Diversity of Salmonella serotypes in cull (market) dairy cows at slaughter.
OBJECTIVE
To determine the diversity of Salmonella serotypes isolated from a large population of cull (market) dairy cows at slaughter.


METHODS
Cross-sectional study.


METHODS
Salmonella organisms isolated from the cecal-colon contents of 5,087 market dairy cows.


METHODS
During winter and summer 1996, cecal-colon contents of cull dairy cows at slaughter were obtained from 5 US slaughter establishments. Specimens were subjected to microbiologic culturing for Salmonella spp at 1 laboratory. Identified isolates were compared with Salmonella isolation lists published by the Centers for Disease Control and Prevention (CDC) and the National Veterinary Services Laboratory (NVSL) for approximately the same period. The Simpson diversity index was used to calculate the likelihood that Salmonella isolates selected randomly by establishment were different.


RESULTS
Of 58 Salmonella serotypes identified, Salmonella ser. Montevideo was the most prevalent. Two of the top 10 CDC serotypes identified from in 1996, Salmonella ser. Typhimurium and S Montevideo, appeared on our top 10 list; 8 of the top 10 were found on NVSL listings. Thirty-one of 59 S. Typhimurium isolates were identified as DT104 and found at a west slaughter establishment, 30 during the winter and 1 during the summer. The greatest diversity of serotypes was at a southeast establishment during the summer; the least diversity was at a central establishment in the winter.


CONCLUSIONS
58 Salmonella serotypes were isolated from market dairy cows at slaughter and could pose a threat for food-borne illness. Salmonella Montevideo was the most frequently isolated serotype and may contribute substantially to salmonellosis in dairy cattle.
Galland
J C
JC
Food Animal Health and Management Center, College of Veterinary Medicine, Kansas State University, Manhattan 66506, USA.
Troutt
H F
HF
Brewer
R L
RL
Osburn
B I
BI
Braun
R K
RK
Sears
P
P
Schmitz
J A
JA
Childers
A B
AB
Richey
E
E
Murthy
K
K
Mather
E
E
Gibson
M
M
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D002432:Cecum / Q000382:microbiology; D003106:Colon / Q000382:microbiology; D003430:Cross-Sectional Studies; D005260:Female; D005516:Food Microbiology; D011634:Public Health / Q000706:statistics & numerical data; D012475:Salmonella / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D012481:Salmonella Infections, Animal / Q000382:microbiology*; D012621:Seasons; D012703:Serotyping / Q000662:veterinary; D014481:United States