A radioimmunoassay test for tetracyclines (Charm II) was compared with high-pressure liquid chromatography (HPLC) for detection of oxytetracycline (OTC) residues in milk samples from individual lactating cows. Oxytetracycline was administered by 1 of 3 routes (IV, IM, or intrauterine) to 21 lactating dairy cows. A total of 292 duplicate milk samples were collected from milkings before and through 156 hours after OTC administration. Concentration of OTC in these samples was determined by use of the Charm II test and an HPLC method with a lower limit of quantitation, approximately 2 ng of OTC/ml. Samples were also classified with respect to presence of OTC residues relative to the FDA safe concentration (less than or equal to 30 ng/ml), using the Charm II (by control point determination) and HPLC methods. There was a significant (P less than or equal to 0.05) difference between test methods in classification of milk samples with respect to presence or absence of OTC at the FDA safe concentration. A total of 48 of the 292 test results (16.4%) did not agree. Using the HPLC test results as the standard with which Charm II test results were compared, 47 false presumptive-violative test results and 1 false presumptive-nonviolative Charm II test result (a sample containing 31 ng of OTC/ml, as evaluated by HPLC) were obtained. The samples with false presumptive-violative Charm II results contained (less than or equal to 30 ng of OTC/ml, as evaluated by HPLC. In some respects, the Charm II test performed appropriately as a screening test to detect OTC residues in milk samples from individual cows. However, the tendency for the test to yield presumptive-violative test results at OTC concentrations lower than the FDA safe concentration (as evaluated by HPLC), suggests that caution should be exercised in using the test as the sole basis on which a decision is made to reject milk.

In breast cancer treatment, chemotherapy resistance is a major problem where many receptive tumors rebound and develop resistance. When provided in combination, cancer drugs are most successful, thus reducing the risk of developing resistant cancer cells. However, the evaluation of combination therapies has increased rapidly in recent years. Consequently, by repurposing old treatments, the discovery of additional medicines that may interact synergistically with chemotherapy is considered a current medical aim through discovering a new cancer medication or therapeutic strategy. The purpose of this research is to increase the anti-cancer activity of carboplatin (CP) by increasing the apoptotic effect of breast cancer cells (MCF-7) during in vitro experiments in combination with oxytetracycline. Our results showed a high synergistic effect between oxytetracycline and carboplatin, MCF-7 representative cell treated with carboplatin with/without different concentrations of oxytetracycline (5% and 10% of IC50). Oxytetracycline, which potentiated the action of carboplatin and/or had notable activity was reported as a single agent. This research demonstrated the synergistic relationship between oxytetracycline and carboplatin in viability assays. Surprisingly, our findings suggest that inhibiting treatment strategies can extend carboplatin’s therapeutic window, potentially allowing for cancer therapy.

Musculoskeletal system deformities were observed in 24 (34.3%) of 70 neonatal dairy calves that presented with different congenital abnormalities. Among them, 19 calves (27.1%), the majority of which were crossbred Jersey calves of either gender with mean (± s.e.) body weight 22.00 kg ± 1.17 kg and aged 7.11 ± 1.16 days, were presented for treatment of congenital knuckling. Five of the knuckling calves had additional concurrent congenital conditions and were excluded from the present study. All of the remaining 14 calves showing moderate, bilateral fetlock knuckling had a wooden or polyvinyl chloride (PVC) splint applied to the palmar or plantar aspect of the affected limbs. All of the animals received a dose of the analgesic tolfenamic acid intramuscularly, and were randomly allocated to two equal groups. Calves of Group I additionally received oxytetracycline (20 mg/kg intravenous daily for 3 days). The condition resolved satisfactorily in 83.3% and 80.0% calves from the two groups, respectively. The left and right fetlock angle (mean ± SE) reduced significantly (p ≤ 0.01) from 50.57° ± 4.20° to 4.00° ± 2.27° and 48.71° ± 2.37° to 5.33° ± 3.03°, respectively in animals of Group I. In Group II calves, the angles showed reduction from 50.86° ± 2.94° to 4.20° ± 2.75° and from 48.71° ± 3.14° to 6.80° ± 3.34°, respectively. From the present study, it was concluded that bilateral moderate fetlock knuckling in the neonatal dairy calves can be managed satisfactorily with early application of splints. Supplementary use of oxytetracycline at repeated doses of low toxicity had only a marginally beneficial effect.

Introduction: The article presents a rapid and simple analytical procedure for determination of four tetracyclines (oxytetracycline, tetracycline, chlortetracycline, and doxycycline) in animal medicated feedingstuffs. Material and Methods: Two-gramme samples were extracted by a Na₂EDTA-McIlvaine buffer (pH 4)/methanol mixtures (40/60, v/v). The determination was achieved by liquid chromatography using a Zorbax Eclipse XDB C18 analytical column with mass spectrometer detection (LC-MS). Results: Recoveries of the antibiotics from spiked feed samples ranged from 78.2% to 113.5%. The LOD and LOQ for tetracyclines in feeds ranged from 2.8 to 4.2 and from 4.3 to 5.7 mg/kg, respectively. Conclusion: The method was successfully validated and proved to be efficient, precise, and useful for quantification of tetracyclines in medicated feedingstuffs.

The aim of this study was to present two outbreaks of bovine abortion due to Leptospira infection in cattle herds located in the northern part of Sicily (Italy). The animals were positive for Leptospira interrogans serogroup Sejroe serovar Hardjo in a microscopic agglutination test (MAT). A total of 23 Charolaise cows (farm A) and 75 Limousine bulls and Cinisara and Modicana cows (farm B) were enrolled in this study. The blood samples were collected from all subjects at the following time points: before a cycle of intramuscular treatment with oxytetracycline dihydrate (T0), after 5–6 weeks from the treatment (T1), and every 10 weeks until seronegativisation (T2 in Farm A and T3 in Farm B). A serological test (MAT) was used for the diagnosis of leptospirosis. Two samples from farm A (2/23) and 29 samples from farm B (29/75) were positive to Leptospira interrogans, serogroup Sejroe, serovar Hardjo in the MAT. Leptospira spp. DNA was detected by real-time PCR in the urine sample of one positive cow on farm A, and in placenta and brain samples belonging to one aborted foetus on farm B. It is important to use serological and molecular diagnostic techniques complementarily to identify infected individuals.

Multi-class and multi-residue analyses are very complex procedures because of the physico-chemical properties of veterinary drug residues and other contaminants. The purpose of the study was to develop an analytical method for the sensitive determination of 69 analytes in bovine milk by liquid chromatography electrospray ionisation–tandem mass spectrometry. Antimicrobial, anabolic hormone, lactone, β-agonist, mycotoxin and pesticide residues were analysed in 120 raw milk samples from different dairy farms in North Macedonia. Stable isotopically labelled internal standards were used to facilitate effective quantification of the analytes. The linear regression coefficients were higher than 0.99, the limits of detection ranged from 0.0036 to 47.94 μg/L, and the limits of quantification ranged from 0.053 to 59.43 μg/L. The decision limit values ranged from 0.062 to 211.32 μg/L and the detection capability from 0.080 to 233.71 μg/L. Average recoveries of the analytes spiked in raw milk were in the range of 70.83% to 109%, intra-day coefficient of variation (CV) values from 2.41% to 22.29%, and inter-day CV values from 3.48% to 23.91%. The method was successfully applied in the testing of bovine milk samples. In five samples residues were detected. They were sulfadimethoxine (in two samples), enrofloxacin, tetracycline and oxytetracycline and were at concentrations below the EU maximum residue limit. The method is useful for routine testing for this group of chemical hazards in bovine milk.

In the last two decades, the chemical and biological contaminants in livestock and livestock products worldwide have been considered as one of the causes that threatens life of both man and animals. In Sudan very little work has been done in this field. This study was carried out to detect Oxytetracycline (OTC) residues in sheep liver and muscle samples in Khartoum State, Sudan. A total of 150 samples comprising of liver (n=75) and muscle (n=75) of sheep were collected from three different localities in Khartoum State during the period from March to September 2013. The OTC residues were detected using high performance liquid chromatography (HPLC) and one plate test (OPT). The results of HPLC showed that the level of OTC residues in liver samples above maximum residue limit (MRL) was 4% (n=3/75) and under MRL was 96%. Regard to muscle samples, the level of OTC residues above MRL was 60.3% (n=35/58), whereas, under MRL was 39.7%. Using OPT, 14.7% (n=11/75) and 6.7% (n=5/75) of liver and muscle samples showed inhibition zone, respectively. It is concluded that OTC residues are detected in sheep liver and muscle sample with different levels in Khartoum state. Further investigation on level of OTC residues in other farm animals and other organs throughout the country is recommended. [J Adv Vet Anim Res 2015; 2(3.000): 321-325]

A total of 180 eggs (20 batches each represented by 3 eggs) of the farm, balady, and organic egg samples were collected in October 2021 from markets in Ismailia governorate, Egypt, and examined for detection of the oxytetracycline, ciprofloxacin, and gentamicin residues by using HPLC-Ms/Ms. The farm and balady eggs contained 20% with mean values of 69.95±1.78 and 43.6±2.65 ppb, respectively, and all of them were below the permissible limits and accepted. They contained 20% and 60% with mean values of 26± 0.21 and 39.58±5.58 ppb, respectively, and all positive samples were unaccepted. Both egg types were free from gentamicin residues, meanwhile, all organic eggs were clear from the three antibiotic residues under investigation. The study also revealed the distribution of oxytetracycline and ciprofloxacin in albumin and yolk after oral administration and their residues in the 6th-day eggs were (750 and 500 ppb) and (500 and 319 ppb), respectively. The effect of boiling for 15 minutes on oxytetracycline and ciprofloxacin residues in albumin and yolk was also investigated and showed a reduction% of (88 and 90) and (90.5 and 87.5), respectively. Meanwhile, the frying of whole eggs for 5 minutes reduced their concentration by 94.3% and 94.5%, respectively. In conclusion, the antibiotic residues in edible eggs are a serious risk that should be monitored, and it's significant to highlight the importance of efficient boiling and frying of eggs in reducing these residues and relieving their hazards to the consumer's health.

OBJECTIVE To identify clinical or clinicopathologic variables that can be used to predict a positive PCR assay result for Anaplasma phagocytophilum infection in equids. ANIMALS 162 equids. PROCEDURES Medical records were reviewed to identify equids that underwent testing for evidence of A phagocytophilum infection by PCR assay between June 1, 2007, and December 31, 2015. For each equid that tested positive (case equid), 2 time-matched equids that tested negative for the organism (control equids) were identified. Data collected included age, sex, breed, geographic location (residence at the time of testing), physical examination findings, and CBC and plasma biochemical analysis results. Potential predictor variables were analyzed by stepwise logistic regression followed by classification and regression tree analysis. Generalized additive models were used to evaluate identified predictors of a positive test result for A phagocytophilum. RESULTS Total lymphocyte count, plasma total bilirubin concentration, plasma sodium concentration, and geographic latitude were linear predictors of a positive PCR assay result for A phagocytophilum. Plasma creatine kinase activity was a nonlinear predictor of a positive result. CONCLUSIONS AND CLINICAL RELEVANCE Assessment of predictors identified in this study may help veterinarians identify equids that could benefit from early treatment for anaplasmosis while definitive test results are pending. This information may also help to prevent unnecessary administration of oxytetracycline to equids that are unlikely to test positive for the disease.