Modifications of platelet aggregation during treadmill section and obstacle course in athletic horse

Effect of Regular Training on Platelet Function in Untrained Thoroughbreds

Training has a significant effect on the physiology of blood coagulation in humans and in horses. Several hemostatic changes have been reported after exercise in the horse but data available are inconclusive. The aim of this study was to investigate platelet activation and primary platelet-related hemostasis modifications in young never-trained Thoroughbreds in the first incremental training period in order to improve knowledge on this topic. Twenty-nine clinically healthy, untrained, 2-year-old Thoroughbred racehorses were followed during their incremental 4-month sprint exercise training. Blood collection was performed once a month, five times in total (T-30, T0, T30, T60, and T90). Platelet aggregation was measured by light transmission aggregometry in response to various agonists: adenosine diphosphate (ADP), collagen, and calcium ionophore A23187. Platelet function was evaluated using a platelet function analyzer (PFA-100®) using collagen/ADP and collagen/adrenaline cartridges. Nitrite-nitrate (NOx) plasma concentrations were measured via a colorimetric assay to assess in vivo nitric oxide bioavailability. Platelet activation was also investigated through gene expression analyses (selectin P-SELP, ectonucleotidase CD39-ENTPD1, prostaglandin I2 synthase-PTGIS, endothelial nitric oxide synthase 3-NOS3). Differences among the time points were analyzed and mean ± SEM were calculated. Significant modifications were identified compared with T-30, with an increase in platelet aggregation (collagen:32.6 ± 4.8 vs. 21.6 ± 4.9%; ADP: 35.5 ± 2.0 vs. 24.5 ± 3.1%; A23187: 30 ± 4.7 vs. 23.8 ± 4%) and a shorter closure time of C-ADP cartridges (75.6 ± 4.4 vs. 87.7 ± 3.4 s) that tended to return to the baseline value at T90. NOx concentrations in plasma significantly increased after 30 days of the training program compared with the baseline. The first long-term training period seems to induce platelet hyperactivity after 30 days in never-trained Thoroughbreds. Regular physical training reduces the negative effects of acute efforts on platelet activation.

Effect of acupuncture on hematologic, muscular biomarkers, fibrinogen and serum lactate parameters in training rodeo bulls

The study aimed to evaluated the effects of acupuncture in rodeo bulls in training, by determining hematological variables, creatine kinase (CK), aspartate aminotransferase (AST), fibrinogen, and plasma lactate. Thirty adult healthy bulls, crossbred, were included in the study and randomly allocated into two groups of 15 animals, according to the use of acupuncture treatment for six months (GA) or not (GB). The variables were measured 30 min before (TP₀) and 10 min (TP_10min), 12 (TP_12h), 24 (TP_24h), 48 (TP_48h), and 72 h (TP_72h) after a single episode of jumping emulating rodeo exercise. The GB group showed variations in hemoglobin between TP₀ and TP_10min (p = 0.002) and TP₀ and TP_12h (p = 0.004), and the GA presented an increase in eosinophil values between TP₀ and TP_12h (p = 0.013) and TP₀ and TP_24h (p = 0.034). Leukopenia was observed in GB between TP_10min and TP_72h ((p = 0.008). The CK values were high (↑ 300 UI/l) after exercise until the TP_24h, and decreased in TP_48h, in both groups. The plasma lactate elevation was lower in the GA at TP_10min (p = 0.011), TP_12h (p = 0.008), TP_72h (p < 0.001). The rodeo bulls submitted to acupuncture treatment showed smaller variations in hemogram, elevated eosinophils levels, and lower plasma lactate levels after exercise.

Effect of First Long-Term Training on Whole Blood Count and Blood Clotting Parameters in Thoroughbreds

Training has a strong effect on the physiology of hematological parameters and blood coagulation, both in humans and in horses. Several blood changes have been reported after exercise in horses but available data differ. We aimed to investigate modifications in complete blood count and some hemostatic parameters induced by the first training period in young untrained Thoroughbred racehorses to detect a possible labile blood coagulability in racehorses. Twenty-nine untrained 2-year-old Thoroughbreds were followed during their incremental 4-month sprint exercise schedule. Blood collection was performed once a month, five times (T-30, T0, T30, T60 and T90), before and during the training period for measurement of complete blood count (CBC) and blood clotting parameters (prothrombin time-PT, activated partial prothrombin time-APTT, thrombin clotting time-TCT, fibrinogen-Fb, thrombin-antithrombin complex-TAT). Differences among the time points for each parameter were analyzed (ANOVA, Kruskal-Wallis one-way analysis of variance, p < 0.05). In Thoroughbreds, the first long-term exercise workout period was found to induce a statistical increase in red blood cell indexes and lymphocytes, eosinophils and platelet counts, as well as a hypercoagulability state evident at 30 days of training, which returned to basal levels after 90 days. Regular physical exercise seems to blunt the negative effects of acute efforts on hematological and clotting parameters, an effect that may be attributed to the training condition.

Changes in blood coagulation induced by exercise training in young athletic horses

Prothrombin Time (PT), Activated Partial Prothrombin Time (APTT), Fibrinogen concentration (Fbg) and Platelet number (Plt) were evaluated in 20 young athletic horses during a training program. A standardized exercise test (SET) was performed every month for three months. The V4 variations (the speed, in m/min, reached at the blood lactate concentration of 4 mmol/l) obtained for each test were calculated to assess the effect of training program on athletic performance. Blood samples were collected at 20-day intervals over a period of 80 days from the beginning of the training program. The V4 (P < 0.001), PT (P < 0.001), APTT (P < 0.01), Fbg (P < 0.01) and Plt (P < 0.001) varied throughout the training period showing that the modifications of clotting mechanism in response to training period may be considered as a normal physiological response of the hemostatic system to training exercise.