The mounting economic pressures caused by soaring prices for fuel, fertiliser, feeds, and utilities are being felt by farmers around the world. With the additional demand on farmers to reduce the environmental impact of their farming activities, improving the efficiency of crop and animal production is paramount now, more than ever, for the future of the agricultural industry. For this to be achieved it requires a significant reduction in emissions of greenhouse gases (GHG), such as carbon dioxide, ammonia and methane.
With no sign of change for the better on the horizon, drying cereals with a moisture content of 14-22% will not be an option this season due to a shortage of fossil oil and gas in combination with sky-rocketing prices. But what is the best alternative for the farmer´s pocket and the planet? The answer is simple and straightforward: stick to the standard method of treating moist cereals with propionic acid-based preservatives as opposed to urea-based products! The research behind it is very clear. There is no question about the efficacy of either method in preventing mould growth during storage. However, between the time of applying the additive and opening the clamp about 40-50% of the nitrogen added by urea-based products is lost in thin air. When the clamp is opened, up to 30% more nitrogen is lost during feed-out, which is evidenced by the smell. The urine-like smell is that of volatilised nitrogen in the form of ammonia!
Regarding treatment costs, we are looking at around £40/t for urea-based products vs approximately £20/t for propionic acid-based products (e.g. CrimpSafe Hi-Dry applied at 6 lt/t). An unlikely shortage of soluble nitrogen in the TMR can be avoided by adding feed-grade urea in the mixer wagon, which results in zero nitrogen losses by volatilisation.
In a recent beef trial using grass silage as the sole forage source, Huuskonen et al (2020) clearly showed that better dry matter intake and liveweight gain were attained by the cattle fed moist, crimped grain compared to those fed dried grain. Furthermore, there was a lower efficiency of dietary protein utilisation by the animals fed on urea-treated grain compared with those fed on the propionic acid-treated grain. This concludes that urea-based additives are not only detrimental to the pocket and the planet but are also not beneficial to the animal!
For decades farmers have been crimping and ensiling cereals with a moisture content of 25-35%, combining high cost-efficiency with significant advantages over cereals harvested and processed at lower moisture levels. These advantages include lower field losses, higher yields, higher digestibility, lower mycotoxin concentrations and higher flexibility regarding harvest date.
However, stability during feed-out must be ensured by using suitable silage additives to prevent DM losses, mainly manifested as the climate-relevant carbon dioxide formed during storage and emitted into the air after the clamp is opened. Although heterofermentative inoculants and chemical preservatives (e.g. CrimpSafe 300) both control heating, there are significant differences between them when it comes to controlling the amount of carbon dioxide released. As shown in Figure 2 where heterofermentative inoculants, applied to high-moisture crimped barley, facilitate carbon dioxide-forming pathways by using sugar and/or lactic acid to produce antifungal acetic acid. All heterofermentative lactic acid bacteria possess proteolytic activity, resulting in dry matter losses and increase greenhouse gases.
Based on the current barley price of £310/t, and a DM loss reduction of about 15kg/t DM ensiled by applying the chemical preservative, the savings amount to £4.65/t DM ensiled. The chemical preservative also combines a high efficacy against heating of crimped and ensiled cereals with a low amount of carbon dioxide formed during storage, which is better for the farmer’s pocket and the planet.
In summary, the current financial and environmental challenges make the efficient production and preservation of home-grown cereals a key factor in sustainably maintaining the profitability of livestock production.