Effect of monensin controlled release capsules on blood metabolites in periparturient dairy cows

Abstract

Monensin is a carboxylic polyether ionophore producedby a naturally occurring strain of Streptomycescinnamonensis. 1 Monensin is available in variousforms for use in cattle. It can be incorporated into feed as a powderor given as a ruminal bolus by the use of controlled releasedcapsules. 2–4 The capsules consist of a plastic cylinder with foldingwings, which allow the capsule to be retained in the rumen. 1,3 Monensin improves the efficiency of energy metabolism, increasesthe flow of protein to the small intestine, alters mineral metabolismand decreases the occurrence of ruminal disorders, includingbloat and lactic acidosis. 2 Its effects on energy metabolism are todecrease butyrate concentration, increase propionate concentra-tion, a glycogenic effect that is independent of rumen fermenta-tion, and to decrease the circulation of free fatty acids. 2,3 Therefore, the potential effects of monensin on glucose productionare of great importance to dairy cows in early lactation, especiallythose with a negative energy balance and at risk for ketosis. 1–3,5 The objective of this study was to investigate the efficacy ofthe monensin controlled release capsule (Rumensin® CRC),administered prepartum, on blood metabolites in periparturientdairy cows.