Hematologic, biochemical, and protein electrophoretic values in captive tawny owls (Strix aluco)

BACKGROUND: The tawny owl (Strix aluco) is a protected species in Italy. Orphaned, injured, and ill owls often are sheltered and treated in rehabilitation centers, where hematologic and biochemical analyses would be helpful to evaluate and monitor the status of their health. OBJECTIVES: The major aim of this work was to assess hematologic and biochemical constituents together with protein electrophoretic fractions in healthy tawny owls. In addition, we compared laboratory methods for determining hemoglobin (Hgb), total protein, and albumin concentrations. METHODS: Heparinized blood samples were collected from 10 clinically healthy adult captive tawny owls between March 2001 and November 2003 for CBC, routine biochemical analysis, and protein electrophoresis. Alternate methods for Hgb (estimation as HCT/3 vs spectrophotometry), total protein (biuret vs refractometry), and albumin (bromcresol green vs electrophoresis) concentrations were compared in 34 samples from 16 unhealthy adult owls and 8 nestlings. RESULTS: Results were reported as mean, median, and range (minimum-maximum). Significant differences and poor concordance were observed between methods for Hgb, total protein, and albumin. CONCLUSIONS: Hematologic and plasma biochemical values in captive tawny owls may be useful in evaluating and monitoring the health of this species in captivity.     

Blood chemistry, protein electrophoresis, and hematologic values of captive Spanish imperial eagles (Aquila adalberti).

Hemograms and plasma chemistry values are presented for six male and six female, adult, clinically normal, captive Spanish imperial eagles (Aquila adalberti). No value was substantially different from that which might be predicted on the basis of work in other related species. This data should prove useful for the interpretation of laboratory findings in future clinical cases of this endangered species of eagle.     

A contribution for the definition of serum chemistry values in captive adults Antillean manatees (Trichechus manatus manatus Linnaeus, 1758)

Serum chemistry analyses represents a fundamental tool for the diagnosis and understanding of diseases in marine mammals. Although several studies are being conducted within the field of clinical pathology, haematological and serum chemistry data for Antillean manatees are deficient. The purpose of this study was to determine serum chemistry values for captive Antillean manatees within the CMA/Ibama facility in Brazil. Serum samples were obtained from five captive adult Antillean manatees fed with seagrass and analysed for aspartate aminotransferase, alanine aminotransferase, bilirubin, alkaline phosphatase, urea, creatinine, glucose, triglycerides, cholesterol, total protein, albumin, globulin, phosphate, chloride, calcium and uric acid. Blood chemistry parameters were determined using a semi-automatic analyzer. Maximum, minimum, mean and standard deviations were calculated for each serum chemistry parameter. Differences on the values of males and females were verified using an unpaired Student's t-test. All the parameters analysed were similar between sexes, with exception of AP, which was higher in females (191.43 +/- 31.86 U/l). Alanine aminotransferase and uric acid values for Trichechus manatus manatus are reported for the first time in this paper. This study is the first to report serum chemistry parameter values for long-term captive male and female Antillean manatees. Therefore, the lower values of albumin, phosphate, chloride, cholesterol and triglycerides obtained here highlight the importance of clinical pathology during health monitoring of captive marine mammals.     

Normal serum activities of some diagnostic enzymes in dromedary camel in Sudan

76 adult camel (30 males and 46 females) sera were surveyed for the normal activities of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine phospho-kinase (CPK), -glutamyl transpeptidase (GGT) and lactate dehydrogenase (LDH). The values recorded for the above enzymes were compared to other data in the literature.     

Clinical biochemistry in healthy manatees (Trichechus manatus latirostris).

Florida manatees (Trichechus manatus latirostris) are endangered aquatic mammals living in coastal and riverine waterways of Florida and adjacent states. Serum or plasma biochemical analyses are important tools in evaluating the health of free-ranging and captive manatees. The purpose of this study was to measure diagnostically important analytes in the plasma of healthy manatees and to determine whether there was significant variation with respect to location (free-ranging versus captive), age class (small calves, large calves, subadults, adults), and gender. No significant differences in plasma sodium, potassium, bilirubin, glucose, alanine aminotransferase, or creatine kinase were found among these classes of animals. Compared to free-ranging manatees, captive animals had significantly lower mean concentrations of plasma chloride, phosphate, magnesium, triglycerides, anion gap, and lactate. Captive manatees had significantly higher mean values of total CO2, calcium, urea, creatinine, alkaline phosphatase, gamma-glutamyltransferase, total protein, albumin, and albumin/globulin ratio than did free-ranging animals. Differences in the environments of these two groups, including diet, temperature, salinity, and stress, might account for some of these results. The higher plasma lactate and anion gap concentrations and lower total CO2 concentrations of free-ranging manatees were probably due to greater exertion during capture, but the lack of elevated plasma creatine kinase activity relative to captive animals indicates that there was no serious muscle injury associated with capture. Plasma phosphate decreased and total globulins increased with age. Plasma cholesterol and triglyceride concentrations were highest in small calves. Plasma aspartate aminotransferase was higher in large calves than in adults and subadults, and the albumin/ globulin ratio was higher in subadults than in adults. Plasma total CO2 was higher and chloride was slightly lower in females than in males.     

Serum chemistry reference values in free‐ranging North Atlantic male walruses (Odobenus rosmarus rosmarus) from the Svalbard archipelago

Background: Information regarding health and disease is limited for walruses, a keystone species in arctic marine ecosystems. Serum chemistry analysis is a useful clinical tool for the health assessment of walruses, but only a few captive Pacific walruses have been evaluated. Objectives: The aim of this study was to determine serum chemistry reference values for free‐ranging male Atlantic walruses (Odobenus rosmarus rosmarus) on Svalbard and to assess potential differences in animals with low and high tissue levels of organic pollutants. Methods: Blood samples were collected from 17 wild, adult, male Atlantic walruses chemically immobilized with etorphine at eastern Svalbard (Norway). Serum was obtained for routine biochemical analysis as well as nonesterified free fatty acids (NEFA) and cortisol tests. Serum protein concentration was also measured by agarose gel electrophoresis. Results: Reference values (ranges) included alanine aminotransferase (12–51 U/L), aspartate aminotransferase (54–137 U/L), alkaline phosphatase (42–243 U/L), creatine kinase (32–506 U/L), lactate dehydrogenase (480–1322 U/L), amylase (0–23 U/L), lipase (68–298 U/L), total protein (68–91 g/L), albumin (25.3–34.8 g/L), creatinine (84–137 μmol/L), urea (8.2–19.9 mmol/L), bilirubin (0–4 μmol/L), cholesterol (4.4–7.3 mmol/L), NEFA (0.1–0.4 mmol/L), triglycerides (0.6–2.2 mmol/L), calcium (2.0–2.7 mmol/L), phosphorus (1.7–2.8 mmol/L), sodium (147–162 mmol/L), potassium (4.7–7.4 mmol/L), chloride (102–115 mmol/L), and cortisol (<28–214 nmol/L). Walruses exposed to high levels of organic pollutants (n=6) had significantly lower (P=.022) phosphorus concentration than those with low levels of pollutants (n=6). Conclusions: The clinical chemistry reference values determined in this study can serve as baseline data for future health‐related studies of walruses in a changing Arctic and may also be helpful for health evaluations of walruses in captivity. Impacts of the exposure of marine mammals to organic pollutants should be further investigated.     

Diet manipulation as treatment for elevated serum iron parameters in captive raggiana bird of paradise (Paradisaea raggiana)

Elevated serum iron parameters were lowered through dietary manipulation in captive Raggiana bird of paradise (Paradisaea raggiana). Study birds were part of a captive breeding program consisting of two males and one female, captive born, 3.5-9 yr of age. Serum iron, total iron binding capacity (TIBC), percentage saturation, body weight, albumin, aspartate aminotransferase, and hematocrit were monitored at regular intervals for 2.5 yr. Routine diet consisted of a variety of fruits, vegetables, a multivitamin supplement, and a commercial low iron avian pellet, with a dietary iron content of 55 mg/kg (dry matter basis) or 1.12 mg iron/bird/day. Dietary treatment involved removal of the commercial avian pellet for 30 days at 6-to 12-mo intervals, resulting in an iron content of 42 mg/kg (dry matter basis) or 0.64 mg iron/bird/day. Average serum iron and TIBC were decreased by 75% (TIBC) to 80% (serum iron) ofpretreatment values after one 30-day treatment. Average iron saturation levels were lowered by 10% of pretreatment values after one 30-day treatment. Average hematocrit, albumin, aspartate aminotransferase, and body weight remained unchanged. No adverse effects were noted through the 2.5-yr evaluation period, and breeding behavior was undisturbed. Periodic removal of low iron commercial pellets in the diet of captive bird of paradise is a safe and effective method for lowering serum iron values without need for handling. Periodic application of this technique may be useful as a preventive tool to maintain appropriate serum iron values in avian species susceptible to iron storage disease.     

Hematology and serum chemistry values of the European brown hare

Background: Hematology and serum biochemistry values can be useful for evaluating the health of populations of captive and free-living European brown hares ( Lepus europaeus ). However, current information is fragmented and incomplete.
Objective: The objective of this study was to determine normal hematology and serum chemistry values for a population of captive European brown hares and to investigate differences related to sex and age.
Methods: Routine hematology and serum chemistry values were determined for 48 captive European brown hares in Catalonia (northeastern Spain): 21 young (6 males and 15 females) and 27 adult (14 males and 13 females) hares. Blood was obtained by auricular venipuncture while animals were physically restrained. Results were expressed as the mean ± SD, and reference intervals were calculated as the mean ± 2SD.
Results: RBC count, PCV, concentrations of hemoglobin, total protein, albumin, gamma globulin, urea nitrogen, and creatinine, and alanine aminotransferase activity were significantly higher in adults than in young hares, and alkaline phosphatase activity and total bilirubin concentration were lower. Sex differences were not observed.
Conclusions: Hematology and serum chemistry results obtained in this study are considered representative for healthy captive European brown hares. A single reference interval can be used for values from male and female hares, however, age-specific intervals are needed for some analytes.     

Serum biochemistry of captive and free-ranging gray wolves (Canis lupus).

Normal serum biochemistry values are frequently obtained from studies of captive sedentary (zoo) or free-ranging (wild) animals. It is frequently assumed that values obtained from these two populations are directly referable to each other. We tested this assumption using 20 captive gray wolves (Canis lupus) in Minnesota, USA, and 11 free-ranging gray wolves in Alaska, USA. Free-ranging wolves had significantly (P < 0.05) lower sodium, chloride, and creatinine concentrations and significantly higher potassium and blood urea nitrogen (BUN) concentrations; BUN to creatinine ratios; and alanine aminotransferase, aspartate aminotransferase, and creatine kinase activities relative to captive wolves. Corticosteroid-induced alkaline phosphatase activity (a marker of stress in domestic dogs) was detected in 3 of 11 free-ranging wolves and in 0 of 20 captive wolves (P = 0.037). This study provides clear evidence that serum biochemical differences can exist between captive and free-ranging populations of one species. Accordingly, evaluation of the health status of an animal should incorporate an understanding of the potential confounding effect that nutrition, activity level, and environmental stress could have on the factor(s) being measured.     

Clinical chemistry values and tissue enzyme activities in western barred bandicoots (Perameles bougainville)

BACKGROUND: The western barred bandicoot, Perameles bougainville, is an endangered Australian marsupial species whose survival is threatened by a papillomatosis and carcinomatosis syndrome. Investigations to characterize this syndrome would benefit from species-specific clinical chemistry data. OBJECTIVES: The purpose of this study was to determine plasma biochemical reference values and to determine enzyme activities in various tissues of P. bougainville. METHODS: Heparinized blood samples were collected by jugular venipuncture from 53 clinically healthy bandicoots of both sexes and at 3 geographic locations. Plasma was analyzed for routine clinical chemistry variables using an automated biochemistry analyzer. Tissues obtained following humane euthanasia of 3 bandicoots were analyzed for alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), creatine kinase (CK), alpha-amylase (AML), and gamma-glutamyltransferase (GGT) activities. RESULTS: Significant differences in the results were found for animals based on geographic location and sex; hence, results were expressed as minimum and maximum values. A population reference interval was calculated for AST activity (20-283 U/L). ALT was found mainly in the liver, with lower levels in cardiac and skeletal muscle and kidneys. AST was detectable in many tissues, including the heart, liver, kidneys, and central nervous system; CK was found in skeletal and cardiac muscle and central nervous system; AML was found in the pancreas; and GGT was found mainly in kidneys with lower levels in the intestines and pancreas. CONCLUSIONS: These findings will facilitate the interpretation of clinical chemistry results from P. bougainville and thereby inform population management and clinical decision-making.     

上海水牛生理生化指标的测定和分析

为研究上海水牛生理生化指标含量,选取精神良好、健康的上海水牛犊牛(1岁内)、青年牛(1-2岁)、成年牛(3岁以上),测定了生理指标、血液生理生化指标含量。结果显示,上海水牛的体重随月龄的增加显著增加(P＜0.05),而呼吸频率、心率无显著差异(P＞0.05)。在检测的22项血液生理指标含量中,有10项指标(平均红细胞体积(MCV)、平均红细胞血红蛋白含量(MCH)、平均红细胞血红蛋白浓度(MCHC)、红细胞分布宽度(RDW)、淋巴细胞百分比(%LYM)、单核细胞百分比(%MONO)、中性粒细胞百分比(%NEU)、嗜酸性粒细胞百分比(%EOS)、淋巴细胞(LYM)、单核细胞(MONO))含量差异显著(P＜0.05),其余12项指标(红细胞(RBC)、红细胞比容(HCT)、血红蛋白(HGB)、网织红细胞百分比(%RETIC)、网织红细胞(RETIC)、白细胞(WBC)、嗜碱性粒细胞百分比(%BASO)、中性粒细胞(NEU)、嗜酸性粒细胞(EOS)、嗜碱性粒细胞(BASO)、血小板(PLT)、血小板压积(PCT))含量差异不显著(P＞0.05)。在检测的18项血液生化指标含量中,有9项指标(血糖(GLU)、肌酐(CREA)、磷离子(PHOS)、钙离子(Ca)、总蛋白(TP)、球蛋白(GLOB)、丙氨酸转氨酶(ALT)、胆固醇(CHOL)、胰淀粉酶(AMYL))含量差异显著(P＜0.05),其余9项指标(尿素(UREA)、血尿素氮/肌酐比(BUN/CREA)、白蛋白(ALB)、白蛋白/球蛋白比(ALB/GLOB)、碱性磷酸酶(ALKP)、谷氨酰转移酶(GGT)、总胆红素(TBIL)、甘油三酯(TRIG)、脂肪酶(LIPA))含量差异不显著(P＞0.05)。该研究可为上海水牛的选种选育、生长发育评估、营养状况评估、疾病诊断等提供参考。     

Hematologic, plasma protein, and biochemical profiles of brown pelicans (Pelecanus occidentalis)

OBJECTIVE: To establish hematologic and biochemical reference values for the brown pelican (Pelecanus occidentalis). ANIMALS: 31 captive, healthy, but permanently disabled pelicans and 35 wild-caught, healthy pelicans from a rehabilitation facility on the east coast of Florida. PROCEDURES: Samples of venous blood were collected from each pelican, and hematologic, plasma biochemical, and electrophoretic protein analyses were performed. Student t-tests were used to compare blood values between captive versus wild-caught, adult male versus adult female, and adult versus juvenile pelicans. RESULTS: Hematologic and electrophoretic values were similar between male and female, adult and juvenile, and captive and wild-caught pelicans. Significant sex differences existed for plasma calcium and triglyceride concentrations. Plasma concentrations of calcium, cholesterol, and CO2 content differed between captive and wild-caught adults. No significant differences were found between wild-caught adult and juvenile pelicans. CONCLUSIONS AND CLINICAL RELEVANCE: Our plasma biochemical results are similar to those of other brown pelicans and confamilial species. Additional studies on seabirds are encouraged, as age, sex, reproductive status, feeding habits, and captivity are important variables for health assessment in this and other aquatic species.     

Hematological and plasma biochemical values in captive Eld's-Brow Antlered deer (Cervus eldi thamin) in Thailand

Blood samples were collected from 20 sedated captive Eld's-Brow Antlered deer (Cervus eldi thamin), aged over 1.5 years, to define their mean hematological values (packed cell volume and hemoglobin) and mean plasma biochemical parameters. Male deer had a significantly higher plasma glucose level and aspartate aminotransferase activity than female deer.     

Effect of acepromazine on the signs of capture stress in captive and free-ranging roe deer (Capreolus capreolus)

The differences between the capture stress responses of captive and free-ranging roe deer (Capreolus capreolus) and their modulation by acepromazine, during a period of three hours' physical restraint after capture in drive-nets, were examined in 16 free-ranging and 16 captive roe deer. Eight of the free-ranging and eight of the captive animals received acepromazine intramuscularly, and the other eight free-ranging and eight captive deer received the same volume of saline. Heart rate, body temperature and haematological and serum biochemical parameters were analysed. In the groups treated with acepromazine, the heart rate stabilised sooner, and the red blood cell (RBC) count, haemoglobin concentration, packed-cell volume, the serum activities of creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) and the concentrations of creatinine and lactate were significantly lower, and serum glucose started to decrease earlier, than in the untreated groups. Serum potassium levels decreased over time only in the untreated groups. The body temperature stabilised earlier, and the RBC count, haemoglobin concentration, serum CK, AST, ALT and LDH activities, and serum creatinine, lactate, cholesterol and glucose concentrations were significantly lower in the free-ranging roe deer than in the captive deer.     

Hematology and serum chemistry values of the lesser rhea (Pterocnemia pennata) raised in Patagonian farms (Argentina).

Hematologic and serum chemistry values were determined for chicks, juveniles, and adult farmed lesser rheas (Prerocnemia pennata). Blood samples were taken during March-April 1998 from the brachial veins of lesser rhea, including 64 chicks, 24 juveniles, and 36 adults, raised in Patagonian farms (Argentina). Lesser rhea chicks had significantly lower erythrocyte counts, hematocrit, hemoglobin, red cell indices, and copper than did the juveniles and adult individuals. No significant differences were observed between females and males. Most values were similar to those reported for other ratites. The data obtained provide hematologic and serum chemistry values for lesser rhea from farms.     

Sex-based differences in plasma chemistry and cardiac marker test results in Siamese fighting fowl

BACKGROUND: Variations in the results of plasma chemistry analysis as a function of sex have rarely been demonstrated in avian species. OBJECTIVE: The aim of the present study was to investigate sex-related differences in values for routine biochemical variables, including conventional muscle enzymes, and novel cardiac markers in female and male Siamese fighting fowl. METHODS: Plasma chemistry analytes and cardiac marker proteins (creatine kinase-MB and cardiac troponin T) were measured in 70 Siamese fighting fowl using automated chemistry and immunoassay analyzers. Data were compared by 2-tailed t tests between sexes, and Spearman rank correlation between conventional and novel cardiac markers. RESULTS: Male fowl had significantly higher uric acid concentration and gamma-glutamyltransferase activity; whereas, female fowl had significantly higher total cholesterol, triglycerides, and calcium concentrations, and alkaline phosphatase activity. As compared with female fowl, the fighting cocks also had significantly higher plasma concentrations of creatine kinase-MB and cardiac troponin T. Significant correlations between cardiac troponin T, but not creatine kinase-MB, and the activities of conventional muscle enzymes (creatine kinase, aspartate aminotransferase and lactate dehydrogenase) were observed in male but not in female fowl. CONCLUSION: These results indicate that sex-specific differences exist for several biochemical parameters and cardiac marker proteins in fighting fowl, and that such differences should be considered in interpreting laboratory test results.     

Comparison of Biochemical Values of Paired Serum and Plasma Samples from American Flamingos (Phoenicopterus ruber), Indian Runner Ducks (Anas platyrhynchos), and Hyacinth Macaws (Anodorhynchus hyacinthinus)

Single blood samples from 8 clinically normal adult Indian runner ducks (Anas platyrhynchos), 8 clinically normal American flamingos (Phoenicopterus ruber), and 3 blood samples from each of 4 clinically normal hyacinth macaws (Anodorhynchus hyacinthinus) were collected to compare the biochemical values of paired plasma samples from heparinized blood with those of serum samples from clotted blood. Small but significant differences (P < 0.05) were found between paired serum and plasma samples for some biochemistries. In flamingos, potassium (P = 0.001), albumin (P = 0.03), and alanine aminotransferase (P = 0.02) were significantly higher in serum compared with plasma, whereas total protein (P = 0.04) and globulin (P = 0.01) were significantly lower in serum compared with plasma. In Indian runner ducks, potassium (P = 0.0002), chloride (P = 0.02), and alanine aminotransferase (P = 0.0005) were significantly higher in serum compared with plasma, whereas total CO₂ (P = 0.02) and globulin (P = 0.007) were significantly lower in serum compared with plasma. Serum total protein was lower than plasma levels, but it was not significant (P = 0.05). In hyacinth macaws, total protein (P = 0.02) and the albumin:globulin ratio (P = 0.02) were significantly lower in serum compared with plasma. Although statistically significant, these differences were small and appear unlikely to be of any clinical relevance. There is minimal loss of plasma volume from heparinized blood samples compared with serum volume from clotted blood samples. This allows collection of smaller blood volumes from small or sick birds in a single lithium heparin anticoagulant tube to perform a hemogram on whole blood and a biochemical profile on the separated plasma that provides values similar to those of serum.     

Blood Chemistry and Histological Properties of Wild and Cultured Sea Bass (<Emphasis Type="Italic">Dicentrarchus labrax</Emphasis>) in the North Adriatic Sea

Histological and biochemical procedures were employed to study liver histomorphology and plasma levels of aspartate aminotransferases (AST), alanine aminotransferase (ALT), triglyceride (TRIG), cholesterol (CHOL), glucose (GLU) and total protein (TP) in cultured (CSB) and wild sea bass (WSB) (Dicentrarchus labrax) from the northern part of the Adriatic Sea. Histopathological changes in liver included varying degrees of infiltration and lipid degeneration of hepatocytes in examined cultured fish. No significant differences between median AST values of CSB (44 IU) and WSB (45 IU) were observed. Values of ALT were <5 IU in both groups. TRIG, CHOL, GLU and TP levels were higher in CSB (2.08 mmol/L, 3.67 mmol/L, 10.66 mmol/L and 49 g/L, respectively) than in WSB (0.67 mmol/L, 2.74 mmol/L, 3.68 mmol/L and 36 g/L, respectively). The study showed differences between plasma biochemical parameters and liver histomorphology of CSB and WSB. This can be explained as a consequence of different diets (artificial in contrast to natural foods), which influence energy metabolism.     

Hematology and serum clinical chemistry reference intervals for free‐ranging Scandinavian gray wolves (Canis lupus)

Background: Scandinavian free‐ranging wolves (Canis lupus) are endangered, such that laboratory data to assess their health status is increasingly important. Although wolves have been studied for decades, most biological information comes from captive animals. Objectives: The objective of the present study was to establish reference intervals for 30 clinical chemical and 8 hematologic analytes in Scandinavian free‐ranging wolves. Methods: All wolves were tracked and chemically immobilized from a helicopter before examination and blood sampling in the winter of 7 consecutive years (1998–2004). Seventy‐nine blood samples were collected from 57 gray wolves, including 24 juveniles (24 samples), 17 adult females (25 samples), and 16 adult males (30 samples). Whole blood and serum samples were stored at refrigeration temperature for 1–3 days before hematologic analyses and for 1–5 days before serum biochemical analyses. Reference intervals were calculated as 95% confidence intervals except for juveniles where the minimum and maximum values were used. Results: Significant differences were observed between adult and juvenile wolves for RBC parameters, alkaline phosphatase and amylase activities, and total protein, albumin, γ‐globulins, cholesterol, creatinine, calcium, chloride, magnesium, phosphate, and sodium concentrations. Conclusion: Compared with published reference values for captive wolves, reference intervals for free‐ranging wolves reflected exercise activity associated with capture (higher creatine kinase activity, higher glucose concentration), and differences in nutritional status (higher urea concentration).     

Gender Differences–Induced Changes in Serum Hematologic and Biochemical Variables in Mangalarga Marchador Horses After a Marcha Gait Competition

The aim of this study was to investigate whether marcha exercise results in changes in serum hematologic and biochemical variables and whether this condition differs in male and female horses. Thirty-five Mangalarga Marchador horses, 18 males and 17 females were included in the study. Blood samples were obtained before and immediately after a marcha competition. Samples were used for measurement of hematocrit (HCT), hemoglobin concentration (HGB), red blood cell (RBC), total and differential white blood cell (WBC), total protein (TP), albumin (Alb), aspartate aminotransferase (AST), gamma glutamyltransferase (GGT), creatine kinase (CK), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatinine (Crea), and urea (BUN) levels. Data were submitted to analysis of variance using the SAS statistical program, and means were compared by the Tukey test (P < .05). In both males and females, RBC, HCT, AST, and GGT activity increased in response to exercise, but there were no significant differences between genders. In females, significant increases in TP, BUN, Crea, CK, and LDH levels were detected after the marcha gait, but no such changes were detected in males. Total WBC concentrations increased in response to the exercise in both, males and females; however, there were no differences between genders. Plasma HGB, Alb, and ALP levels after marcha gait did not differ in both genders. Marcha exercise–induced significant hematologic and biochemical changes in serum of Mangalarga Marchador horses, independently of gender. However, females presented more blood changes after marcha gait. Gender differences should be taken into consideration in experiments with athletic horses.