Grass and maize combination creates winter ration challenges

A combination of dry, high fibre grass silages and maize silages with lower starch degradability means finding ways to boost ration palatability and throughput will be vital this winter to optimise production.

Dr Robin Hawkey, senior nutritionist for Mole Valley Feed Solutions, said that although average protein levels in later cut grass silage improved as more samples came in, this silage is still relatively low in protein and high dry matter. This has been reflected in milk production.

Dr Hawkey said: “Cows aren’t milking as well as expected. Milk fat and proteins are flying and fertility and body condition seem excellent, but I think we’re a couple of litres light per cow because of this low milk potential silage.”

Where you’d usually expect first cut to be the best cut of the season and subsequent cuts to decline in quality, analysis shows that second, third and fourth cuts are actually fairly similar to later first cuts, although proteins have recovered slightly.

Dr Hawkey said the fact all cuts are, on average, higher dry matter and higher in NDF will create challenges with intakes and rumen throughput, which are essential for production.

“At the same time, early indications suggest this year’s maize silages are relatively dry and, although the starch is quite high at 33%, starch degradability is lower than the previous couple of years,” he said.

“This will improve the longer the crop is in the clamp, but those farmers who are forced to feed it immediately in combination with dry grass silage, may struggle with dry rations and undegraded starch grain coming through in the dung.”

Dr Hawkey said there are three steps farmers can take to help address these challenges:

Adding water to the diet
Ideally the diet should be around 45-47% dry matter. However, high dry matter grass and maize silages are pushing this in excess of 50% on some farms. To achieve the target dry matter, some farmers are adding water to the diet and seeing good results.

“In some cases, almost every litre put into the mixer wagon is coming back in the bulk tank,” Dr Hawkey said.

Depending on the base ration, this could mean adding four to six litres of water per cow. This is no mean feat, so Dr Hawkey stressed the importance of finding a safe and workable solution to do so.

Adding yeast to the ration
Adding a live yeast to the diet can help rumen metabolism and fibre digestion, and in turn, starch digestion thanks to better rumen function. This could encourage rumen throughput. “The mode of action of live yeast is well documented and numerous trials have reported benefits,” he said.

Supplying plenty of rumen degradable protein
More rumen degradable protein may be needed to make up for low protein forages.

“This rumen degradable protein is needed to get the rumen bugs firing,” Dr Hawkey explained. “Feed grade urea could be fed, however it’s much less available at the moment due to the drop in global gas production. We can however incorporate urea into compounds and blends.”

Other rumen degradable protein sources to consider include soya, rapeseed, sunflower and distillers products. Dr Hawkey said soya is currently actually better value than rape per unit of protein, however rape delivers good levels of protein to the rumen.

As such, he recommends feeding a mix of rape and soya to provide the right balance of rumen degradable energy and protein.

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