Relationships among Udder Characteristics, Milk Yield, and Nonyield Traits

A total of 1604 udder measurements of the area bounded by the four teats was collected on 147 cows to determine relationships among udder area, indices of udder collapsibility, milk yield, rates of milk flow, California Mastitis Test scores, persistency of lactation, and visual appraisal of udder conformation.Direct measurements of the udder were highly repeatable both within and among lactations.Indices of udder collapsibility were not as repeatable.Correlations among udder measurements were large and positive.Milk yield on the day of measure was highly and positively correlated with udder measurements, but correlations with mature equivalent milk yield were lower.Correlations among udder measurements, rates of milk flow, persistency of lactation, and many traits of udder conformation were small.Larger udders were associated generally with higher mastitis test scores, with deeper udders that were more bulgy in front and looser in rear and with flatter udder floors.Indices of udder collapsibility were unrelated to visual appraisal of udder quality.