Impact of haylage harvest and storage technologies on forage microbial contamination

UDC 636.2.085.523.1 IMPACT OF HAYLAGE HARVEST AND STORAGE TECHNOLOGIES ON FORAGE MICROBIAL CONTAMINATION Artemyeva O.A., Candidate of Biological Sciences Duborezov V.M., Doctor of Agricultural Sciences Pavlyuchenkova O.V., Kotkovskaya E.N., Candidates of Biological Sciences Ralkova V.S., Researcher Peresyolkova D.A., Junior Researcher All-Russia Research Institute for Animal Husbandry, Moscow, Russia E-mail: vijmikrob@mail.ru ABSTRACT To develop bacteriological regulations for harvesting and storing haylage, microbial contamination of feeds has been studied using different technologies for harvesting haylage and laying fodder in trench and concrete ring silos, and rolls. It was noted that the analyzed forage samples had no pathogenic microorganisms and Enterobacteriaceae, including Salmonella. There was a lack of toxicity in all analyzed silage samples. The values for the number of mesophilic aerobic and elective anaerobic bacteria, and concentrations of lactic-acid bacteria, mold and yeast fungi in samples were lower than in the feedstock. Microbial contamination values were better for haylage obtained from the plants cut 25 cm above the ground level (when compared to the plants cut to 9 cm height). Rates of contamination were lower in haylage packed into film bags than into trench silos that might give reason to recommend the given harvesting technique. Permissible contaminant levels without any negative impact on haylage quality have been identified. KEY WORDS Haylage; Harvesting technologies; Trench silo; Concrete ring silo; Roll; Forage equipment; Microbiological parameters; Mold; Yeast-like fungi; Mesophilic aerobic and elective anaerobic bacteria. An increase in efficiency of animal husbandry depends on the feed production growth as well as the rise in the fodder quality, decrease in loss of feed nutrients by the means of harvest and storage technology developments. Feeds, feed additives and feedstock should not contain microorganisms, their toxins or their metabolites of unacceptable amount, which represents health risks of farm animals [8]. Safe levels of microorganism contamination in bulky feeds harvested using different technologies should be taken in consideration when developing microbiological regulations. It should be reasonable to determine common indices of safety and certain pathogenic microorganism contents to ensure the health of farm animals and subsequently consumers [1, 4, 9]. Research findings depend on an applied analytical method; that is why, an appropriate standard method should be determined for each microbiological item. However, fodder suppliers and forage producers should have the opportunity of applying analytical and particularly expressive methods differed from the standard methods, provided the use of these alternative methods can yield equivalent results. Moreover, it is necessary to determine the rules of sampling and the methods of analyzing for each item to perform the study more precisely [2]. Vegetative feedstock can run the danger of secondary contamination [5, 6, 7] during technological procedures for feed harvesting (mowing, rolling, turning up, selecting for shredding, and transportation). Layer-specific contamination of vegetative bulk with objectionable microorganisms can be continued in trench silos during packing and with the entries of tractors with trailers. It results in disturbing the optimal conditions for fermentation that can impact on the forage quality [10].