Table 2. Survey-weighted prevalence, by herd and season, of Salmonella sp. shed in feces of 249 culled cows sampled on seven California dairies.

Herd	Prevalence % (SE), na, Nb					P value	Serotype
	Springc	Summer	Fall	Winter	Overall
1	–d	10.0 (7.64), 10,24	0 (−), 10, 31	0 (−), 10, 67	1.97 (1.50), 30, 122	0.538	S. Typhimuium
2	0 (−), 10, 13	10.0 (6.88), 10, 19	0 (−), 10, 24	0 (−), 10, 28	2.26 (1.56), 40, 84	0.80	S. I1 4, 5, 12: i-
3	0 (−), 10, 26	10.0 (8.23), 10, 31	0 (−), 10, 41	20.0 (10.88), 10, 30	7.11 (3.24), 40, 128	0.124	S. Montevideo
4	0 (−), 10, 61	10.0 (9.44), 10, 65	0 (−), 10, 71	0 (−), 10, 52	2.61 (2.43), 40, 249	0.182	S. Bardo
5	0 (−), 10, 17	0 (−), 10, 20	10.0 (8.58), 10, 38	0 (−), 10, 36	3.42 (2.94), 40, 111	0.209	Unidentified Salmonellae
6	10.0 (3.02), 10, 11	0 (−), 9, 9	–	–	5.50 (1.66), 19, 20	0.424	S. rough type O
7	0 (−), 10, 16	10.0 (8.16), 10, 30	0 (−), 10, 31	0 (−), 10, 23	3.00 (2.45), 40, 100	0.164	S. Montevideo
All	0.76 (0.23), 60,144	8.54 (3.75), 69, 198	1.61 (1.38), 60, 236	2.54 (1.38), 60, 236	3.42 (1.07), 249, 814	0.074

Notes:

^aNumber of dairy cows randomly selected for fecal sampling from the list of cows identified for culling at sampling day.

^bNumber of dairy cows identified for culling at sampling day.

^cStudy year and seasons included summer (July 1–September 30, 2014), fall (October 1–December 31, 2014), winter (January 1–March 31, 2015) and spring (April 1–June 30, 2015).

^dNo samples cultured due to non-random selection of culled cows.

^eUnidentified polyvalent positive Salmonella sp.