[Objective assessment of udder filling degree in diary cattle during shows]

Overbagged udders are commonly seen at dairy cow shows in Switzerland and abroad due to prolonged milking intervals. In recent years various studies documented the negative effects of prolonged milking intervals and examined the objectivity of an ultrasound-based assessment scheme for determining udder filling. In addition, risk factors were calculated which lead to udder edema outside the puerperal phase. For example, the effects of a sudden increased 24-hour milking interval were altered behavior (reduced feeding time, increased rumination time) and a significantly increased cell count in experimental cows. Edema formation was observed sonographically in the subcutaneous udder tissue at the sites of predilection known from previous studies. No evidence of edema was observed in cows milked at 12 hour intervals. Based on these results, a new scoring system was defined using ultrasound images of show cows (grade 0 = no edema, grade 1 = slight, grade 2 = moderate, grade 3 = severe edema). Results documented that experienced clinicians were able to score ultrasound images reliable (interobserver reliability κ = 0.815, three different clinicians; intraobserver reliability κ = 0.90 and κ = 0.85, two clinicians) and little variability existed between the clinicians. A prolonged milking interval was identified as the main risk factor. Modified Swiss Dairy Show Regulations were implemented by January 1st, 2018 and ultrasonographic examinations proofed to be reliable in practice. Since January 1st, 2019 visual scoring of the udder filling is evaluated as part of a pre-show inspection. The sonographic evaluation can be used as a reliable diagnostic addition.