A randomized controlled study evaluating milking performance and udder health on a New York dairy farm using a novel...

Development of automated ways to prepare udders before harvesting milk has allowed for more consistent application of procedures like disinfecting, stimulating, and drying, therefore replacing manual techniques. Holsteins (n = 326) at one NY dairy were enrolled in a randomized, controlled clinical trial to determine the effect of a device that uses a vortex of water, air, and disinfectant to clean and dry teats on milk yield, milk flow rates, teat end cleanliness, odds of bimodal milk flow, and udder health indices. Cows were randomized into one of 2 treatment groups and measurements were collected in a double 24 parallel parlor over 7-wk. Udder preparation for the VORTEX group consisted of using a trigger-activated vortex of water, chemical, and pressurized air to disinfect, clean, and dry teats before attachment of the milking unit. Udder preparation for the control group (TRAD) included application of disinfectant using a foamer cup, manual stripping, and a cloth towel cleaning and drying step before attachment of the milking unit. Compliance to routines, which targeted 12 s of stimulation, 120 s of preparation-lag time, and the same target disinfectant concentration for both groups, was evaluated weekly. Digital milk meters were used to determine session milk yield, duration of milking, and average and maximum milk flow rates, while bi-monthly DHIA testing captured milk yields and linear score (LS) measurements. Vacuum measurement devices were used to determine the incidence of bimodality. Percentage of dirty teat ends was evaluated using gauze impressions. Generalized mixed regression models were used to describe the effect of treatment on the outcome variables. Least squares means (95% CI) were not meaningfully different for cows that were prepared with the vortex device versus the traditional routine, respectively, for: milk yield per session [15.43 (15.10-15.76) and 15.05 (14.71-15.39) kg], test day milk yield [45.8 (45.0-46.6) and 45.3 (44.5-46.2) kg], duration [4.96 (4.80-5.13) and 4.83 (4.66-5.00) min], average flow rate [3.16 (3.14-3.19) and 3.18 (3.16-3.21) kg/min], and maximal flow rate [4.35 (4.26-4.43) and 4.24 (4.16-4.32) kg/min]. The odds of bimodal milk flow were higher for cows that were prepared using the vortex device (odds ratio = 2.4; 95% CI = 1.3 - 4.7). There was an interaction between treatment and test day for LS. Linear scores for the 1st, 2nd, and 3rd post enrollment test days [LSM (95% CI)] were 1.95 (1.69-2.21), 1.82 (1.54-2.11), and 2.51 (2.18-2.84) for the VORTEX cows and 1.25 (0.99-1.85), 1.54 (1.23-1.85), and 1.38 (1.00-1.76) for the TRAD cows, respectively. There was a higher odds of dirty teat ends in the VORTEX group (odds ratio = 1.23; 95% CI = 1.00-1.51). The odds of a subclinical infection, defined as a baseline LS graduating from <4 to ≥4, favored the TRAD group (odds ratio = 3.98; 95% CI = 1.64-9.71). Although use of the vortex device did not affect milk production, milking duration, or flow rates, replacing the traditional strip-and-wipe procedures may influence bimodality and udder health, likely due to differences in teat stimulation quality and less precise cleaning, respectively.