Effects of racing and gender on viscoelastic properties of horse blood

Analytical Validation of MINI-PET as Point-of-Care for Erythrocyte Sedimentation Rate Measure in Horses

The erythrocyte sedimentation rate (ESR) is a widely used diagnostic assay in human medicine but nowadays poorly applied in veterinary medicine. This test measures the speed (millimeters per hour) at which red blood cells settle in a whole anticoagulated blood tube. In human medicine, high ESR values are associated with various disorders, including infections, rheumatoid arthritis, oncologic diseases, and other inflammatory conditions. The ESR can also be influenced by some factors such as age and gender. In veterinary medicine, the ESR with the Westergren manual method was almost forgotten over the years due to blood consumption and long turn-around time. The instrument MINI-PET, using a modified Westergren method, does not require blood consumption or release waste product and recently has been applied in canine medicine. The aims of the study in the horse were as follows: to establish the appropriate time to read the ESR with the Westergren reference method; to compare the MINI-PET ESR results with the reference technique; to assess the ESR reference intervals with MINI-PET; and to establish the ESR stability from collection at different time points by MINI-PET. Using 150 horses, we established 60 minutes as the appropriate time for ESR reading with the Westergren method. Moreover, ESR results obtained in 8 minutes with MINI-PET showed a good correlation with the Westergren ESR. Reference intervals (RIs) with MINI-PET were established in mm/h for the healthy horses (geldings 18.6-100.1; stallions, 13.8-55.7; and mares 1-73.7) according to the American Society of Veterinary Clinical Pathology guidelines. In addition, the ESR stability from the blood collection time was evaluated in the MINI-PET on 15 horses: at room temperature, ESR is stable up to 8 hours and at 4°C up to 24 hours. In conclusion, MINI-PET represents a rapid and reliable tool for measuring ESR in horses, offering a valid option to replace the traditional manual technique.

Studies on exercise physiology of the racehorse performed in Japan during the period from the 1930s to the 1970s: respiration and heart rate during exercise and the effect of exercise on blood characteristics

After publication of the epic report on equine exercise physiology by Matsuba and Shimamura in 1933, papers on exercise physiology of the racehorse in Japan began appearing in scientific journals and increased in number. In 1944, respiration during exercise at a walk, trot, and canter was measured by recording expiratory sounds with a microphone attached near the nostril. Respiratory frequency during cantering was synchronized with stride frequency, and expiratory sounds were found to occur during the stance phase of the trailing forelimb. Development of a radiotelemetry system in 1964 for electrocardiogram recording enabled the first recording of an equine electrocardiogram during field exercise that included fast galloping and calculation of heart rate (HR) during exercise. During low intensity exercise including walking, trotting, cantering and extended cantering, HR increased from 45 beat/min during pre-exercise to 150 beat/min at an extended canter. HR increased to 200 beat/min or more in most horses during 100 m of high-intensity sprint galloping. When blood lactate was measured after 3 days of draft work in 12 warhorses in 1934, no increase in blood lactate was found. The erythrocyte sedimentation rate (ESR) was decreased by intense exercise and also decreased as training increased. It was suggested that measuring changes in ESR and body weight in relation to training might become useful as a screening index of training, condition, and fatigue. This evaluation method was named the “ESR-body weight method.”

Relationship between serum cortisol levels and some physiological parameters following reining training session in horse

The changes of cortisol, red blood cells (RBC), hemoglobin (Hb), hematocrit (Hct), heart rate (HR), respiratory rate (RR) and rectal temperature (RT) were evaluated after a reining training session in eight Quarter Horses. All parameters were measured before exercise (T0), immediately after exercise (T1), 1 h after exercise (T2), 2 h after exercise (T3) and 24 h after exercise (T4). One-way analysis of variance (ANOVA) for repeated measures, followed Bonferroni's post hoc test, showed a significant effect of the reining training session (P < 0.0001) on cortisol, RBC, Hb, Hct, HR, RR and RT. Simple linear regression analysis showed the positive correlation (P < 0.05) between cortisol changes and variations of studied parameters in T1, T3 and T4. Exercise-induced cortisol concentrations reflect the physiological response of reining training, suggesting that the changes observed are useful to assess the performance in reining horses and their reining training adaptability.

Highly athletic terrestrial mammals: horses and dogs

Evolutionary forces drive beneficial adaptations in response to a complex array of environmental conditions. In contrast, over several millennia, humans have been so enamored by the running/athletic prowess of horses and dogs that they have sculpted their anatomy and physiology based solely upon running speed. Thus, through hundreds of generations, those structural and functional traits crucial for running fast have been optimized. Central among these traits is the capacity to uptake, transport and utilize oxygen at spectacular rates. Moreover, the coupling of the key systems--pulmonary-cardiovascular-muscular is so exquisitely tuned in horses and dogs that oxygen uptake response kinetics evidence little inertia as the animal transitions from rest to exercise. These fast oxygen uptake kinetics minimize Intramyocyte perturbations that can limit exercise tolerance. For the physiologist, study of horses and dogs allows investigation not only of a broader range of oxidative function than available in humans, but explores the very limits of mammalian biological adaptability. Specifically, the unparalleled equine cardiovascular and muscular systems can transport and utilize more oxygen than the lungs can supply. Two consequences of this situation, particularly in the horse, are profound exercise-induced arterial hypoxemia and hypercapnia as well as structural failure of the delicate blood-gas barrier causing pulmonary hemorrhage and, in the extreme, overt epistaxis. This chapter compares and contrasts horses and dogs with humans with respect to the structural and functional features that enable these extraordinary mammals to support their prodigious oxidative and therefore athletic capabilities.

Cortisol and haematochemical variables of horses during a two day trekking event: effects of preliminary transport

REASONS FOR PERFORMING STUDY

Trekking is a noncompetitive sport, involving maximal skeletal muscle effort. Exercise and transport may involve significant energy expenditure and give rise to substantial stress. Few studies have examined the combined effect of exercise and additional preliminary transport on adrenocortical and haematochemical responses in horses during trekking.

OBJECTIVES

To ascertain whether exercise and additional preliminary transport before trekking would affect the circulating cortisol levels and haematochemical variables of horses during a 2 day trekking event.

MATERIALS AND METHODS

Twenty-nine healthy horses were used. Twenty-four horses were transported over distances of 70 km the day before trekking and 5 horses were stabled at the starting place. Blood samples were taken from horses at 16.00 h the day before trekking; and at 08.30 h and 17.30 h before and after the first day of trekking; at 08.30 h and at 13.30 h before and after the second day of trekking. Serum cortisol and haematochemical variables were determined in duplicate by using commercial test kits. One-way analysis of variance for repeated measures (RM-ANOVA) was applied to determine whether trekking and transport had any effects.

RESULTS

Trekking significantly (P < 0.01) affected total protein, albumin, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), PCV and cortisol changes in transported horses and only urea and PCV (P < 0.01) changes in untransported horses. Untransported horses showed lower basal total protein (P < 0.05) and albumin (P < 0.01) concentrations, higher urea concentrations (P < 0.001) at the second day and lower cortisol levels after the first and the second (P < 0.05) day of trekking than transported horses.

CONCLUSION

These data show that the preliminary transport stress induced additional significant changes of cortisol and haematochemical patterns in horses after trekking.

Hemoglobin levels and athletic performance in elite speed skaters during the olympic season 2006

OBJECTIVE

To test the hypotheses that the hemoglobin (Hb) distribution curve in elite male and female long track speed skaters is not normally distributed and that there is a positive relationship between competitive success and Hb concentration.

DESIGN

A venous blood sample was taken before the events from all skaters. The Hb concentration distribution curves of all ranked from 1 to 30 were tested for normality. In addition, individual Hb concentrations were plotted against ranking in the matching events.

SETTING

2006 major championships and Olympic winter games.

PARTICIPANTS

All elite male and female speed skaters (217 men and 200 women) competing in major international championships in 2006 and in the Olympic winter games 2006.

MAIN OUTCOME MEASUREMENTS

Hb concentration and individual ranking in the matching event.

RESULTS

The mean Hb levels in men and women were 15.7 +/- 0.8 g/dL and 14.0 +/- 0.7 g/dL, respectively. The distribution curve in men would meet the criteria for normal distribution when 4 values from 2 skaters with naturally high Hb levels were neglected. In the women, the distribution curve did not meet the criteria for normality because of low frequency in the right side of the distribution curve and a high frequency at the left side. The curve failed to have a steep drop off at the right side. When plotting Hb concentration against ranking, there is no correlation and relationship between Hb concentration and competitive success.

CONCLUSIONS

The Hb concentrations are within the normal range for endurance athletes, and there is no indication that the values are titrated toward the upper allowed limit. In addition, there is no relationship between Hb concentration and competitive success in elite speed skaters.

Reticulocyte changes after experimental anemia and erythropoietin treatment of horses

Availability of recombinant human erythropoietin (EPO) has facilitated use to enhance red blood cell production, and therefore aerobic performance, in human and equine athletes. Recombinant human EPO promotes growth and differentiation of equine erythroid precursor cells, but in some horses repeat administration induces immune interference with endogenous EPO resulting in fatal anemia. Although blood reticulocyte parameters acquire unique changes in humans treated with EPO, with manual enumeration methods, horses were not considered to release reticulocytes from the bone marrow into circulation, even under severe erythropoietic stress. The goals of this study were to determine whether reticulocytes could be detected and characterized in horses that are anemic or have been treated with EPO using a modern hematology analyzer. Anemia was induced in six horses by removal of 30 ml of blood/kg of body wt over 24 h. After 28 days, the horses were treated twice with 55 U/kg of EPO (Eprex), and after 65 days they were treated thrice with 73 U/kg of EPO. Blood samples were analyzed with the ADVIA120 instrument every 3–5 days and bone marrow samples 7 days after anemia and EPO treatments. Analysis of blood reticulocyte parameters by ANOVA in a randomized complete block design determined that anemia and EPO induced significant ( P ≤ 0.05) increases in red cell distribution width and reticulocyte mean cell volume. Parameters changed only after EPO treatment were cellular hemoglobin concentration mean, mean cell volume, reticulocyte concentration, proportion of macrocytic reticulocytes, and reticulocyte cellular hemoglobin. These findings indicate that horses under erythropoietic stress and after EPO treatment release reticulocytes with unique characteristics into circulation.