Evidence of Horse Exposure to Anaplasma phagocytophilum, Borrelia burgdorferi, and Leishmania infantum in Greece through the Detection of IgG Antibodies in Serum and in an Alternative Diagnostic Sample-The Saliva.

Among the various zoonotic pathogens that infect horses, Anaplasma phagocytophilum, Borrelia spp. and Leishmania spp. have gained scientific interest, and relevant molecular and serological studies in horses have been conducted worldwide. Moreover, human and veterinary medicine have extensively applied alternatives to serum diagnostic samples-such as saliva-for detecting pathogens or antibodies. In this study, we investigated the exposure of horses in Greece to A. phagocytophilum, B. burgdorferi, and L. infantum, and we assessed the diagnostic accuracy of saliva compared to serum in detecting IgG antibodies against the abovementioned pathogens. Paired saliva and serum samples were collected from 317 horses from different regions in Greece. The paired samples were examined using the indirect fluorescent antibody test (IFAT) for detecting IgG antibodies against A. phagocytophilum, B. burgdorferi, and L. infantum. Sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were determined to assess the validity of saliva as an alternative to serum. The receiver operating characteristic (ROC) curve revealed that the optimal cut-off value for detecting antibodies against all the examined pathogens in saliva was 1/10. Higher seropositivity rates were found for B. burgdorferi (15.14%) and A. phagocytophilum (14.19%) compared to L. infantum (1.26%). The detection of IgG antibodies using IFAT in saliva samples had a good test performance compared to serum. The two sample types had a substantial to almost perfect agreement. Although the sensitivity was moderate (70.83-75.56%) in all cases, the specificity was almost perfect to perfect (99.63-100%). This study provides the first evidence that horses in Greece are exposed to A. phagocytophilum and B. burgdorferi and confirms that the seroprevalence of L. infantum in horses in Greece remains low. Our findings suggest that saliva sampling coupled with IFAT could be successfully applied for detecting IgG antibodies against these important zoonotic pathogens in large-scale epidemiological studies in horses, at the population level, as an alternative to serum.

Hepatic Coccidiosis in Wild Rabbits in Greece: Parasite Detection on Liver Imprints and the Associated Biochemical Profile.

(1) Background: Rabbit hepatic coccidiosis, caused by Eimeria stiedae, is a devastating disease with high morbidity and mortality rates. The disease is well described in rabbits, but little is known about E. stiedae infection in wild rabbits. In this study, we investigated the presence of E. stiedae infection in wild rabbits from the island of Lemnos, Greece, where this species is overpopulated, and the effects of infection on common hepatic biomarkers. (2) Methods: We used liver impression smears to detect the coccidian oocysts, and we defined the liver biochemical profile of the infected individuals. (3) Results: Overall, 13.3% of the liver imprints examined were positive for the presence of coccidial oocysts. The activities of liver enzymes, that is, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and glutamyltransferase (GGT), as well as globulins (GLOB), were increased while the concentrations of albumins (ALB), total proteins (TP) and the albumin to globulin (A/G) ratio were decreased in the infected individuals compared to the non-infected ones. (4) Conclusions: This study adds to the current knowledge on the pathogens affecting wild rabbits and those circulating in this population on the island of Lemnos, Greece. Moreover, we showed that E. stiedae infection exerts pathological effects on the hepatocyte integrity and liver function of wild rabbits, as reflected by the abnormal values of liver injury and dysfunction biomarkers.

Redox Status and Hematological Variables in Melatonin-Treated Ewes during Early Pregnancy under Heat Stress.

The preovulatory follicles and preimplantation stage embryos are found to be rather sensitive to heat stress due to their low potential for scavenging reactive oxygen species (ROS). The aim of the present study was to assess the impact of melatonin administration on redox status and hematological variables during the preovulatory period and early stages of embryogenesis in heat-stressed ewes in vivo. Forty Karagouniko-breed ewes were divided in two groups, the melatonin (M, n = 20) group and control (C, n = 20) one. All animals were subjected to heat stress throughout the study, which lasted forty days (D0 to D40). In M group, melatonin implants were administered on D0. Then, oestrous synchronization was applied (D19-D33). On D34, six rams were introduced into the ewe flock for mating. Ultrasonographic examination was conducted on D73 for pregnancy diagnosis. The temperature humidity index (THI), the rectal temperature (RT), and the number of breaths per minute (BR) were evaluated twice daily. Redox biomarkers, namely total antioxidant capacity (TAC), reduced glutathione (GSH), and thiobarbituric acid reactive substances (TBARS), were assayed in blood samples collected on D0, D33, and D40. In addition, packed cell volume (PCV), white blood cells (WBCs), leukocyte differential count, and cortisol assessment were conducted in blood samples on D33 and D40. The results indicated improved fertility rate and mean number of lambs born per ewe due to improved redox status (p < 0.05) in ewes that received melatonin implants 34 days approximately before the onset of oestrus. The PCV decreased in both groups between the two time-points (p < 0.05). However, the NEU/LYMPH ratio decreased (p < 0.05) only in group M. The low cortisol levels and the decreased NEU/LYMPH ratio in both groups support the hypothesis that ewes of the indigenous Karagouniko breed may exhibit adaptation to environmental thermal stress. The administration of melatonin as an antioxidant regime may improve the reproductive competence of heat stressed ewes and may also enhance their ability to adapt at high ambient temperatures.

Evaluation of Heller's reaction and the urine dipstick method alone or in combination to detect proteinuria in sheep.

BACKGROUND: Urine dipstick and Heller's reaction are easy first-line screening tests for the detection of proteinuria; however, the performance of these methods in alkaline ovine urine is largely unknown. OBJECTIVE: The aim of this study was to evaluate the diagnostic performance of Heller's reaction alone or in combination with dipstick for the detection of proteinuria in sheep, using the urine protein to creatinine ratio (UP/C) with two cut-off values as the reference method. METHODS: Ninety-eight urine samples were collected from sheep using the transient apnea method. Heller's reaction, the dipstick method, and the UP/C ratio were used to assess proteinuria. The results were statistically analyzed twice, based on two different UP/C cut-off values of 0.2 and 0.5. Cohen's kappa value was used to determine the agreement between the UP/C ratios and Heller's reaction, the dipstick method, or the combination of methods. Sensitivity, specificity, and positive and negative likelihood ratios were calculated. ROC curves were also generated, and the areas under the curve (AUC) were evaluated to determine the optimal threshold for the numerical values of the two methods. RESULTS: Heller's reaction is more specific (96.67% and 96.00% when the cut-off value is 0.2 and 0.5, respectively) than the dipstick method, while the dipstick method was more sensitive (91.18% and 91.30%, when the cut-off value was 0.2 and 0.5, respectively) than Heller's reaction for the detection of proteinuria. Both tests were accurate when any grade >0 was considered positive. CONCLUSIONS: Proteinuria can almost be excluded in ovine urine samples with negative Heller's reaction and dipstick test.

Repeatability and reproducibility of microscopic examination of adhesive tape strip cytology slides for the quantification of Malassezia spp. in canine skin.

BACKGROUND: The optimal microscopic magnification and number of optical fields of adhesive tape strip cytological slides that should be examined when searching for Malassezia yeasts on canine skin are unknown. OBJECTIVES: To determine the optimal magnification and the minimum number of optical fields that should be examined to maximise intraobserver repeatability and interobserver reproducibility. MATERIALS AND METHODS: Seven experienced examiners counted, twice, the number of yeasts in 10, 20, 30, 40 and 50 optical fields of 40 slides at ×400 and ×1000 magnification. RESULTS: The number of yeasts per unit surface area was significantly higher at ×1000 compared to ×400 magnification. Repeatability and reproducibility for counting the yeasts was very poor. CONCLUSIONS AND CLINICAL RELEVANCE: Adhesive tape strip cytological slides should be examined microscopically for Malassezia spp. at ×1000 magnification. The repeatability of this examination for counting the yeasts is poor.

Contexte - Le grossissement microscopique optimal et le nombre de champs optiques des lames cytologiques de bandes adhésives à examiner lors de la recherche de levures Malassezia sur la peau de chien sont inconnus. Objectifs - Déterminer le grossissement optimal et le nombre minimal de champs à examiner pour maximiser la répétabilité intra-observateur et la reproductibilité inter-observateur. Matériels et méthodes - Sept examinateurs expérimentés ont compté, deux fois, le nombre de levures dans 10, 20, 30, 40 et 50 champs de 40 lames aux grossissements ×400 et ×1 000. Résultats - Le nombre de levures par unité de surface était significativement plus élevé au grossissement ×1 000 par rapport au grossissement ×400. La répétabilité et la reproductibilité du comptage des levures étaient très médiocres. Conclusions et pertinence clinique - Les lames cytologiques de bandes adhésives doivent être examinées au microscope pour Malassezia spp. à un grossissement ×1 000. La répétabilité de cet examen de comptage des levures est faible.

Introducción- se desconoce el aumento microscópico óptimo y el número de campos ópticos de los portaobjetos citológicos en tiras de cinta adhesiva que deben examinarse al buscar levaduras Malassezia en la piel canina. Objetivos- determinar el aumento óptimo y el número mínimo de campos ópticos que deben examinarse para maximizar la repetibilidad intraobservador y la reproducibilidad interobservador. Materiales y métodos- siete examinadores experimentados contaron dos veces el número de levaduras en campos ópticos de 10, 20, 30, 40 y 50 de 40 portaobjetos con aumentos de x ×400 y ×1000. Resultados- el número de levaduras por unidad de superficie fue significativamente mayor con un aumento de ×1000 en comparación con un aumento de ×400. La repetibilidad y reproducibilidad para contar las levaduras fue muy pobre. Conclusiones y relevancia clínica - Los portaobjetos citológicos en tiras de cinta adhesiva deben examinarse microscópicamente para detectar Malassezia spp. con un aumento de ×1.000. La repetibilidad de este examen para contar las levaduras es pobre.

Contexto - A ampliação microscópica ideal e o número de campos ópticos das lâminas citológicas de fita adesiva que devem ser examinados nas pesquisas de leveduras do gênero Malassezia em cães são desconhecidos. Objetivos - Determinar a magnificação ideal e o número mínimo de campos ópticos que devem ser examinados para maximizar a repetibilidade intraobservador e a reproducibilidade interobservador. Materiais e métodos - Sete examinadores experientes contaram duas vezes o número de leveduras em 10, 20, 30, 40 e 50 campos ópticos de 40 lâminas nas magnificações de x400 e x1000. Resultados - O número de leveduras por unidade de área de superfície foi significativamente maior em x1000 em comparação com a ampliação de x400. A repetibilidade e a reprodutibilidade para a contagem de leveduras foi muito pobre. Conclusões e relevância clínica - Lâminas de citologia por fica adesiva devem ser examinadas microscopicamente para Malassezia spp a uma magnificação de x1.000. A repetibilidade deste exame para contagem de leveduras foi pobre.

Detection of Antibodies Against Toxoplasma gondii in Filter Paper-Dried Blood Dot Spots Compared with Serum in Pigs and Assessment of Variation Associated with Packed Cell Volume.

The aim of this study was to assess the agreement between anti-Toxoplasma gondii IgG antibody detection in serum and filter paper (FP) blood spots using the indirect immunofluorescence antibody assay (IFA) and to evaluate the potential impact of the packed cell volume (PCV) on antibody detection in FPs. A pair of a serum and an FP sample was collected from 96 sows at various farms in Greece, with previously identified high seropositivity and/or risk factors associated with high seropositivity against T. gondii. The PCV value was determined using the microhematocrit method. IFA was used for the detection of antibodies against T. gondii. T. gondii-specific antibodies were detected in 45.8% serum samples and 41.6% FP samples showing almost perfect agreement. Detection in FP samples presented high sensitivity (87.1-92.8%) and excellent specificity (100%) when compared with detection in serum, regardless of the PCV values. The findings of this study support the reliability of FPs for the evaluation of the serological status of swine against T. gondii. FPs could be a good alternative sample type compared with serum for large-scale epidemiological studies.

Effects of Phenolic Phytogenic Feed Additives on Certain Oxidative Damage Biomarkers and the Performance of Primiparous Sows Exposed to Heat Stress under Field Conditions.

The aim of this study was to investigate the effects of two commercial phenolic phytogenic feed additives (PFAs) on sows under heat stress conditions of high summer temperatures for seven days before and seven days after the farrowing. The PFA-1 product was a mixture based on the plants Emblica officinalis, Foeniculum vulgare, Citrus sinensis and nut fiber, while the PFA-2 product was a mixture based on plants Andrographis paniculata, Glycyrrhizia glabra, Tinospora cordifolia and nut fiber. A total of 48 primiparous sows were divided into three groups: T1-control group: regular gestation (GF) and lactation feed (LF); T2 group: regular GF and LF supplemented with PFA-1; T3 group: regular GF and LF supplemented with PFA-2. Each sow in the T2 and T3 groups received 5 g daily of the PFA-1 and PFA-2 product, respectively, for seven days before and seven days after the farrowing. Blood samples were collected from all groups 24 h after farrowing. Thiobarbituric acid--reactive substances (TBARS) and protein carbonyl (CARB) concentrations were determined in the sow plasma. The body condition scoring (BCS) and the backfat of sows on the farrowing and weaning days along with reproductive parameters and litter characteristics were recorded. The highest number of stillborn piglets and the largest interval from weaning to estrus were observed in the T1 group. The lowest number of alive 24 h after birth and weaning piglets and the lowest BCS and backfat at weaning were also recorded in the T1 group. TBARS and CARB concentrations were significant higher in the T1 group compared to all other groups. In conclusion, the use of phenolic PFAs seems to reduce oxidative damage caused by heat stress and ameliorate performance in primiparous sows.

Evaluation of an Indirect Immunofluorescence Assay for the Detection of Anaplasma phagocytophilum Antigen in Ovine Buffy Coat Smears.

Diagnosis of anaplasmosis is challenging considering the great variation in clinical signs and the limitations of the available diagnostic assays, while the detection of carrier animals that play a significant role in disease epidemiology as reservoirs is of great significance. In this study, we evaluated the diagnostic accuracy of a newly developed indirect immunofluorescent assay (Ag-IFAT) for the detection of A. phagocytophilum antigens in buffy coat specimens, alone and in combination with cytology, using PCR as a reference. Blood samples were collected from 138 sheep of the Chios breed from six farms in Greece. A buffy coat was extruded from the centrifuged blood. Buffy coat smears were used for cytological examination and the Ag-IFAT assay. The Ag-IFAT assay presented excellent specificity (100%) and high sensitivity (85.4%) for the detection of A. phagocytophilum antigens in buffy coats, and it has an almost perfect agreement with PCR and cytology (κ value = 0.88 and 0.85, respectively). A. phagocytophilum antigens are likely to be detected using Ag-IFAT in a PCR-positive animal, as indicated by the good performance of the assay. Overall, this assay presents high diagnostic accuracy, and it could be used for the detection of animals during the early stage of infection.

Wild Rabbit Exposure to Leishmania infantum, Toxoplasma gondii, Anaplasma phagocytophilum and Babesia caballi Evidenced by Serum and Aqueous Humor Antibody Detection.

Wild rabbits (Oryctolagus cuniculus) can be important sentinel species for the presence of zoonotic pathogens. Therefore, we collected blood samples from wild rabbits harvested by hunters during the hunting season 2019-2020 on the island of Lemnos, to determine exposure of wild rabbits to the zoonotic pathogens Leishmania infantum, Toxoplasma gondii, Anaplasma phagocytophilum and Babesia caballi, as well as aqueous humor to assess its diagnostic performance in terms of sensitivity, specificity, positive and negative likelihood ratios. Antibodies against these pathogens were detected by Indirect Immunofluorescence Antibody (IFA) assay. Out of the 72 wild rabbits included in the study, 4.2%, 5.5%, 18% and 9.7% were seropositive to L. infantum, T. gondii, A. phagocytophilum and B. caballi, respectively. Although less frequently, antibodies were also detected in aqueous humor of wild rabbits. The antibody detection in aqueous humor presented 100% specificity but decreased sensitivity compared to serum suggesting that aqueous humor could be successfully used in epidemiological studies to confirm exposure at the population level but has little diagnostic value at the individual level. This is the first report on the seropositivity of wild rabbits to A. phagocytophilum and B. caballi and the detection of antibodies against A. phagocytopylum, L. infantum, T. gondii and B. caballi in the aqueous humor.

Effect of storage time on the urine protein: creatinine ratio in alkaline ovine urine.

The urine protein:creatinine (UPC) ratio is considered the reference method to assess proteinuria. Its diagnostic value in ovine medicine needs further elucidation. In population monitoring and/or for research purposes, it is convenient to collect many samples simultaneously and store them for later analysis. However, analyte stability data are required to ensure reliable results. We used 15 of 90 urine samples collected from sheep to assess the effect of storage time on the UPC ratio. After centrifugation, the supernatant of each sample was divided into 6 aliquots. Urine protein and creatinine concentrations were determined immediately in one aliquot using the pyrogallol red and a modified Jaffè method, respectively. The other aliquots were stored at -18°C. Based on the absence of active sediment, alkaline urine pH, and UPC ratio ≥0.2, we included 15 samples in our study. The UPC ratio was determined in the stored aliquots 2, 7, 14, 21, and 60 d after collection. The data were analyzed with univariate ANOVA. No significant difference was observed in the urinary concentrations of protein, creatinine, and the UPC ratio (0.8 ± 0.84 in conventional units and 0.09 ± 0.095 in SI units) among different times (p > 0.05). The UPC ratio remained stable for 2 mo in ovine urine samples stored at -18°C.

Neospora caninum and/or Toxoplasma gondii Seroprevalence: Vaccination against PCV2 and Muscle Enzyme Activity in Seropositive and Seronegative Pigs.

Neospora caninum and Toxoplasma gondii affect both humans and animals worldwide. To investigate their seroprevalence and differences in seropositivity between pigs vaccinated and unvaccinated against porcine circovirus 2 (PCV2), as well as differences in muscle enzyme activity between seropositive and seronegative pigs, blood samples were collected from 380 sows. Antibodies against T. gondii and N. caninum were detected by an indirect immunofluorescence antibody (IFA) assay, while the activities of creatine kinase (CK) and aspartate aminotransferase (AST) were biochemically assessed. Out of the 364 sows finally included in the study, 4.4%, 3.5%, and 0.5% were seropositive to T. gondii, N. caninum, or both. A significantly higher percentage of seropositivity against T. gondii and/or N. caninum in PCV2 unvaccinated pigs compared with vaccinated pigs was observed. Increased serum activities of CK and AST were detected in 71.43% and 100% of only against T. gondii (T+) and 63.64% and 90.91% of only against N. caninum (N+) seropositive sows, respectively, and were significantly higher compared to seronegative animals. T. gondii and N. caninum seropositivity, especially in presumed immunocompromised pigs, and the evidence of muscle damage highlight their importance as a zoonotic pathogen and animal model of human infection, respectively.

Hematological Features in Sheep with IgG and IgM Antibodies against Borrelia burgdorferi sensu lato.

Exposure of sheep to Borreliaburgdorferi sensulato (s.I.) complex, the causative agent of Lyme borreliosis (LB), has been reported in tick-abundant areas worldwide, while no data have been reported in Greece. The aim of the study was to identify the hematological alterations in sheep with seropositivity against Borrelia burgdorferi (s.I.). Blood samples were obtained from 318 tick infested sheep for blood analysis and serological determination of IgG and IgM antibodies against B. burgdorferi by indirect immunofluorescence antibody (IFA) assay after exclusion of endo-ectoparasites and other tick-borne infections. A total number of 162 sheep met the inclusion criteria, allocated in four groups based on the presence or absence of IgG and/or IgM; sheep found negative for IgM and IgG (Group A), positive for IgM (Group B), positive for both IgM and IgG (Group C) and positive for IgG (Group D). Anemia, thrombocytopenia and normal or decreased leukocyte count, mainly due to lymphopenia were the main hematological features observed in seropositive sheep. The presence of these features raises the suspicion of Borrelia infection in tick infested sheep. The seropositivity of 23.58% in sheep raises concerns of Borrelia circulation, especially in rural areas and potential risk of transmission to humans.

Potential Acute Renal Injury in Sheep with Bluetongue Serotype 4.

Bluetongue is a vector-borne disease with epidemic potential. Recently, outbreaks of Bluetongue were reported across Greece, caused by the Bluetongue virus (BTV) serotype 4. Regarding its pathogenesis, BTV infection involves various target organs with limited data referring to the kidneys. The objective of this study was to identify the possible impact of BTV infection on kidneys using common renal biomarkers. Urine and blood samples collected from 30 sheep with clinical signs of bluetongue (BTV sheep) and 30 clinically healthy sheep (normal sheep) from the same farms were finally selected and included in the study from an initial population of 47 sheep per group, based on the absence of active urine sediment. Complete urinalysis was performed and urine protein to creatinine ratio (UPC) and urine gamma-glutamyl transferase to creatinine (UGGTC) ratio were determined. Blood urea nitrogen (BUN), creatinine, total proteins, albumin (ALB), and inorganic phosphate (P) were determined in serum samples. UPC and UGGTC were significantly higher (p < 0.05) in BTV sheep compared to normal, whereas urine specific gravity (USG) was significantly lower (p < 0.05). Cylindruria was also detected in BTV sheep, and absence of azotemia in BTV and normal sheep. All these findings are indicative of renal tubular injury and/or dysfunction and suggestive of an association between BTV infection and acute damage of renal tissue.

Quantitative and Morphological Blood Cell Findings Associated with the Presence of Antigen and/or Antibodies Against Anaplasma phagocytophilum in Sheep.

Anaplasma phagocytophilum is the causative agent of a disease known as tick borne fever in sheep, although fever is not always present. Due to inconclusive clinical signs, diagnosis is based on the cytological or molecular detection of the microorganism in blood and/or the determination of antibodies against A. phagocytophilum. The aim of the study was to determine the alterations caused by the presence of antibodies and/or the antigen of A. phagocytophilum in the blood cell count and morphology in sheep. Cytology and indirect immunofluorescence assay were performed for detection of antibodies and the antigen of A. phagocytophilum, respectively. The samples were divided into four groups depending on the result of the antigen and antibody detection. The samples that were only positive for antigen detection had mild anemia, leukopenia (lymphopenia), and thrombocytopenia. The samples that were positive in both assays had anemia, leukopenia (neutropenia and lymphopenia), and thrombocytopenia. Samples that were positive only for antibody detection had mild leukopenia. Morphological findings in infected sheep included band neutrophils, toxic neutrophils, reactive lymphocytes, and activated monocytes. The hematological findings along with cytological and serological tests can contribute to the assessment of the stage of the disease. A combination of leukopenia and thrombocytopenia raises a strong suspicion of the disease. When the microorganism and antibodies are simultaneously present, sheep are more susceptible to secondary complications. The first reported morphological findings and the quantitative hematological alterations are indicative of an inflammatory reaction, antigenic stimulation, and stress.

Estimation of white blood cell and platelet counts in ovine blood smears, and a comparison with the ADVIA 120 hematology analyzer.

BACKGROUND: Manual evaluation of blood cell counts on stained blood films is a common procedure in resource-limited laboratories of farm animal clinics. Moreover, settings for sheep blood cell counts are not provided on most veterinary hematology analyzers. OBJECTIVES: We aimed to (a) compare the results of white blood cell (WBC) counts evaluated microscopically on ovine blood smears with those obtained by the ADVIA 120 hematology analyzer and validate appropriate correction factors for the manual technique; and (b) assess the two suggested factors to calculate platelet counts on blood smears in sheep. METHODS: The blood samples of 57 sheep were used to generate a regression equation between the average WBC count per field and the WBC count determined using the ADVIA 120 analyzer. Thirty-one new ovine samples were used to assess the agreement between the calculated WBC counts based on a generated equation and those obtained by the analyzer using the Passing-Bablok test and Bland-Altman plots. Similarly, agreements between platelet counts using two different factors for platelet calculation were assessed using the Bland-Altman plot. RESULTS: The average bias of calculated WBC counts was 0.4%, with precision and accuracy being over 95%. Regarding calculated platelet counts, Bland-Altman plots revealed a bias of 26.4% and 1.4% when the average number of platelets per field was multiplied by 15 000 and 20 000, respectively. CONCLUSIONS: Microscopic WBC counting in ovine blood is a reliable alternative to automated analyses using the generated equation. A better agreement between the two methods was observed when a factor of 20 000 was used to calculate platelet counts in ovine blood smears.

Comparison between the urine dipstick and the pH-meter to assess urine pH in sheep and dogs.

BACKGROUND: Urine pH is an integral part of a complete urinalysis, and is commonly measured in veterinary practice using semiquantitative reagent strips. OBJECTIVE: The aim of this study was to compare the urine pH of dogs and sheep, using visual interpretation of dipstick reactions, and using a pH-meter as the reference method. Agreement between the 2 methods was also assessed. An additional objective was to compare the urine pH before and after centrifugation. METHODS: A total of 50 voided urine samples from sheep and 52 from dogs were collected into sterile containers. For pH measurements, 2 methods were used, a pH-meter and urine dipstick reagent pads. Measurements were performed using urine samples before (whole urine) and after centrifugation (urine supernatant). For comparison of the 2 methods, Passing and Bablok regression analysis and Bland-Altman plots were used. RESULTS: The equation created to assess agreement between the 2 methods in dogs showed a constant bias at -0.14 and a positive proportional bias at 0.98. From a clinical standpoint, total bias was below and above the maximum acceptable bias in sheep and dogs, respectively. Clinically acceptable bias was also found using centrifuged urine samples in sheep, but the urine pH values before and after centrifugation were nearly identical in dogs. CONCLUSION: Urine dipstick reagent pads and pH-meters can be used interchangeably to determine urine pH in sheep without needing centrifugation. In contrast, pH-meters provide more accurate pH measurements than urine dipstick pads in canine urine, which is not improved by centrifugation.