A wet winter and spring are likely to be felt into the coming winter feeding season if the results of the first 500 samples analysed this year by Trouw Nutrition, are anything to go by.

Add in the delay in cutting of first cuts in many parts of the country and it has been a double whammy.

“The combination of the mild winter and extremely wet conditions has had an impact on the harvesting season and the quality of silages produced,” comments Nacia Bonnick, ruminant technical support co-ordinator at Trouw Nutrition.

The mild winter extended the growing season resulting in higher covers of older, over-wintered grass in the spring. Then the prolonged wet conditions impacted the application of slurry and fertiliser and delayed the timing of first cuts with implications for quality.

“Results from our pre-cut tracker indicated the optimal cutting date would have been mid-April through to the first week of May, but field conditions prevented many farmers from taking cuts to help preserve season long conditions and reduce soil contamination.

“The delayed harvest has resulted in a higher proportion of older and overwintered material in clamps which tends to be more fibrous and less digestible.”

The average early first cut this year is 33.7% dry matter which is higher than last year’s crops which were 30.9%. Average ‘D’ value is lower at 68.6% reflecting the age of ensiled material. Consequently metabolisable energy has decreased marginally to 11.0MJ/kgDM.

NDF is higher than usual for a good first cut, combined with very high lignin levels, at 38g/kg DM, means forages will ferment more slowly which will have implications for supplementation and intakes. Crude protein levels are slightly depressed at 14.4%, which in part will be due to the inability to get on fields with fertiliser.

“Overall forages will need careful supplementation to get the most milk from forage, control purchased feed costs and reduce the carbon footprint per litre,” Ms Bonnick continues.

To compensate for the lower digestibility, she says rations may need to include ground cereals and rumen energy sources to promote digestibility and intakes. Overall rumen health would be considered safe given the low acid load and high fibre index from silages.

“It will be essential to supplement and balance both total fermentable protein and carbohydrates, both of which are lower than last year. This will ensure good rumen function and efficiency and microbial protein yield.

"Alongside supplementation of rumen fermentable carbohydrates and protein, I would expect bypass protein supplementation will be required to support milk production. The obvious choice may be soya, but this should be considered in terms of carbon footprint and cost. Other good sources of protein could include rapeseed meal, protected rape and distillers.

Ms Bonnick stressed that averages are only a guide. What is important is the silage actually being fed and she urged farmers to analyse clamps regularly to understand the forage being fed and allow accurate and cost-effective supplementation.

Early first cut averages 2023- 2024 (source: TNGB)

Units 2024 2023

Dry Matter % 33.7 30.9

Protein % DM 14.4 14.3

D Value % 68.6 69.4

ME MJ/kg DM 11 11.1

NDF % DM 46.7 44.5

ADF % DM 29.7 27.6

Lignin g/kg DM 38.4 40.1

Sugars % DM 1.7 0.9

pH 4.1 4

Lactic Acid g/kg DM 84.9 79.1

VFA g/kg DM 24.9 44.4

Ammonia % 3.3 3.9

Rapidly Fermentable Protein g/kg DM 88 92.5

Total Fermentable Protein g/kg DM 103.4 104.1

Rapidly Fermentable Carbohydrates g/kg DM 190.9 192.8

Total Fermentable Carbohydrates g/kg DM 434.2 417.2

Acid Load 47.5 48.5

Fibre Index 187.6 178.2