Influence of food, storage temperature, and time on the extracorporeal viability of ruminal fluid of cattle

Rumen fluid obtained from slaughter houses is sometimes used for transfaunation. In this study, we evaluated the ruminal fluid of cattle fed on pasture or pasture and concentrate and slaughtered recently. The rumen fluid samples were stored in a water bath, at ambient temperature, cooled, or frozen and subjected to physical, chemical, and microbiological evaluation for 24 h. The color, consistency, and odor changed primarily in the cooled samples, followed by the ambient temperature and water bath samples. The pH of fresh ruminal fluid was 7.5 in the pasture group and 6.4 in the pasture and concentrate group. The methylene blue reduction time of the fresh ruminal fluid was 2.35 min in the pasture group and 1.86 min in the pasture and concentrate group; the best values were observed in the water bath group. The chloride content was 15.7 mEq/l in the pasture group and 16.3±3.6 mEq/l in the pasture and concentrate group. A predominance of gram-negative bacteria was observed. The concentration of protozoa was 51.5 in the pasture group and 47.5 × 104/ml in the pasture and concentrate group, with a slight predominance of small protozoa; motility was better in the water bath samples than in the ambient temperature, cooled, and frozen samples. The viability of ruminal fluid collected from freshly slaughtered cattle was influenced by food provided in vivo; however, changes as a function of time and storage temperature were more remarkable. The rumen fluid was viable for up to 9 h when stored in the water bath (38°C) and 2 h at ambient temperature, and it was observed to be nonviable when subjected to cooling or freezing.