Milk And Plasma β-Hydroxybutyrate Concentrations in Holstein Transition Cows Supplemented with a Monensin Controlled-Release Capsule

Abstract

Ketosis is a common calving-related disorder affecting dairy cows during the transition period. Subclinical ketosis is characterized by serum β-hydroxybutyrate (BHB) levels > 1000 to 1400 μmol/L. The highest incidence of subclinical ketosis occurs within the first two to three weeks oflactation. The Ketolac® test (Nagoya, Japan) is designed for detection of BHB in milk. Therefore, it is a practical tool for diagnosing subclinical ketosis in early postpartum dairy cows. If prevention is not considered during the transition period, cows will be at higher risk of developing ketosis. Monensin is an ionophore that affects rumen fermentation, resulting in increased propionic acid production with a concurrent decrease in the molar proportion of acetate and butyrate. As a result, monensin has been used to prevent ketosis and calving-related disorders in dairy cattle.

It is hypothesized that dairy cows supplemented with monensin and fed diets containing citrus pulp would experience a decreased incidence of subclinical ketosis. Therefore, the objectives of this study were to determine the effect of a monensin controlled-release capsule applied at dry-off on the proportion of cows with concentrations of milk BHB > 200 μmol/L, and to associate these findings with the concentration of serum BHB at 14 d postpartum in Holstein dairy cows fed diets containing citrus pulp.