Retrospective study

Abstract

Downer cows, defined as a bright and alert cow recumbent for more than 1 day, are often challenging cases for veterinarians and farmers. This article reviews findings for 37 downer dairy cows that originally become recumbent from hypocalcemia ( milk fever) on commercial dairy farms in Australia. Clinical examination determined that they had apparently recovered from primary hypocalcemia, and remained recumbent from secondary damage. There was a wide range of secondary damage, which mainly affected the musculoskeletal system, but other parts of the body were also affected. It was concluded that downer cow syndrome is due to clinically important secondary damage, defined as "secondary damage that can cause recumbency in its own right, or delay or prevent recovery from the primary cause of the recumbency". Clinically important secondary damage in downer cows can present in a wide range of types, and is not necessarily confined to the musculoskeletal system. This study demonstrated a wider range of secondary damage than considered in the literature. When managing recumbent dairy cows, in addition to the primary etiology of the recumbency, veterinarians must consider secondary damage.