Somatic cell count status across the dry period as a risk factor for the development of clinical mastitis in the subsequent lactation.

摘要: The objective of this study was to determine the risk clinical mastitis in first 120 d lactation based on previous somatic cell count (SCC) history a herd with very low prevalence contagious pathogens. A total 218 cows from university were enrolled at dry-off. Duplicate quarter milk samples collected all quarters dry-off, postcalving (2 9 milk), and before treatment cases that occurred during subsequent lactation. Quarter SCC statuses across dry period defined comparison between date dry-off sampling periods. relationship probability developing status other explanatory variables assessed using logistic regression. In postcalving, 68 47 cows. Of experienced microbiologically positive case, same microorganism never isolated obtained or consistently Coagulase negative staphylococci most prevalent pathogens subclinical intramammary infection, whereas gram-negative common pathogen associated cases. Quarters had least 1 case 4.2 times more likely have current than did not [odds ratio (OR) = (1.8, 10.0)]. greater fourth parity second [OR (1.4, > =200,000 cells/mL 2.7 experience <200,000 both periods (0.97, 7.67)].