Aug 19, 2020
How much of your maize will you get to feed?
Aug 19, 2020
Article as seen in British Dairying – August 2020
National Technical Support Manager Roy Eastlake says that the wastage rates widely seen with maize silage represent a major drain on potential profitability.
“Maize costs on average £740/ha to grow (MGA Costings 2020), making it essential that as much of the crop as possible is fed to maximise the return on investment,” he explains. “When you grow a crop your aim is to maximise the nutrients grown and preserved. Yet every year the typical dry matter losses that can be saved in maize clamps is around 15%.
“Every year around 6.0 million tonnes of maize silage are made for dairy cows, which at 32%DM equates to 1.92 million tonnes of dry matter. Wasting 15% means that every year around 288,000 tonnes of dry matter will have been wasted, which at a cost of £99/tDM adds up to £28.5 million of wasted feed production costs. Then the wasted feed value has to be replaced with purchased feeds, greatly increasing the impact of waste on margins.
“With an estimated 5000 dairy farmers growing maize in the UK, this works out at £5,700 per farm and to this must be added the cost of replacing the feed value with extra concentrates. So this is why reducing waste must be a priority.”
Mr Eastlake says the focus must be on preservation and utilisation to increase the amount of maize actually fed and says the starting point is to cut the crop at the optimum stage to maximise the quality of the harvested material and giving the best possible starting point.
He advises checking the maturity class of the variety being grown as this will give an indication of how early you may be able to harvest. Then he stresses the importance of walking the crop regularly, checking the maturity of the cob and the dry matter of the stem.
He says the ideal time to harvest the crop is at a dry matter content of around 32% and when cobs are mature and starch yield is maximised, with the target of a minimum 30% starch content.
“Keep in regular contact with your contractor so they know your expected harvest date and can factor this into their plans so you are cutting the best quality crop you can.”
Once the crop is cut the challenge is to make sure that the maximum proportion of dry matter and nutrients harvested are fed which means doing everything possible to reduce waste from the point of harvest through to feedout by increasing the aerobic stability of the feed.
“The good news is that we know a great deal about the causes of waste in maize silage and this means we know what to do to reduce the impact. And this means winning the battle with yeasts and moulds.”
He says that waste in maize is a consequence of the actions of yeasts and moulds that are present in all crops. They become a problem when exposed to oxygen.
“Upon exposure to air, the wild spoilage yeasts start using the remaining sugars and lactic acid to grow, leading to a loss of acidic conditions, vital for the preservation of silage. They also burn off energy and feed value by producing heat, leading to the clamp heating up which can reduce palatability and digestibility (Fig 1).
“Moulds and other opportunistic microorganisms then become active, adding to the spoilage process and resulting in a second increase in silage temperature. While wild yeasts metabolize soluble sugars and lactic acid, moulds can utilise cellulose and other cell wall components, increasing the already considerable losses of nutrients and DM.
“Moulds have a fuzzy or dusty appearance due to their characteristic filamentous growth and the production of masses of spores on structures sticking up out of the filamentous mat. It is commonly assumed that the presence of mouldy patches or spots on the silage face indicate that aerobic deterioration has started. The truth is that by this stage it is well advanced.”
Mr Eastlake says successful strategies to reduce waste begin and end with stopping yeasts and moulds by reducing their numbers and restricting their access to oxygen both while the clamp is sealed and after it is opened by taking an integrated approach to the problem.
He says the starting point is the crop in the field. He advises leaving a reasonable stubble to keep the crop clean. He stresses the importance of not letting the crop get too dry, pointing out that crops over 35% dry matter are harder to consolidate.
“Good consolidation is a vital first stage in reducing access to oxygen. Inadequate rolling causes problems both at ensiling and feedout, resulting in increased DM losses and reduced silage quality. A good target density all over the clamp should be losses and reduced silage quality. A good target density all over the clamp should be 240kgs DM/m3 (750kgs fresh weight/m3 ). This can be achieved by layering the silage into the clamp in layers no more than 20cm thick and filling the clamp in a progressive wedge method with a slope of no more than 30 degrees.
“Once the clamp is consolidated it needs to be well sealed with a high quality proven oxygen barrier such as the Silostop Orange or Max products and new plastic sheeting before being fully weighted down, particularly on the shoulder.
In addition to minimising the ingress of oxygen with thorough clamping, Mr Eastlake says that new inoculant technologies allow you to reduce the numbers of yeasts and moulds on the crop at ensiling.
“If we can reduce the initial populations, we can reduce the opportunity they have to multiply. And this is where inoculants containing heterofermentative bacteria like Magniva Platinum Maize and Maize Elite have a big role to play.”
Magniva Platinum crop and condition specific forage inoculants combine the proven strain L buchneri NCIMB 40788 with the totally new patented bacterium L Hilgardii CNCM I-4785.
“Lallemand’s L. Buchneri has long been the gold standard for aerobic stability but when paired with Hilgardii, the two work in synergy,” Mr Eastlake continues. “During the fermentation they quickly produce a number of antifungal compounds to significantly reduce the level of yeasts and moulds, improving immediate aerobic stability, meaning clamps can be opened safely after just 15 days. In trials, the populations of spoilage organisms were reduced by over 90% (Fig 2).
They also improve longer term aerobic stability, protecting the silage while the clamp is open.
“The antifungal compounds produced by Magniva Platinum inoculants significantly reduce the populations of both yeasts and moulds so reducing the threat.”
Mr Eastlake says the next challenge in reducing waste is when the clamp is opened and air is introduced. He explains that once a clamp is opened, air quickly penetrates the crop. In a well-consolidated clamp air will penetrate beyond the face up to one metre but this can increase to four metres in inadequately consolidated clamps which we often see with maize. The extent of any problem can be reduced by careful face management.
“Only roll back the minimum amount of top sheet and make sure the edge is heavily weighted to stop it lifting. Move across the face quickly, ideally in less than a week, taking thinner wafers if necessary. Always use a block cutter or equivalent to minimise disturbance of the face and throw away any spoilt material to prevent it contaminating clean material in the clamp.
“Planning now and using a combination of improved clamp and ensiling management together with a proven effective crop specific inoculant will minimise the wastage of maize silage and have a significant impact on farm performance and profitability this winter, improving dairy margins and the return on your investment in maize,” Mr Eastlake predicts.
For more information on MAGNIVA Forage Inoculants CLICK HERE.