Hypocalcemia in Postparturient Dairy Cows: Our History Prevents our Progress

Principal Investigator: Jessica McArt

Department of Population Medicine and Diagnostic Sciences
Sponsor: National Institute of Food And Agriculture-USDA
Grant Number: 2019-67015-29446
Title: Hypocalcemia in Postparturient Dairy Cows: Our History Prevents our Progress
Project Amount: $500,000
Project Period: April 2019 to April 2022

DESCRIPTION (provided by applicant): 

Parturient dairy cows require an enormous quantity of calcium for colostrum and milk production. So much that some cows no longer have sufficient calcium for proper muscle contraction and cannot stand. Although this severe form of hypocalcemia, known as milk fever, has become an uncommon occurrence through advances in nutrition and management, milk fever’s pernicious cousin, subclinical hypocalcemia, now plagues nearly 50% of cows. Although experts argue over its definition, we agree on two things: subclinical hypocalcemia is bad for both cows and the dairy industry – it increases the risk of disease and reduces milk production, and we do not know how to treat it. Our antiquated methods of milk fever identification and treatment do not work for subclinical hypocalcemia, and our ideology must change for us to succeed. We hypothesize that transient subclinical hypocalcemia is a normal physiological response to the sudden calcium deficiency initiated by lactation, whereas chronic subclinical hypocalcemia signals a maladaptation of calcium homeostasis. Improved knowledge, prevention, and diagnosis of chronic subclinical hypocalcemia play vital roles in routing this pervasive disorder, and thus, we propose to: 1) identify modulatory differences in calcium homeostasis among high-producing dairy cows, 2) determine the impact of delayed calcium administration on chronic subclinical hypocalcemia, and 3) produce a method to determine hypocalcemia status via milk analysis. Our approach will provide a metabolic foundation for the design of effective preventative strategies and an alternative to invasive testing methodology. It thus presents a promising strategy to improve animal health and enhance production efficiency.