Relationship between in vitro antimicrobial sensitivity of bovine subclinical mastitis isolates and treatment outcome in lactating dairy cows

The objective of the present study was to determine whether there was an association between in the in vitro antimicrobial sensitivity test results of subclinical mastitis pathogens and bacteriological cure following intramammary treatment using a combination of nafcillin, penicillin, and streptomycin [NPS]. Eighty-six intramammary pathogens from 43 cows were examined in this study. Most intramammary infections were due to coagulase-negative staphylococci, coliforms, and environmental streptococci. The antibiotic sensitivity to NPS was determined using the Kirby-Bauer disc diffusion method. Bacteriological cure rates for sensitive, intermediate, and resistant isolates in the standard treatment group [3 intramammary infusions of NPS once daily] were 84.44, 88.9, and 100%, respectively. These figures in the extended treatment group [6 intramammary infusions of NPS once daily] were 100% for the 3 categories. Bacteriological cure was not associated with the sensitivity test result. Based on this study, Kirby-Bauer sensitivity test results were not useful as predictors of the bacteriological outcome of subclinical mastitis treated with intramammary NPS

Conventional and extended intramammary therapy of persistent subclinical mastitis using nafcillin-pencillin-dihydrostreptomycin in lactating dairy cattle

The objective of the present study was to compare the efficacy of conventional and extended intrammamary [IMM] therapy of persistent subclinical mastitis in lactating dairy cattle using nafcillin-penicillin-dihydrostreptomycin combination [NPD]. Sixty-five dairy cows with 126 infected quarters were enrolled in the study. Infected cows were allocated randomly to 1 of 3 different treatment regimens: [1] conventional group: NPD administered IMM 3 times at 24-h intervals [20 infected cows, 43 intramammary infections [IMI]], [2] extended group: NPD administered IMM 6 times at 24-h intervals [23 cows, 43 IMI], and [3] untreated control group [22 cows, 40 IMI]. The overall bacteriological cure [BC] rates for subclinical IMI were 86.04%, 100%, and 20% for the conventional, extended and the control groups, respectively; indicating a higher BC rate [P<0.0001] for the treated groups than the control group. Significant difference [P=0.029] concerning the BC rate was also observed between the extended and the conventional groups. Significant difference [P=0.0021] in somatic cell count [SCC] was detected between the extended and the conventional groups. Significant difference [P=0.0021] in somatic cell count [SCC] was detected between the extended and the control group. Fat percentage increased in the conventional [P=0.029] and in the extended [P<0.0001] groups, and protein percentage increased only in the extended group [P=0.0016]. There was no significant difference in posttreatment milk production between the groups [P>0.05]. Results of this study indicate that NPD therapy was effective in eliminating subclinical IMI in lactating dairy cows, and that extended therapy enhanced BC rate and reduced SCC

Relationship between in vitro susceptibility of bovine subclinical mastitis isolates and bacteriological outcome of intramammary treatment with cefquinome

The objective of the present study was to determine whether there was an association between the in vitro antimicrobial susceptibility test results of subclinical mastitis pathogens and bacteriological outcomes of intramammary treatments using cefquinome. A total of 110 intramammary pathogens from 51 cows were assessed in this study. Most intramammary infections were due to coagulase-negative staphylococci, environmental streptococci, and coliforms. The antimicrobial susceptibility to cefquinome was determined using the Kirby-Bauer disc diffusion method. Bacteriological cure rates for the sensitive, intermediate, and resistant isolates in the standard treatment group [three intramammary infusions of 75 mg cefquinome at 16 h intervals] were 82.4%, 90%, and 87.5%, respectively. These figures in the extended treatment group [six intramammary infusions of 75 mg cefquinome at 16 h intervals] were 83.3%, 100%, and 100%, respectively. Treatment outcomes were not associated with the results of sensitivity tests in the standard group. However, in the extended group, the probability of a bacteriological cure was lower in quarters from which cefquinome-sensitive pathogens were isolated than the quarters from which intermediate or resistant pathogens were isolated. Based on this study, the Kirby-Bauer susceptibility test result is a poor predictor for the bacteriological cure of subclinical mastitis treated with intramammary cefquinome

Effect of systemic antibacterial administration during prepartum period on coagulase negative Staphylococcal intramammary infection in Holstein Heifers

A total of 183 coagulase negative Staphylococcal infected quarters and 64 uninfected quarters were randomly allotted to 4 experimental groups: infected quarters that did not receive any treatment [positive control group; n = 60]; infected quarters that received Tylosin [n = 61] or Cefquinome [n = 62] and also uninfected quarters that did not receive any treatment were considered as negative control group [n = 64]. Treated heifers received Tylosin or Cefquinome 10 to 14 days before the expected calving date. The bacteriological cure rate based on sampling obtained 3 days after calving was significantly higher [P<0.01] in mammary glands treated with systemic Tylosin [85.3%] than in the positive control group and mammary glands treated with systemic Cefquinome [69.4%]. At the same time Tylosin treated heifers had significantly lower [P<0.01] somatic cell count scores compared to the positive control and Cefquinome groups. With the exception of one heifer that calved 8 days earlier than the expected calving date, there was no detectable antibiotic residues in the milk of the treated heifers on the 3rd day of lactation

[ estimation of national average of milk somatic cell count and production losses due to subclinical mastitis in commercial dairy herds in Iran]

Using the database of the Animal Breeding Center of Iran and based on the eligible test-day data from 78969 cows in five provinces: Tehran [with 44129 cows], Ghazvin [6668], Zanjan [1767], Isfahan [7572], Khorasan-e-Razavi [14521] and others [4312] the averages of 426850 +/- 966840 and 473860 +/- 605330 cells/ml of milk somatic cell count [SCC] was calculated for individual cows and herds respectively. A Pearson's correlation coefficient of -0.174 revealed a highly significant negative correlation between test-day milk production and SCC [p<0.01]. The annual production losses of approximately 150000 tons of raw milk in the price of 420 billion Rials were estimated at the national level

Association between digital disorders and reproduction indices in dairycows:study on farm level

This prospective longitudinal study deals with the associations between digital disorders and reproduction indices in dairy cattle on a farm in the vicinity of Tehran. It was carried out on 225 postparturient Holstein heifers. The evaluation of lameness due to digital disorders on postpartum period of heifers were done and after diagnosis of lameness [based on a 5 points lameness scoring system], the digital lesions and reproduction data of lame cows were recorded in a pre-established questionnaire and comparison with reproduction indices of other healthy heifers were made statistically using Chi Square and Student "t" tests and the relative risk "R.R." for each of indices was calculated and 95% confidence interval was made. Seventy-six cows among 225 cows were diagnosed lame in the period of study [30 months]. Digital dermatitis [28.9%] and Sole ulcer [21.2%] were the most prevalent lesions. All reproduction indices in this study including Projected minimum average days open, Days to first service, Projected minimum calving interval, Days in milk, Services per pregnancy for all cows, Services per pregnancy for pregnant cows, Conception rate at first service and Overall conception rate were found significantly different between lame and control groups [p < 0.0005]. 95% confidence interval for R.R. indicated that in lame cows the relative risk of negative rates of reproduction indices are significantly higher than non lame cows. It was concluded that pain and stress due to digital lesions play a key role in suppressing observable behavioral estrus which follows to negative changes of reproduction indices and other undesired consequences. On the other hand, pain may also suppress feeding and ruminating functions, leading to negative energy and protein balances and a low Body Condition Score [BCS] specifically in postpartum period. Thus, in order to mitigate the undesired effects of lameness on reproductive system and reproduction performance, early diagnosis and treatment of digital lesions is needed to be established

[Effect of reducing dose of GnRH analogue used in heat-synch program on pregnancy rate and day open of dairy cows]

To reduce the cost of hormones used in Heat-synch protocol in dairy cows. Enpenimental study.144 Holstein cows, at 50 days postpartum. Cows randomly assigned into 3 groups: [1] 40 cows; 7.5micro g luliberin, IM. [2] 45 cows; 15 micro g luliberin, IM. Seven days later in both groups, 150 micro g D-cloprostenol, IM 25 hours later Img Estradiol Benzoate was injected. Cows olserved for 48 hours and inseminated based on standing heat. Cows that did not display estrus were inseminated at 48 hours after estradiol injection. [3]Control: group in=59, did not received any treatment and were inseminated 12 hours after displaying estrus. Pregnancy was diagnosed on day 42 after AI via rectal palpation.Days open and pregnancy rate were analyzed by One-way ANOVA and chi square tests, respectively.The number of days open did not differ among experimental groups [group one: 104.17 +/- 7.76 days, group two: 106.28 +/- 6.24 days and the third group: 111.86 +/- 2.33 days [P>0.05]. Pregnancy rate to the first service was not different among groups [group one: 47.5%, 19/40, group two: 48.88%, 22/45, third group: 32.20%, 19/59][P>0.05]. In conclusion, reducing the dose of GnRH analogue [Luliberin] to half of the full dose did not affect pregnancy rate and days open. Therefore the cost of Heat-synch program can be reduced by using half dose of Luliberin

[ effect of a mastitis control program onsome udder health and milk quality indices in a large dairy herd in Tehran province]

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