Short Communication: Bulk Tank Total Bacterial Count in Dairy Sheep: Factors of Variation and Relationship with Somatic Cell Count

• Published in: Journal of dairy science 2006-02, Vol.89 (2), p.549-552
• Main Authors: Gonzalo, C., Carriedo, J.A., Beneitez, E., Juárez, M.T., De La Fuente, L.F., San Primitivo, F.
• Format: Article
• Language: English
• Subjects: Animals; Bacteria; breed differences; bulk milk; bulk tank milk; Cell Count; Colony Count, Microbial; dairy animals; ewe milk; ewes; Female; Mastitis - diagnosis; Mastitis - microbiology; Mastitis - veterinary; Milk - cytology; Milk - microbiology; milk quality; milk tanks; milking; milking parlors; Mycoplasma agalactiae; Mycoplasma Infections - diagnosis; Mycoplasma Infections - veterinary; plate count; Reproducibility of Results; Sheep; Sheep Diseases - diagnosis; Sheep Diseases - microbiology; Species Specificity; total bacterial count
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.S0022-0302(06)72117-8

A total of 9,353 records for bulk tank total bacterial count (TBC) were obtained over 1 yr from 315 dairy ewe flocks belonging to the Sheep Improvement Consortium (CPO) in Castilla-León (Spain). Analysis of variance showed significant effects of flock, breed, month within flock, dry therapy, milking type and installation, and logSCC on logTBC. Flock and month within flock were important variation factors as they accounted for 22.0 and 22.1% of the variance, respectively. Considerable repeatability values were obtained for both random factors. Hand milking and bucket-milking machines elicited highest logTBC (5.31), whereas parlor systems with looped milkline (5.01) elicited the lowest logTBC. The implementation of dry therapy practice (5.12) showed significantly lower logTBC than when not used (5.25). Variability in logTBC among breeds ranged from 5.24 (Awassi) to 5.07 (Churra). However, clinical outbreaks of contagious agalactia did not increase TBC significantly. A statistically significant relationship was found between logTBC and logSCC, the correlation coefficient between the variables being r = 0.23. Programs for improving milk hygiene should be implemented for both total bacterial count and somatic cell count variables at the same time.