Silage making is about preserving as much high quality forage as possible, especially when grown on one’s own farm, as it is a major contributor to farm profitability. This starts with harvesting the crop at its optimum quality and yield, retaining as much of it as possible, and feeding it out efficiently by minimising losses at each stage.
Good compaction and stack management are important when making maize and whole crop cereal silages, to exclude as much air as possible and promote a rapid fermentation. The slower the fermentation, the more nutrients are lost, the less stable the silage once the stack or pit is opened, and the less palatable it will be.
Using a proven silage inoculant has been demonstrated to speed up the rate of fermentation, and retain more of the original crop. The most effective inoculants contain a mixture of enzymes and high numbers of homofermentative bacterial strains that only produce lactic acid. The enzymes ensure the bacteria have quick access to sufficient sugars to enable them to multiply rapidly and produce sufficient lactic acid to stabilise the silage as quickly as possible.
Silages made using this type of bacteria are generally more stable than untreated silages after opening. However, in some cases silage along the pit face heats up due to aerobic respiration due to mould and yeast growth. This has led to the introduction of silage inoculants containing specific strains of heterofermentative bacteria (Lactobacillus buchneri) that produce lactic and acetic acid. The acetic acid inhibits the growth of moulds and yeasts, to help preserve the quality of silage for longer.
When choosing an effective inoculant one should look at the numbers of bacteria supplied, and whether the product has EU registration, as this can only be achieved through independent scientific trials demonstrating the efficacy of each strain of bacteria used. Also, trials in the USA resulted in the FDA only allowing claims for aerobic stability for inoculants supplying at least 400,000 colony forming units of L. buchneri per gram of wet forage.
Inoculants can only work effectively if air is excluded from stacks or pits, and air leakage can result in considerable losses of silage under covers. Recently introduced oxygen barrier sheets have been demonstrated to reduce oxygen diffusion by 60 times relative to standard covers, and reduce mould growth and dry matter losses by 50% in the top metre of stacks.
As featured in NZ Dairy Farmer