategy.
Metabolisable Energy (MJ/kg DM)
11.01
10.74
11.02
D value (%DM)
68.8
67.12
68.9
Impact of weather Winter temperatures and rainfall have a significant impact on the quality of grass silage. The weather for the last four winters (Dec, Jan and Feb) have followed the pattern below, with resulting impacts on the quality of subsequent harvests.
Protein (%DM)
13.1
13.1
13.4
NDF (%DM)
50.3
54.9
47.4
2012/13
2013/14
2014/15
2015/16
Average temperature (°C)
3.3
5.2
3.9
5.5
Average rainfall (mm)
350
545
367
529
Source: MET office
Silage quality is affected by warm, wet winters because high levels of rain fall increases the risk of leached nutrients and higher temperatures allow continued grass growth which utilises energy.
Source: ForFarmers
What does that mean harvest 2016 has in store, and is there anything you can do to help mitigate the effects of the warm wet winter and ensure you maximise silage quality? There are six key areas to focus on to improve silage quality. 1. Forage planning Produce a forage budget for all livestock on the farm over the next 12 months (using clamp volume, forage DM and bulk density). Ask yourself two key questions: • How much grass silage does my system require? • Does current acreage and clamp content provide an excess or shortfall of forage for the year ahead?
If you predict an excess of forage, consider reseeding ground to improve forage quality. If you predict a shortfall, now is the time to investigate buying in bulk feed alternatives, such as blends, co-products or standing crops. 2. Cutting strategy Balance the timing of first and subsequent silage cuts in order to maximise both silage quality and quantity. Whilst an early first cut can produce lower tonnage, grass quality will be higher and further silage cuts will achieve better yields. Early Cutting
Conventional Cutting
1st Cut
2nd Cut
1st Cut
2nd Cut
ME (MJ/kg DM)
11.8
11.4
11.1
11.3
Yield (t DM/ha)
4.2
4.1
5.5
2.5
Total yield (t DM/ha)
8.3
8.0
Energy harvested (MJ)
96,300
89,300
Milk yield potential (litres)
18,519
17,173
Adapted from: Thomas, Bax and Osman. 1998
3. Harvesting Harvesting grass silage at the correct time significantly improves its digestibility and energy content. Carry out regular visual checks of silage fields and cut grass before heading to ensure the best quality silage. Pre-cut grass analysis is useful to help assess nutrient content of grass and potential fermentation issues once clamped. Key pre-cut nutritional parameters are: Analytical Result
Value
Dry Matter (%)
>20.0
Water Soluble Carbohydrate (%DM)
>15.0
Nitrate (%)
< 0.15 (1500mg/Kg)
Cut grass mid-morning or early afternoon to minimise moisture levels and maximise sugar content. Ensure a 24-hour wilt (48 hour wilts should be the maximum for clamp silage) to achieve an optimal DM content of around 30%. Encourage rapid re-growth and reduce soil contamination by cutting at a height of 7.5cm. 4. Silage additives: If used correctly, a crop-specific innoculant will help improve silage quality, stability and preservation. Look for additives that meets the needs of your crop.
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< 27% Low Dry Matter – fermentation problems • Silage requires a rapid pH drop • Preserve protein and stop secondary fermentation 27-35% High Dry Matter – aerobic stability problems • Prevent yeast and mould growth • Reduce heat and lost energy Low DM
20%
High DM
25%
30%
Fermentation
35%
40%
Grass Silage DM%
Aerobic stability
5. Clamp To prevent spoilage, clear the clamp of any sources of contamination such as mud or old silage. To maximise consolidation, the clamp should be filled in thin layers (approximately 30cm/12 inches) and ensure that silage is well rolled. Well-weighted top sheets are essential to create stable, well-preserved silage and consider using side sheets to help construct an airtight seal. Oxygen barrier layers under a thicker top sheet can also reduce shoulder and surface waste. 6. Feed out Seal the clamp for a minimum of four weeks (six if possible) to allow a complete fermentation. To correctly balance silage with compound feed, blends and co-products it is very important that you understand the quality of your silage. Dry NIR silage analysis provides accurate assessment of silage nutrient content and fermentation profile. Take a core sample when silage is sealed, once again when it is opened and then regular face samples to ensure accurate rationing. Good clamp face management when feeding will prevent spoilage and reduce waste. Try to minimise loose silage on the clamp floor and use a shear grab (in a downward motion) to maintain a compact face. Attention to detail when harvesting and ensiling grass silage will help you to maximise milk production from forage. For more information about quality silage production, silage inoculants and silage analysis (interpretation) contact your ForFarmers account manager.
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