Microbiological Safety of the Technology of Accelerated Manure Processing

Modern animal husbandry requires new environmentally friendly technologies for the processing and disposal of its by-products (BPAH), namely, manure and manure effluents from livestock complexes. One of these technologies is the production of reconstituted litter (RL) in Bedding Recovery Units (BRUs) from cattle manure, introduced at one of the dairy complexes in Kirov oblast. The recycling technology used made it possible to obtain a homogeneous product of a soft, loose consistency, high hydroscopicity, and brown color with a weak characteristic earthy odor. Manure processing in BRUs for 24 h at a temperature of 69 ± 4°C contributes to a significant decrease in the humidity of manure effluents and an increase in the mass fraction of organic matter, ash content, and pH, as well as a significant decrease in the total number of microorganisms (MOs) (by 68.2 times) and species diversity (by 2.2 times). Proteus, Fusobacterium, Prevotella, Pseudomonas, Peptococcus, Aspergillus, and Klebsiella, which are among the causative agents of mastitis, have disappeared from the microbiota. The numbers of opportunistic enterococci decreased from (8.0 ± 0.5) × 106 down to (5.0 ± 0.5) × 104 CFU/mL. After processing in BRUs, bifidobacteria took a dominant position in the composition of microbiota in RL (63% of the total number of identified MOs). This fact should be regarded as an advantage of the technology used and one of the advantages of the RL. However, conditionally pathogenic microorganisms of the genera Clostridium, Bacteroides, Peptostreptococcus, Veillonella, and Candida showed high resistance to manure effluent processing in BRU. According to the chemical analysis results, keeping cattle on RL led to the accumulation of nitrogen, phosphorus, and potassium in litter manure, which is due to the gradual degradation of organic components of RL during recycling. The results presented can be used to optimize the parameters of processing cattle manure using BRUs to improve the quality of RL.