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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.

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.

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.

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.

Data on the feeding, management, and training schedules during the week before the competition were collected via a face-to-face survey of riders competing in dressage, show jumping, or eventing at 1* and 3* level competitions. Data were collected using a pro forma recording sheet, and measurements of horse height, weight, and body condition score (BCS) were also obtained. A total of 158 of 582 riders (and horses) were surveyed, providing a response rate of 27%. The mean height, weight, and median BCS of the horses were 162 ± 1 cm, 533 ± 5 kg, and 6 (interquartile range [IQR], 5–7), respectively. The majority of horses were at pasture, most (68%, 107 of 158) 24 hr/d and fed supplementary feed either once (42%, 67 of 158) or twice daily (54%, 86 of 158). The supplementary feed was predominately a commercial premix feed (90%, 142 of 157) with additional alfalfa chaff or ensiled chopped alfalfa. The horses were offered approximately 60 MJ digestible energy (DE)/d (33–86 MJ DE/d) from supplementary feed. The horses worked for a median of 6 d/wk (IQR, 5–6 d/wk) with one rest day. The median total time trained during the week was 200 minutes (135–265 minutes), which consisted of eight separate training activities. There was no difference in time spent on different activities between the disciplines. Individual training activities were 30–40 minutes, and the median number of competitions per month was 2 (IQR, 2–3). Training workload and pattern of work were similar to reports from other countries, with the exception that many riders regularly added a “hack out” after training.

The aim of the study was to use spatial and multiple correspondence analysis (MCA) to describe and compare the regional proportion and spatial pattern of volumetric bone mineral density (BMD v ) values within loaded regions of the plantar metatarsal epiphysis of young horses in race training. A single 2 mm transverse peripheral quantitative computed tomography ‘slice’, 10 mm proximal from the distal limit of the sagittal ridge of the distal metatarsal epiphysis was obtained from 14 2-year-old Thoroughbred fillies (7 exercised and 7 controls). Six regions of interest were generated and examined for relative BMD v using MCA. The spatial distribution of BMD v was statistically examined at two sites loaded by the proximal sesamoid bones using geographical information software. The BMD v response was focal with distinct regional differences in relation to load. Deposition of new bone within existing high density bone contributed to a greater bone fraction and the distinct profile of clusters of uniformly distributed high density bone as well as a lower proportion of lower density bone in exercised horses. The MCA and spatial analysis provided statistical techniques to quantify and describe non-invasively the exercise induced changes in bone that had previously been described using microradiography of thin slices and by block-face imaging. These statistical techniques may prove useful in quantifying spatial patterns of response to load.

There are no published data on racetrack configuration or the surface conditions of racing in New Zealand. Data on the physical shape and dimensions of racetracks were obtained from Google Earth and an online database (www.nzracing.co.nz). An electronic extract of all race records (horse and track condition details) covering the 7-year period from 2005/2006 to 2011/2012 were obtained from New Zealand Thoroughbred Racing Inc. Track data were examined in relation with the following categories: oval track, egg shaped, and other. Track condition data were described as official penetrometer or going data. Physical descriptions were obtained of the 49 official racetracks used in the 2011/2012 season. There were 27 oval-shaped, 16 egg-shaped, and five other-shaped tracks with most racing occurring in a counter clockwise direction (39 of 49). The median racetrack circumference was 1,800 m (interquartlie range, 1,600–1,800 m). There was no significant effect of track shape on the physical dimensions of the turns (home straight or back straight turn) or of the estimated centrifugal force. There were few fast tracks (penetrometer, 2.0–2.5) reported (8 of 1,093 races) and an even distribution of races among good (393 of 1,093), dead (204 of 1,093), slow (261 of 1,093), and heavy (227 of 1,093) tracks. Tracks were significantly heavier in winter (P = .001). Change in going during a race meeting was limited, with a median of one-point change (interquartlie range, 1–2) on the going scale. The consistency of the racing direction, track circumferences, and turn dimensions in association with a consistent pattern of track going during a season implies a relatively consistent racing surface is available for horse racing in New Zealand.

The data for this study were collected from 7 mares (10 ± 1.6 years old) when their foals were 4-, 15-, 30-, 45-, or 60-days-old. On each occasion, the foals were anesthetized and placed out of sight of the mare and the mares' behavior, heart rate, and cortisol response to foal separation in either the presence of a foal phantom, a square shape, or no visual stimuli were measured. In the presence of the foal phantom, anxious ( P = 0.119) and agitated ( P = 0.524) mare behavior was not significantly different from baseline values. The mares had significantly elevated behavior scores for 5 out of 6 criteria when the square phantom was presented and were significantly more active (higher scores for fidgety and active criteria) when no visual stimuli (control) were provided. Based on the data presented in this study, the use of a phantom image of a foal with neutral ear and tail position may be an effective nonchemical method of calming mares during separation from their foal.

The effects of compounded medroxyprogesterone acetate (MPA) on follicular activity and estrous behavior were evaluated. Eighteen cycling mares were assigned to one of three treatment groups. Mares in the MPA group (n = 6) were injected intramuscularly with 1,600 mg MPA (week 1), then 400 mg weekly for the next 5 weeks. Saline mares (n = 6) were injected intramuscularly weekly for 6 weeks. Altrenogest mares (n = 6) received 10 mL orally daily for 7 weeks. Mares were teased daily for 60 days and categorized as displaying estrous, diestrous, or neutral behavior. Transrectal ultrasound examinations were performed three times weekly, or daily when a 30-mm follicle was identified, until ovulation. Blood samples were harvested weekly for analysis of progesterone concentration and daily from days 14 to 23 for analysis of luteinizing hormone (LH) concentration. Mares treated with saline or MPA showed normal intervals of diestrus and estrus during the study. All altrenogest mares showed behavioral diestrus during treatment. All mares in the saline and MPA groups showed normal follicular development and ovulations. No altrenogest mares ovulated during treatment; four mares returned to estrus and resumed normal follicular development after treatment ceased. Progesterone analyses agreed with transrectal ultrasonographic ovarian activity for all mares. LH levels were lower for altrenogest-treated mares compared with MPA-treated and saline-treated mares during the treatment period. In conclusion, compounded MPA at dose rates and intervals used in this study was not effective in suppression of estrus, follicular development, or LH secretion in mares.

Ovulation-inducing agents are routinely used in broodmare practice. The objective of this study was to compare the efficacy of two compounded deslorelin products and human chorionic gonadotropin (hCG) in inducing ovulation in a clinical reproduction program. Breeding records of 203 mares administered an ovulation-inducing agent during the 2006 breeding season were reviewed. Estrous cycles were included for comparison if agents were administered when the largest follicle was 35 to 45 mm in diameter and endometrial edema was present. There was no significant difference ( P > .05) in interval to ovulation for mares receiving deslorelin (1.9 ± 0.7 days) or hCG (2.0 ± 0.7 days). The percentage of mares that ovulated within 48 hours after treatment was also not significantly different between the agents (90.1% and 88.3%, respectively). In summary, clinical efficacy at inducing a timed ovulation in estrual mares with follicles 35 to 45 mm was similar between compounded deslorelin and hCG.

The Thoroughbred industry is New Zealand’s largest equine industry, which contributes approximately $NZ 1.4 billion, or 1%, to New Zealand’s gross domestic product. In line with international trends, and more recently in response to the global economic crisis, there has been a contraction and rationalisation of both the racing and breeding sectors. Over the last 20 years there has been considerable rationalisation and loss of heterogeneity within the Thoroughbred industry, with a reduction in the number of mares bred and foals produced. The production of Thoroughbreds in New Zealand has historically operated on levels: one sector of the industry was heavily focused on the production of horses for the domestic market and the other sector had greater emphasis on the production of horses for export. However, in recent years there has been a progressive reduction in production of individuals for the domestic market, while the export market has remained relatively stable. This change in production practice can be quantified by the changes in the selection practices of Thoroughbred broodmares over three generation intervals. Over three generations (dams, 2nd and 3rd dams) there was an increase in the percentage of broodmares that had a race record from 45% (3rd dams) to 81% of the active broodmares born in 1999. There was some evidence of assortative mating and preferential retention of broodmares sired by expensive (80% of fillies)

s / Theriogenology 70 (2008) 576–591 588 receiving hCG (2500 units IV). Mares were inseminated 12 h later with 500 million progressively motile sperm, and rebred with cooled semen the following day. Ovulation was confirmed via daily transrectal ultrasonography and embryo recovery was attempted 7 or 8 d post-ovulation. Data were analyzed with Fisher’s Exact Test and ANOVA, and results are tabulated below