Early grass silage results indicate good quality

23 Jun 2020

With more than 600 first-cut grass silage samples now analysed at its laboratory in Ashbourne, Trouw Nutrition GB says that early indicators are that quality is good.

“But, as ever, the key to making the most of grass silage will be regular analysis throughout the season combined with careful balancing of the diet,” says the company’s Liz Homer.

Disruptive winter

As expected, there is a range in quality reflecting the disruptive winter and spring weather that which impacted on cutting dates and grass growth during the winter.

“Most grass continued to grow during the winter, meaning that some crops contain a high proportion of older grass. This will impact on quality but, overall, producers have made some good feed to act as the foundation for winter diets,” she adds

Target range

“At 35.5% dry matter, crops are at the higher end of the target range. This reflects the warm, dry weather in April and May.

“ME content is high at 11.4MJ/kgDM, reflecting good levels of NDF at 44%DM. And we saw an increased use of pre-cut testing this year, suggesting that more producers are looking to time cutting more precisely.”

Energy content

While energy content is good, Dr Homer adds that the silages have a low fibre index and high acid load. “This means that rumen health could be an issue and this needs to be managed when diets are formulated.”

She says that crude protein reflects the disruptive season and the difficulties in applying fertiliser, followed by a prolonged dry period and reduced nitrogen uptake. “Overall crude protein is lower than usual at 14.6%.

“But silages submitted are, generally, well fermented with a pH of 4.2, moderate sugars, ammonia

and VFAs. As expected with a drier crop, lactic acid is slightly lower.”

 

Table 1: Nutrient analysis for early first-cut silages 2020 (Source: TNGB)

Nutrients

Minimum

Average 2020

Maximum

Dry Matter (%)

19.1

35.5

60.9

Protein (%DM)

8.1

14.6

20.4

D Value (%)

58.0

71.5

76.1

ME (MJ/kgDM)

9.3

11.4

12.2

NDF (%DM)

36.2

44.1

58.8

Fermentation Quality

 

 

 

pH

3.5

4.2

5.4

Sugars (%DM)

0.2

3.4

9.7

NH-3 N (%DM)

1.1

3.1

9.0

VFA (g/kgDM)

0.7

15.1

59.5

Lactic Acid (g/kgDM)

12.0

71.2

147.1

NutriOpt Analysis

 

 

 

RFC (g/kgDM)

135.6

202.6

247.9

TFC(g/kgDM)

362.1

457.5

578.1

RFP (g/kgDM)

44.9

90.5

129.1

TFP (g/kgDM)

51.9

110.3

156.5

Acid Load

32.7

49.5

57.4

Fibre Index

145.5

176.9

238.1

DyNE (MJ/kgDM)

4.7

6.3

7.4