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United States Department of Agriculture

Agricultural Research Service

Title: Fecal Shedding of Salmonella Spp by Dairy Cows on-Farm and at Cull Cow Markets

Authors
item Wells, S - UNIVERSITY OF MINNESOTA
item Cray, Paula
item Dargatz, D - USDA-APHIS-VS-CEAH
item Ferris, K - USDA-APHIS-NVSL
item Green, A - USDA-APHIS-VS-CEAH

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 17, 2000
Publication Date: October 8, 2000
Citation: Wells, S.J., Cray, P.J., Dargatz, D.A., Ferris, K., Green, A. 2001. Fecal shedding of salmonella spp by dairy cows on-farm and at cull cow markets. Journal of Food Protection. Vol 64. No. 1. P. 3-11.

Interpretive Summary: Salmonella is ubiquitous in nature and can cause gastroenteritis in man and animals. It can also be transferred from animals to man through the consumption of contaminated foodstuffs. Little is known about the prevalence of Salmonella within food animals. As part of a national study of the US dairy cow population, fecal samples were collected from representative cows on 91 dairies and 97 cull dairy cow markets in 19 states and cultured for the presence of Salmonella. Susceptibility to antimicrobials used in human and veterinary medicine was also determined on the recovered Salmonella isolates. Salmonella was recovered from 5.4% of milk cows, 18.1% of milk cows expected to be culled within 7 days, and 14.9% of culled dairy cows at markets. On a premise basis, Salmonella shedding in milk cows was detected on 21.1% of dairies and 66% of cull dairy markets. The percent of herds with at least one cow with detectable Salmonella fecal shedding was higher during the sampling period from May through July, in herds with at least 100 milk cows, and in herds in the South region. A majority of isolates (88.9%) were susceptible to all 17 antimicrobials evaluated; multiple resistance was an infrequent occurrence. This study provides information describing the distribution of Salmonella fecal shedding from dairy cows on-farm to veterinarians, commodity groups and industry and will serve as a baseline for future studies.

Technical Abstract: As part of a national study of the US dairy cow population, fecal samples were collected from representative cows on 91 dairies and 97 cull dairy cow markets in 19 states. Salmonella spp. were recovered from 5.4% of milk cows, 18.1% of milk cows expected to be culled within 7 days, and 14.9% of culled dairy cows at markets. On a premise basis, Salmonella shedding in milk cows was detected on 21.1% of dairies and 66% of cull dairy markets. The percent of herds with at least one cow with detectable Salmonella fecal shedding was higher during the sampling period from May through July, in herds with at least 100 milk cows, and in herds in the South region. The most common Salmonella serogroups isolated were E (30.8% of isolates) and C1 (28.6%); the most common serotypes isolated were S. Montevideo (21.5% of isolates), S. cerro (13.3%) and S. Kentucky (8.5%. Fecal shedding of S. typhimurium or S. typhimurium var. Copenhagen was infrequent (2.8%of isolates). A majority of isolates (88.9%) were susceptible to all 17 antimicrobials evaluated; multiple resistance was an infrequent occurrence. This study provides information describing the distribution of Salmonella fecal shedding from dairy cows on-farm and will serve as a baseline for future studies.

Last Modified: 7/25/2014
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