This study aimed to evaluate the effect of different dry period lnghts (DPLs) on the udder health and fertility during the subsequent lactation. The impact of subclinical mastitis (SCM) and clinical mastitis (CM) on the reproductive efficiency were also investigated. Holstein-Friesian cows (n=894) were included in the study of udder health, of which only multiparous cows (n=499) were included in the investigation of the impact of different DPLs on the udder health and reproductive efficacy in the subsequent lactation. Cows were classified according to the DPLs into 3 groups: Short (SDPL, <40 d), Traditional (TDPL, 40-60 d) and Long (LDPL, >60 d). A limit of 200,000 somatic cell/mL milk was established to separate between healthy and mastitic udder status. Accordingly, samples with 500,000-1,000,000 cell/ml were referred to cows affected with SCM and samples with >1,000,000 cells/ml were mentioned to cows affected with CM. A higher proportion of infected udder was detected in cows with LDPL (39.19%) Moreover, a higher proportion of SCM was recorded for cows with LDPL (17.57%) compared with that recorded for cows with SDPL (8.0%) and TDPL (6.13%). A higher proportion of CM was recorded for cows with a long dry period (LDP, 8.11%) compared with that recorded for cows with SDPL (4.0%) or with TDPL (4.8%). Cows with SDPL showed the best intervals reproductive indices compared with that recorded for both TDPL and LDPL. Furthermore, LDPL was found to be associated with significantly lower CR (33.11±2.91%), lower PR (50.39±3.97%) and higher NSPC (1.98±0.37) compared with values that recorded for either SDPL or TDPL. Cows with either SCM or CM showed the longest interval reproductive indices, less CR and PR and number of inseminations to become pregnant compared with healthy udder cows. A lower proportion of affected udder was recorded for Primiparous cow (24.3%) compared with that showed by multiparous cows (32.46%). Cows affected with mastitis during the voluntary waiting period (VWP) showed longer intervals to the first detected estrus and first services while those affected during the service period (SP) showed longer calving to conception intervals, lower CR and lower PR especially when the SCC exceed 500,000 cell/ml milk. Cows experienced udder infection during the SP showed the lowest PR (32.54% & 36.44%) and required more NSPC. In conclusion, a significant linkage among different dry period lengths and both the incidence of mastitis and fertility were recorded, with the best results were recorded for cows with TDPL and SDPL. Extending the dry period above 60 days increased the incidence of both clinical and subclinical mastitis and exerted a negative impact on the reproductive performance. The occurrence of mammary infection during the VWP increased the calving to first estrus and first service intervals, while its occurrence during the SP prolonged the days open, and extremely reduced the conception and pregnancy rates.

Introduction: Quercetin is a polyphenolic flavonoid which has been used in traditional Chinese medicine as a natural therapeutic agent with a broad spectrum of activities (antioxidant, anticancer, neuroprotective, anti-inflammatory, antiviral and antibacterial). The aim of this study was to develop and validate a rapid and simple ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method for the determination of quercetin in milk. Material and Methods: Sample preparation was based on a liquid-liquid extraction with 0.5% formic acid in acetonitrile. The chromatographic separation was performed on a ZORBAX SB-C18 column with methanol and 0.5% formic acid as a mobile phase. Results: The procedure was successfully validated. The mean recovery of the analyte was 98%, with the corresponding intra- and inter-day variation less than 10% and 15%, respectively, and the repeatability and reproducibility were in the range of 3%–7.2% and 6.1%–12%, respectively. The lowest level of quantification was 1.0 μg/kg. Conclusion: The proposed method was successfully applied in evaluating the pharmacokinetics of quercetin in milk obtained from dairy cows with clinical mastitis after intramammary administration.

Introduction: The aim of the study was to evaluate the occurrence of enterococci in inflammatory secretions from mastitic bovine udders and to assess their antimicrobial resistance. Material and Methods: A total of 2,000 mastitic milk samples from cows were tested in 2014–2017. The isolation of enterococci was performed by precultivation in buffered peptone water, selective multiplication in a broth with sodium azide and cristal violet, and cultivation on Slanetz and Bartley agar. The identification of enterococci was carried out using Api rapid ID 32 strep kits. The antimicrobial susceptibility was evaluated using the MIC technique. Results: Enterococci were isolated from 426 samples (21.3%). Enterococcus faecalis was the predominant species (360 strains), followed by E. faecium (35 isolates), and small numbers of others. The highest level of resistance was observed to lincomycin, tetracycline, quinupristin/dalfopristin (Synercid), erythromycin, kanamycin, streptomycin, chloramphenicol, and tylosin. Single strains were resistant to vancomycin and ciprofloxacin. All isolates were sensitive to daptomycin. E. faecalis presented a higher level of resistance in comparison to E. faecium, except to nitrofurantoin. Conclusion: The results showed frequent occurrence of enterococci in mastitic cow’s milk and confirmed the high rate of their antimicrobial resistance.

Objective: This work aimed to determine the resistance and/or the susceptibility to antibiotics of staphylococci isolated from cattle with mastitis in the North of Algeria. Materials and Methods: The disk diffusion method was carried out to reveal the antibiotic resis¬tance in accordance to the National Committee for Clinical Laboratory Standards guidelines in the Mueller-Hinton agar. Results: Coagulase-negative Staphylococci (CNS) isolates showed more resistance to Cefoxitin, Amoxicillin + Clavulanic Acid, Vancomycin, Trimethoprime Sulfamethoxazole, Clindamycine, Neomycin, and Erythromycin than Coagulase-positive Staphylococci (CPS). CPS were more resis¬tant to Penicillin and Tetracycline as compared to CNS strains; however, all these strains presented sensitivity to Gentamicin and neomycin. Conclusion: The Staphylococci showed high resistance to the beta-lactam antibiotics. As far as the authors know, these molecules are used with or without control in different protocols to prevent and cure the mastitis in Algeria. [J Adv Vet Anim Res 2019; 6(2.000): 231-235]

Objective: The objective of this study was to develop a low-cost kit for the detection of subclinical mastitis (SCM) and to check its validity, reproducibility, and efficacy at the field level. Materials and Methods: A total of 550 quarter milk samples from crossbred dairy cows were collected, of which 400 milk samples were used to validate the newly developed BLRI mastitis test (BMT) kit to justify its efficacy as an individual test kit in detecting SCM based on somatic cell count (SCC) by direct microscopic count (DMC). The efficacy of the newly developed BMT was compared with the California Mastitis Test (CMT) kit. Another 150 milk samples were subjected to SCC determined by DMC and DCC (De Laval cell counter®) categorized by CMT and BMT scores. Results: A SCM test kit, namely, BMT kit was successfully developed in this study. The percentage accuracy of CMT and BMT were 76.75% and 75.75%; sensitivity 69.36% and 67.56%; specificity 85.95% and 85.85%; positive predictive value 86.03% and 85.71%; negative predictive value 69.23% and 68%, respectively. A p value of 0.001 was found for both CMT and BMT. However, CMT and BMT had no significant difference in sensitivity (p = 0.778). Average SCCs (cells/ml) determined by DCC and DMC, respectively, were mostly corresponded to the SCC ranges of both CMT and BMT scores. Conclusion: The newly developed BMT kit is an independent, cheap, farmer-friendly, first country made, and reliable SCM diagnostic test kit that can be used at field condition. [J Adv Vet Anim Res 2019; 6(3.000): 425-430]

Objective: The objective of this study was to identify the multi-drug resistance (MDR) Klebsiella sp. from mastitis milk samples. Materials and Methods: In the current research, 48 clinical mastitis milk samples were collected from Rangpur division, Bangladesh. Confirmation of bovine mastitis (BM) was done by the California Mastitis Test (CMT). All the CMT positive isolates were subjected for the identification of Klebsiella sp. using through a series of cultural and biochemical tests. MDR Klebsiella sp. isolates were determined using the disk diffusion method, and minimum inhibitory zones were measured by following Clinical and Laboratory Standards Institute. MDR patterns of the isolates were also subjected to study by using housefly (Musca domestica). Results: Among the isolates, 62.5% (n = 30/48) revealed the presence of Klebsiella sp. Eight antimicrobial agents including Amoxicillin, Novobiocin, Erythromycin, Vancomycin, Cephradine, Tetracycline, Bacitracin, Methicillin, and housefly (M. domestica) showed complete resistance to Klebsiella sp. On the other hand, Chloramphenicol, Gentamicin, Ciprofloxacin, Azithromycin, Norfloxacin, Levofloxacin, and Nalidixic acid showed sensitivity. Conclusion: This study helps to treat BM with effective antibiotics and helps in an epidemiological study in Rangpur division as well as helps to create public health awareness. [J Adv Vet Anim Res 2019; 6(3.000): 362-365]

Mycoplasma bovis is a major cause of pneumonia, arthritis, and mastitis in cattle and can lead to significant economic losses. Antimicrobial resistance is a concern and further limits the already short list of drugs effective against mycoplasmas. The objective of this study was to examine changes in in vitro minimum inhibitory concentrations (MICs) of antimicrobials of aminoglycoside, fluoroquinolone, lincosamide, macrolide, pleuromutilin, phenicol, and tetracycline classes for 210 M. bovis isolates collected from 1978 to 2009. The MIC(50) values of the various antimicrobials were also compared. The MIC(50) levels for enrofloxacin and danofloxacin remained low (0.25 μg/mL) across all 3 decades. MIC(50) levels for tetracyclines, tilmicosin, and tylosin tartrate were low in the 1980s, then increased in the 1990s and remained high. In the 1980s, MIC(50) levels were low for clindamycin, spectinomycin, and tulathromycin, increased in the 1990s to 8 μg/mL (clindamycin) and 32 μg/mL (spectinomycin and tulathromycin), then decreased again in the 2000s. Members of the fluoroquinolone class of antimicrobials had the lowest MIC(50) levels across all 3 decades, which suggests in vitro susceptibility of M. bovis to this class of antimicrobials. Statistically significant associations were observed between MIC values for chlortetracycline, oxytetracycline, tylosin tartrate, and tilmicosin; between clindamycin, tulathromycin, spectinomycin, and tiamulin; and between tylosin tartrate and clindamycin. Changes in MIC levels of various antimicrobials over time show the importance of monitoring the susceptibility of mycoplasmas to antimicrobials. The number of antimicrobials that showed elevated MIC(50) levels, and therefore possibly reduced in vitro effectiveness against M. bovis, supports initiatives that promote prudent use of antimicrobials in agriculture.

South Africa is a large country of approximately 1.22 million km², made up of nine provinces with three climatic zones. Farming in the country is mostly defined by regional differences. Of the different organisms isolated from milk samples of dairy cows, Staphylococcus aureus poses a challenge to maintain udder health and wholesome dairy products for human consumption. Antibiotic resistant bacteria are therefore a potential health hazard. The objective of this study was to investigate the seasonal and regional relationships of antibiotic resistance of S. aureus, of which little is known. This study was undertaken to evaluate a data set of 3410 S. aureus isolates, taken from milk samples with a somatic cell count of > 400 000 cells/mL from commercial dairy herds. These isolates were tested for antimicrobial susceptibility using the Kirby Bauer method for ampicillin, cloxacillin, penicillin G, clindamycin, oxy-tetracycline, cephalexin, cefuroxime and tylosin. The samples were from 830 dairy herds, out of the estimated 2000 commercial dairy herds in South Africa. All the antibiotics tested, except for cephalosporins, showed a predicted prevalence of resistance of above 50% in most provinces, which is a concern. The lowest prevalence of resistance to the majority of the categories of antibiotics tested was present in KwaZulu-Natal during spring. The cephalosporins had the lowest levels of prevalence of bacterial resistance in Gauteng during winter. Resistance patterns of S. aureus to the eight antibiotics varied in the different seasons and provinces, possibly because of different weather conditions, and the action and spectrum of antibiotics.