Table 1.

Descriptive statistics by frequency of laboratory submissions sent to DTU Vet laboratory for testing PRRSV during the period from 2007 to 2010 for breeding (Breed) and production (Prod) herds. Each laboratory submission consisted of individual blood samples collected from the same herd on the same day

Year	2007		2008		2009		2010
Herd type	Breed	Prod	Breed	Prod	Breed	Prod	Breed	Prod
Total number of tested herds	237	2982	233	2729	228	2720	220	2673
Median number of submissions per herd (Q1 – Q3)	12 (12–13)	1 (1–1)	12 (12–13)	1 (1–1)	12 (12–13)	1 (1–1)	12 (12–13)	1 (1–1)
Total number of samples	31,505	73,561	33,430	69,233	30,572	67,640	33,420	64,668
Median number of samples per herd (Q1–Q3)	10 (10–15)	20 (17–20)	10 (10–15)	20 (16–20)	10 (10–10)	20 (15–20)	10 (10–15)	20 (15–20)