“…The observed values for plasmatic Phosphorus, Calcium, and Magnesium did not differ from the recommended level for dairy cows in the NRC (NRC, 2001), also they were within the normal range of mineral concentration for mid-lactating cows, as reported by the Animal Health Laboratory at that University of Guelph (Hoff and Duffield., 2015). However, a lower dose of M12 showed similar effectiveness than AB used in a higher dose to regulate rumen pH and mineral uptake under the same challenging rumen conditions, taking into consideration that Southern Chilean milk production is characterised by pasture grazing systems with low energy and mineral imbalances associated to concerning scenarios for metabolic diseases like hypocalcemia and hypomagnesemia (Melendez et al, 2023). These metabolic diseases have an economic impact on the herd where hypomagnesemia and hypocalcemia, especially in a subclinical form, are important due to their high prevalence, affecting grazing production systems reaching 48.9% and 64.8%, respectively.…”