Date: 14/07/26
Positive maize harvest expected, but keeping silage cool and stable is key
Prolonged hot, sunny weather this season has left most of the country’s maize crops looking promising – though crops in the East are showing signs of moisture stress and progressing quickly through the growth stages. Lientjie Colahan, forage technical support at Lallemand Animal Health, says if the weather continues to be hot with scattered showers as forecasted over the coming weeks, most of the country can expect a very positive maize harvest, with good crop yields and high starch content. “If the maize reaches a dry matter above 35%, there’s the risk of heating during feed-out due to the abundance of starch and lactic acid,” she says. “Higher starch and the lactic acid required to conserve the crop mean there will be lots of nutrients for spoilage bacteria, yeasts and moulds to consume. These organisms grow in the microscopic gas voids in the clamp, and when the crop is dry it’s harder to compact, so the voids will be larger, exacerbating the issue,” Ms Colahan explains. “In these conditions, aerobic stability will be your biggest concern. If you don’t treat it with an inoculant, the yeasts and moulds will remain active for longer as the crop ferments after closing the clamp, increasing the risk of mycotoxins which can significantly affect everything from cow productivity to fertility. “Ultimately, the best way to protect silage quality throughout the process is to treat it with an inoculant as it will inhibit yeast and mould growth, and therefore mycotoxin development,” she says.
An inoculant acts as an insurance policy to smooth out uncertainty – giving you the maximum value from the crop when conditions are favourable and making the best of what you have in less ideal conditions, she adds.
When choosing an inoculant, Ms Colahan advises farmers opt for a product with an antifungal component such as Magniva Platinum Maize, as those designed only to aid fermentation will likely increase heating at feed-out.
“Farmers who use a homofermentative-only inoculant are at risk of seeing their maize clamps heating up very quickly once opened, so they will lose more feed value going to the cow. Whereas those who use the combination inoculant should see the clamp staying nice and cool, with more nutrients going to the cow.”
However, Ms Colahan says the fact that maize ferments easily has led some growers to believe an inoculant is unnecessary.
“Maize will ferment without an inoculant if conditions are favourable, but that’s a false economy because the aim is not just to ensure fermentation, it’s to preserve nutrients and produce a higher-quality feed for livestock, especially when then clamp is opened.”
The bulk of the country’s maize crop is expected to be cut in September this year, though some may be as early as the first two weeks of August because of the dry weather.
“The golden rule is that once the crop tassels; six weeks later will be the first indication of when to cut it for silage,” she says.
“For conventional varieties, rather than stay-green varieties, the leaves at the bottom of the plant will start drying off and become crispy, while those towards the top will still be green.
“You can also look at the ‘milk line’ on the cob, which grows throughout the kernel as the plant matures. When this is two-thirds of the way down the kernel, that’s the ideal harvest stage where you have the balance of as much starch as you can get, but you still have a digestible plant.”
Ultimately, strategic use of the right inoculant can reduce the risk of mycotoxins and ensure farmers capitalise on the nutritional value of this year’s maize silage crop.
Source: press release issued by BELLA.