Table 3. Descriptive statistics of the number of Defined Daily Doses (DDD_vet) per cow and year for antimicrobials used to treat udder disease, based on European Medicines Agency technical units.

Study population: 232 dairy herds where cows were treated with antimicrobials during a one-year observational period.

	Herds where treatment necessary	% of 232	nDDDvet/cow/year
			Mean	SEM	Median	Minimum	Maximum
All udder diseasea
Total AMC	214	92%	1.33	0.09	0.86	0.04	9.99
HPCIA	183	79%	0.73	0.08	0.41	0.03	9.67
Acute mastitis
Total AMC	205	88%	1.21	0.09	0.71	0.03	9.99
HPCIA	175	75%	0.71	0.08	0.36	0.03	9.67
Chronic mastitis
Total AMC	72	31%	0.48	0.05	0.34	0.02	2.55
HPCIA	40	17%	0.25	0.04	0.16	0.03	1.05

Notes.

^aSome farms may have reported cases of both acute and chronic mastitis over the study period, meaning that the sum of farms reporting acute and chronic mastitis exceeds the total number of farms with udder disease.

nDDD_vet/cow/year

number of defined daily doses per cow and year

SEM

standard error of the mean

AMC

antimicrobial consumption

HPCIA

highest priority critically important antimicrobial