Acupuncture Needle Stimulation on Some Physiological Parameters After Road Transport and Physical Exercise in Horse

The aim of this study was to evaluate the effect of acupuncture (AG) treatment on some hematochemical parameters in five Thoroughbred horses after road transport and exercise. Horses competed in two official races. For each race, animals were transported from their stables to the racetrack. Horses transported and competed in the first race represent the control group. Two weeks later, the same horses competed in the second race. Before road transport, they were treated with AG. From animals, blood samples were collected at rest (T_PRE), after unloaded (T_POST), 30 minutes after unloaded (T_POST30), at rest in the transit stall (R_PRE), at the end of the race (R_POST), and 30 minutes after the race (R_POST30). The effect of transport, exercise, and AG was evaluated on blood lactate, glucose, red blood cell, hemoglobin, hematocrit, mean corpuscular volume, and erythrocyte osmotic fragility (EOF) values. A significant effect of transport (P < .05) and exercise (P < .01) was found on all studied parameters in both groups. A significant effect of AG on lactate, glucose, and EOF values was found in transported (P < .001) and exercised horses (P < .05). The results found in this study showed that transport and exercise are potential stressors for the athlete horse that may affect its welfare and physical performance. The data suggest that AG stimulation promoted the increase of blood glucose values and the reduction of lactate and EOF levels suggesting its role in the improvement of the physiological adaptation to stressful stimuli and of physical performance of Thoroughbred horses.     

Effect of ascorbic acid administration on erythrocyte osmotic fragility of pigs transported by road during the hot-dry season

The experiments were performed in order to determine the effect of 8-h road transportation of pigs on erythrocytes osmotic fragility during the hot-dry season, and the ameliorative role of ascorbic acid. Twenty-three adult pigs comprising of both sexes served as subjects for the study. Thirteen pigs administered ascorbic acid (AA) per os 30 min before transportation, at a dose rate of 100 mg/kg served as experimental animals, while ten pigs administered with distilled water per os served as control, and were transported for 8 h during the hot-dry season. EDTA blood samples collected a day before (pre-transportation), immediately after 8-h transportation and 7 days post-transportation were used to determine erythrocyte osmotic fragility. The ambient temperature (AT) and relative humidity (RH) measured within the vehicle ranged between 30.5 – 39.0°C and 40.0 – 71.0% respectively. These values were outside the thermoneutral zone for the pig, indicating that the season was thermally stressful. Results obtained showed a significant difference (p < 0.05) in percent haemolysis recorded at NaCl concentrations of 0.4% and 0.6% immediately after transportation in experimental pigs and at 0.5, 0.6, 0.8 and 0.9% NaCl concentrations in experimental pigs 7 days post-transportation. In conclusion, result from the present study indicated that 8-h road transportation during the hot-dry season could induce stress resulting in haemolysis of erythrocytes and AA administration ameliorated the stress.     

Effect of Age and Performance on Physical,Hematological, and Biochemical Parameters in Endurance Horses

Endurance horses are subjected to heightened stress even after several conditioning protocols. Hence, the goal of this study was to examine the effect of age and performance on the hematology, biochemistry, and physical parameters after an endurance race. Eighteen horses aged 6-15 years were grouped into 80-km race category. All the horses were physically examined, and blood samples were collected postrace. After physical examination, the poor (n = 9) and good (n = 9) performance horses were identified. Potassium concentration was significantly higher (P < .05) in the good performance horses; chloride concentration was significantly higher (P < .05) in the poor performance horses. The mean blood glucose concentration of the poor performance horses in all the age-groups was significantly higher (P < .05). The mean blood lactate concentration was significantly lower (P < .05) in the poor performance horses. There was significant effect of performance on heart rate (P < .031), capillary refill time (P < .013), and gut motility (P < .05). Univariate Fisher exact test results were significantly higher for skin recoil (P < .03), mucous membrane (P < .03), and gait (P < .04) in the performance categories. In conclusion, the influence of age was seen in the poor performance category in relation to lactate, but age did not influence other physical, hematological, and biochemical parameters of the endurance horses. Thus, further studies are required to determine whether physical, hematological, and biochemical parameters during training could be used to estimate performance in endurance horses based on age.     

Conflict Behavior in Show Jumping Horses: A Field Study

The study objective was to determine if there was a relationship between behavioral and physiological stress measures in sport horses and their performance. Nineteen horses competed in show jumping events (6 housed at the center and 13 transported), while 5 horses at home training served as controls. The competition horses were assigned to “light” (obstacles ≤100 cm) and “difficult” class (obstacles >100 cm). The conflict behaviors (CBs/min) in two rounds were calculated. Total faults were classified as “less faults” (≤one fault) or “more faults” (>one fault). Salivary cortisol concentration (SCC) before the first round (SCC-SP1), 20 minutes (SCC-SP2), and 60 minutes after the second round (SCC-SP3) was measured. The increase (SCC-in) and decrease (SCC-dec) in SCC were calculated. No effect of competition was found. Horses that waited longer for the second round had greater CB (P < .05). Conflict behavior was more frequent in horses from the “more faults” (P = .05) and “difficult” (a tendency; P = .06) classes. No correlation of CB with SCC was found. SCC-SP2 was greater in “more faults” (P < .01) and “transported” (P < .01) horses. Competition increased the SCC (P < .05), whereas SCC-SP2 was greater in less successful horses (P < .05). Transported horses and horses with more faults had the greatest SCC-SP2 and SCC-dec (P < .05). Our results suggest that horses which presented stress response were also less successful in competition. The adoption of effective methods to reduce transport and competition stress could enhance welfare and performance of sport horses during competition.     

Flavonoid mixture ameliorates increase in erythrocyte osmotic fragility and malondialdehyde concentration induced by Trypanosoma brucei brucei-infection in Wistar rats

The experiment was performed with the aim of investigating the effect of a flavonoid mixture, Daflon® 500 mg (DF) on the erythrocyte fragility and lipoperoxidative changes, induced by Trypanosoma brucei brucei infection in Wistar rats. Fifty adult male rats randomly divided into five groups of 10 animals each were used. Rats in the control group were administered (1 mL/kg) distilled water only, while the other groups were infected with T. brucei brucei and treated with Daflon® 500 mg and/or Diminazene aceturate. At the end of 5 weeks, EDTA-blood samples and serum samples were collected from the rats, and were used to determine erythrocyte osmotic fragility (EOF) and serum malondialdehyde (MDA) concentration respectively. The results showed that EOF and MDA concentration significantly (P < 0.05) increased in the infected untreated group when compared to the treatment groups. Treatment with Daflon® 500 mg and Diminazene aceturate significantly (P < 0.05) reduced trypanosome-induced increases in EOF and lipoperoxidative changes, suggesting possible antioxidant properties of Daflon® 500 mg and its therapeutic value in trypanosomosis.     

Effects of l-glutamine on rectal temperature and some markers of oxidative stress in Red Sokoto goats during the hot-dry season

The experiment investigated the ameliorative effects of l-glutamine administration on rectal temperature (RT), erythrocyte osmotic fragility (EOF), serum antioxidant enzyme activities and malondialdehyde (MDA) concentration in Red Sokoto goats during the hot-dry season. Twenty eight healthy Red Sokoto goats, comprising 14 experimental (administered 0.2 g/kg of l-glutamine dissolved in 10 mL of distilled water, once daily for 21 days) and 14 control (administered equivalent of distilled water) goats served as subjects. Rectal temperature (measured at 6:00, 13:00 and 18:00 h) and blood samples (taken at 8:00 h) were obtained from all subjects weekly, before, during and after l-glutamine administration. Data obtained were compared using one-way repeated-measures ANOVA, followed by Tukey’s post-hoc test. The dry-bulb temperature, relative humidity and temperature-humidity index for the study period ranged between 24.0 and 37.5 °C, 26.0 and 84.0% and 73.0 and 86.3, respectively. l-glutamine administration decreased (P < 0.05) RT, EOF and MDA and increased superoxide dismutase (SOD) activity in experimental group, compared to controls during weeks 1, 2 and 3. Glutathione peroxidase (GPx) and catalase activities were higher (P < 0.05) in the experimental group than in the controls only during week 1 of l-glutamine administration. In conclusion, l-glutamine administration mitigated increases in RT, EOF and serum MDA concentration and enhanced serum SOD, GPx and catalase activities and may be beneficial in heat-stressed goats during the hot-dry season.

     

Serum Protein Fraction in Mature Horses and Relationship With Metabolic and Hematological Parameters

This study was conducted to determine the effect of age on serum protein fractions and their relationship with metabolic and hematological profiles in mature horses. Twenty-five mature Italian Saddle horses (mean age 13.6 ± 4.8 years) fed the same diet (grass hay and concentrate) were stratified according to age as first maturity, M1 (≤10 years old); second maturity, M2 (>10 and <15 years old); and old, O (>15 years), to be monitored every 28 days for a continuous period of 140 days. Horses in group O had higher plasma protein and thiol concentrations and white blood cell and neutrophil counts than the other two groups. Serum α₂-globulin concentrations were positively correlated with total plasma cholesterol (r = 0.514; P < .001), alkaline phosphatase (r = 0.430; P < .001), aspartate aminotransferase (r = 0.339; P < .001), ceruloplasmin (r = 0.321; P < .001), glutamic pyruvate transaminase (r = 0.444; P < .001), reactive oxygen metabolites (r = 0.426; P < .001), and blood neutrophil counts (r = 0.344; P < .01), and negatively with plasma bilirubin (r = −0.522; P < .001) and creatinine (r = −0.400; P < .001). These results suggest differences in hematological and metabolic profile in Italian Saddle horses after 15 years of age, resulting mainly from changes in plasma proteins and inflammatory mediators. The α₂-globulins fraction seems a quick but reliable marker of an inflammatory situation that, successively, should be better investigated with specific metabolites or enzymes.     

Hematological and Blood Biochemical Characteristics of Newborn Heavy Draft Foals After Dystocia

The negative impact of equine dystocia on hematological and serum biochemical profile of neonatal foals remains unknown, particularly in heavy draft horses that show high incidence of dystocia. This study aimed to reveal the hematological and serum biochemical profile of the foals born in normal delivery and examine the effect of dystocia on blood properties in heavy draft newborn foals. In the normal birth group (n = 23), stage II labor was <30 minutes, with spontaneous or assisted delivery with mild traction by one or two people. In the dystocia group (n = 13), stage II labor was ≥30 minutes, with strong traction by more than three people or mechanical tools with or without correcting fetal displacement. Blood samples were collected from the jugular vein at 0, 1, and 12 hours and 1 and 2 days after foaling. Red blood cells, hemoglobin concentration, and packed cell volume remained significantly lower in the dystocia group than in the normal birth group. The white blood cell count was significantly higher in dystocia foals (1 day: P < .05). Dystocia foals had significantly higher cortisol (1 hour: P < .05), urea nitrogen (1 hour: P < .05), and creatine kinase activities (1 hour: P < .01, 12 hours: P < .05). This study revealed that dystocia foals were more likely to be affected by anemia, physical stress, and muscle damage than normal birth foals.     

Hemato-biochemical responses to packing in donkeys administered ascorbic acid during the harmattan season

Experiments were performed to investigate the effect of ascorbic acid (AA) in reducing hemato-biochemical changes in pack donkeys during the cold-dry (harmattan) season. Six experimental donkeys administered orally AA (200 mg/kg) and six control donkeys not administered ascorbic acid were subjected to packing. Blood samples were collected from all donkeys for hematological and biochemical analyses. In the control donkeys, packed cell volume (PCV), erythrocyte count and hemoglobin concentration (Hb) decreased significantly (P<0.05) at the end of packing. In the experimental donkeys, there was no significant difference between the pre- and post-packing values of PCV, erythrocyte count and Hb. In the control donkeys, the neutrophil and neutrophil:lymphocyte ratio increased significantly (P<0.05) post packing, but in the experimental donkeys, the pre- and post-packing values were not significantly different. The eosinophil count increased significantly (P<0.05) in experimental and control donkeys post packing. In conclusion, packing exerted significant adverse effects on the hematological parameters ameliorated by AA administration. AA may modulate neutrophilia and induce a considerable alteration of erythroid markers in donkeys subjected to packing during the harmattan season.     

The Influence of Topically Applied Oil–Based Palatants on Eating Behavior in Horses

Palatants may be added to equine feed and medication either during or after manufacturing to enhance product acceptance. Prior studies have examined a variety of palatants but results have been limited and inconsistent. Therefore, the objective of this research was to evaluate topically applied oil–based palatants on feeding preferences in horses. Stock-type horses (n = 10) were used in this paired preference test across a two-phase study. Phase one compared six palatants (banana, anise, peppermint, apple, spearmint, and orange) to a control (corn oil), whereas phase two compared preference among palatants (anise, apple, and peppermint). Feeding stocks were utilized and horses were allowed 15 seconds for olfaction followed by 3 minutes for consumption. Variables recorded included first diet sniffed and consumed, first action, aversive behaviors, excessive salivation, and consumption. Each trial was also video-recorded and number of chews were counted. Data were analyzed using chi-square and t tests in SAS version 9.4 with P < .05 established as significant. Findings from phase one reveal excessive salivation was observed less frequently (P < .05) for most palatants with the exception of peppermint and orange. Orange negatively impacted palatability indicated by less consumption when compared with the control (P = .02), although there was no impact on chews per gram. No difference between control and treatment diets for first sniff or first consumed was observed when analyzed individually in either phase one or two, although there was a moderate positive correlation (ф = 0.39, P = .04) between olfaction and consumption during the peppermint and anise comparison. Consumption as the first action was consistent across all trials (P < .05). Anise was preferred over apple and peppermint as indicated by higher total consumption (P < .05) in phase two. These data indicate that oil-based palatants can affect feed preferences in horses with increased palatability from anise and decreased palatability from orange flavors.     

Pharmacokinetic Assessment of the Marker Active Metabolites 4-Methyl-amino-antipyrine and 4-Acetyl-amino-antipyrine After Intravenous and Intramuscular Injection of Metamizole (Dipyrone) in Healthy Donkeys

Metamizole (MT) is an analgesic and antipyretic drug labelled for use in humans, horses, cattle, swine, and dogs in some countries. Metamizole is rapidly hydrolyzed to the active primary metabolite 4-methyl-amino-antipyrine (MAA). MAA is formed in much larger amounts compared to other minor metabolites. Among the other secondary metabolites, 4-amino-antipyrine (AA) is also relatively active. The aim of this research was to evaluate the pharmacokinetic profiles of MAA and AA after administration of 25 mg/kg MT by intravenous (IV) and intramuscular (IM) routes in healthy donkeys. Six jennies were randomly allocated to two equally sized treatment groups according to a 2 × 2 crossover study. Blood was collected at predetermined times within 24 hours, and plasma was analyzed by a validated HPLC UV method. Plasma concentrations of MAA after IV and IM administrations of MT were detectable from 5 minutes to 10 hours in all the donkeys. Plasma concentrations of AA were detectable from 5 minutes to 8 hours, but in smaller amounts. C_max (P < .01), AUC_0-last, AUC_0-∞, AUMC_0-last, and MRT (P < .05) were statistically different between the IV and IM groups. The AUC_IM/AUC_IV ratio of MAA was 1.37. The AA concentrations were lower than those found for MAA. The AA plasma versus time curves profiles after the two routes of administration of MT were variable (within the groups) and different (between the groups). T_max, λz, and AUC_0-last were found to be statistically different between the groups (P < .05). The AUC_IM AA/AUC_IV AA ratio was 2.26.     

Oxidative Stress Associated With Spasmodic,Flatulent, and Impaction Colic in Draft Horses

The aim of the present study was to evaluate the oxidative stress level and antioxidant trace elements status associated with spasmodic, flatulent, and impaction colic in draft horses. For this purpose, venous blood samples were obtained from 20 randomly selected clinically healthy draft horses (control group) and 60 draft horses with different types of colic (spasmodic colic, n = 20; flatulent colic, n = 20; and impaction colic, n = 20). In horses with flatulent and impaction colic, there was a significant (P < .05) decrease in the total antioxidant capacity and activity of reduced glutathione (GSH) and catalase (CAT) as well as level of selenium, copper, zinc, and iron. However, there was a significant (P < .05) increase in the activity of superoxide dismutase (SOD) and in the level of malondialdehyde (MDA), interleukin-6 (IL-6), and manganese. Meanwhile, glutathione reductase (GR) was significantly (P < .05) increased in flatulent colic and significantly (P < .05) decreased in impaction colic. The oxidative stress index (OSI) was significantly (P < .05) increased in horses with flatulent and impaction colic. In horses with flatulent colic, there was a negative correlation between CAT and SOD (r = −0.446), MDA and zinc (r = −0.450), and IL-6 and zinc (r = −0.470). However, those with impaction colic, a negative correlation was recorded between CAT and MDA (r = −0.602), copper and GSH (r = −0.474), iron and GR (r = −0.511), and OSI and GR (r = −0.662). The results of the present study indicate that oxidative stress, with alteration of antioxidant trace element levels, is a feature of flatulent and impaction colic in draft horses.     

Effect of Experience on Adrenocortical and Thyroid Responses of Arabian Horses to Gymkhana Games

Gymkhana is an equestrian event consisting of speed pattern racing and timed games for riders on horses. The aim of the study was to evaluate the effects of gymkhana competition on total cortisol and total and free iodothyronine changes in 23 Arabian purebred horses, by taking into account the effects of previous sport experience on gymkhana riding events. Compared with pre-competition values, an increase of total cortisol concentration has been observed in experienced horses at 30 minutes (P < .001) after exercise and in inexperienced horses both at 5 minutes (P < .05) and at 30 minutes (P < .01) after exercise. Compared with pre-competition values, an increase of total triiodothyronine (T₃) concentration has been observed in experienced horses at 5 minutes (P < .05) after exercise. Data obtained showed that gymkhana riding events induced differential adrenocortical and thyroid responsiveness according to previous experience of sport horses. Hence, cortisol and iodothyronine patterns may provide additional information for the monitoring of gymkhana riding performance.     

Postprandial Blood Glucose and Insulin Responses of Horses to Feeds Differing in Soluble Fiber Concentration

In humans, the consumption of soluble fibers reduces glycemic response after a meal. We hypothesized high soluble fiber diets would reduce and delay postprandial glucose and insulin responses in horses. In a 4 × 4 Latin square design experiment, four Quarter Horse geldings were adapted to diets containing orchardgrass hay (ORCH) or ORCH with 1 of 3 treatment ingredients: molassed sugar beet pulp (BEET), almond hulls (HULL), or steam-crimped oats (OATS). Blood was serially sampled for 6 hours after feeding 0.15% body weight (BW) of the treatment ingredient (meal test) or 1.1 g starch/kg BW from oats plus the treatment ingredient (starch test) to evaluate glycemic and insulinemic responses. Glycemic response during the meal test peaked between 60 and 90 min after feeding (P < .05) and tended to be altered by diet (P = .071) and diet × time (P = .076). Serum insulin was affected by diet (P = .008), time (P < .001), and diet × time (P < .001) during the meal test, with concentrations lower in ORCH compared with BEET and OATS (P < .05). In the starch test, glucose was lower (P < .05) in ORCH and HULL compared with BEET and insulin was lower (P = .046) in ORCH compared with BEET. In both tests, horses took longer (P < .05) to consume HULL, likely influencing postprandial responses. Future research integrating the functional properties of feeds with physiological responses will be necessary to elucidate how soluble fiber affects postprandial glucose metabolism in horses.     

Relationships Among Plasma Proteins,Hematological Values,and Gender in Thoroughbred and Miniature Horses

Our objective was to investigate the relationships among plasma proteins, hematological values, and gender in Thoroughbred (nine females and 16 males) and miniature (30 females and four males) horses. Twenty-two protein bands, ranging from 8 to 264 kDa, were detected in horse plasma. Red blood cells, hemoglobin, and hematocrit were negatively correlated (r ≤ −0.29; P < .05) with bands 13 and 17 but positively correlated (r ≥ 0.40; P < .01) with band 3. A negative correlation (r ≤ −0.27; P < .05) was detected between bands 1, 8, and lymphocytes. Neutrophils were positively correlated with bands 1 and 8. Basophils had a positive correlation (r = 0.36) with band 12 and negative correlation with bands 11 (r = −0.30) and 13 (r = −0.48). Platelets had positive correlations (r ≥ 0.24; P < .10) with bands 3, 4, 5, 10, 14, 19, and 22. The relative intensities of protein bands 4, 16, and 22 were affected (P < .05) by an interaction of breed and gender. Gender effects (P < .05) were detected for plasma protein bands 1 (1.6 vs. 2.4 ± 0.23), 5 (2.6 vs. 3.6 ± 0.25), and 11 (8.7 vs. 13.2 ± 1.1), respectively, for females and males. Breed effects (P < .05) were detected for plasma protein bands 5 (2.5 vs. 3.8 ± 0.25) and 11 (9.0 vs. 12.9 ± 1.1), respectively, for Thoroughbreds and miniatures. When developing new pathophysiological tools for equine disease diagnosis and therapy, breed and gender effects should be considered.     

Nitrogen Retention and Plasma Amino Acid Responses in Mature Geldings Fed Three Dietary Concentrations of Lysine

Six mature Quarter Horse geldings (age, 11.5 ± 4.7 years; body weight [BW], 526 ± 9.2 kg) were used in a replicated 3 × 3 Latin square design to determine the effects of three dietary lysine (Lys) levels on nitrogen (N) retention and plasma amino acid (AA) concentrations. The geldings were fed a basal diet of concentrate and Bermuda grass hay supplemented with synthetic essential amino acids (EAA) to meet estimated requirements for EAA. Geldings were fed one of three dietary treatments: (1) a basal diet deficient in Lys (L−; 0.027 g of Lys•kg⁻¹ BW•d⁻¹); (2) a basal diet supplemented with synthetic Lys to meet National Research Council (NRC; 2007) requirements (L+; 0.036 g of Lys•kg⁻¹ BW•d⁻¹); or (3) a basal diet supplemented at twice the recommended Lys requirement (2 × L; 0.070 g Lys•kg⁻¹ BW•d⁻¹). Horses fed the 2 × L diet had higher N intakes (P = .0056) than horses fed either the L− or L+ diet. However N retention (P = .63) was not different between treatments. Plasma Lys was greater (P < .0001) in 2 × L than L− and L+ diets. Plasma threonine (Thr; P < .01), methionine (Met; P = .03), and total plasma non-EAA (P < .05) concentrations decreased as dietary Lys increased. These results suggest N retention is not a good response criterion for evaluating the AA requirements of mature horses. However, plasma AA data indicated more efficient use of Thr and Met when horses were fed dietary Lys in concentrations greater than the current requirement recommended by the Nutrient Requirements of Horses (National Research Council, 2007).     

Assessment of Gastric Ulceration and Gastrin Response in Horses with History of Crib-Biting

It was hypothesized that horses exhibiting crib-biting (CB) have a greater degree of gastric mucosal damage and higher serum gastrin response to concentrate feeding than non-crib-biting (NCB) horses. Eighteen mature horses, 9 CB and 9 NCB, were used to determine prevalence and severity of gastric mucosal damage and effect of concentrate feeding on circulating gastrin. Horses were maintained on pasture with free access to hay and fed a pelleted concentrate diet twice daily. Number of crib-bites and duration of cribbing bouts were recorded in a 24-hour period. Endoscopic examinations (EE) of the squamous mucosa were performed and gastric fluid sampled after 24 to 28 hour feed removal. Following EE, horses were returned to pasture for 72 hours. Blood was collected following 12-hour feed removal (0 minutes), and at 60 and 120 minutes after consuming 1 kg of concentrate. Mean number of crib bites in 24 hours was 1,558 ± 303 with CB peaking prior to and during the afternoon feeding (3:30 PM, P < .05). There were no differences in the number or severity of ulcers, prevalence of hyperkeratosis, or baseline gastric pH between CB and NCB. Serum gastrin concentration at 60 and 120 minutes was greater (P < .05) and tended to be greater (P < .06), respectively, in CB than in NCB horses following feeding of concentrate. Crib-biting behavior in horses maintained on pasture was not associated with gastric mucosal damage; however, consumption of concentrate feed resulted in greater serum gastrin concentration in CB horses.     

Relationship Between Neutrophil Activity,Oxidative Stress,Acute Phase Response,and Lameness Grade in Naturally Occurring Acute and Chronic Joint Disorders in Horses

We hypothesized that in horses with naturally occurring joint disorders, the neutrophil response, acute phase response (APR), and oxidative stress parameters elevated significantly and are markers of increased inflammatory response in these conditions. Therefore, the first aim of the study was to evaluate neutrophil response, oxidative status, and APR. The neutrophil activity was assessed on the basis of elastase, myeloperoxidase (MPO), and alkaline phosphatase release, whereas free radical generation was assessed on the basis of nitric oxide and superoxide production. Acute phase response was estimated on the basis of fibrinogen or haptoglobin plasma concentration and oxidative stress on the basis of malondialdehyde plasma concentration. Then, these parameters were compared with lameness grade, and correlation coefficients between them were calculated. The study was conducted on 43 horses divided on control group of healthy horses (n = 17), acute lameness (AL) group (11 horses), and chronic lameness (CL) group (15 horses). The neutrophil activity from horses of both groups of joint disorders (AL and CL) was significantly (P < .01) higher in comparison with healthy horses. Elastase release was 67.28 ± 1.89% of maximal activity in AL group in comparison with 51.72 ± 1.75% in healthy horses and 62.61 ± 1.54% in CL group. The highest values of other enzymes were also noted in AL group. Moreover, in AL group release of elastase and MPO positively correlated (P < .01) with grades of lameness. These findings revealed the mutual relation between studied parameters and obtained results may be useful in the development of new therapeutic strategies in the treatment of acute and chronic joint disorders in horses.     

Sperm Susceptibility to Oxidative Stress in the Retuertas Endangered Horse

In order to determine whether the high level of inbreeding of the Retuertas endangered Horses may increase the vulnerability to oxidative stress of the sperm, the susceptibility to lipid peroxidation (LPO) of sperm membranes was evaluated in cooled extended ejaculates. Extended ejaculates (INRA 96) from four Retuertas horses and nine ejaculates from pure Spanish horses were received within 24 hours of collection at our laboratory. An aliquot was analyzed and served as time 0 control. The rest of the ejaculates were split into two additional aliquots: the first aliquot served as an incubation control and the second aliquot received an oxidative insult (Fe₂SO₄). Membrane LPO, motility parameters, membrane integrity, and mitochondrial membrane potential were evaluated. The oxidative insult induced a significant increase in the percentage of sperm with LPO in the Retuertas horses (P < .05). Total and progressive motility were not affected by the oxidative insult in both groups. However, curvilinear velocity (VCL), average velocity (VAP), straightness index (STR), and amplitude of lateral head displacement (ALH) were significantly affected by the treatment (P < .05) in the Retuertas horse population. The membrane integrity of sperm in this group was also affected: the percentage of sperm with intact membranes decreased (57.31% ± 7.76% vs. 47.52% ± 8.28%); and the percentage of necrotic sperm increased (33.27% ± 7.83% vs. 44.85% ± 9.16%) (P < .05). Finally, the oxidative insult increased the population with low mitochondrial membrane potential in these wild horses. We concluded that the high level of inbreeding of this particular breed apparently leads to a higher susceptibility to lipid peroxidation.     

Prognostic Significance of Oxidative Stress Markers in Colitis Associated with Phenylbutazone Administration in Draft Horses

The present study was carried out to assess the prognostic significance of oxidative stress markers in draft horses with colitis associated with phenylbutazone administration under field condition. For this purpose, a total of 40 native breed draft horses were studied. Based on case history, physical examination, and postmortem findings, diagnosis was made. According to the clinical outcome, horses were categorized into survivors and nonsurvivors. Clinically, there was significant association between nonsurvivors and anorexia (P < .01), stasis of intestinal motility (P < .01), melena (P < .01), and diarrhea (P < .001). Biochemically, malondialdehyde and nitric oxide showed a significant increase (P < .05) in nonsurvivors compared with survivors, whereas activities of superoxide dismutase showed a significant decrease (P < .05). Analysis of receiver operating characteristic curve indicated a high sensitivity and specificity of malondialdehyde, nitric oxide, and superoxide dismutase levels (P < .001) to predict the clinical outcome of colitis. Additionally, total protein and albumin showed a significant decrease in nonsurvivors compared with survivors; however, aspartate aminotransferase, sorbitol dehydrogenase, urea, and creatinine showed an increase (P < .05). The present results suggest that estimation of oxidative stress markers and antioxidant parameters may be useful predictors of the clinical outcomes of colitis associated with phenylbutazone administration in draft horses.