First-cut silage analysis: fibre and energy lower than 2021

A higher proportion of overwintered material means this year’s first-cut silages are tending to have higher fibre and lower energy levels compared with last year.

But the trend, shown in Trouw Nutrition’s first-cut silage analysis, means a lower acid load. This makes them safer for the rumen, said Liz Homer of Trouw Nutrition GB.

See also: 7 top tips on how to respond to rising dairy costs

“During the spring, grazed grass samples showed a high fibre index and low acid load, reflecting higher NDF [neutral detergent fibre] content.

“A similar situation was seen with pre-cut grass silage testing,” said Dr Homer, discussing 500 silage samples.

“This is now apparent in many of the silage samples seen so far with higher NDF content, which is influencing nutritive content and how forages will behave in the rumen, and the type of supplementation which will be required.” 

Sheep manage swards 

Some farms in northern England and south-west Scotland have also seen a trend for early winter growth at the base of the sward, said Jerry Trowbridge of Lakeland Scottish.

“Every farm is different, and the important thing is the amount of silage you sample as grass seed mixtures and cutting dates can all vary,” said Mr Trowbridge.

“Some farms with wintering sheep have found they have removed that growth in the bottom and left a clean pasture. Some remove the sheep eight weeks before cutting dates.”

Quality over quantity wins

Farms able to take an early first cut and capture higher D values in mid- to late April have been rewarded with very good silages that are feeding well in the South West. 

Some crops have analysed at up to 12.1 metabolisable energy (ME) and 18.5% crude protein, said Emily Alvis of Douglas Green Consulting.

“Sugars have been a little variable depending on the week crops were cut, but those farms that have already opened first-cut are seeing very good intakes and cows performing well,” said Ms Alvis. 

“The higher NDF silages are from those who held off cutting and went for bulk, but the quality has been comprised. Quality over quantity always wins.”

“I have seen one sample with a high acid load, but, when mixed with starchy forage and using a rumen buffer, has balanced quite well and not caused any yield or fertility issues.”

She said many second cuts have now been taken in good conditions, meaning hopes were high for good quality silage. 

Drive intakes

Taking the average figure of Trouw’s analysis, Mr Trowbridge said for a dairy cow eating 12kg dry matter (DM) a day of grass silage, the energy drop from 11.71 ME to 11.45 ME (0.26 MJ/kg DM) should not make a huge amount of difference.

“The drop in metabolisable energy across 12kg of silage is about 3.12MJ, which is roughly 0.6 litres of milk, and possibly a bit more because of potentially low DM intakes,” he told Farmers Weekly.

“In order to make the best of that silage, it needs to be presented well and balanced with a starchy, sugary feed – perhaps a little bit of cereal.”

With so much volatility in the feed markets, Mr Trowbridge suggested that farmers get used to higher cereal prices and stressed that milk prices have lagged behind, but have now caught up.

Given silage analyses, he reminded farmers that dry matter intakes would be important.

So discussions about chop length, push-ups and ration palatability, by possibly adding molasses and salts with the nutritionist, would be worthwhile. 

He reminded businesses to analyse feed costs on a DM basis to get a true picture of value as costs increased.

Catchy May brings low DMs

Some silage was made in catchy weather in northern areas, particularly north of Penrith, resulting in low DMs of 22-25%, which should ring alarm bells on acidity and fermentation. 

This is according to David Keiley of Kite Consulting who reported pit slippage across parts of southern Scotland. He said an acid buffer, limestone flours, yeasts or similar products could be used to correct this. 

“People with low dry matters silages should consider how the crop will ferment,” said Mr Keiley. “There may be issues with acidity and butyric fermentation if the crop was taken in wet, catchy conditions.”

“On the positive side, protein levels have been reasonable, and this is a good thing considering soya and rape prices.” He added that farmers had invested in sulphur, nutrient analyses and optimising soil pH. “Lots of farmers have worked on soil pH levels and applying sulphur, and it’s paid off in terms of protein, bulk and using nitrogen more efficiently.”

Last year’s high oil content – about 10% – was “back to normal” at 6-7% as April was not as cold, he added. 

“I’ve seen a lot of energy levels around 11.1-11.6ME. Most people went for first cut around that first weekend in may and we please. They have got a second cut off now and that’s come in ok as well.”