Feeding Focus April 17

FEEDING

FOCUS April 2017 • Issue 23

Can you improve silage quality?

Every additional 1,000 litres of milk obtained from forage can reduce production costs by as much as two pence per litre. With the grass silage harvest just around the corner, now is the time to assess your grass silage strategy.

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, Feb) has followed the pattern below impacting on the quality of subsequent harvests.

2013/14

2014/15

2015/16

2016/17

Average temperature (°C)

5.2

3.9

5.5

5.0

Average rainfall (mm)

545

367

529

252

(A)

(B)

(C)

(D)

Source: MET office

Silage quality is affected by warm, wet winters because high levels of rainfall increases the risk of leached nutrients and higher temperatures allow continued grass growth which utilises energy.

Harvest 2014

Harvest 2015

Harvest 2016

Dry Matter (%)

31.9

32.8

35.1

D value (%DM)

67.12

68.9

66.0

Protein (%DM)

13.1

13.4

NDF (%DM)

54.9

47.4

(A)

(B)

(C)

What effect can improved silage quality have?

Higher silage D value (digestibility) can mean improved forage intakes, increased milk yields and lower concentrate feed rates. The table below shows the milk yield for dairy cows fed different silage quality at two concentrate feed levels. Cows fed higher quality silage (79 D) require less concentrate to achieve similar milk outputs than cows fed average quality silage (69 D).

Concentrates (kg/cow/day) Silage D value (%DM)

4

8

79

29.1 litres

32.8 litres

69

24.7 litres

27.3 litres

Difference

-4.4 litres

-5.5 litres

Source: Teagasc

Is high quality silage achievable?

Comparison between analysis of first cut silage taken from the UK and Netherlands show high D value silage is possible if key management areas are focused on.

UK

Netherlands

Difference

Dry Matter (%)

32.1

45.4

+13.3

13.4

Crude Protein (%DM)

13.4

17.2

+3.8

52.7

D value (%DM)

68.3

79.3

+11

Source: ForFarmers

Source: ForFarmers

What does that mean harvest 2017 has in store and is there anything you can do to help maximise silage quality?

Focus areas for quality silage: 1. 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. Increase cutting frequency, i.e. cut every 35 days and more often for higher D value silage.

3. Silage additives If used correctly, a crop-specific inoculant will help improve silage quality, stability and preservation. Look for additives that meet the needs of your crop.

Early Cutting

27-35% High Dry Matter – aerobic stability problems • Prevent yeast and mould growth • Reduce heat and lost energy

Conventional Cutting

1st Cut

2nd Cut

1st Cut

2nd Cut

ME (MJ/kg DM)

11.8

11.4

11.3

11.1

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

2. Harvesting Harvesting grass silage at the correct time significantly improves its digestibility. Carry out regular visual checks of silage fields and cut grass before heading to ensure the best quality silage. Precut 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 (36 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.

<27% Low Dry Matter – fermentation problems • Silage requires a rapid pH drop • Preserve protein and stop secondary fermentation

Low DM

20%

25%

Fermentation

High DM

30%

35%

40%

Grass Silage DM%

Aerobic stability

4. 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. 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.

5. Feed out Seal the clamp for a minimum of four weeks (six if possible) to allow a complete fermentation. It is very important you understand the quality of your silage.

Dry NIR (Silage Manager) silage analysis provides accurate assessment of silage nutrient content and fermentation profile.

Take a core sample when silage is sealed and then regular face samples to ensure accurate rationing through the feeding period.

For more information about maximising milk production from your forage, please contact your ForFarmers Account Manager.