Intramammary Administration Research Articles

Effect of Intramammary Hypochlorous Acid Administration on Subclinical Mastitis in Dairy Cows

Effect of Intramammary Hypochlorous Acid Administration on Subclinical Mastitis in Dairy Cows

Continuous sampling of healthy and mastitic quarters of lactating cattle by ultrafiltration after intramammary ceftiofur hydrochloride administration.

Pharmacological activity of intramammary drugs depends on adequate drug concentrations within the cistern, but sampling is often limited. Insight into the active drug concentration within the mammary cistern may assist in determining effective and appropriate therapeutic decisions for cows being treated for mastitis. Evaluate the disposition of ceftiofur hydrochloride administered intramammary in diseased and nondiseased quarters. Whole milk and ultrafiltrate sampling techniques were compared. Ten mature, late lactation Holstein (n = 9) and Jersey (n = 1) dairy cows (422-670 kg) with naturally occurring clinical mastitis, producing between 1.4 and 15.9 kg/day of milk. Ultrafiltration probes were placed in both mastitic and healthy quarters. Each quarter was treated with 2 doses of 125 mg ceftiofur hydrochloride suspension, and whole milk and milk ultrafiltrate samples were collected. Ceftiofur concentrations in composite whole milk and milk ultrafiltrate were analyzed. The maximum concentration of ceftiofur was higher in ultrafiltrate samples, but no differences were identified in healthy or mastitic quarters. The use of ultrafiltration probes provides a novel technique for free drug concentrations within the mastitic and healthy bovine mammary gland. Significant inter- and intracow variability and lower daily milk weights may overestimate ceftiofur concentrations available within the cistern. The pharmacokinetic (PK) parameters reported in milk ultrafiltrate will help establish a link between the PK and the corresponding drug effect, potentially providing a meaningful rationale for the selection of a safe and effective dose in cows with mastitis.

Intramammary administration of lipopolysaccharides at parturition does not affect the transfer of passive immunity in goat kids

This study evaluated the effect of feeding colostrum obtained from an intramammary administration (IA) of LPS from Escherichia coli (O55:B5) to dairy goats at parturition, on goat kid performance, biochemical parameters (i.e., calcium, lactate dehydrogenase, glucose, total proteins, albumin, and urea) and immune status (i.e., IgG and IgM) during the first month of life. At birth, goat kids were weighted (d 0) and immediately allocated into either the LPS group (n = 15) or the control (CON) group (n = 21) based on the experimental group of the dam. At parturition, 20 multiparous dairy goats were allocated in 1 of the 2 experimental groups (LPS vs. CON). The LPS group received an IA of saline solution (2 mL) containing 50 µg of LPS in each half udder whereas goats in the CON group received an IA of saline solution (2 mL) without LPS. Goat kids were bottle-fed dam colostrum equivalent to 10% of the birth BW divided in 2 meals (i.e., at 3 and 12 h relative to birth), and then fed twice daily with milk replacer ad libitum. Individual milk intake (MI) and BW were recorded on d 7, 15, 21 and 30 of life. Blood samples were collected on d 0, 1, 2, 4, 7, 15, 21 and 30 after birth. Data were analyzed using the MIXED procedure of SAS (9.4; SAS Institute Inc.). The model included IA, time (T), and their interaction (IA × T) as fixed effects, and sex and litter size as random effects. Both groups showed similar MI, except on d 7 relative to birth as the LPS group showed higher MI than the CON group (910.5 ± 69.77 and 683.9 ± 59.64 mL, respectively; mean ± SEM). No differences in BW or rectal temperature were observed between groups, neither in plasma IgG nor IgM concentrations. Despite the IA did not affect calcium, glucose, LDH, total protein, and albumin concentrations an interaction between the IA and T was observed for urea concentration, showing the LPS group higher urea concentrations than the CON group on d 0 (20.1 ± 1.34 and 20.0 ± 1.25 mg/dL, respectively). In conclusion, feeding colostrum from goats that received an IA of LPS at parturition does not affect goat kid performance, plasma immunoglobulin concentrations and serum metabolites during the first month of life.

The use of stem cells in the treatment of mastitis in dairy cows

Mastitis is a multifactorial inflammatory disease. The increase in antibiotic resistance of bacteria that cause mastitis means that cattle breeders would prefer to reduce the use of antibiotics. Recently, therapies using mesenchymal stem cells (MSCs) from various sources have gained significant interest in the development of regenerative medicine in humans and animals, due to their extraordinary range of properties and functions. The aim of this study was to analyze the effectiveness of an allogeneic stem cells derived from bone marrow (BMSC) and adipose tissue (ADSC) in treating mastitis in dairy cattle. The research material consisted of milk and blood samples collected from 39 Polish Holstein-Friesian cows, 36 of which were classified as having mastitis, based on cytological evaluation of their milk. The experimental group was divided into subgroups according to the method of MSC administration: intravenous, intramammary, and intravenous + intramammary, and according to the allogeneic stem cells administered: BMSC and ADSC. The research material was collected at several time intervals: before the administration of stem cells, after 24 and 72 h, and after 7 days. Blood samples were collected to assess hematological parameters and the level of pro-inflammatory cytokines, while the milk samples were used for microbiological assessment and to determine the somatic cells count (SCC). The administration of allogeneic MSCs resulted in a reduction in the total number of bacterial cells, Staphylococcus aureus, bacteria from the Enterobacteriaceae group, and a systematic decrease in SCC in milk. The therapeutic effect was achieved via intravenous + intramammary or intramammary administration.

Pharmacokinetics of long-acting cephapirin and cloxacillin after intramammary administration in dairy goats.

Determining the pharmacokinetics of intramammary antimicrobials in goats can assist in predicting appropriate meat and milk withdrawal intervals for drugs that are effective at treating subclinical mastitis due to non-aureus Staphylococci during the dry period. Twenty-four healthy, lactating does were enrolled in this study. Half were administered 300 mg of cephapirin benzathine (ToMORROW, Boehringer Ingelheim Vetmedica, Duluth, GA) via intramammary infusion into each half of the udder. The remaining does had 500 mg cloxacillin benzathine (Orbenin DC, Merck & Co., Rahway, NJ) administered per half. Plasma was collected before treatment and for 7 days post-treatment followed by analysis via liquid chromatography with tandem mass spectroscopy. Pharmacokinetic parameters were determined using noncompartmental methods via commercial software (MonolixSuite). The mean maximum concentration (Cmax) of cephapirin of 0.073 μg/mL was noted at 7.06 h post-administration (Tmax). The area under the plasma concentration curve based on the final sampling point (AUClast) was 1.06 h × μg/mL. The mean residence time until the final sampling point (MRTlast) was 13.55 h. Mean terminal half-life (T½) of cephapirin was 6.98 h. In CLOX does, Cmax was 0.074 μg/mL with a Tmax of 18 h, AUClast was 5.71 h × μg/mL, T½ was 77.45 h, and MRTlast was 65.36 h. Despite both products being formulated with benzathine salts, marked differences were noted in pharmacokinetic parameters including AUC, T1/2, and MRTlast. This data will be used to plan sampling schedules for milk and tissue residue depletion studies for both products.

Pharmacokinetics and relative bioavailability study of two cefquinome sulfate intramammary infusions in cow milk.

In this study, two intramammary infusions of cefquinome sulfate were investigated for pharmacokinetics and bioavailability. Twelve lactating cows for each group were administered an effective dose of 75 mg/gland for cefquinome, with milk samples collected at various time intervals. The concentrations of cefquinome in milk at different times were determined by the UPLC-MS/MS method. Analyses of noncompartmental pharmacokinetics were conducted on the concentration of cefquinome in milk. Mean pharmacokinetic parameters of group A and group B following intramammary administration were as follows: AUClast 300558.57 ± 25052.78 ng/mL and 266551.3 ± 50654.85 ng/mL, Cmax 51786.35 ± 11948.4 ng/mL and 59763.7 ± 8403.2 ng/mL, T1/2 5.69 ± 0.62 h and 5.25 ± 1.62 h, MRT 7.43 ± 0.79 h and 4.8 ± 0.78 h, respectively. Pharmacokinetic experiments showed that the relative bioavailability of group B was 88.69% that of group A. From our findings, group B (3 g: 75 mg) shows a quicker drug elimination process than group A (8 g: 75 mg), which suggests that the withdrawal period for the new formulation may be shorter.

Intramammary administration of lipopolysaccharides at parturition enhances immunoglobulin concentration in goat colostrum

In newborn ruminants, transfer of passive immunity is essential to obtain protection against pathogens. This study aimed to increase the permeability of the blood-milk barrier using intramammary lipopolysaccharides (LPS) in goats at parturition to modulate colostrum composition. Twenty multiparous Majorera dairy goats were randomly allocated in one of the two experimental groups. The LPS group (n = 10) received an intramammary administration (IA) of saline (2 mL) containing 50 µg of LPS from Escherichia coli (O55:B5) in each half udder at parturition. The control group (n = 10) received an IA of saline (2 mL). Rectal temperature (RT) was recorded, and a blood sample was collected at parturition (before IA). In addition, RT was measured, and blood and colostrum/milk samples were collected on day (d) 0.125 (3 hours), 0.5 (12 hours), 1, 2, 4, 7, 15 and 30 relative to the IA. Goat plasma immunoglobulin G (IgG) and M (IgM) and serum β-hydroxybutyrate, glucose, calcium, free fatty acids, lactate dehydrogenase and total protein concentrations were determined. Colostrum and milk yields as well as chemical composition, somatic cell count (SCC), IgG and IgM concentrations were measured. The MIXED procedure (SAS 9.4) was used, and the model included the IA, time, and the interaction between both fixed effects. Statistical significance was set as P < 0.05. Goats from the LPS group showed higher RT on d 0.125, 0.5 and 4 relative to the IA compared to the control group (PIA×Time = 0.007). Goat serum biochemical variables and plasma IgG and IgM concentrations were not affected by the IA. Colostrum and milk yield as well as chemical composition were not affected by the IA, except for milk lactose percentage that was lower in the LPS group compared to the control group (4.3 ± 0.08 and 4.6 ± 0.08%, respectively PIA = 0.026). Colostrum SCC was higher in the LPS group than in the control group (3.5 ± 0.09 and 3.1 ± 0.09 cells × 106/mL, respectively; PIA = 0.011). Similarly, milk SCC increased in the LPS group compared to the control group (PIA = 0.004). The LPS group showed higher IgG (PIA = 0.044) and IgM (PIA = 0.037) concentrations on colostrum than the control group (31.9 ± 4.8 and 19.0 ± 4.8 mg/mL, 0.8 ± 0.08 and 0.5 ± 0.08 mg/mL, respectively). No differences in milk IgG and IgM concentrations between groups were observed. In conclusion, the IA of LPS at parturition increases RT, SCC and IgG and IgM concentrations in colostrum without affecting either yield or chemical composition.

Comparison of the Efficacy of Intramammary or Injectable Antibiotic Administration against Staphylococcal Mastitis in Ewes.

The objectives of the work were (a) to compare the efficacy of two routes for antibiotic administration in the treatment of mastitis in ewes and (b) to assess the potential importance of the timing of the initiation of the therapeutic regime on the outcome of the treatment. The ewes were allocated at random into three equal groups; intramammary inoculation with a Staphylococcus simulans isolate was performed, and clinical mastitis developed. The ewes in groups T1 (n = 6) and T2 (n = 6) were treated by the intramammary administration of ampicillin and dicloxacillin (two administrations with a 12-h interval). The ewes in group T3 (n = 6) were treated by the intramuscular injection of ampicillin and dicloxacillin (0.75 mL per 10 kg bodyweight, three injections with a 24-h interval). In the ewes in groups T1 and T3, treatment started immediately when the clinical signs of mastitis were first detected during the periodic examination of the ewes; in the ewes in group T2, treatment started 24 h after the clinical signs of mastitis were first detected. The animals were monitored clinically; mammary secretion samples were collected for bacteriological and cytological examinations. The median duration of the clinical signs was 4.75, 7.13, and 4.75 d for T1, T2, and T3; significant differences in clinical severity between the groups were seen until the 7th day post-treatment. The median duration of bacterial recovery was 3.25, 8.00, and 8.00 d for T1, T2, and T3; significant differences in the frequency of bacterial recovery between the groups were seen until (64.1%, 94.9%, and 96.2% of the samples) and after (2.9%, 16.7%, and 11.8%) the 7th day post-treatment. The median period required for the complete cure (clinical, bacteriological, and cytological) was shorter in the T1 than in the T2 and T3 ewe groups: 20.0, 32.0, and 24.5 d, respectively. The findings cover a gap in the available literature regarding the treatment of clinical mastitis in ewes. Early treatment resulted in the improved cure of the infection. The comparison of the intramammary and injectable routes for antibiotic administration indicated some benefit for the former, primarily in the post-treatment somatic cell counts.

Potential of ESBL-producing Escherichia coli selection in bovine feces after intramammary administration of first generation cephalosporins using in vitro experiments

Selection and spread of Extended Spectrum Beta-Lactamase (ESBL) -producing Enterobacteriaceae within animal production systems and potential spillover to humans is a major concern. Intramammary treatment of dairy cows with first-generation cephalosporins is a common practice and potentially selects for ESBL-producing Enterobacteriaceae, although it is unknown whether this really occurs in the bovine fecal environment. We aimed to study the potential effects of intramammary application of cephapirin (CP) and cefalonium (CL) to select for ESBL-producing Escherichia coli in the intestinal content of treated dairy cows and in manure slurry, using in vitro competition experiments with ESBL and non-ESBL E. coli isolates. No selection of ESBL-producing E. coli was observed at or below concentrations of 0.8 µg/ml and 4.0 µg/ml in bovine feces for CP and CL, respectively, and at or below 8.0 µg/ml and 4.0 µg/ml, respectively, in manure slurry. We calculated that the maximum concentration of CP and CL after intramammary treatment with commercial products will not exceed 0.29 µg/ml in feces and 0.03 µg/ml in manure slurry. Therefore, the results of this study did not find evidence supporting the selection of ESBL-producing E. coli in bovine feces or in manure slurry after intramammary use of commercial CP or CL-containing products.

Intramammary rapamycin administration to calves induces epithelial stem cell self-renewal and latent cell proliferation and milk protein expression

Mammary epithelial stem cells differentiate to create the basal and luminal layers of the gland. Inducing the number of differentiating bovine mammary stem cells may provide compensating populations for the milk-producing cells that die during lactation. Inhibition of mTOR activity by rapamycin signals self-renewal of intestinal stem cells, with similar consequences in the mouse mammary gland and in bovine mammary implants maintained in mice. The implementation of these results in farm animals for better mammary development and production was studied in 3-month-old calves. mTOR activity decreased by ~50% in mammary epithelial cells subjected to 3-week rapamycin administration, with no negative consequences on mammary morphology or β-casein expression. Subsequently, stem cell self-renewal was induced, reflected by a higher propagation rate of cultures from rapamycin-treated glands compared to respective controls and higher expression of selected markers. Followed by 4-day estrogen and progesterone administration, rapamycin significantly induced proliferation rate. Higher numbers of basal and luminal PCNA+ cells were detected in small ducts near the elongating sites as compared to large ducts, in which only luminal cells were affected. Rapamycin administration resulted in induction of individual milk protein genes' expression, which was negatively correlated to their endogenous levels. The inductive effect of rapamycin on luminal cell number was confirmed in organoid cultures, but milk protein expression decreased, probably due to lack of oscillation in rapamycin levels. In conclusion, intramammary rapamycin administration is an effective methodology to reduce mTOR activity in bovine mammary epithelial cells and consequently, induce stem cell self-renewal. The latent positive effect of rapamycin on epithelial cell proliferation and its potential to improve milk protein expression in calves may have beneficial implications for mature cows.

The Effects of Intra-Ductal Mammary Administration of Orexin-A Antagonist (SB-334867) on the PPARγ and SREBP1c Gene Expression and Serum Adiponectin Levels in Lactating Rats

Introduction: Orexin A and adiponectin are involved in controlling metabolism and energy distribution in the body during lactation. Lactation is a process with high demand for lipid synthesis. Peroxisome proliferator-activated receptor gamma (PPARγ) and sterol regulatory element-binding protein 1 (SREBP1c) are two transcription factors that regulate milk lipid synthesis. The goal of this study was to assess the effects of mammary administration of the orexin A receptor antagonist on the expression of PPARγ and SREBP1c genes as well as serum adiponectin levels in the lactating rats. Methods: Orexin A receptor antagonist (SB-334867) was injected intraductal into the mammary glands of lactating female rats at three doses of 1, 2 and 4 μg/kg BW in a solvent volume of 50 μL. The gene expressions of PPARγ and SREBP1c were measured using real-time polymerase chain reaction (PCR), along with serum levels of adiponectin using ELISA. Results: The results of quantitative RT-PCR showed a significant decrease in the relative expression of PPARγ and SREBP1c genes compared to that of the control group. The rate of reduction at a dose of 4 µg/kg BW SB was greater than the doses of 1 and 2 µg/kg BW SB-334867. The serum levels of adiponectin significantly decreased in the 4 µg/kg BW SB group compared to that of the control group.Conclusion: These results indicated that intra-mammary administration of 4 µg/kg orexin-A antagonist in lactating rats decreased the gene expression of two transcription factors involved in milk fat synthesis, accompanying by a reduction in serum adiponectin level.

A dominant clonal lineage of Streptococcus uberis in cattle in Germany

Bovine mastitis causes enormous economic losses in the dairy industry with Streptococcus uberis as one of the most common bacterial pathogens causing clinical and subclinical variations. In most cases mastitis can be cured by intramammary administration of antimicrobial agents. However, the severity of the clinical manifestations can vary greatly from mild to severe symtoms. In this study, a comparative genomic analysis of 24 S. uberis isolates from three dairy farms in Germany, affected by different courses of infection was conducted. While there were sporadic mild infections in farm A and B, a large number of infections were observed within a very short period of time in farm C. The comparison of virulence genes, antimicrobial resistance genes and prophage regions revealed no features that might be responsible for this severe course. However, almost all isolates from farm C showed the same, novel MLST profile (ST1373), thus a clonal outbreak cannot be excluded, whereby the actual reason for the particular virulence remains unknown. This study demonstrates the importance of extensive metagenomic studies, including the host genomes and the environment, to gain further evidence on the pathogenicity of S. uberis.

Effects of bovine casein hydrolysate as a dry cow therapy on prevention and cure of bovine intramammary infection, milk production, and somatic cell count in the subsequent lactation

The primary objectives were to investigate the efficacy of bovine casein hydrolysate (bCNH) as a dry cow therapy at (1) preventing new intramammary infection (IMI) postpartum of all bacteria and coagulase-negative staphylococci (CNS), and (2) curing existing subclinical infections, mainly of CNS. The secondary objective was to measure the effects of bCNH on milk yield, composition, and somatic cell count (SCC) during the lactation postcalving. The trial was conducted as a randomized, blinded controlled experiment. Israeli Holstein dairy cows (n = 170) in first or higher lactations were recruited from 4 large commercial dairy herds. Cows were enrolled following clinical examination and bacteriological sampling of each quarter, which was the experimental unit. Random allocation was implemented at the cow level. All quarters of 100 cows were treated with 1 dose of bCNH (60 mg diluted in 20 mL of sterile solution) and those of 70 control cows were treated with saline solution. Clinical assessment of each cow's general appearance, teat-end leakage, and teat morphology was performed for 0, 1, 2, 3, 7, and 14 d after treatment, together with follow-up clinical observation and clinical examination of udder quarters. Quarter aseptic milk samples were obtained for bacteriological culture 48 h pretreatment, at time of treatment, and 3 and 5 d postcalving. Multivariable analyses were conducted to study the effects of bCNH on cure and prevention of IMI, adjusting for parity, farm, average of daily milk yield for 305 d, and average of monthly SCC values for 305 d of previous lactation. The odds of preventing IMI in cows treated with bCNH at dry-off were 2.15 times higher [95% confidence interval (CI): 1.15 to 4.00] than in cows treated with saline. Prevention was mostly of CNS. The odds of preventing CNS in cows treated with bCNH at dry-off were 2.20 times higher (95% CI: 1.58 to 3.07) than in control cows. The odds of curing IMI caused by CNS in cows treated with bCNH at dry-off were 4.80 times higher (95% CI: 0.75 to 30.75) than in saline-treated cows. Log SCC, adjusted to that of the previous lactation, was lower in the bCNH group compared with controls for 305 d in milk postcalving. The average milk yield per day for 305 d, adjusted to average daily milk yield of previous lactation, was higher by 2.1 kg in the bCNH group compared with controls (95% CI: 1.21 to 3.20). Clinical assessment of udders and cows posttreatment showed no negative effects of bCNH. Incidence of stillbirth, clinical mastitis, retained placenta, endometritis (5 to 12 d postcalving), ketosis, abortions, and reproduction did not differ between the 2 groups. Results suggest that a single intramammary administration of bCNH at dry-off effectively increases milk yield and lowers SCC, prevents new IMI during the dry period, and may be a beneficial alternative for curing existing IMI at dry-off, mainly by CNS.

The Effect of Hesperidin, Chrysin, and Naringenin on Somatic Cell Count in Mastitis Dairy Cows After Multiple Intramammary Administration

Abstract Hesperidin (HE), chrysin (CH) and naringenin (NA) are flavonoids, being the most important group of polyphenols, and show anti-inflammatory properties which have been demonstrated on various models. Polyphenols have a lot of biological properties, such as antioxidative, antiviral, immunomodulatory and anticancer activities. However, the effect on mastitis has not been yet described. This research aimed to analyse the tolerability of selected polyphenols after multiple intramammary administrations (IMM) as well as to investigate their potential impact on somatic cell count (SCC) in mastitis dairy cows. The study was performed on 12 Polish Holstein Blackand- White cows in their 4th to 6th lactation. Only animals with inflammation in one-quarter of the udder were selected. The selection was based on SCC and clinical assessment. The experiment was performed with multiple intramammary administrations with each of these polyphenols in dairy cows affected with mastitis. Polyphenols were administered at a dose of 30 mg/quarter/day. Milk samples for SCC, blood plasma samples for pharmacokinetics and blood haematology and biochemistry (selected blood parameters were tested) were collected at baseline, treatment period and within the recovery period. Positive effects concerning the SCC in milk of mastitic cows were confirmed for all tested polyphenols.

TURNOVER MONITORING OF ANTIMICROBIAL VETERINARY MEDICINAL PRODUCTS IN UKRAINE USED IN THE TREATMENT OF MASTITIS IN DIARY COWS

The goal of this study was to continue the implementation of the OIE recommendations for monitoring sales amounts of antimicrobial veterinary medicinal products. The subject of the study were intramammary antimicrobial veterinary medicinal products, which were used to treat and prevent mastitis in cows. The problem of diagnostic, treating, and preventing mastitis is crucial for farms, as mastitis is a multifactorial disease that can cause significant economic losses. One of the principal factors in the development of mastitis is the invasion of pathogens, which causes subclinical and clinical infections of the udder. Antimicrobials for intramammary use has been a significant advance in the treatment of this disease, in both the lactation and dry-off periods. The study was conducted over four periods (from January 1 to December 31) during 2016-2019. The data were obtained through a written survey of marketing authorization holders and distributors and evaluated by qualitative and quantitative indices. Characteristics of annual sales amounts during 2016-2019 are presented by classes of antimicrobial substances in «kg» and «%» of active ingredients, as well as in defined daily DDDvet and course DCDvet doses for 1000 animals. Intramammary antimicrobial veterinary medicinal products occupied (0.06-0.44) % part among all antimicrobials sold.&#x0D; The classes of antimicrobial substances that are most often sold (penicillins, aminoglycosides, tetracyclines) were determined and were shown the differences in their use in the composition of products intended for lactating and dry cows. Mass fractions were also determined, and daily DDDvet and course DCDvet doses per 1000 animals were calculated, which allowed revealing particular trends in sales of antimicrobial veterinary medicinal products for intramammary administration. The defined course doses for the products intended for lactating cows were 5 times higher, than for the products used in the dry-off period.&#x0D; First-generation and third-generation cephalosporins and fluoroquinolones were among the critically important veterinary medicinal products, but their sales were not annual. Cephalosporins of all generations and fluoroquinolones are characterized by a tendency to decrease in sales amounts, which testify to their prudent use following the National Action Plan to Combat Antimicrobial Resistance, 2019.&#x0D; This study is maintenance of the national monitoring system implementation for the rational and prudent use of antimicrobial products in veterinary medicine.

PK/PD integration and pharmacodynamic cutoff of cefquinome against cow mastitis due to Escherichia coli.

Cefquinome is the fourth generation of cephalosporin approved solely in animal usage. In order to slow down the resistance development of E.coli to cefquinome, and to protect and maintain the effectiveness of cefquinome, an ex vivo PK/PD modeling of cefquinome against E.coli in cows after intramammary infusion administration was conducted. The epidemiologic cutoff (ECOFF) and pharmacodynamic cutoff (COPD) of cefquinome against E.coli in lactation cows after intramammary infusion administration were recommended. The MICs of cefquinome against 1073clinical E.coli isolates ranged from 0.015 to >64μg/ml, and the ECOFF was defined as 0.125μg/ml. The pharmacokinetic results showed that cefquinome maintained high concentration in milk for a long period with the T1/2β of 10.60h after intramammary infusion in dairy cows. The drug concentration in skimmed milk was still as high as 0.15mg/ml after 48h. Cefquinome displayed bacterial killing effect at 2× MIC with the initial inoculum of 106 cfu/ml in vitro; however, the same effect was attained with a concentration as high as 32× MIC with the initial inoculum of 108 cfu/ml both in artificial medium and in skimmed milk. The initial inoculum is an important factor on time-killing curve accounting for weakened killing pattern of cefquinome. The AUC0-24h /MIC index correlated well with ex vivo efficacy. The AUC0-24h /MIC values for bactericidal effect were 50, 016, and 67,644, respectively, for initial inoculum of 106 and 108 cfu/ml, indicating the bacterial loading or the severity of infection would infect the PK/PD modeling results. The ex vivo PK/PD-based population dose prediction indicated a target attainment rate (TAR) at the existing daily dose (75mg/udder) of 84.77% against E.coli. Thus, it was recommended as rational dosage. The COPD of cefquinome against E.coli was determined as 8μg/ml at the dose of 75mg/udder. The derived ECOFF, COPD, together with ex vivo PK/PD-based population dose prediction served as important steps in the establishment of optimum dose regimen and provided a useful interpretative criterion to categorize the antimicrobial susceptibility testing results of cefquinome.

Baicalin decreases somatic cell count in mastitis of dairy cows

Abstract Baicalin is a flavonoid that has an influence on molecular processes. It possesses anticancer, anti-inflammatory, antiviral, antioxidative, and antithrombotic properties. It was found that baicalein treatment attenuated the damage of the mammary gland induced by LPS, suppressed the activity of myeloperoxidase, TNFα, and IL-1β in mice with mastitis. The aim of the study was a pilot analysis of baicalin tolerability after intramammary (IMM) administration and its impact on somatic cell count (SCC) after multiple IMM treatment on dairy cows with clinical mastitis. Moreover, the determination of baicalin in milk was performed by the sensitive ultra-high performance liquid chromatography with tandem mass spectrometry. The pharmacokinetic analyses were performed using Phoenix® WinNonlin® 6.4 and ThothPro v 4.1 software. Twelve dairy cows with clinical mastitis were selected for this study. The pharmacodynamic endpoint was SCC level and the clinical investigation was also carried out. Baseline SCC analysis was performed every 24 h among all cows three days before the first dose (B1–B3). After the baseline monitoring, 8 days of treatment (T1–T8) was performed and 8 days within recovery period SCC level was observed (R1–R8). Starting from T1 to T8, a decrease of SCC in relation to baseline was characterized by a declining trend. The presented results confirm the effect of baicalin on the reduction of SCC in mastitis in dairy cows after this therapy. The current study has shown that baicalin accumulation was not confirmed.

Efficacy Prediction of Four Pharmaceutical Formulations for Intramammary Administration Containing Aloe vera (L.) Burm. f. Combined With Ceftiofur or Cloxacillin in Lactating Cows as an Alternative Therapy to Treat Mastitis Caused by Staphylococcus aureus.

Synergy or additive effect between Aloe vera (L.) Burm.f. and beta-lactam (β-lactam) antibiotics has been reported against Staphylococcus aureus, one of the most important etiological agents of cow mastitis. The goal of the present study was to predict the efficacy of intramammary formulations containing the Aloe vera gel extract in the combination with cloxacillin or ceftiofur at low concentrations in lactating cows as an alternative therapy. Each quarter of 20 healthy Holstein Friesian lactating cows were treated with a single dose of one of the following formulations, corresponding to one of these treatment groups: A1, A2, A3, and A4. A1 and A2 contained cloxacillin at 0.25 and 0.5 mg/ml, whereas A3 and A4 contained ceftiofur 0.25 and 0.5 mg/ml, respectively. In addition, all formulations contained 600 mg/ml of an alcoholic extract of Aloe vera. Milk samples were taken at predefined time points. Antibiotics and aloin (active compound of Aloe vera) concentrations were assessed by liquid chromatography mass spectrometry system (LC-MS/MS). Pharmacokinetic profiles were obtained, and the efficacy index, the fraction of dosing interval in which the antimicrobial concentration remains above the minimum inhibitory concentrations (MICs) (T > MIC) for each formulation, was calculated considering MIC values against Staphylococcus aureus ATCC 29213 as obtained for the combination Aloe vera + antibiotic and aloin concentration in the extract. Mammary gland safety assessment was performed for each combination. Values of the main efficacy index for this study, T > MIC (h) for Aloe vera were 23.29, 10.50, 27.50, and 13.89, whereas for cloxacillin or ceftiofur were 19.20, 10.9, 19.74, and 15.63, for A1, A2, A3, and A4, respectively. Only A1 and A3 reached aloin and antibiotic recommended values as predictors of clinical efficacy for cloxacillin, ceftiofur, and aloin (50, 70, and 60%, respectively), assuming a dose interval of 24 h. The efficacy index values obtained suggest that A1 and A3 might be an effective therapy to treat bovine mastitis caused by S. aureus after a single dose. Nevertheless, further trials in S. aureus mastitis clinical cases are mandatory to confirm the efficacy of Aloe vera formulations.

Veterinary Treatment Approach and Antibiotic Usage for Clinical Mastitis in Danish Dairy Herds.

Danish veterinarians’ treatment approach and use of antibiotics for clinical mastitis were investigated through a web-based questionnaire. The objective of the study was to describe and evaluate how the clinical mastitis treatment practice in Danish dairy herds corresponds to evidence from the literature and legislative requirements, in order to suggest directions for improvements and approaches encouraging the prudent use of antibiotics. In total, 174 veterinarians working with cattle received the questionnaire and 85 (48.9%) completed it. Their answers suggested that the Danish treatment approach for clinical mastitis generally relies on combined systemic and intramammary antibiotic administration (92% would use this often or always) and almost always includes supportive treatment with nonsteroidal anti-inflammatory drugs (99% would use it often or always in combination with antibiotic therapy). While collecting milk samples in order to target treatment towards pathogens is a priority in the legislation and for veterinarians, the direct application seems hindered due to the waiting time with the currently used analysis practice. Consequently, 91% reported that they would start treatment immediately after clinical examination often or always. The results of this investigation show that there is a potential for improvement in targeting treatments towards the causative pathogen by encouraging methods that allow for a more rapid reliable pathogen determination. When this issue has been addressed, the available evidence on the best treatment practice of Gram-negative-caused mastitis cases can be applied properly, reducing the volume of antibiotic treatments with limited expected effect. Additionally, investigating the potential of reducing combined administration to only intramammary treatment in Gram-positive cases could be a further step towards a more prudent antibiotic strategy.

Efficacy of Panax ginseng extract combined with cephalexin as a dry cow therapy.

Our objective was to evaluate the efficacy of intramammary administration, at drying-off, of a Panax ginseng extract (PGe) combined with cephalexin (Ceph) on the post-calving bacteriological cure rate of pre-existing intramammary infections (IMI) and on the occurrence of new IMI during the dry period. In addition, milk yield and somatic cell count (SCC) in the post-treatment lactation were evaluated. One hundred and eight late-lactation cows were randomly divided into two experimental groups and were treated at drying-off with Ceph alone or PGe combined with Ceph.Cure rates for IMI present at drying-off were similar for both treatments (OR = 0.95, 95% CI = 0.33-2.74). Cure rates for Staphylococcus aureus were lower (OR = 15.4, 95% CI = 1.66-142.52) in quarters treated with PGe + Ceph than in those treated with Ceph alone. Intramammary infusion of PGe + Ceph at drying-off had no effect on preventing new dry period IMI (OR = 0.75, 95% CI = 0.38-1.51), compared with infusion of Ceph alone. Milk production and SCC in the ensuing lactation were not affected by PGe + Ceph treatment. In conclusion, addition of PGe to dry cow therapy did not show any advantage over the use of dry cow therapy alone.