Relationship among specific bacterial counts and total bacterial and somatic cell counts and factors influencing their variation in ovine bulk tank milk
- 1 February 2013
- journal article
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 96 (2), 1021-1029
- https://doi.org/10.3168/jds.2012-5915
Abstract
To analyze the relationship among the counts of different organisms and total bacterial count (BTTBC) and somatic cell count (BTSCC) as determined in dairy laboratories in ovine bulk tank milk, 751 bulk tank milk samples from 205 dairy sheep flocks belonging to Consortium for Ovine Promotion (CPO) were collected between January and December 2011. Four samplings were carried out in each flock, once per season, throughout 1 yr. Variables analyzed were bulk tank counts of thermoduric, psychrotrophic, coliform, and gram-positive catalase-negative cocci (GPCNC) bacterial groups. Thermoduric, psychrotrophic, and coliform species were significantly related to BTTBC, whereas GPCNC were correlated with both BTTBC and BTSCC variables. Highest counts were for psychrotroph and coliform groups, and a moderate to high correlation (r=0.51) was found between both variables, indicating that poor cleaning practices in the flocks tend to select for less-resistant organisms, such as gram-negative rods. In addition, BTTBC correlated with BTSCC (r=0.42). Some variation factors for specific bacterial counts, such as breed, season, milking type, dry therapy, and milk yield, were also analyzed. Flock information was collected from flock books, annual audits, and the CPO traceability system. Psychrotrophs and coliforms had elevated counts in winter, whereas GPCNC were higher in summer and in hand-milked flocks. Dry therapy contributed to the reduction in psychrotrophic bacteria; therefore, some strains of mammary pathogens could also be psychrotrophic bacteria. Results of this study would be helpful for troubleshooting milk quality problems and developing premium payment systems in dairy sheep.Keywords
Funding Information
- Spanish Ministry of Education
- Science Ministry of Science and Innovation
This publication has 25 references indexed in Scilit:
- Short communication: Influence of storage and preservation on microbiological quality of silo ovine milkJournal of Dairy Science, 2011
- Short Communication: Bulk Tank Total Bacterial Count in Dairy Sheep: Factors of Variation and Relationship with Somatic Cell CountJournal of Dairy Science, 2006
- Evaluation of Rapid Somatic Cell Counters Under Different Analytical Conditions in Ovine MilkJournal of Dairy Science, 2004
- Enterococci in foods—a conundrum for food safetyInternational Journal of Food Microbiology, 2003
- Mastitis of dairy small ruminantsVeterinary Research, 2003
- The role of intramammary pathogens in dairy goatsLivestock Production Science, 2003
- Mammary Pathogens and Their Relationship to Somatic Cell Count and Milk Yield Losses in Dairy EwesJournal of Dairy Science, 2002
- Enterococci from foodsFEMS Microbiology Reviews, 2002
- Enterococcal diversity in the environment of an Irish Cheddar-type cheesemaking factoryInternational Journal of Food Microbiology, 2001
- Serum Concentrations of Copper, Iron, and Zinc During Escherichia coli-Induced MastitisJournal of Dairy Science, 1993