In Vitro Alterations in Ruminal Parameters by Megasphaera Elsdenii Inoculation on Subacute Ruminal Acidosis (sara)

SARA is a common and serious problem in well-managed and intensive dairy herds or beef cattle operations, because of triggering other metabolic disorders and causing lactation-fertility losses. It is a metabolic disease in dairy cattle that occurs during early and mid-lactation and has traditionally been characterized by low rumen pH, but lactic acid does not accumulate as in acute lactic acid acidosis. Managing the disease, rather than eliminating it, has been suggested in high-producing dairy herds. SARA was induced in vitro to appraise the effectiveness of Megasphaera elsdenii inoculation. Rumen fluid was collected from 2 ruminally cannulated Holstein heifers. Medium was prepared by mixing macromineral (200 ml), micromineral (0.1 ml), buffer (200 ml), reduction (40 ml) and resazurin (1 ml) solutions as well as distilled water (400 ml). The media was then added with a test diet consisting (g/kg) of 550-soluble starch, 260-glucose, 60-cellulose, 70-cellobiose and 60-tripticase, at levels of 10, 15, 20, 25, 30, 40, 50, 70 and 100 g/l. After determining its level causing SARA as reflected by pH (~5.8) in preliminary experimentation, the substrate (test diet, 25 g/l) were incubated with presence of 0, 10, 10, and 10cfu M. elsdenii per ml at 39°C for 24 h. Rumen parameters were analyzed by 2-way ANOVA. It is determined that most of the tested parameters are not influenced after inoculation of M. elsdenii, but the level of NH3-N (P<0.002) and Butyric acid (P<0.006) in rumen fluid, are observed to increase with the growth of bacterium level. When the bacterium is inoculated in the level of 7 cfu ml, it is reached to the highest level of butyric acid (20.29 mM). It is showed that the existent evidence is similar to other studies. In conclusion, addition of M. elsdenii into media, one of the predominant lactate-utilizing bacteria failed to reverse SARA in vitro.