Silage and animal health

Abstract

The process of preserving crops by fermentation in silos is under the control of the farmer to a much lesser degree compared to the level of control by the manufacturer over the production of other fermented foods, such as cheese and yoghurt. Additives designed to direct the extent and pattern of the fermentation are relatively unpopular in most countries, and their use is not guaranteed to remove the risk of undesirable components in silage. Hazards to animal health associated with silage fall into three categories: (1) undesirable micro-organisms e.g. Listeria, enterobacteria, clostridia and moulds; (2) undesirable chemicals, e.g. mycotoxins, and (3) excess acidity and other metabolic disorders. In some regions of Europe, the production of silage is discouraged or prohibited because of the risk of undesirable microbes. The princIpal risk in these areas is that of the secondary fermentation of cheese made from milk contaminated by bacterial spores, rather than a direct hazard of contaminated silage to animal health. With the possible exception of high dry matter silage conserved in large bales, respiratory hazards to animals from moulds and their spores generally are less from silage than hay. Mycotoxins and phytoestrogens may survive the ensiling period and constitute risks to animal health. Relatively little is known about the epidemiology of diseases that may be linked to undesirable chemicals and excess acidity in silage. Therefore, research is needed to define epidemiologically and mechanistically the risks to animal health and to the human food chain from silages contaminated with pathogenic bacteria and mycotoxins, and to understand more completely the relationships between the physical and chemical compositions of silage and metabolic disorders in animals.

A new probiotic and bacteriocin-producing strain of Enterococcus faecium EF9296 and its use in grass ensiling

“…The use of silage for animal feeding was sometimes associated with pathological problems, including listeriosis (Wiedeman et al, 1996). Because Listeria can grow at low temperatures (Tienungoon et al, 2000), hay silage stored in large plastic bags was frequently contaminated (Wilkinson, 1999). Concerning the counts of Bacillus and Listeria colonies in our experiment, a decrease in bacilli during the ensiling period and a decrease in Listeria at the end of ensiling and after 2 days of aerobic exposure were observed.…”

Aflatoxins Biochemistry and Molecular Biology - Biotechnological Approaches for Control in Crops

“…It is well established that mycotoxin contamination of agricultural product can occur in the field as well as during storage (Wilkinson, 1999). Since phytopathogenic fungi such as Fusarium and Alternaria spp can produce mycotoxins before or immediately post harvesting several strategies have been developed including biological and cultural control practices to help mycotoxin contamination occurring in this way.…”

Emerging or re-emerging bacterial zoonoses: factors of emergence, surveillance and control

“…Foodborne infections caused by zoonotic agents have become more frequent throughout the last decades [53]. As far as animal food is concerned, the same is true for Listeria monocytogenes carried by cattle ingesting contaminated silage [61].…”