Losses from silage reduce feed value and can be linked to animal diseases. For example, visibly spoiled black or mouldy silage in the outer layers of silos and bales has lost at least 40% of the original dry matter (DM) ensiled. The lost DM comprised plant cell contents - sugars, acids and proteins - totally digestible by the animal. What remains has very low digestibility. Worse still, spoiled silage can contain high levels of listeria, clostridial spores and mycotoxins that cause disease and contaminate milk and dairy products.
Spoiled silage should be discarded to the manure pit and not used as animal feed. Also, rejected silage left in the feed trough or ring feeder should be discarded and not re-fed to other stock. Cattle, sheep and goats have highly developed senses of smell and can detect abnormal odours that humans cannot. We decide subjectively what is spoiled and what is unspoiled silage, but we may be wrong. The animal should be the judge of silage acceptability. Feed intake can be depressed severely if silage that has been exposed to air is included accidentally in the diet. In addition, exposure of animals to pathogenic microorganisms and toxins can result in a range of health issues, from increased incidence of infections because the immune system is damaged, to severe disease and death due to toxicosis.
Managing to reduce silage losses involves harvesting a clean crop at the correct maturity and chop length suitable for the dry matter, with as little soil contamination as possible. Packing the harvested crop carefully into bunkers at high density, aiming for 220 kg DM/m3 or 750 kg fresh weight/m3 and covering with a proven film to prevent oxygen entry will reduce outer layer losses during storage. Silostop oxygen barrier film restricts oxygen transmission to a very low level compared to standard polyethylene. Silostop has been proven by independent research to halve outer layer losses and prevent contamination with undesirable microorganisms compared to conventional polyethylene sheeting and clingfilms. Reduced outer layer loss means less labour is required to discard spoiled silage. There is also less risk of accidentally including spoiled silage in the animals’ diet.
Finally, silage should not be left lying around after it has been moved. Some silage, especially well-preserved material can be very unstable on exposure to air, and feed-out should involve minimal exposure of silage to air after it has been removed from the silo, or the bale has been unwrapped. Aerobic stability of outer layer silage is increased by over two days in silage stored under Silostop compared to conventional polyethylene film. This enhanced aerobic stability is especially useful in situations where rate of feed-out is low, or when ambient temperatures are high.
To sum up, silage losses can be reduced by paying close attention to harvesting and silo filling and by covering with Silostop oxygen barrier film. The benefits of using Silostop should be evident in improved animal health and production.
