Effects of udder edema on parlor behavior in first- and second-lactation Holstein dairy cows

Udder edema (UE) is a metabolic disorder that most commonly occurs around the transition period. However, gaps exist in our knowledge about its effects on parlor behavior. The aim of this study was to examine the prevalence and effects of UE on behavior in the milking parlor during udder preparation and active milking from 2 to 9 days in milk in first- (FL) and second-lactation (SL) Holstein dairy cattle. Each cow (n = 375) was observed once and monitored from the point of first contact during udder preparation through the first 5 min of active milking. Behavior measurements include step, kick, and kicking off the milking unit. Cows were determined to have UE when the rear udder medial suspensory ligament lost definition and was softened due to the presence of interstitial fluid. In this study, 237 out of 247 (95.6%) FL cows and 104 of 128 (81.3%) SL cows presented with UE. First-lactation cows with UE had a higher step rate (3.97 steps/session) when in contact during udder preparation and attachment (2.80 steps/session), and kick rate during milking (2.68 kicks/milking session) compared with SL cows with UE (2.37 steps/session, 1.25 steps/session, 1.24 kicks/milking session). Those FL cows with UE had a lower step rate during milking (6.04 steps/milking session) compared with FL cows without UE (7.20 steps/milking session). The FL cows with UE had a higher average count of kicking off the milking unit (μ = 0.220 kick-offs) than SL cows with UE (μ = 0.029 kick-offs) and FL cows without UE (μ = 0.091 kick-offs). The results indicate that UE is prevalent among dairy cattle, and the disorder has effects on behaviors presented in the milking parlor. Reducing UE has the potential to decrease step and kick behaviors to improve welfare of transition cows and reduce risk to dairy caretakers in the milking parlor.