ABSTRACT
Objective: to evaluate the effect of a mastitis control program [based on the mastitis prevention, elimination and monitoring] on a herd udder health and milk quality status
Design: field trial
Animals: a large Holstein dairy herd of 1150 dairy cows
Procedure: 1] Evaluating the herd udder health status [by CMT and milk sampling born 19.34% of the milking cows for bacteriologic culture, 2] Canying out a control program [Consisted of: blitz treatment of Shep. ag., Post milking teat dipping by a 2.5% povidone Iodine solution with 5% glycerin, dry cow combination therapy, systemic antibiotic therapy of late pregnant heifers, bedding management, early detection, and good record keeping of clinical cases as well as continuous monitoring of udder health and milk quality by using bulk tank milk analysis], 3] Reevaluating the herd udder health status [by CMT and milk sampling from 13.2% of the milking cows for culture]. Statistical analysis: Chi-square test, Analysis of variance,Correlation coefficient, Fisher's exact test
Results: 1] Significant decrease in point prevalence, and incidence rates of clinical mastitis, relative 6equency of CMT-positive quarters, relative frequency of samples from which Strep. ag., Staph. Aureus and Coliforrns yielded and distribution of Strep. ag. and Staph. aureus in clinical cases, 2] Significant increase in relative frequency of samples from which C. bovis yielded, relative frequency of samples yielding no microorganism and dishibution of environmental Streptococci, C. bovis and no growth in clinical cases, 3] Significant decrease followed by an increase in BTSCC [with an average of 225080 cells/ml], significant decrease in staph. count [with an average of 2726 cfu/ml] being noticed at the beginning of monitoring only, and absence of significant differences in TBC, Coli. Count and Strep. count [with averages of 56996,17131 and 9948 cfu/ml, respectively]. In addition, in 76% of weekly bulk tank milk samples, Strep. ag. and Staph. aureus were not detected, 4] No correlation between the concentrations of major contagious pathogens and herd BTSCC and a significant positive correlation between staph. count and BTSCC were observed
Clinical implications: seemingly, the achievement of further improvement in mastitis status of the studied herd [i.e., eradication of Strep. ag. and effective control of Staph. aureus] would be subjected to: Continuous supervising of post milking teat disinfection and shifting from teat spraying to dipping, monthly measurement of individual cow SCC, washing and disinfecting teat cup liners between cows during milking and using more effective dry period intramarnrnary preparations as well. In addition to improve quality of herd milk, good udder preparation prior to milking is advised