Heart Rate, Net Cost of Transport, and Metabolic Power in Horse Subjected to Different Physical Exercises

Central and Peripheral Fatigue Evaluation during Physical Exercise in Athletic Horses by Means of Raman Spectroscopy

The evaluation of the performance levels in athletic horses is of major importance to prevent sports injuries. Raman spectroscopy is an innovative technique that allows for a rapid evaluation of biomolecules in biological fluids. It also permits qualitative and quantitative sample analyses, which lead to the simultaneous determination of the components of the examined biological fluids. On the basis of this, the Raman spectroscopy technique was applied on serum samples collected from five Italian Saddle horses subjected to a standardized obstacle course preceded by a warm-up to evaluate the applicability of this technique for the assessment of central and peripheral fatigue in athletic horses. Blood samples were collected via jugular venipuncture in a vacutainer tube with a clot activator before exercise, immediately after exercise, and 30 min and 1 h after the end of the obstacle course. Observing the obtained Raman spectra, the major changes due to the experimental conditions appeared in the (1300-1360) cm^-1 and (1385-1520) cm^-1 bands. In the (1300-1360) cm^-1 band, lipids and tryptophan were identified; in the (1385-1520) cm^-1 band, leucine, glycine, isoleucine, lactic acid, tripeptide, adenosine, and beta carotene were identified. A significant effect of exercise was recorded on all the sub-bands. In particular, a change immediately after exercise versus before exercise was found. Moreover, the mean lactic concentration was positively correlated with the Raman area of the sub-band assigned to lactic acid. In this context, the application of Raman spectroscopy on blood serum samples represents a useful technique for secondary-structure protein identification to investigate the metabolic changes that occur in athletic horses during physical exercise.

Welfare of equidae during transport

In the framework of its Farm to Fork Strategy, the Commission is undertaking a comprehensive evaluation of animal welfare legislation. This opinion deals with the protection of horses and donkeys during transport. While the opinion focuses primarily on road transport of horses, there are specific sections dealing with the transport of horses on roll-on-roll-off ferries, horses transported by air and the transport of donkeys. In addition, the opinion covers welfare concerns in relation to a specific scenario identified by the European Commission related to the transport of horses on long journeys to slaughterhouses. Current practices related to transport of horses during the different stages (preparation, loading and unloading, transit and the journey breaks) are described. Overall, 13 welfare consequences were identified as being highly relevant for the welfare of horses during transport based on severity, duration and frequency of occurrence: gastro-enteric disorders, handling stress, heat stress, injuries, isolation stress, motion stress, prolonged hunger, prolonged thirst, respiratory disorders, resting problems, restriction of movement, sensory overstimulation and separation stress. These welfare consequences and their animal-based measures are described. A variety of hazards were identified related to factors such as inexperienced/untrained handlers, lack of horse training, structural deficiencies of vehicles/facilities, poor driving skills/conditions, horse separation/regrouping, unfavourable microclimatic and environmental conditions and poor husbandry practices. The opinion contains general and specific conclusions in relation to the different stages of transport. Recommendations to prevent hazards and correct or mitigate welfare consequences have been developed. Recommendations were also developed to define quantitative thresholds for microclimatic conditions within the means of transport and for space allowance. The development of welfare consequences over time was assessed in relation to maximum journey time.

Variations in cost of transport and their ecological consequences: a review

Movement is essential in the ecology of most animals, and it typically consumes a large proportion of individual energy budgets. Environmental conditions modulate the energetic cost of movement (cost of transport, COT), and there are pronounced differences in COT between individuals within species and across species. Differences in morphology affect COT, but the physiological mechanisms underlying variation in COT remain unresolved. Candidates include mitochondrial efficiency and the efficiency of muscle contraction-relaxation dynamics. Animals can offset increased COT behaviourally by adjusting movement rate and habitat selection. Here, we review the theory underlying COT and the impact of environmental changes on COT. Increasing temperatures, in particular, increase COT and its variability between individuals. Thermal acclimation and exercise can affect COT, but this is not consistent across taxa. Anthropogenic pollutants can increase COT, although few chemical pollutants have been investigated. Ecologically, COT may modify the allocation of energy to different fitness-related functions, and thereby influence fitness of individuals, and the dynamics of animal groups and communities. Future research should consider the effects of multiple stressors on COT, including a broader range of pollutants, the underlying mechanisms of COT and experimental quantifications of potential COT-induced allocation trade-offs.

Cost of transport, but not gluteus medius and red blood cells monocarboxylate-transporters density differentiated Brazilian Sport Horses at two performance levels

Cost of transport (COT) and monocarboxylate transporters (MCTs) could affect the ability to perform fast actions during a jumping discipline. This study aimed to compare the COT and evaluate the MCT1, MCT4, and their auxiliary protein CD147 content in the gluteus medius and RBCs of Brazilian sport horses (BH), a breed developed for jumping competitions, with low-level (LL) or intermediate-level (IL) jumping capacities. The physiological difference between the horses was assessed by an incremental jump test (IJT), in which the cost of lactate (COT_LAC) and heart rate (COT_HR) of running were determined for each animal by the ratio between each variable and the running speed. Western blotting was performed on muscle and RBC membranes to quantify MCT1, MCT4, and CD147. IL showed lower COT_LAC and COT_HR than LL at all jumping heights. The amount of MCT1, MCT4, and CD147 found in muscle and RBCs were not dependent on performance level. Muscle MCT4 and MCT1 were correlated positively with CD147. We conclude that the relatively small differences between performances did not relevantly influence MCT expression in BH. While MCT analyses are inaccessible for most trainers and veterinarians, the cost of transport measurements is a feasible and sensitive tool to distinguish intermediate and low-level jumping horses.

How Much Energy Vaquejada Horses Spend in a Field Simulation Test?

Vaquejada is a high-intensity and short-duration exercise in which helper horses (HH) are responsible to keep a bull running in a line while pull horses (PH) work to put the bull down after 100 m of running. The purpose of this study was to quantify and compare energy expenditures (EE), transport costs (COT) and metabolic energy requirements (Pmet) of horses used in Vaquejada. Thus, eight Quarter Horses, in randomly formed pairs, performed a vaquejada simulation test (VST), which consisted of three races on a sand track (130-150 m), with a 5-min interval between them. All horses used an integrated heart rate (HR) and GPS monitoring system (V800, Polar Electro) and, from these data, EE, COT and Pmet were calculated using the formulas: EE (J/kg/min) = 0.0566 × HR^1.9955, COT = (HR-35)/kg/m × 10³ and Pmet = (HR-35)/min/kg. Blood samples were collected for lactate analysis at rest, immediately after the first, second and third race and after 30 min of recovery. Data obtained were submitted to one-way ANOVA and Tukey tests (p ≤ 0.05). In VST, HH had higher EE and higher HR at trot; while PH presented higher EE and HR at canter. Finally, considering total VST, PH had higher EE and COT, while HH had higher Pmet. Lactate was higher in PH. Despite practicing the same sport, PH and HH should be considered distinct athletes, and these must be considered to set up appropriate physical and nutritional programs, which will lead to better performance and guarantees of well-being.

Exploring the Origin and Relatedness of Maternal Lineages Through Analysis of Mitochondrial DNA in the Holstein Horse

Maternal lineages are important for the breeding decision in the Holstein horse breed. To investigate the genetic diversity of the maternal lineages and the relationships between founder mares, the maternal inherited mitochondrial genome (except the repetitive part of the non-coding region) of 271 mares representing 75 lineages was sequenced. The sequencing predominantly revealed complete homology in the nucleotide sequences between mares from one lineage with exceptions in 13 lineages, where differences in one to three positions are probably caused by de novo mutations or alternate fixation of heteroplasmy. We found 78 distinct haplotypes that have not yet been described in other breeds. Six of these occurred in two or three different lineages indicating a common ancestry. Haplotypes can be divided into eight clusters with all mares from one lineage belonging to the same cluster. Within a cluster, the average number of pairwise differences ranged from zero to 16.49 suggesting close maternal relationships between these mares. The results showed that the current breeding population originated from at least eight ancestral founder mares.

Air Speed to Increase Rate of Cool Out for Horses After Intense Exercise

Cooling out horses is a common practice after intense exercise. Typical cooling procedures include both walking and drenching (often with scraping). The cool out is performed to ensure the horses physiologic responses returned to a baseline range as quickly as possible. The use of water in cool out provides the greatest potential for removing heat from the animals. However, adding air velocities that can increase evaporation rates from the horses can potentially increase the rate of cool out; thereby reducing the time until the horses' physiologic measurements return to baseline. This study measured the rate of cool out for 7 Thoroughbreds, which were run on the track for 1 or 1.5 miles. Animals were provided a combination of walking and drenching in addition to 3 fan treatments no fan, fan directed at lateral side, and fan directed at posterior. Physiologic responses were analyzed using the Multivariate analysis of variance (MANOVA) procedure and while no significant differences were found in the rate of cool out, trends indicated both rectal temperature (P = .10) and heart rate (P = .11) returned to baseline more quickly with the addition of a fan.

Plasmapheresis Effect on Hematological and Biochemical Parameters in Athletic Horses Subjected to Exercise

To evaluate the effect of plasmapheresis on clinical, hematological, and biochemical parameters after exercise, a plasmapheresis session was realized on six jumping horses (plasmapheresis group) that underwent three consecutive days of physical graded exercise. The control group (n = 6) went through the same exercise but not subjected to the plasmapheresis session. Seventeen milliliters of plasma/kg of body weight was harvested from each horse. The procedure was well tolerated by the horses. The plasmapheresis leads to a significant increase of the hemoglobin, hematocrit, red blood cell, white blood cell, and lymphocytes counts. Plasmapheresis induced a very significant decrease (P < .001) of albumin and globulin levels and of total protein, which were reestablished 24 hours later. Plasmapheresis also generated a very significant increase (P < .001) in sodium levels and a significant decline of potassium (P < .05) and calcium (P < .01) levels. Several other biochemical variables remained unchanged. Results also showed that, after a significant rise of lactate, aspartate aminotransferase, and creatine kinase levels which are subsequent to the exercise, the plasmapheresis session induced a very significant continuous decrease (P < .001) of these parameters. The present work has demonstrated that the plasmapheresis is able to modify the physiology after exercise and to affect both the hematology and the biochemistry of the blood hematobiochemical parameters in horses subjected to physical exercise.

Workload of official contests, net cost of transport, and metabolic power of Mangalarga Marchador horses of marcha batida or picada gaits

This study aimed to characterize the maximum heart rate (HR) and the intensity of official marcha contests (OMC) and to compare the cost of transport (COT) and metabolic power (Pmet) of Mangalarga Marchador (MM) horses of marcha batida (MB) and marcha picada (MP) gaits. Twenty-two MM horses participated in this study. The experiment was conducted in 3 phases: 1) maximum effort test (MET), 2) OMC, and 3) standardized marcha test (SMT). To characterize the HR, 19 horses (14 MB and 5 MP) underwent a MET. Of those, 13 (9 MB and 4 MP) were monitored during the OMC, which consisted of 4 stages: marcha, walk, functional trial, and rest. The average heart rate (HR) in each stage of the OMC was related to the HR to determine their relative intensity. The SMT was performed with 14 horses (9 MB and 5 MP), of which 11 had already participated in the previous stages. The COT and Pmet were calculated from the HR values obtained during the SMT. Blood samples were collected to analyze plasma lactate concentration ([Lac]). One-way ANOVA or 1-way repeated-measures ANOVA followed by the Tukey's test ( < 0.05) were used to analyze the results. The average HR was 211 ± 11 and 214 ± 11 beats/min (bpm) for the MB and MP groups, respectively, with no difference ( = 0.7066) between them. The [Lac] increased as a result of the MET ( < 0.05), with no difference between groups ( > 0.05). This indicated that horses of both groups had the same physical fitness levels. The OMC stages defined in our study differed ( < 0.05) regarding the relative intensity of the HR, except for the walk and standing stages, which were similar ( = 0.0875). The MP group presented greater COT ( = 0.0247) and Pmet ( = 0.0193). It can be concluded that the mean HR of MM horses (MB and MP) is 212 ± 11 bpm. The OMC of the MM breed can be characterized as an effort of intermittent and submaximal intensity. In addition, the locomotion of the MB horses is probably more energetically efficient than that of MP horses.

Heart rate and velocity in Vaquejada horses during field tests

The use of heart rate (HR) monitors for horse training assessment under field conditions has been expanded because its use facilitates the understanding of horse fitness levels. Work has been carried out to determine the HR, velocity (V) and exercise time for pull and helper horses submitted to the Vaquejada simulation test (VST). The test was used on 70 Quarter Horses that had trained and competed for more than 6 months. The VST consists of two horses, a puller and a helper, and a bull, all running on a soft sand track. A race cycle consists of three runs with the bull. Pull horses run one cycle and helper horses run two cycles. A Polar V800-GPS HR monitor for equines was used to measure several parameters: time, V and HR. The results were analysed by ANOVA and a Tukey test with P set at 5%. It was shown that pull horses developed an HRmax of ~200 bpm and an HRmin ~110 bpm, both higher than the helper horses (P<0.05). However, the HRmed of pull horses (~150 bpm) and helper horses (~139 bpm) in C-2 trials were not substantially different from one another (P>0.05). Additionally, both groups of horses had similar maximum (~8.90 m/s) and average (~1.87 m/s) velocities (P>0.05). In analysing the distribution of HR among five rate categories, we determined that pull horses presented a higher percentage of their HR above 170 bpm in comparison to helper horses (P<0.05). It was concluded that, based on VST results, pull and helper horses presented different HRmax, HRmed and HRmin values, even when V and duration were similar, and that pull horses perform more intensive work than helper horses.

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.

The impact of full vs. half chukka playing strategies on recovery in low goal polo ponies

Polo is a popular equestrian sport; matches comprise of 4-6 periods or chukkas. Players commonly change ponies between chukkas, but can also change ponies within a chukka, known as ‘half-chukkering’, anecdotally believed to ‘save’ the horse by preventing fatigue and facilitating recovery. The current study aimed to test this hypothesis and evaluate the impact of half versus full chukka playing strategies in low goal polo. Resting heart rates (HR) were established for 48 polo ponies competing in low goal tournaments. Riders selected their normal pony playing strategy, either full (n=32) or half (n=15) chukkas. HRs were recorded at the end of play and during recovery; for the full chukka and second half chukka period at 2, 4, 6, 10 and 20 min, or until ponies returned to play after the first half chukka (≥6 min). To enable comparison of recovery from exercise, HR data recorded during recovery was also expressed as a percentage of maximal HR for individual ponies. ANOVA analyses investigated differences during recovery between ponies playing full chukkas and the second half chukka period, and within the two half chukkas played. At the end of play, full-chukka horses' HR were lower than their 2nd half chukka counterparts, 95±13.1 bpm compared to 103±7.7 bpm, but this was not significant (P≯0.05). Significant differences in HR did occur throughout the subsequent recovery period: at 2 min (P<0.003) and between 4-20 min (P<0.0001), with full-chukka ponies recovering faster. No differences occurred during recovery (P≯0.05) between the two half chukka periods although mean HR differed at the end of play (1st: 100±7.7 bpm; 2nd: 103±7.8 bpm). Playing strategies influence ponies' cardiovascular recovery; full chukka ponies recover more quickly than those playing in consecutive half chukkas. Therefore, implementing a full chukka playing strategy is advocated to optimise pony welfare and performance in low goal polo.