BACKGROUND: Subclinical mastitis plays an important role in the economic losses of dairy cattle farms. Staphylococcus aureus is one of the most important causes of this disease. Treatment of this disease with synthetic antibiotics has complications like antibiotic resistance. Using herbal antibiotics can be an excellent way to reduce these side effects.OBJECTIVES: This study aimed to determine the minimum inhibitory concentration of alcoholic extract of olive leaf on Staphylococcus aureus isolated from milk of cows with subclinical mastitis to achieve herbal treatment.METHODS: This study was conducted on 175 Holstein female cattle. The milk samples of 60 cows were obtained with the sterilized method, and Subclinical mastitis-positive cases were determined using the California mastitis test. Staphylococcus aureus bacteria were isolated from positive samples by culture method, and the minimum inhibitory concentration of olive (Olea europaea L.) leaves alcoholic extract on isolated bacteria was determined by microdilution method.RESULTS: From 175 cows under study, 60 cows had a positive California mastitis test, and Staphylococcus aureus separated from milk samples of 14 cows. The minimum inhibitory concentration of olive (Olea europaea L.) leaves extract on this bacterium was 12000 ppm.CONCLUSIONS: Alcoholic extract of olive (Olea europaea L.) leaves has an antimicrobial effect on Staphylococcus aureus as a cause of mastitis. The minimum concentration required for this effect was 12000 ppm. Further studies on the impact of this plant on other bacterial causes of subclinical mammary inflammation in cows and investigation of the effective substances in the extract are needed.

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.

Contagious agalactia (CA) is a disease affecting small ruminants with worldwide distribution and caused by several mycoplasmas, especially M. agalactiae. The main option for systematic diagnosis under monitoring control programmes is the enzyme-linked immunosorbent assay (ELISA) test. This study was designed to appraise the performance of two commercial indirect ELISA tests using M. agalactiae p48 protein and one using total protein, for antibody detection in small ruminants after natural infection with different M. agalactiae strains. We carried out the test evaluation using sera of confirmed M. agalactiae-positive goats with clinical signs. In addition, test agreement was assessed by kappa between the three commercial ELISA tests. All three ELISA tests showed high validity scores (Youden’s J: 72.9–84%). The sensitivity values for the P48 protein-based tests were 76.9% and 84.6%, and was 79% for the total protein-based test. The specificity of all tests was 100%. In addition, between the total protein-based ELISA test and the other two ELISA tests based on the P48 protein, the agreement was substantial (kappa: 0.762–0.763) and the agreement between the latter two tests was almost perfect (kappa: 0.93). The validity parameters for all tests allowed their application for diagnostic purposes in lactating goats excreting M. agalactiae in milk and presenting clinical signs. The agreements show that any of these ELISA tests could be equally well used for diagnosis in programmes against CA.

Dairy cows may infrequently give milk tinged with blood after calving, which is a condition termed haemolactia. Economic losses for dairy farmers are caused by cases of haemolactia because of the condemnation of such milk, potential contamination of good bulk tank milk with haemolactic milk, and need for veterinarian intervention. This study was performed to elucidate the oxidative status of dairy cows with haemolactia during the peripartum period. Plasma glutathione peroxidase, malondialdehyde (MDA) and superoxide dismutase concentrations along with serum vitamin A, C and E concentrations were determined as indices of oxidative stress. The sampled dairy cows comprised two haemolactic (n = 11 and n = 6) and two non-haemolactic (n = 11 and n = 6) groups. On the first day when haemolactia was identified in colostrum (at mean 2.1 days after parturition), a significantly increased concentration of plasma MDA was noted in the haemolactic group. During the prepartum period, low levels of serum vitamin E were continuously observed from prepartum week 4 to the parturition day but only in the haemolactic group. These results demonstrate that continuous low levels of serum vitamin E in the prepartum period may play a pivotal role as a requisite factor in the onset of haemolactia after calving.

Pseudomonas species is one of the psychotropic bacteria that can survive in low-tempered milk and dairy products besides producing heat-resistant spoilage enzymes. In this study, one hundred and fifty samples of milk and some dairy products were analyzed. The overall prevalence of Pseudomonas spp. was 44.66% (0% pasteurized milk, 16% butter, 20% pasteurized cream, 48.5% Talaga cheese, 50% bulk milk tank, 66.6% raw market milk, and 70% in raw cream). From 67 positive samples, eighty-three isolates were confirmed biochemically as Pseudomonas spp. The most prominent species were P. aeruginosa, then P. fluorescence, P. Fragi, P. psychrophile, P. proteolytica, P. alcaligens, P. lundensis, and P. brenneri by a percent of 38.5%, 37.5%, 10.8%, 6%, 2.4%, 2.4%, 1.2%, and 1.2%, respectively. Fourteen antibiotic discs were selected to measure the antimicrobial susceptibility of 59 isolates of Pseudomonas spp. The higher antimicrobial resistance was against Ampicillin (100%) followed by Colistin (98%), while the antibiotic sensitivity was higher against Imipenem (96.6%) then Meropenem (91.5%). The average MAR index of isolated Pseudomonas spp. was 0.462. Ten isolates of antimicrobial resistance serotypes of P. aeruginosa were O11: E, O8: C, O5: B, O4: F, and O2: B. Molecular identification of P. aeruginosa, P. fluorescence, and P. fragi was carried out using polymerase chain reaction (PCR) to determine their virulence genes (LasB, ExoS, pilB for P. aeruginosa, aprX for P. fluorescence and carA gene for P. fragi). High levels of antimicrobial-resistant (AMR) Pseudomonas spp.  threaten public health and cause global concern. The economic and public health impacts were discussed.

This study investigated dexamethasone (DXM) residues in the milk from intramuscularly dosed dairy cows and established the withdrawal time (WT) of DXM in milk. Eighteen healthy Holstein cows were injected with 20 (DXM-1) or 40 mL (DXM-2) of a drug containing 1 mg/mL of DXM. After administering DXM, milk samples were collected from all cows at 12-hour intervals for five days. The DXM residue concentrations in milk were determined by liquid chromatography-tandem mass spectrometry. The correlation coefficient of the calibration curve was 0.9966, and the limits of detection and quantification (LOQ) were 0.03 and 0.1 μg/kg, respectively. The recoveries were 97.0% to 104.0%, and the coefficient of variations was less than 7.22%. After treatment, DXM in DXM-1 was detected above the LOQ in two milk samples at 36 hours and below the LOQ in all milk samples of DXM-2 at 48 hours. Using the WT calculation program WT 1.4, the withdrawal periods of DXM-1 and DXM-2 in milk were established to be two days. In conclusion, the developed analytical method is sensitive and reliable for detecting DXM in milk. The estimated WT of DXM in bovine milk is shorter than the current milk WT recommendation of three days for DXM in lactating dairy cows.

In this study, it was planned to examine the mineral levels in the milk of different dog breeds during the lactation period. Calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) concentrations were analyzed in dog milk. In this research 6 Labradors, 6 German Shepherds, 6 Pointers, 5 Turkish Tazis (sighthound), 5 Setters, 7 Malinois, and 5 Golden Retrievers (a total of 40 dogs) of 3 to 4 years of age were used as research materials, all of which were under same management and feeding conditions. All dogs were on diets appropriate for gestation and lactation periods. Adequate milk volume could be collected 23 weeks after parturition, and there were no known medical problems. Each day's samples were kept capped and refrigerated after being collected. The concentrations of calcium, magnesium, potassium, sodium, copper, zinc, manganese and iron, were analyzed by using Varian Brand 30/40 model AAS device.The Ca, K, Na, Zn, Mn and Fe levels of milk samples from different dog breeds had no significant difference. The highest Mg level was determined in Pointer breed milk samples, and the lowest was determined in Setter milk samples. The highest Cu levels among the inspected races were in Labrador milk samples, whereas the lowest levels were determined in Setter breeds.This data shows that most of the analyzed milk content of different breeds of dogs did not change significantly during the same lactation period, and any present difference could be taken into account when evaluating breeding studies.