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Tackle silage quality issues head on to avoid performance loss

The atrocious summer weather has had a big impact on silage quality, with independent data showing the wettest 20% of tested first cut grass silages averaged just 20.1% dry matter (DM), and the driest 20% averaged 44.7% DM. Even those samples with reasonable metabolisable energy (ME) tend to be low in rumen fermentable energy (FME).

“The vast majority of silages didn’t see enough sunshine during growth and prior to ensiling,” states Trident nutrition manager Dr Michael Marsden. “Many also contain large quantities of fermentation acids, and the result is generally low rumen FME values.

“The immediate impact is a drop-off in rumen fermentation efficiency and a subsequent reduction in nutrient supply to the animal, particularly protein. It means that many cattle just aren’t performing as well as would be expected at this time of year.”

According to Dr Marsden, beef producers will need to monitor growth closely – if poor weight gain isn’t spotted until close to finishing, it’ll be too late to recover lost margin and more feed will be needed than if identified early. And with a high speed of finishing vital to the rapid turnover that underpins beef unit profitability, it’s important to act quickly to get cattle back on track.

“In most cases it is possible to get cattle performing as normal, rather than just accepting slower growth. And even though feed prices are generally much higher than they were a year ago, if rations are formulated correctly, the returns will be worth the extra investment,” he adds.

The problems extend to maize and wholecrop cereal silages, both badly hit by the high rainfall, low temperatures and limited sunshine. Many will be wet and acidic, with low starch levels contributing to low rumen FME, and will require careful balancing in the ration.

“Start by supplying additional rumen FME, with a mix of sugars, starch and digestible fibre the best combination to help kick-start fibre digestion, support rumen microbial protein production and buffer the rumen against acidosis,” advises Dr Marsden. “Liquid feeds like molasses, pot ale syrup and bioethanol wheat distillery syrup are great value this winter, and not only supply the sugars needed, but also improve palatability and intake of poor quality silages.

“For starch, one option is the downgraded wheat available this year, typically at a discount of maybe £15/t for very low bushel weights. Just make sure you treat high moisture or sprouting wheat to preserve the grain until it can be fed, either using acid – add up to 1% propionic acid by weight – or urea, which will also add extra effective protein to the ration and acts as a rumen buffer.”

It’s also important not to over-feed starch in the presence of high-acid silages. Supply some of the energy as digestible fibre from soya hulls, sugar beet feed or wheat feed, and include either cereal or oilseed rape straw (chopped) at around 7.510.0% of the dry matter to provide the structural fibre needed to promote good rumen function and saliva production (a natural buffer).

“And if the individual straights you want are in short supply, consider buying them as a blend,” Dr Marsden adds. “Blends are easy to feed, cost-effective and the blenders will probably have stocks of even the most popular feed ingredients.”

Yeasts and rumen buffers are also likely to have a role to play in keeping acidosis under control, particularly where additional starch and sugars are being added to already acidic silages. Conversely, if silages are dry and mouldy, consider using a mycotoxin binder to protect cattle health and keep performance on target.

Table 1 shows some example rations for balancing the various silages likely to be a challenge this year. If ration mixing equipment isn’t available, a custom blend can provide nearly everything needed to balance this year’s forages in a single feed.

Table 1 – Examples for balancing silage-based beef rations (400kg liveweight, gaining 1.35kg/day)

	kg FW/cow/day
	Wet, acidic grass silage	Dry, low ME grass silage	Low starch, wet maize silage
Wet, acidic grass silage	12.0	-
Dry grass silage	-	12.0	-
Low starch, wet  maize silage	-	-	10.0
Straw	1.0	0.5	1.0
Rolled low bushel weight wheat	3.0	3.5	2.5
Sugar beet feed	1.5	-	1.0
Soya hulls	-	1.0	-
Bioethanol wheat distillery syrup Wheat distillers grains	- 1.0	- 0.75	2.5 1.0
Combined yeast/rumen buffer (Vistacell AB)	0.05	-	0.05
Vitamin/mineral premix	0.1	0.1	0.1
Dry matter (%)	47.0	48.5	47.5
Energy (MJ ME/kg DM)	11.5	11.5	11.7
Protein (% of DM)	13.6	13.4	14.0
Starch + sugars (% of DM)	25.5	25.6	30.0
NDF (% of DM)	37.5	40.0	33.0
All feed Cost (£/head/day) 1	1.39	1.47	1.39

¹ Costs calculated using average prices correct at time of going to press, 29t bulk loads for Nov-Apr delivery on-farm, within 50 miles of source. Prices will vary with load sizes and distance from source. Forage costs included at £80/t DM.

“If cattle still aren’t performing once the supply of rumen FME has been corrected, consider topping up nutrient supply with supplements that bypass the rumen,” Dr Marsden concludes. “Protected fats can help overcome energy shortages, though for beef cattle should perhaps be a last resort. However, both heat-treated rapemeal and rumen-protected soyabean meal are extremely cost-effective sources of the high quality protein needed to support fast growth, particularly in young cattle and especially bulls.

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