Strategic Use of a Bolus Containing Calcium Chloride and Calcium Sulfate as a Supplemental Source of Calcium in Periparturient Dairy Cows

Abstract

The onset of lactation results in a physiologically significant loss of calcium. The loss of blood calcium requires increased mobilization of skeletal stores and a concurrent increase in the absorption of dietary calcium. The inability of the animal to maintain calcium homeostasis can result in hypocalcemia. Hypocalcemia can manifest itself as a clinical disease which limits mobility. In less severe cases of hypocalcemia, the animal maintains normal mobility and locomotion, but other muscle functions such as GI tract mobility can be altered. Strategies to enhance the periparturient dairy cow's ability to maintain calcium homeostasis includes limiting total calcium intake, modifying the dietary cation-anion difference, injecting cows with calcium immediately after calving, and/or administering an oral calcium supplement immediately after calving. A project has been designed to investigate the strategic use of a mineral supplement dosed as an oral bolus at calving to increase free ionized calcium immediately post-partum.