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Horse racing and training is a physically demanding sport. The aims of this study were to quantify the physical activities of jockeys during a working week and to investigate self-reported fall and injury incidence rates of jockeys at work. A daily workload diary examining workday and physical activities was emailed to all jockeys licensed to ride in a race in New Zealand in 2020. Sixty-three jockeys (25 apprentices, 33 professional and 5 amateur riders) began the diary, representing 38% of the licensed population of jockeys in New Zealand. Jockeys worked a median of 44 (interquartile range (IQR) 33-57) hours, 6-days per week. A median of 7 (IQR 6-9) horses were ridden per day, comprising 58% of work time, with 11 (IQR 7-15) hours per week spent at training pace. Elite jockeys (high performance in the premiership table) spent more time riding in races (1.1, IQR 0.7-1.2 hours per week) than non-elite jockeys (0.0, 0.0-0.4, P=0.01), with 29% (IQR 0-54%) of their weekly rides as race rides. Extra physical training was conducted by 72% of jockeys, which consisted mainly of low intensity exercise such as pleasure riding (56%) and walking (43%). Falls during morning exercise work were recorded by 87% of respondents, 40% of which had sustained an injury in the previous 12 months. Jockeys who participated in extra physical training had higher fall incidence rates per 1000 horses ridden in morning exercise work (3.5, 95% confidence interval (CI) 3.1-3.9, P=0.002) but lower fall incidence rate in race riding (2.1, 95% CI 1.5-2.8, P

Context The type of forage offered to horses varies in physical form, moisture content and nutrient quality, and these variables could affect the intake, passage rate and digestibility of the forage consumed. Aims To investigate the changes in passage rate of digesta through the gastrointestinal tract in horses fed four different forage-based diets (diet effect). Methods Thoroughbred mares (n = 6) were stabled in loose boxes for 6 weeks. During Weeks 1, 3 and 5 (washout periods), all horses were fed freshly cut pasture, either in restricted quantities (Week 1) or ad libitum (Weeks 3 and 5). Using a 3 × 3 Latin square design during Weeks 2, 4 and 6, each pair of horses was abruptly transitioned to one of three conserved forage-based diets (chopped ensiled forage fed exclusively or with oats, or perennial ryegrass hay with oats) fed ad libitum. At the beginning of each week, indigestible polyethylene markers (n = 200) were administered to the horses via a nasogastric tube, followed immediately by transition to the new diet. Key results There was a significant diet effect on the daily dry-matter intake of feed (P < 0.0001), percentage of time spent eating (P < 0.001), frequency of voiding faeces (P < 0.05) and quantity of faeces voided (P < 0.0001). There was a significant horse effect on the daily dry-matter intake of feed (P < 0.0001) and quantity of faeces voided (P < 0.0001), but no differences in the percentage of time spent eating or the frequency of voiding faeces. There were significant diet and horse effects on the time to recovery of the first marker in the faeces (P < 0.01 and P < 0.01 respectively) and the mean retention time of markers in the gastrointestinal tract (P < 0.05 and P < 0.001 respectively). Mean retention time was negatively correlated with feed intake and quantity of faeces voided (r2 = –0.51 and r2 = –0.64 respectively). Conclusions Longer mean retention time was associated with a greater fibre content in the diet and a restricted feed supply, thus supporting the hypothesis that horses alter mean retention time on the basis of a nutrient absorption optimisation model. Implications Feed composition, but also the quantities offered, may alter measurement of apparent feed digestibility in horses.

This narrative review collates data from different equestrian disciplines, both amateur and professional, to describe the physiological demands, muscle activity and synchronicity of movement involved in jockeys riding in a race and to identify limitations within our current knowledge. A literature search was conducted in Web of Science, Google Scholar, PubMed and Scopus using search terms related to jockeys, equestrian riders and their physiological demands, muscle use, movement dynamics and experience. Abstracts, theses and non-peer reviewed articles were excluded from the analysis. Jockeys work at close to their physiological capacity during a race. The quasi-isometric maintenance of the jockey position requires muscular strength and endurance, specifically from the legs and the core, both to maintain their position and adapt to the movement of the horse. Synchronous movement between horse and rider requires a coordinated activation pattern of the rider’s core muscles, resulting in less work done by the horse to carry the rider, possibly leading to a competitive advantage in race riding. Reports of chronic fatigue in jockeys demonstrate poor quantification of workload and recovery. The lack of quantitative workload metrics for jockeys’ limits calculation of a threshold required to reach race riding competency and development of sport-specific training programmes. Until the sport-specific demands of race riding are quantified, the development of evidence-based sport specific and potentially performance enhancing jockey strength and conditioning programmes cannot be realised.

After establishing a baseline of stipendiary stewards' reporting using the paper-based system in the 2015/16 and 2016/17 seasons of harness racing, it is important to examine if the implementation of an online system has altered frequency and descriptors used for clinical outcomes. The objective of this study was to describe the race level injury and reporting outcomes, and horse- and race-level variables associated with the rate of the reporting of these outcomes during the 2019/20 and2020/21 harness racing seasons in New Zealand. The introduction of the online system was associated with few (0.01%) miscoding events associated with horse identification. There was a shift in the frequency of reporting non-incident examinations, possibly due to better definition and prompts within the online system. The coding category, no observable abnormalities detected (NOAD) had the greatest number of entries, reflecting that the majority of examinations were associated with general screening rather than adverse events occurring during warm-up or the race. The frequency of recordings for most clinical findings was consistent between the old paper-based system and the new online system. The incidence of musculoskeletal fractures remained low (0.12 per 1,000 starts, 95%CI = 0.05-0.28). The online system has the potential to provide a useful tool to prospectively monitor the reporting of injuries and conditions associated with harness racing in New Zealand.

BACKGROUND Strongylid and ascarid parasites are omnipresent in equine stud farms, and ever-increasing levels of anthelmintic resistance are challenging the industry with finding more sustainable and yet effective parasite control programs. OBJECTIVES To evaluate egg count levels, bodyweight and equine health under defined parasite control protocols in foals and mares at two Standardbred and two Thoroughbred stud farms. STUDY DESIGN Longitudinal randomised field trial. METHODS A total of 93 foals were enrolled and split into two treatment groups, and 99 mares were enrolled and assigned to three treatment groups. All horses underwent a health examination, and episodes of colic or diarrhoea were recorded at each faecal collection date. Bodyweights were assessed using a weight tape, and mares were body condition scored. Group A foals (FA) were dewormed at 2 and 5 months of age with a fenbendazole/ivermectin/praziquantel product, while group B foals (FB) were dewormed on a monthly basis, alternating between the above-mentioned product and an oxfendazole/pyrantel embonate product. Group A mares (MA) were dewormed twice with fenbendazole/ivermectin/praziquantel, group B mares (MB) were dewormed with the same product, when egg counts exceeded 300 strongylid eggs per gram, and group C mares (MC) were dewormed every 2 months, alternating between the two products. Health data were collected monthly for 6 months (foals) and bimonthly for 13 months (mares). Data were analysed with mixed linear models and interpreted at the α = 0.05 significance level. RESULTS There were no significant bodyweight differences between foal groups, but MA mares were significantly lighter than the other two groups. Very few health incidents were recorded. Foals in group FA had significantly higher ascarid and strongylid egg counts, whereas no significant differences were observed between mare groups. MAIN LIMITATIONS Study duration limited to one season. CONCLUSIONS Anthelmintic treatment intensity was lowered from the traditional intensive regimes without measurable negative health consequences for mares and foals.

Purpose: To enhance performance in race riding, knowledge of current training workload is required. The objectives of this study were to quantify the physiological demands and profile the muscle activity of jockeys riding track-work. Methods: Ten apprentice jockeys and 48 horses were instrumented with heart-rate monitors, accelerometers, and a surface electromyography BodySuit (recording 8 muscle groups: quadriceps, hamstrings, gluteal, lower back, obliques, abdominal, trapezial, and pectoral) that recorded continuously while riding their normal morning track-work. Data were extracted and time matched into 200-m sections for analysis once the jockey reached steady-state canter (6.9 m·s−1). Results: Jockeys rode a mean (±SD) of 6 (1) horses each morning over 2.5 hours, spending ∼30 minutes at a canter (8.8 [ 0.7] m·s−1), with mean heart rate of 129 (11) beats·min–1 and ratings of perceived exertion representing easy-/moderate-intensity exercise. Mean magnitude of horse (0.17 [0.01] m) and jockey center of mass (0.16 [0.02] m) displacement per stride differed from that of the jockey’s head (0.11 [0.01] m, P P Conclusions: The physiological demands of riding track-work were low, with no evidence of fatigue. Future research on jockeys in races as comparison would identify the specific requirements of a jockey-specific physical conditioning program.

Vitamin D requirements for most animals are expected to be fulfilled through daily exposure of the skin to solar ultraviolet B radiation. The synthesis of vitamin D

Background Mesenchymal stromal cells (MSCs) are believed to be hypoimmunogeneic with potential use for allogeneic administration. Methods Bone marrow was harvested from Connemara (n = 1), Standardbred (n = 6), and Thoroughbred (n = 3) horses. MSCs were grouped by their level of expression of major histocompatibility factor II (MHC II). MSCs were then sub-grouped by those MSCs derived from universal blood donor horses. MSCs were isolated and cultured using media containing fetal bovine serum until adequate numbers were acquired. The MSCs were cultured in xenogen-free media for 48 h prior to use and during all assays. Autologous and allogeneic MSCs were then directly co-cultured with responder leukocytes from the Connemara horse in varying concentrations of MSCs to leukocytes (1:1, 1:10, and 1:100). MSCs were also cultured with complement present and heat-inactivated complement to determine whether complement alone would decrease MSC viability. MSCs underwent haplotyping of their equine leukocyte antigen (ELA) to determine whether the MHC factors were matched or mismatched between the donor MSCs and the responder leukocytes. Results All allogeneic MSCs were found to be ELA mismatched with the responder leukocytes. MHC II-low and universal blood donor MSCs caused no peripheral blood mononuclear cell (PBMC) proliferation, no increase in B cells, and no activation of CD8 lymphocytes. Universal blood donor MSCs stimulated a significant increase in the number of T regulatory cells. Neutrophil interaction with MSCs showed that universal blood donor and MHC II-high allogeneic MSCs at the 6 h time point in co-culture caused greater neutrophil activation than the other co-culture groups. Complement-mediated cytotoxicity did not consistently cause MSC death in cultures with active complement as compared to those with inactivated complement. Gene expression assays revealed that the universal blood donor group and the MHC II-low MSCs were more metabolically active both in the anabolic and catabolic gene categories when cultured with allogeneic lymphocytes as compared to the other co-cultures. These upregulated genes included CD59, FGF-2, HGF, IDO, IL-10, IL-RA, IL-2, SOX2, TGF-β1, ADAMSTS-4, ADAMSTS-5, CCL2, CXCLB/IL-8, IFNγ, IL-1β, and TNFα. Conclusions MHC II-low MSCs are the most appropriate type of allogeneic MSC to prevent activation of the innate and cell-mediated component of the adaptive immune systems and have increased gene expression as compared to other allogeneic MSCs.

The management of competition horses in New Zealand often involves rotations of short periods of stall confinement and concentrate feeding, with periods of time at pasture. Under these systems, horses may undergo abrupt dietary changes, with the incorporation of grains or concentrate feeds to the diet to meet performance needs, or sudden changes in the type of forage fed in response to a lack of fresh or conserved forage. Abrupt changes in dietary management are a risk factor for gastrointestinal (GI) disturbances, potentially due to the negative effects observed on the population of GI microbiota. In the present study, the faecal microbiota of horses was investigated to determine how quickly the bacterial communities, (1) responded to dietary change, and (2) stabilised following abrupt dietary transition. Six Thoroughbred mares were stabled for six weeks, consuming freshly cut pasture (weeks 1, 3 and 5), before being abruptly transitioned to conserved forage-based diets, both offered ad libitum. Intestinal markers were administered to measure digesta transit time immediately before each diet change. The conserved forage-based diets were fed according to a 3 × 3 Latin square design (weeks 2, 4 and 6), and comprised a chopped ensiled forage fed exclusively (Diet FE) or with whole oats (Diet FE + O), and perennial ryegrass hay fed with whole oats (Diet H + O). Faecal samples were collected at regular intervals from each horse following the diet changes. High throughput 16S rRNA gene sequencing was used to evaluate the faecal microbiota. There were significant differences in alpha diversity across diets (p &lt, 0.001), and a significant effect of diet on the beta diversity (ANOSIM, p = 0.001), with clustering of samples observed by diet group. There were differences in the bacterial phyla across diets (p &lt, 0.003), with the highest relative abundances observed for Firmicutes (62–64%) in the two diets containing chopped ensiled forage, Bacteroidetes (32–38%) in the pasture diets, and Spirochaetes (17%) in the diet containing hay. Major changes in relative abundances of faecal bacteria appeared to correspond with the cumulative percentage of intestinal markers retrieved in the faeces as the increasing amounts of digesta from each new diet transited the animals. A stable faecal microbiota profile was observed in the samples from 96 h after abrupt transition to the treatment diets containing ensiled chopped forage. The present study confirmed that the diversity and community structure of the faecal bacteria in horses is diet-specific and resilient following dietary transition and emphasised the need to have modern horse feeding management that reflects the ecological niche, particularly by incorporating large proportions of forage into equine diets.

OBJECTIVE To evaluate the elastic modulus of various ligaments of the forelimbs of cadaveric horses. SAMPLE 408 ligaments from 37 forelimbs of 10 Thoroughbred cadavers and cadavers of 9 other horse breeds. PROCEDURES Collateral ligaments and straight and oblique sesamoid ligaments were harvested from the proximal interphalangeal, metacarpophalangeal, carpal, and elbow joints of both forelimbs of all 19 horses. Ligament dimensions were measured, and the elastic modulus was determined by tensile testing the ligaments with a strain rate of 1 mm•s−1. RESULTS Elastic modulus of the ligaments differed significantly among joints. Highest mean ± SE elastic modulus was for the medial collateral ligament of the metacarpophalangeal joints of Thoroughbreds (68.3 ± 11.0 MPa), and the lowest was for the lateral collateral ligament of the elbow joints of other breeds (2.8 ± 0.3 MPa). Thoroughbreds had a significantly higher elastic modulus for the collateral ligaments of the proximal interphalangeal and metacarpophalangeal joints, compared with values for the other breeds. There was large variation in elastic modulus. Elastic modulus was negatively affected by age. In the ligaments in the distal aspect of the forelimbs, elastic modulus was negatively affected by height at the highest point of the shoulders (ie, withers). CONCLUSIONS AND CLINICAL RELEVANCE Cross-sectional area and elastic modulus of collateral ligaments in the forelimbs of equine cadavers differed between breeds and among joints, which may have been reflective of their relative physiologic function under loading during exercise.

Seasonal variation in the faecal microbiota of forage-fed horses was investigated over a 12-month period to determine whether the bacterial diversity fluctuated over time. Horses (n = 10) were maintained on pasture for one year, with hay supplemented from June to October. At monthly intervals, data were recorded on pasture availability and climate (collected continuously and averaged on monthly basis), pasture and hay samples were collected for nutrient analysis, and faecal samples were collected from all horses to investigate the diversity of faecal microbiota using next-generation sequencing on the Illumina MiSeq platform. The alpha diversity of bacterial genera was high in all samples (n = 118), with significantly higher Simpson’s (p &lt, 0.001) and Shannon-Wiener (p &lt, 0.001) diversity indices observed during the months when horses were kept exclusively on pasture compared to the months when pasture was supplemented with hay. There were significant effects of diet, season, and month (ANOSIM, p &lt, 0.01 for each comparison) on the beta diversity of bacterial genera identified in the faeces. While there was some inter-horse variation, hierarchical clustering of beta diversity indices showed separate clades originating for samples obtained during May, June, and July (late-autumn to winter period), and January, February, and March (a period of drought), with a strong association between bacterial taxa and specific nutrients (dry matter, protein, and structural carbohydrates) and climate variables (rainfall and temperature). Our study supports the hypothesis that the diversity and community structure of the faecal microbiota of horses kept on pasture varied over a 12-month period, and this variation reflects changes in the nutrient composition of the pasture, which in turn is influenced by climatic conditions. The findings of this study may have implications for grazing management and the preparation of conserved forages for those horses susceptible to perturbations of the hindgut microbiota.

Despite significant immunosuppressive activity, allogeneic mesenchymal stromal cells (MSCs) carry an inherent risk of immune rejection when transferred into a recipient. In naïve recipients, this immune response is initially driven by the innate immune system, an immediate reaction to the foreign cells, and later, the adaptive immune system, a delayed response that causes cell death due to recognition of specific alloantigens by host cells and antibodies. This review describes the actions of MSCs to both suppress and activate the different arms of the immune system. We then review the survival and effectiveness of the currently used allogeneic MSC treatments.

A cross-sectional survey was conducted to determine the seroprevalence of Leptospira in a cohort of horses and to evaluate potential risk factors for Leptospira seropositivity in horses in New Zealand. The convenience sample included 499 Thoroughbred racing and breeding horses from 25 commercial properties in North Island, New Zealand. A questionnaire was used to collect demographic data on horses and property-level information on grazing and management practices, pest (rodent) management, access to natural waterways, other livestock on the property, and possible contact with wildlife. The microscopic agglutination test was used to test sera for serovars Ballum, Copenhageni, Hardjo (bovis), Pomona, and Tarassovi. Logistic regression was used to investigate the risk factors for Leptospira seropositivity to at least one serovar and for each serovar individually. A total of 124 (25%, 95% confidence interval (CI) 21&ndash, 29%) horses had positive titres to any one of the five serovars. The seroprevalence of Ballum, Copenhageni, Hardjo (bovis), Pomona, and Tarassovi was 5% (95% CI 3&ndash, 7%), 9% (95% CI 7&ndash, 12%), 6% (95% CI 4&ndash, 8%), 6% (95% CI 4&ndash, 8%), and 6% (95% CI 4&ndash, 8%), respectively. Broodmares, compared to racehorses and alternately grazing horses with sheep, increased the odds of exposure to any one serovar, whilst grazing the same time as sheep and alternately grazing horses with cattle increased the odds of exposure to Ballum and Hardjo (bovis), respectively. Historical exposure to Leptospira in racing and breeding horses was identified, and risk factors were consistent with pasture-based exposure.

The objectives of this study were to quantify the external workload of thoroughbred racing jockeys in relation to their experience and racing performance. The number of rides of 786 jockeys and apprentices who rode in 407,948 flat and 13,648 jumps racing starts over 14 seasons were examined. Jockey work (ride numbers, seasons riding) and performance characteristics (race falls or wins) between cohorts with low (1&ndash, 10), middle (10&ndash, 200) and high (&gt, 200) numbers of rides per season were compared. Flat racing apprentices had more rides per season (25, interquartile range [IQR] 7&ndash, 97 vs. 14, IQR 3&ndash, 222, p &lt, 0.001) but fewer rides per race day (2, IQR 1&ndash, 4 vs. 4, IQR 2&ndash, 6, p &lt, 0.001) than flat racing jockeys. Flat racing jockeys in the high workload cohort (23%) were responsible for 83% of the race-day rides, riding in a median of 375 (IQR 283&ndash, 520) races per season. These jockeys had half the fall rate (Incidence rate [IR] 1.0, 95% CI 0.9&ndash, 1.1) and 1.4 times the success rates per 1000 rides (IR 98, 95% CI 97&ndash, 99) than jockeys in the low and middle workload cohorts (p &lt, 0.05). Most jockeys had light workloads, greater risk of injury and lower winning rates than the smaller cohort of jockeys with heavier workloads. This disparity in opportunity and success between cohorts indicates inefficiencies within the industry in recruitment and retention of jockeys. These data provide a foundation to further studies investigating jockey competition-specific fitness and its effect on both riding success and reducing injury risk.

As a herd species, the horse strongly desires social contact and interaction with conspecifics. Anxiety associated with social isolation may confound the display and interpretation of behavior associated with pain. This study examined the effect of anxiety (social isolation) on the behavior and heart rate variability indices associated with mild somatic pain in a cohort of Standardbred mares. Using a randomized block design, 6 adult Standardbred mares (12 ± 1 years old) were exposed to 4 stimuli: (1) baseline: control, (2) anxiety, (3) pain, and (4) anxiety-pain while loose in a 15 × 15 m yard. Each treatment consisted of a 5-minute control: baseline and subsequent 5 minute stimuli. Baseline included the presence (visual, olfactory, and tactile) of a consistent conspecific herd mate in the neighboring yard. Anxiety was induced by social isolation (removal of the conspecific), and mild somatic pain was induced with the application of a (neck) skin pinch. Pain resulted in a reduction in locomotion (median, 10; interquartile range [IQR], 5-14) compared with baseline (median, 19; IQR, 18-21; P = 0.02). Anxiety was associated with an increase in locomotion (median, 22; IQR, 16-25; P = 0.02) and restlessness (median, 20; IQR, 14-26) compared with the pain stimuli (median, 5; IQR, 3-5; P = 0.001). Anxiety also increased the vocalization (median, 2; IQR, 2-4) and contact-seeking behavior (median, 15; IQR, 13-17) of the horses compared with the pain and baseline stimuli. Anxiety-pain was only associated with an increase in restlessness behavior compared with baseline (median, 13; IQR, 9-20 vs. median, 2; IQR, 0-4; P = 0.001). Mean heart rate increased during anxiety (104 ± 12) and anxiety-pain (105 ± 10) compared with baseline (48 ± 4) ( P P

Racehorses in New Zealand predominantly train counter clockwise. This training pattern has been associated with between forelimb differences in bone mineral density profile and asymmetrical limb loading after training. At present, there is limited data on the hoof conformation of these racehorses. Distal forelimb and digital hoof conformation data were collected from 75 Thoroughbred racehorses (2–5 years old) from two training yards. Digital conformation was subjectively graded, and multiple hoof measurements were made with a modified tire gauge (sole and sulci depth) and from digital photographs. All the horses were shod by two registered master farriers within a median of 15 (interquartile range [IQR], 1–25) days before measurement. There were few distal limb conformation abnormalities scored. Most (62/75) horses presented with some deviation from normal hoof parameters, with 2 (IQR, 1–3) abnormalities reported per horse. The most common hoof abnormality was uneven sulci, which was identified in 43 horses and 59 affected hooves, followed by higher medial hoof wall height in 38 horses and 53 affected hooves. Many of the linear and hoof angle measurements and their ratios were within the bounds reported within the literature and indicative of a balanced foot. The length and width measurements increased with horse age. The dorsal hoof wall (DHW) length:heel length ratios were consistently less than 3:1, and the absolute difference between toe and heel angle was generally greater than 5°. Between limb hoof variation was identified for a number of the morphologic measurements including frog length and sole length and the ratio of sole width:sole length. Flat feet (lack of concave solar surface) were identified in 21/75 (28%) horses and in 28/150 (19%) forelimb hoofs. More horses had a flat left foot (10/75) than right foot (4/75), but seven horses had both feet classified as being flat. Flat feet had 2.4 (1.1–5.6, P = .036) greater odds of presenting with uneven sulci. These data indicate that uneven sulci depth and flatter hooves with may be a typical presentation of Thoroughbred feet. Asymmetry in measurements between limb may reflect the greater loading of the left forelimb when race training counter clockwise.

There are limited data on the training and management practices of Standardbred trainers in New Zealand. The aims of this study were to describe the 2-year-old training practices of Standardbred trainers and to examine if there were differences in the production process between public (commercial) and amateur (licensed-to-train) trainers. An online Qualtrics survey was conducted after the 2016/7 racing season and completed by 154 Standardbred trainers, 88 (57%) of which had 2-year-olds in training. Descriptive statistics were used to describe the data stratified by public and licensed-to-train trainers. Most of the 2-year-old horses in work were homebred (bred by the trainer), with public trainers more likely to break in their horses themselves (85% vs. 64%, P = .04). The training pattern of 2-year-olds was similar for public trainers and licensed-to-train trainers, and was influenced by either convenience or the physical maturity of individual horses. Most trainers were reluctant to retire any 2-year-old. The prevalence of involuntary breaks for 2-year-olds was low (9.1%, 95% CI 6.6%-12.4%). Most trainers used 800 m (½ mile) oval, crusher dust ("all-weather") or sand tracks, with most public trainers using tracks with banked corners (88% vs. 59%, P.01) and recording the times of horse workouts (79% vs. 45%, P.01). The cross-section of trainers surveyed reflected the nature of the Standardbred industry in New Zealand with a high bias toward amateur owner/breeder/trainers, with few horses in work than public trainers who had a more commercial focus.

Horses are used in many equine and veterinary science degree programmes during practical teaching classes for students to develop and refine their handling and clinical skills. There are few studies investigating the stress responses of these horses within the teaching environment. The aim of this study was to evaluate the physiological and behavioural responses of teaching horses during three types of practical teaching classes: equine handling (EH), medical rectal examination (MR) and mare reproductive rectal examination (RR). The study population included 20 teaching horses from three herds (mean time in herd of 7 ± 3 years). The horses’ heart rate (HR) was assessed before (horses in holding yard and entering the stocks/teaching yard), during (horses in stocks/teaching yard, with or without interaction with students or lecturer) and after (horses in holding yard and leaving the stocks/teaching yard) a practical class. In addition, behaviour (pawing, eating hay, vocalisation, head surveying, tail swishing, repetitive head movement, shifting weight backwards and ears orientation) of the horses used during rectal examination classes was recorded. Median class duration was 99.50 min (IQR: 95.75−112.25 min) for EH, 37.50 min (IQR: 32.25−40 min) for MR, and 47 min (IQR: 47−48 min) for RR classes. Horses interacted with students for 26 % (RR) to 40 % (EH and MR) of the classes’ duration. There was no change in median HR (35 bpm, interquartile range [IQR]: 33–39 bpm) between activities during EH classes. Median HR was greater when horses entered the stocks compared to the holding yard before the class in MR (entering stocks: 52.5 bpm, IQR: 43–58 bpm; yard-before: 39 bpm, IQR: 36–40 bpm; p = 0.047) and RR (entering stocks: 46 bpm, IQR = 41–49 bpm; yard-before: 37 bpm, IQR: 33−41 bpm; p = 0.031) classes. For both rectal examination classes, horses spent most of their time eating hay (MR: 94 %, IQR: 73–100 %; RR: 61 %, IQR: 46–79 %). In RR classes, horses spent less time eating hay (36 %) and had their ears pointed backwards more frequently (1.39 occurrences/min) during an interaction with a student compared to no interaction. Limited physiological and behavioural stress responses were observed in response to the three types of practical classes, suggesting this population of teaching horses may be habituated to both their use and environment for teaching.

Retrospective management and owner-reported injury data, and measurement of forelimb hoof conformation, were collected via a cross-sectional survey from a convenience sample of 96 registered show jumping (n = 67) and dressage (n = 29) horses. Most of the horses were medium- to upper-level performers, aged 9 (interquartile range [IQR] 7–12) years, and in the current rider's ownership for 28 (IQR 12–60) months. The horses were trained 45 (IQR 35–60) minutes, 6 days per week, on a sand or sand mix arena. Failure to train for ≥7 days was reported in 26 of 96 horses, generally associated with lameness diagnosed by a veterinarian (16/29), with a median time-off of 26 (IQR 14–93) days. During the preceding 12 months, 33% of the riders had been working with the farrier on hoof-related issues, 30% of which had involved ≤2 issues. This remedial work often involved a veterinarian (14/30) or allied health practitioner (6/30). Most horses were hot shod (67/89) with conventional fullered shoes. Uneven feet were identified in 16 of 89 horses but were not positively associated with inability to train, possibly reflecting the minor variation between feet. Uneven feet were associated with variation in heel length and angle measurements and a greater sole length and reduced sole width, rather than smaller and boxy. Multiple correspondence plots identified an association of uneven feet with the dressage horses rather than show jumping horses.

Professional thoroughbred racing jockeys repeatedly work close to physiological capacity during races, whilst maintaining low body weights, on a daily basis with no off-season. The effects of this on their career length is unknown. The aim of this study was to examine the career lengths and reasons for loss from the industry of 674 jockeys and apprentices who rode over 14 racing seasons and 421,596 race day starts in New Zealand. Descriptors were compared between jockeys in short (1&ndash, 2 years), middle (3&ndash, 9 years) and long (&gt, 10 years) career cohorts with descriptive statistics and Kaplan&ndash, Meier survival curves. The median career length for jockeys was 2 years (IQR 1&ndash, 6). Long career cohort jockeys (11%) had lower carried weights (IQR 56&ndash, 57 kg, p = 0.03), 40 times the median number of rides per season (248, IQR 61&ndash, 434, p &lt, 0.001), half the rate per 1000 rides of falling (1.1, 95% CI 1.0&ndash, 1.2, p = 0.009) and 1.3 times the rate of winning (100, 95% CI 99&ndash, 101, p &lt, 0.01) than jockeys in the short career cohort. Jockeys who rode over 200 races per season had careers three times longer than jockeys with fewer races per season (p &lt, 0.001). Half of the 40% of jockeys who failed to complete their apprenticeship were lost from the industry in their first year of race riding. In conclusion, most jockeys had short careers where the workload of a jockey and their ability to obtain rides had greater impact on career longevity than their performance.

CellTrace Violet™ is a commonly used fluorescent dye used with flow cytometry to identify cell proliferation. Activated equine lymphocytes were examined using flow cytometry, microscopy and tritiated thymidine proliferation assays. CellTrace Violet™ was incorporated into the equine lymphocytes effectively. Equine lymphocytes proliferated when activated with pokeweed mitogen, but did not proliferate when previously stained with CellTrace Violet™. Serial dilutions of CellTrace Violet™ did not eliminate the inhibition of activated lymphocytes. Equine lymphocyte viability was greater than 90 % for both stained and unstained cells. Based on these data, CellTrace Violet™ is not recommended for the assessment of lymphocyte proliferation in equine cells. The mechanism of inhibition of equine lymphocyte proliferation by CellTrace Violet™ is unknown.

A study was conducted to determine the circadian rhythms and trends of vitamin D metabolites including 25-hydroxyvitamin D3 , 25-hydroxyvitamin D2 , 1,25-dihydroxyvitamin D and parathyroid hormone, in addition to serum calcium, phosphorus and magnesium concentrations in horses over 48 h on the shortest and longest days of the year in 2013. Five healthy adult horses (Equus caballus) were on a constant pasture feeding regimen, and blood samples were collected from each horse every 3 h over a 48-h period, starting at 07:00 PM on day one and finishing at 07:00 PM on day three, for the measurement of calciotropic hormones and electrolytes. There was a significant difference between the serum concentration of calciotropic hormones, iCa, tCa, P and tMg between the shortest (winter) and longest (summer) days of the year in horses. Serum concentration of 25OHD3 was very low and mostly undetectable. Serum iCa, 1,25(OH)2 D and PTH concentrations clearly showed a circadian rhythm on the longest days of the year and serum tCa, P and tMg concentrations showed a diurnal pattern on the longest days (summer) of the year. None of the analytes showed any circadian rhythm on the shortest days (winter) of the year. The result of this study could have significant relevance to equine athletes travelling to international equestrian competitions and facing a huge time and seasonal differences that might affect their ability to adjust their circadian rhythms to new time zones.

The aim of the study was to conduct a cross-sectional survey of a cohort of national and Federation Equestre Internationale (FEI) level riders to provide an overview of the management and training practices of endurance horses in New Zealand. Data were collected from a convenience sample of 53 riders participating at four endurance rides (including a 3* FEI event). The questions covered demographics of the rider and horse as well as general management and training practices. Before the first competitive ride of the season, horses were ridden a median of five (interquartile range [IQR], 4–6) days a week and were in training for a median of eight weeks (IQR, 6–9). The first competitive ride of the season marked the transition from long slow distance work to more competition-specific work. Increases in training were associated with a reduction in distance, an increase in speed, and no change in frequency. Conditioning often incorporated farm work, hill work, and hacking. After a competitive ride, just over half (57%; 24/42) of respondents gave their horses 1 day off for every 10 km ridden in the ride. Most respondents (81%; 42/52) reported key milestones for their horses during training; heart rate and Global Positioning System (GPS) monitors were used by 61% (31/51) and 63% (31/49) of respondents, respectively. This pilot study highlighted that many riders collected heart rate and GPS data, suggesting there is scope for further detailed studies to gain more accurate training data on endurance horses in New Zealand.

Simple Summary There is currently limited information on the types, or risk, of injuries occurring for horses racing in flat races in New Zealand. Race reports and records from six racing seasons were used to determine the reasons why horses failed to finish a race. In total, 544 horses failed to complete a race, of which 177 were due to veterinary events. Most of the veterinary events that occurred during a race were classed as musculoskeletal injuries (136/177; 77%). The rate of musculoskeletal injuries during a race, 0.72 per 1000 starts, was lower than the rates reported for other racing jurisdictions. The condition of the track and the distance of the race were associated with the rate of musculoskeletal injury during a race. There may be differences in the training programmes and racing schedules for horses in the southern hemisphere, which may have contributed to the low rates reported in this study. Abstract The objective of the study was to determine the incidence of veterinary events that resulted in a horse failing to finish a race and identify risk factors for musculoskeletal injury (MSI) during a race. Data were obtained on Thoroughbred flat race starts in New Zealand between 1 August 2005 and 31 July 2011 (six racing seasons). Stipendiary Steward’s reports were key-word searched to identify veterinary events that prevented a horse from finishing a race. Race data were used calculate the incidence of veterinary events per 1000 horse starts and Poisson regression was used to investigate risk factors for MSI. There were 188,616 race starts and 177 reported veterinary events. The incidence of MSI on race day was 0.72 per 1000 starts, whilst the incidence of respiratory events was 0.21 per 1000 starts. The rate of MSI was significantly lower on ‘dead’ and ‘slow’ tracks compared with ‘good’ tracks and significantly greater in longer races (≥1671 m) compared with races of ≤1200 m. The rate of MSI during flat races in New Zealand appears lower than that reported worldwide, which may be due to the management and training of horses in New Zealand or differences in case definitions used in comparable studies.

During the past 20 years, there has been a contraction in the New Zealand Thoroughbred industry and, to a lesser extent, within the Standardbred industry. These changes have seen an increasing proportion of the market being associated with fewer larger commercial farms. Many of these farms manage their own mares, and the mares and foals of several clients. This, in turn, has increased the similarity of the management of breeding and young stock within New Zealand. The temperate climate allows the majority of the management of breeding and young stock to be pasture based. The predominant pasture is ryegrass–clover mix that has been demonstrated to provide adequate nutrition for growth and development. The temperate climate also permits management of horses at pasture year round, which is proposed to stimulate development of the musculoskeletal system. Apart from a brief period during weaning, most young stock remain at pasture from birth until the start of yearling preparation. Free access to pasture exercise provides the opportunity to stimulate the musculoskeletal system for the future challenges as a racehorse. The export focus of many of the equine industries heavily influences the management decisions. Despite the availability of good-quality pasture post-weaning, many foals receive up to 50% of the daily dietary energy requirement as concentrates, possibly reflecting the emphasis on early sales as yearlings and the drive to optimise growth. The observations of drench resistance of common internal parasites presents an emerging problem for pasture-based production systems. A large proportion of the Thoroughbred foal crop is exported as yearlings or ready to run 2-year-olds. There is an increasing trend for Standardbreds to be sold as yearlings and this has resulted in changes in the management of Standardbred young stock.

The Thoroughbred and Standardbred studbooks are the largest in New Zealand, where the production of horses is pasture based. Each racing studbook is closed, and both have well structured systems in place for recording breeding data. There are significant pressures on the Thoroughbred and Standardbred breeding industries with declining broodmare numbers, and increasingly large book sizes for popular stallions. The breeding season for Thoroughbreds is very short, with disparity between the official breeding season and the physiologic breeding season for mares. These issues are confounded by variable gestation lengths of mares, making it difficult for mares to maintain yearly foaling patterns. However, the reproductive efficiency of Thoroughbred mares is improving, mainly due to veterinary and stud management practices such as those to ensure that dry mares are cycling at the start of the breeding season, foaling mares are bred on foal heat, and that mares are kept in good body condition at breeding. There is also a bias towards breeding younger mares with high fertility in preference to older mares, unless they have desired genetics or successful offspring. Careful management of popular Thoroughbred stallions ensures that large books of mares can be covered by natural service. In contrast, Standardbred stallions are collected every-other-day using an artificial vagina, allowing the breeding of mares at distant locations by artificial insemination, using chilled or frozen semen. Breeding horses kept at pasture under New Zealand conditions requires excellent stud management and veterinary management to achieve good outcomes.

Context. At pasture, the nutritional status of mares will change due to a dynamic association between their energy requirements and the energy supply. Change in the plane of nutrition can influence reproductive performance measures in the mares. To help optimise nutritional and operational management of mares on stud farms, the nutritional status of Thoroughbred broodmares and the factors influencing the energy supply and demand were investigated. Aims. To assess nutritional status of the Thoroughbred broodmare herds under ‘normal’ New Zealand commercial stud-farm conditions. Methods. The energy intake, energy requirement and energy balance during the last 3 months of pregnancy and the first 5 months of lactation were modelled for mares with an initial bodyweight of 450 kg, 500 kg, 550 kg and 600 kg, and foaled at 0, 15, 50, and 90 days after 1 September. Key results. For all foaling dates and bodyweights, mares were in positive energy balance during the last 3 months of pregnancy (6.1–8.5%). Energy balance decreased as pregnancy progressed, followed by a large and acute energy deficit that was initiated soon after foaling and continued during lactation. The energy deficit during lactation varied between –8.6% and –12.4%, depending on the foaling date modelled. Mares foaling later in the season (50–90 days after 1 September) had greater and longer (30–50 days) postpartum energy deficit than did mares that foaled earlier in the season, who recovered within 20 days postpartum. The modelled changes in the energy balance would be large enough to initiate mobilisation of the fat reserve (body condition), and could, therefore, explain the observation of delayed postpartum to conception interval observed with later-foaling mares on commercial farms. Conclusions. There is a large and prolonged energy deficit soon after foaling and throughout 150 days of lactation in Thoroughbred mares managed under New Zealand commercial grazing conditions. Foaling later in the season can cause a mismatch in energy supply and demand that would increase and prolong the energy deficit. Implications. These findings suggest a need for stud farms to actively manage the pasture supply and monitor the mare’s BWT and BCS changes in an attempt to optimise the mare’s nutritional status and reproductive performance.

The present review examines the commercial production of racing and sport horses in New Zealand, describing the size and scope of the industries, the management and feeding, and the training and wastage of race (Thoroughbred and Standardbred) and sport horses. The number of horses per head of population in New Zealand (30/1000 people) is high by international standards and the main equine industries generate ~2% of national gross domestic product. In New Zealand the Thoroughbred breeding and racing industry dominates organised equestrian activity (economically and numerically). Furthermore, this Thoroughbred bias has an influence on equestrian culture and may explain, in part, the high proportion of Thoroughbred sport horses registered for eventing in New Zealand, which is in contrast to other international sport-horse populations. An understanding of the production, management and structure of the racing and sport industries in New Zealand is paramount to ensure the health and welfare of the equine athlete and the continuing success of the industries.

The welfare debate around horse racing appears to be focussed on musculoskeletal injury and the racing of 2-year-olds. Much of this debate appears contrary to the evolutionary history of the horse as a cursorial animal and the capability of the equine musculoskeletal system to respond to the demands of race training. Epidemiological studies have reported that 2-year-old racehorses have a longer time period from entering training to the first race and a greater number of lost training days than older horses. However, this is, in part, due to the time taken to learn to train and the impact of dorsal metacarpal disease, which is due to loading of naïve as opposed to immature tissue. Across several racing jurisdictions and codes, it has been demonstrated that horses that train and race as 2-year-olds have longer, more successful, careers than those that start racing later in life. This positive trend has also been observed with horses starting in equestrian sport at an early age. The literature on the growth and development of the horse indicates that the musculoskeletal system is primed for activity and loading from an early age. Additional exercise for the young horse has a positive rather the negative effect, with many tissues having a sensitive period for ‘priming’ when the horse is a juvenile. This implies that under many modern management systems, the challenge to horse welfare is not ‘too much exercise too soon’ but ‘too little too late’. The current limitation in our understanding is the lack of knowledge of what is the correct exercise dose to optimise the musculoskeletal system. Modern management systems invariably provide too little exercise, but is the exercise data from feral horses the ‘gold standard’, or more a reflection of what the horse is capable of if resources such as food and water are limited? Further research is required to refine our understanding of the optimal exercise levels required and development of greater precision in identifying the sensitive periods for priming the musculoskeletal system.