Short communication: Risk factors for sonographically detectable udder edema in overbagged cows at dairy shows.

At dairy cow shows, the appearance of the udder is very important. To show cows at their best, udders are often presented in an overbagged state by extending milking intervals before the show. This practice represents an animal welfare issue because it is associated with behavior changes (e.g., excessive abduction and decreased eating time) and may affect the health of the animal. The aim of the current study was to determine the association between various parameters (e.g., milk yield, days in milk, milking procedures, or administration of nonsteroidal anti-inflammatory drugs, steroids, or diuretics) and the sonographically detectable udder edema score. Data were collected from the show catalogs, by interviewing the exhibitors, by analyzing official veterinary treatment protocols and official milking data, via laboratory analysis of blood samples, and by sonographic examinations of the udders at the show. For sonographically detectable udder edema scoring, 3 scans were taken, 1 on each fore quarter and 1 incorporating both rear quarters at the level of the median suspensory ligament. For grading the scans, a scoring system of 4 grades (score 0 = no edema, 1 = slight edema, 2 = moderate edema, 3 = severe edema) was used. Data from 321 cows of different breeds were collected at 4 highly competitive Swiss dairy shows (shows A-D) between January and September 2017. To determine risk factors for sonographically detectable udder edema, data were analyzed with 2 different logistic regression models. In model 1, the odds ratios were 3.33 (milking intervals of ≥16 h vs. <14 h), 3.84 (show A vs. show C), and 7.39 (dairy breeds vs. dual-purpose breeds). Milking intervals of dairy breeds were significantly higher than those of dual-purpose breeds. In model 2, milking interval was the only significant risk factor with an odds ratio of 9.00 for milking intervals of ≥16 h. Only the milking intervals represented a relevant risk factor in both models; therefore, we concluded that the previously described sonographic udder edema scoring is a useful technique for detecting overbagged udders at dairy shows. Its routine implementation may improve cow welfare at dairy shows.

Technical note: Evaluation of a sonographic overbagging edema scoring system for show cows: Comparison with visual inspection.

Overbagged udders are commonly seen at dairy cow shows due to prolonged milking intervals. The aims of this study were to describe the prevalence of udder edema in dairy cows at shows as determined by sonography and to suggest a sonographic scoring system, which was evaluated for reproducibility and repeatability. At 4 highly competitive Swiss dairy cow shows, 319 cows of various breeds were examined. Sonographic scans-1 from each fore quarter and 1 from the rear, representing both hind quarters-were collected by 3 experienced veterinarians at defined positions predisposed to overbagging edema. Sonographic scans were scored with the aid of a newly suggested scoring system (score 0 = no edema, grade 1 = slight edema, grade 2 = moderate edema, grade 3 = severe edema). Further, 139 video sequences from behind while the cows were walking and the same number of photographs of the udder each from the left, right, and behind were selected. The photographs and video sequences were visually scored for different parameters as 0 = not present or 1 = present except for abduction, which was scored on a visual analog scale (0 = no abduction; 100 = maximal imaginable abduction). Visual scores were then compared with the sonographic scoring (Pearson's chi-squared). The prevalence of udder edema scores 1, 2, and 3 was 14.0, 6.5, and 2.3%, respectively. Interobserver reliability for objective sonographic scoring (κ = 0.815) and intraobserver agreement (κ = 0.90 and 0.85 for 2 different observers) was estimated as "almost perfect." Interobserver agreements for visual parameters were κ = 0.40 or less except for teat shape (κ = 0.52). Classification of the videos resulted in better interobserver agreement; when rating hind limb abduction, Spearman correlation coefficient was 0.61, whereas κ = 0.61 for absence of udder movement. Udder movement and teat shape were significantly associated with the edema score. The higher inter- and intraobserver reliability of the sonographic edema scoring compared with the visual scoring system indicates that the newly suggested scoring system might be used in the future to objectively identify udder edema in cows at dairy shows.