Don’t let hot air spoil your silage

Silage expert highlights dry matter and nutrient loss in uncovered pits and poorly managed feed-out where oxygen can get into silage

mbfi hay day

If you think you’ve packed that silage enough, pack it again.

That’s among the tidbits from John McKinnon of JJM Nutrition Services in Saskatoon as Manitoba farmers prepare for what’s potentially another bad forage year.

Late rains, a delayed or even skipped first hay cut, thin stands, frosts and a generally cold spring all have livestock producers considering other alternatives this season.

Why it matters: More and more beef producers are putting up silage, in a quest for more reliable and less weather-reliant feed.

Some farmers were considering not cutting, but to instead graze the hay land, something that itself raised concerns over winter feed supply.

In the third week of June, southwest provincial livestock specialist Jane Thornton reported a jump in calls from producers considering greenfeed and expected more producers would turn to that option this year to top off feed. Silage is also a part of that discussion, and one that Thornton notes is spilling more and more into the beef industry.

“I’ve noticed in the last few years that silage for beef producers has become a much bigger thing,” she said.

“It used to be that silage was only for dairy.”

Manitoba’s unpredictable weather is a big part of why more producers find themselves drawn to the practice, she said.

“To get off a good dry hay is very difficult,” Thornton said. “If you can shorten that window and get all of your feed up in a three-day window, it’s very helpful.”

Learning curve

Putting up silage properly is a skill, though, and farmers trying the practice need to keep best practices for putting up quality silage at the top of mind.

McKinnon’s first piece of advice to pack tightly will come as no surprise to those familiar with silage — it minimizes oxygen levels in the silage pit. While it’s basic advice, he also says it’s one of the most common errors he sees, regardless if the silage is being baled and wrapped or piled.

“It doesn’t matter what system you look at, if you don’t exclude the oxygen, if you don’t get proper packing in a bunker or if you don’t get things tight in a bale-wrapping situation, that oxygen that remains present in there basically leads to heating and that heating leads to mould and that mould can lead to mycotoxins,” he said.

Proper chopping plays into that ability to pack. Barley, for instance, should be chopped into 0.4- to half-inch pieces for ideal packing, he said.

Producers have already accepted significant loss if they don’t cover their piles, McKinnon also warned.

“The oxygen penetrates it and you get this abnormal reaction occurring early on in fermentation that causes a lot of heat to be generated, causes the denaturation of the protein,” McKinnon said.

The end result is a “browning” and “burnt” effect that causes protein to be unavailable to the animal, as the compromised feed passes through the digestive tract largely unscathed.

McKinnon estimates that an uncovered 20,000- to 30,000-ton silage pit would lose 38 per cent of its dry matter in the first three feet.

“Some of these silage piles, when you look at the size of them and you calculate out the volume of that top two to three feet, there is an awful lot of silage in that area of the pit,” he said.

Producers who don’t cover may argue it’s too costly or laborious, he said, adding extra labour is more likely to sway large producers against the practice.

“I often hear an excuse (that), ‘we put in “x” number of tonnes and that silage pit is completely empty in June, so we feed everything in there. We don’t lose anything.’ But they don’t recognize they’re losing dry matter content and they’re losing energy content and protein quality,” he said.

Feeding practices

Producers may also be losing feed unnecessarily on the back end. McKinnon urged producers to think about how they’re handling feed-out, to avoid secondary fermentation when the face of the pile is exposed and air can once again get in.

Producers should only remove what is needed that day, although digging at least six inches deep into the pile will help remove the silage that’s been exposed before it can spoil. Producers should feed across the face of the pile, McKinnon said, and mouldy and heated feed should be removed before feeding.

Producers may be tempted to push quality limits, particularly if feed is short as it was last year. In late March, Manitoba Agriculture staff expressed concern with feed levels, pointing to 2018’s dismal hay harvest which left some farmers with a fraction of their normal hay. That was compounded by long stretches of below -30 C during the winter that chipped away at already strained feed supplies. Silage piles had dropped quicker than expected, along with other feed supplies, they noted at the time.

McKinnon, however, strongly warned against feeding mouldy silage to pregnant cows in particular, citing an increased risk of abortion. Feedlots will also see an immediate decrease in feed intake, he warned, despite the low-quality feed appearing to disappear in the feed cart mix.

Newer silage inoculants largely target that back-end loss, DuPont Pioneer agronomist Derwyn Hammond said. Inoculants designed to shorten the aerobic silage phase — the first hours or days where plants are using up the last oxygen and silage is heating, but protein is also breaking down — are nothing new. They’ve been on the market since the late ’70s. More recently however, companies have unveiled products that limit spoiling once the silage face is exposed or help break down fibre better to improve digestibility.

Producers should still ensure proper moisture, maturity, chopping at the right length and packing, regardless of if they are reaching for an inoculant, he added.

Some top-tier products can “improve the digestibility a little bit,” he said. “But largely it’s about preserving quality. It’s not about improving the quality of poor silage.”

Producers should take a hard look at where their losses are in the silage process, and choose a product that targets that loss, he said.

About the author


Alexis Stockford

Alexis Stockford is a journalist and photographer with the Manitoba Co-operator. She previously reported with the Morden Times and was news editor of  campus newspaper, The Omega, at Thompson Rivers University in Kamloops, BC. She grew up on a mixed farm near Miami, Man.



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