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. 2016 Sep 15;3:79. doi: 10.3389/fvets.2016.00079

Table 3.

Descriptive statistics for cow and herd level factors considered in the analysis of the susceptibility of bovine intramammary infection-associated environmental streptococci against eight antimicrobials.

Variable N % Minimum 25th percentile Median 75th percentile Maximum
Lactation number
 1 33 18.6
 2 44 24.9
 3 100 56.5
Stage of lactation at sample collection
Early (0–100 days in milk) 92 52.0
Mid (101–200 days in milk) 40 22.6
Late (201+ days in milk) 45 25.4
Lactating herd size 41 50 58 83 199
Mean days in milka 146 167 174 184 215
Mean 24 h milk production (kg)a 26 29 31 32 40
Mean somatic cell count (1,000 cells/mL)a 107 161 183 266 327

aWithin herd averages were calculated using data collected by the regional Dairy Herd Improvement agency over the course of the study period (2007 and 2008).