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Clenbuterol (β

Clenbuterol, (RS)-1-(4-amino-3,5-dichlorophenyl)-2-(tert-butylamino)ethan-1-ol, as Ventipulmin is an FDA approved β2 agonist medication for the management of airway obstruction in horses. Administration above the FDA approved doses for clenbuterol produces repartitioning effects, which have led to restrictions on its use in human athletics and Quarter Horse and Thoroughbred racing. Clenbuterol, however has long been used therapeutically at FDA approved doses in Harness racing. The goal of this study was to identify a withdrawal time guideline for its use at FDA approvsed dose levels in Harness racing, where horses may start at seven-day intervals. Eight healthy, moderately fit Standardbred horses (4 mares, 4 geldings, weight 491±40 kg, age 13±2 years) were administered 0.8 μg/kg of clenbuterol as Ventipulmin syrup twice daily (BID) for three days. Blood samples were collected prior to dosing and at 1, 24, 48 and 96 h post administration. Clenbuterol was quantified in all samples using the New York Drug Testing and Research Laboratory ISO-17025 Racing and Medication Testing Consortium (RMTC) accredited quantitative procedure. The lower limit of quantitation of the method was 1.0 pg/ml, and three data points at 96 h post administration were censored. One horse developed diarrhoea and data from this horse was excluded from the overall analysis. Plasma regulatory thresholds were calculated using the 95/95 tolerance method and Gauss Camp Meidell at P=0.05 and P=0.001. Horses were also evaluated for effects of clenbuterol on body composition using body mass and ultrasound measurements of rump fat thickness. There were no effects (P>0.05) of clenbuterol on any of the measures including fat mass and fat free mass and thus no repartitioning effect was observed. The pharmacokinetic data and the 96 h data set support the therapeutic use of clenbuterol in Harness horses at the FDA approved 0.8 μg/kg BID dose for three days and suggest a 41 pg/ml regulatory threshold for a 96 h withdrawal time with a P=0.001 probability of randomly exceeding this regulatory threshold.

The objective of this study was to investigate the changes in Glut-4 expression in gluteus muscle, and in the plasma concentrations of hormones and metabolites during the suckling period, after weaning, and after exercise training in foals. Our hypotheses were Glut-4 abundance will decrease following metabolite and hormonal concentration between neonatal period and late development but will increase with exercise training. Eight clinically normal Standardbred foals were used in this study, and they stayed with their mothers from birth until weaning at 6 months. After weaning, the foals were randomly divided in two groups: an exercise group (EX) (n=4; ~282 kg) which trained 3 d/wk for 12 wks and a control group (n=4; ~271 kg) without structured exercise. Venous blood samples were obtained immediately after birth (0.05). Plasma lactate, insulin and cortisol concentrations decreased during the first three months of lactation while glucose and leptin concentrations increased (P0.05). In conclusion, Glut-4 abundance in gluteus muscle was highest at the birth and decreased during development and exercise training for 12 weeks did not change its’ abundance.

A commonly held belief is that lactate production during exercise limits performance via fatigue. The current study aimed to assess the effects of a supplement marketed as performance enhancing (Lactanase®) on equine exercise performance and plasma lactate concentrations. Lactanase was expected to alter exercise performance and plasma lactate. Eight healthy, unfit Standardbred horses (four geldings and four mares, 9±3 years, 489±33 kg, mean ± standard error) were administered Lactanase (5 doses of 25 g) top-dressed on a commercial pelleted ration or unsupplemented pellets (Control) in a cross-over design experiment. Doses were administered over a four-day period and horses performed a graded exercise test on the fourth day following the final dose of either Lactanase or control. Blood samples (20 ml) were obtained via jugular catheter 30 min prior to exercise, immediately prior to exercise, in the last 10 s of each incremental exercise step, and 5 and 60 min post-exercise. Samples were frozen at -80 °C until further analysis. Data were analysed using a two-way repeated measures ANOVA. Statistically different means were separated using Student-Newman-Keuls and Dunnetts. No differences (P>0.05) in total run time were observed following Lactanase administration. Plasma lactate increased (P0.05) of Lactanase on the plasma lactate response during exercise. Similarly, supplementation did not affect (P>0.05) plasma glucose or total protein at any time point. Exercise did increase plasma total protein (P

Cobalt is a required trace element in animals, but administration in excess is considered dangerous and potentially performance enhancing in equine athletes. This study seeks to determine if cobalt may actually act as a performance enhancing drug (PED) by altering biochemical parameters related to red blood cell production as well as markers of aerobic and anaerobic exercise performance. In addition, for adequate regulation of naturally occurring substances, such as cobalt, its distribution among the population must be defined. In order to identify this distribution, plasma Cobalt was determined from 245 Standardbred horses with no cobalt supplementation from farms in New York and New Jersey, including horses at the Rutgers University Equine Science Center. Samples were analysed by Inductively Coupled Plasma Mass Spectrometry. Seven healthy, race fit Standardbreds (4 geldings, 3 mares, age: 5±3 years, ~500 kg) were used for the PED experiment. An incremental graded exercise test (GXT) to measure maximal aerobic capacity (V̇O2max) and markers of performance, measurement of plasma volume and blood volume as well as the measurement of lactate, erythropoietin (EPO), and various blood haematological factors were determined 7 days prior to cobalt administration. Each horse was administered a sterile solution of cobalt salts (50 mg of elemental Co as CoCl2 in 10 ml of saline, IV) at 9 AM on three consecutive days via the jugular vein. Blood samples were obtained from the contralateral jugular vein before and at 1, 2, 4 and 24 h after administration. Plasma and blood volume were measured one day after the last dose of cobalt, and a post administration GXT was performed the next day. Horses were observed for signs of adverse effects of the cobalt administration (agitation, sweating, increased respiration, etc.). Plasma cobalt concentration increased from a pre-administration mean of 1.6±0.6 to 369±28 μg/l following 3 doses of the cobalt solution (P0.05). There were no observed adverse effects.

metabolomics is the high-throughput, multiparametric identification and classification of hundreds of low molecular weight metabolites in a biological sample. Ultimately, metabolites are the downstream readouts of cellular signalling, transcriptomic and proteomic changes that can provide a comprehensive view of tissue and organismal phenotype. The popularity of metabolomics in human sport and exercise has been gaining over the past decade and has provided important insights into the energetic demands and mechanistic underpinnings of exercise and training. To the contrary, metabolomics in the field of equine exercise physiology is lagging despite the horse's superior aerobic and muscular capabilities, as well as its prominence in competitive sport. As such, this narrative review aims to describe metabolomics, its routine implementation, the various analytical methods applied and the state of its use in the equine athlete. Sufficient attention will be paid to methodological considerations, as well as gaps in the equine literature, particularly with regard to the skeletal muscle metabolome. Finally, there will be a brief discussion of the future directions and barriers to metabolomics use in the athletic horse. A thorough understanding of the metabolomics changes that occur in the equine athlete with exercise will undoubtedly help to improve horse management and health across the lifespan.

This study tested the hypothesis that 12 weeks of training would significantly alter maximal aerobic capacity (VO2max), running capacity, and body composition in mature Standardbred horses, and that these alterations would be maintained over an additional 60 weeks of training. It was also hypothesised that there would be a reversal of the training-induced adaptations with 20 weeks of detraining. Eight rested Standardbred horses (n=4 mares, n=4 geldings, 3-8 years) were trained for 72 weeks and then undertook 20 weeks of detraining in groups of four per two-acre paddocks. Body composition, VO2max, run time to fatigue, and distance completed were assessed before training, at 12 and 72 weeks of training, and after 20 weeks of detraining (92 weeks). VO2max (P

The purpose of this study was to examine the effects of an external nasal strip on thermoregulation during submaximal exercise in Standardbred horses. While several studies have been conducted to determine the effects of the external nasal strip on airway resistance, exercise induced pulmonary hemorrhage, gas exchange, and time to fatigue in maximally exercising horses, the effects of the nasal strip on equine thermoregulation have not yet been examined. It was hypothesized that the application of an external nasal strip would alter central venous temperature (T

Objective, automated early lameness detection plays an important role for animal well-being. The work in this paper uses horse locomotion data collected by wearable inertial measurement units, extracts gait cycle routines and constructs a multi-layer classifier for horse lameness detection, identification, and evaluation. Multi-layer classifier (MLC) is based on support vector machine and K-Nearest-Neighbors methods. Each layer is independently designed and works as a binary classifier. Horse gait classification and limb lameness detection and evaluation are then handled by each layer successively. Experiment results show that the MLC achieves 94 % detection accuracy and also generates superior performance than a deep convolutional neural network-based multiclass classifier in terms of various assessment criteria.

Sturkie's Avian Physiology is a highly regarded textbook for the study of comparative poultry physiology. Less well known, however, is the contribution of Paul D. Sturkie (1909-2002) as a pioneer in the experimental physiology of avian species. His seminal research on the cardiovascular and hemodynamic controls of chickens and egg-laying hens had a notable impact on the poultry industry and breeding practices of farmers. The purpose of this article is to highlight the contributions and practical insights of Paul D. Sturkie to the field of poultry science.

Two groups of unfit Standardbred mares (adult: 9-14 years, 540 kg, n=7) and old (20-25 years, 530 kg, n=5) were used to test two hypotheses, first, that aging and training would alter plasma and muscle glutamine [Gln] and glutamate [Glu] and second, that aging and training would alter Glut-4 expression in skeletal muscle. All animals were housed on pasture with free access to grass and all received hay and supplementation with a commercially prepared supplement (15% crude protein and 3.00 Mcal/kg dry matter) in individual stalls. Mares were fed to meet or exceed NRC (2007) nutrient recommendations for moderate to heavy exercise. The mares were exercise trained in a free-stall motorised circular exercise machine for 30 min/d, 5 d/week, for 8 weeks. Work intensity during training was set at a relative intensity of ~60% of the maximum heart rate, previously determined during an incremental exercise test (GXT). Blood samples and muscle biopsies (gluteus) obtained before and after 8 weeks of training were used for measurement of [Gln], [Glu] and Glut-4 abundance. Samples were collected before the initiation of training and at 24 h after cessation of last bout of exercise in the training period. All samples were immediately frozen in liquid nitrogen and stored at -80 °C until enzymatic analysis for [Gln], [Glu] and Western Blot analysis for Glut-4 protein abundance. Data were analysed by one-way or two-way ANOVA for repeated measures and the Pearson correlation method. Post-hoc differences were identified with the Tukey test. Significance was set at P0.05) in muscle [Glu] due to aging. Training decreased (P0.05) due to training. Glut-4 abundance analysis did not differ (P>0.05) between the young adult and old horses; however, there was a trend (P=0.063) towards an effect of training when samples from both groups were pooled. It was concluded that training and aging produce changes in plasma and muscle [Gln], which may affect immune function in athletic horses, but not in Glut-4.

While exercise has been found to change the faecal microbiome (FM) in laboratory animals exposed over weeks, no studies have identified immediate changes in the FM associated with short spans of intense exercise, ~5 min. The purpose of this study was to test the hypothesis that acute intense exercise would alter the FM in horses. Each horse performed two rounds of testing undergoing both a graded exercise test (GXT) and a parallel standing control (SC) trial before (GXT1 and SC1) and after (GXT2 and SC2) 12 weeks of exercise training. Rectal faecal samples were taken 24 h before and after testing. Bacterial community analysis was done by sequencing the 16s rRNA (V3-V4) region via Illumina Miseq. The relative abundance of the genus Clostridium significantly decreased in SC1 (P0.05). Our results indicate that very intense acute exercise does not alter the faecal microbiome of the Standardbred race horse and that 12 weeks of exercise training does not alter that response.

Effects of social isolation, sham clipping, and novel object exposure on muscular and behavioral responses were investigated in horses. Humans increase muscular tension under psychologically or physically demanding situations and thus, similar conditions were expected to alter stress responses in horses. Eight mature Standardbreds (4 mares, 4 geldings) were exposed to 3 min of social isolation (ISO), sham clipping (CLIP), novel object (NOV), and control (CON) conditions in a replicated 4×4 Latin Square experimental design with 10 min washout periods. Surface electromyography (EMG) and stress-related behaviors were recorded continuously. Median frequency (MF) and average rectified value (ARV) of the EMG signal were calculated for the first, middle, and final 10 sec of each period. EMG data were log transformed prior to analysis with a mixed model, repeated measures ANOVA. Behavior data were analyzed using a negative binomial distribution mixed model ANOVA. Significantly different means were separated using Tukey’s method. More stress-related behaviors (P < 0.05) were observed during ISO (3.25 ± 0.26, LSM ± SE) than CON (1.46 ± 0.29) or CLIP (1.50 ± 0.36). ISO tended (P = 0.054) to produce more stress-related behaviors than NOV (2.31 ± 0.28). CLIP and ISO produced higher (P < 0.05) ARV than CON or NOV in the left and right masseter. CLIP elicited the highest (P < 0.05) MF in the left and right masseter with ISO resulting in lower (P < 0.05) MF than CON. ARV was higher (P < 0.05) in the left cervical trapezius during ISO as compared to all other conditions and in the right as compared to CON and CLIP. In the right cervical trapezius, ISO elicited higher (P < 0.05) MF than CON. Increased stress-related behaviors indicate a stress response was induced. Elevated muscular activity suggests muscular tension can be used in assessing stress.

Anecdotal evidence suggests high horse turnover is a concern in the field of equine assisted services (EAS) with potential negative effects on sustainability. Members of key EAS organizations (American Hippotherapy Association; Professional Association of Therapeutic Horsemanship, International; eagala; Certified Horsemanship Association for a total of 26,000 recipients) were surveyed to characterize horses in EAS programs, their use, and causes of retirement. We expected respondents to indicate horses remained in their programs for relatively short periods of time and list behavior as a leading cause of retirement. The survey (QualtricsⓇ) was distributed via email using a repeat contact strategy of 4 contacts spaced 2–4 wk apart. Descriptive statistics were computed in SAS (v 9.4). Kendall's correlation with Bonferroni correction was used to analyze relationships of retirement causes and longevity with selection procedures and workload. Respondents (n = 176 completed responses; 0.14% response rate) reported 12 ± 8 (mean ± SD) horses and ponies were active in their programs. Animals ranged in age from less than 5 yr (2 ± 5% of animals in program) to 36–40 yr (0.1 ± 1.3%) with the greatest number falling between 16 and 20 yr (34% ± 22%). Donation (40 ± 34% of animals in program), purchase from private owner (23 ± 31%), and free lease (18 ± 26%) were reported as the most common means of acquiring horses and ponies. Animals had been active in the program for less than one yr (4.5 ± 12% of animals in program) to over 20 yr (4.4 ± 18%) with the greatest percentage of animals active for 1–5 yr (37 ± 35%) followed by 6–10 yr (31 ± 31%). Respondents indicated horses and ponies typically worked anywhere from 0 to 1 h/wk (0.6% of respondents) to 42–48 h/wk (0.6%) with the largest number working 4–8 h/wk (20%). When asked reasons for retiring horses and ponies, respondents ranked (1 = most frequent; 7 = least frequent) age (2, 1–3; median, IQR), behavior (2, 1–3), and unsoundness (2, 1–3) as the most frequent reasons followed by burnout (2.5, 1–4), other health issues (3, 2–3), death (4, 2–4), lease expiration (5, 3.5–5), and other reasons. Selection procedures and workload were not significantly corelated with reason for retirement or longevity. Further research is needed to understand how burnout, a behaviorally assessed state, differs from behavioral reasons for retirement and its implications. Collection and analysis of other variables, potentially at an individual animal level, is needed to further our understanding of factors contributing to horse longevity and retirement.

There are many choices for methods of extracting bacterial DNA for Next Generation Sequencing (NGS) from fecal samples. Here, we compare our modifications of a phenol/chloroform extraction method plus an inhibitor removal solution (C3) (ph/Chl+C3) to the PowerFecal® DNA Isolation Kit (MoBio-K). DNA quality and quantity coupled to NGS results were used to assess differences in relative abundance, Shannon diversity index, unique species, and principle coordinate analysis (PCoA) between biological replicates. Six replicate samples, taken from a single ball of horse feces manually collected from the rectum, were subjected to each extraction method. The Ph/Chl+C3 method produced 100× higher DNA yields with less shearing than the MoBio-K method. To assess the methods, the two method samples were sent for sequencing of the bacterial V3-V4 region of 16S rRNA gene using the Illumina MiSeq platform. The relative abundance of Bacteroidetes was greater and there were more unique species assigned to this group in MoBio-K than in Ph/Chl+C3 (P

Exercise has a significant effect on different physiological systems in the body of human and animals. Only limited numbers of published studies in laboratory animals or humans have shown the effect of exercise on the gut microbiota, and no studies have shown this effect in horses. In this study, 8 horses (4 mares, 4 geldings) were exercise trained for 12 weeks, and 4 additional mares were used as a parallel seasonal control. To identify bacterial community changes over time for both groups, rectal faecal samples were collected, DNA was extracted, and the 16S rRNA gene (V3-V4) was sequenced using the Illumina Miseq platform. One-way ANOVA, Shannon diversity index, and Principal Coordinate Analysis (PCoA) were used to identify differences between and among samples. The exercise training group showed significant changes in the levels of Bacteroidetes, Proteobacteria, and Spirochaetes phyla (P0.05). Moreover, with training two genera significantly changed in their relative abundance over time, namely Clostridium and Dysgonomonas (P

An antioxidant derived from a variety of melon purported to be high in superoxide dismutase was fed to horses and the effect on performance and recovery was measured following repeated daily bouts of intense exercise. In a cross-over design study, six unfit Standardbred mares were fed this antioxidant at a rate of 2.0 IU/kg body weight (BW)/d as part of the daily ration for 4 weeks before undergoing a simulated race test (SRT) repeated over a 3-day period. The SRT, designed to simulate the training of Standardbreds, consisted of a 2 min warm-up at 6 m/s followed by a high speed run to fatigue at 125% of the speed calculated to correspond to the horse’s maximal aerobic capacity (VO2max) as determined in a baseline incremental exercise test. Measurements included VO2 and the VO2 recovery time, VO2 at the point of recovery, run time, as well as plasma lactate, and plasma cortisol. Oxidative stress was measured by assessing malondialdehyde (MDA). The results from the study demonstrated that there were no differences (P>0.05) in mean values for the plasma concentrations of lactate, cortisol, or MDA. However, when supplemented with this antioxidant, there was an observable pattern with a small-to-medium effect size of an increase average run time of 14 s. Another important observation was that despite the longer run time, there was a moderate effect for a faster VO2 recovery time. The data suggest that supplementation with 2.0 IU/kg BW of this antioxidant had a modest but non-significant effect on performance and recovery time. Additionally, it did not negatively impact physiology in untrained Standardbred mares.

To test the hypotheses that erythropoietin (rhuEPO) treatment increases systemic hematocrit, maximal O2 uptake (VO2max, by elevated perfusive and diffusive O2 conductances) and performance five female horses (4-13 years) received 15 IU/kg rhuEPO (erythropoietin) three times per week for three weeks. These horses had been splenectomized over 1 year previously to avoid confounding effects from the mobilization of splenic red blood cell reserves. Each horse performed three maximal exercise tests (one per month) on an inclined (4°) treadmill to the limit of tolerance; two control trials and one following EPO treatment. Measurements of hemoglobin concentration ([Hb] and hematocrit), plasma and blood volume, VO2, cardiac output as well as arterial and mixed venous blood gases were made at rest and during maximal exercise. EPO increased resting [Hb] by 18% from 13.3 ± 0.6 to 15.7 ± 0.8 g/dL (mean ± SD) corresponding to an increased hematocrit from 36 ± 2 to 46 ± 2% concurrent with 23 and 10% reductions in plasma and blood volume, respectively (all P