Modulatory effects of TGF-ß1 and BMP6 on thecal angiogenesis and steroidogenesis in the bovine ovary.

Angiogenesis plays an integral role in follicular and luteal development and is positively regulated by several intra-ovarian factors including vascular endothelial growth factor A (VEGFA) and fibroblast growth factor 2 (FGF2). Various transforming growth factor-ß (TGF-ß) superfamily members function as intra-ovarian regulators of follicle and luteal function, but their potential roles in modulating ovarian angiogenesis have received little attention. In this study, we used a bovine theca interna culture model (exhibiting characteristics of luteinization) to examine the effects of TGF-ß1 and bone morphogenetic protein 6 (BMP6) on angiogenesis and steroidogenesis. VEGFA/FGF2 treatment promoted endothelial cell network formation but had little or no effect on progesterone and androstenedione secretion or expression of key steroidogenesis-related genes. TGF-ß1 suppressed basal and VEGFA/FGF2-induced endothelial cell network formation and progesterone secretion, effects that were reversed by an activin receptor-like kinase 5 (ALK5) inhibitor (SB-431542). The ALK5 inhibitor alone raised androstenedione secretion and expression of several transcripts including CYP17A1. BMP6 also suppressed endothelial cell network formation under VEGFA/FGF2-stimulated conditions and inhibited progesterone secretion and expression of several steroidogenesis-related genes under basal and VEGFA/FGF2-stimulated conditions. These effects were reversed by an ALK1/2 inhibitor (K02288). Moreover, the ALK1/2 inhibitor alone augmented endothelial network formation, progesterone secretion, androstenedione secretion and expression of several steroidogenesis-related genes. The results indicate dual suppressive actions of both TGF-ß1 and BMP6 on follicular angiogenesis and steroidogenesis. Further experiments are needed to unravel the complex interactions between TGF-ß superfamily signalling and other regulatory factors controlling ovarian angiogenesis and steroidogenesis.

Results of racetrack examinations of Standardbred horses at race meetings in New South Wales.

This study analysed the race day veterinary reports from harness racing meetings controlled by the New South Wales Greyhound and Harness Racing Regulatory Authority between 1 September 2008 and 30 June 2009. The findings of all prerace and postrace examinations were analysed, and the frequency of observations was recorded. Chi-square testing was used to determine whether the incidence of abnormalities differed between age groups and tracks. A total of 542 meetings were conducted during the period of the study, with veterinary examinations conducted at 395 of these meetings. A total of 520 veterinary examinations (60 prerace and 460 postrace) were conducted. During the period of the study, 3685 horses started 31,393 times. Injuries occurring during the warm-up or start were the most common finding on prerace examination (11 reports) followed by lameness (6 reports). Lameness was the most common problem identified during postrace examinations, occurring at a rate of 2.10 cases per 1000 starts. Other problems identified at a rate of more than 1 per 1000 starts were poor postrace recovery/heat stress (2.04) and lacerations (1.75). Falls occurred at a rate of 1.72 cases per 1000 starts. Two-year-old horses were less likely to be lame than 3, 5 and 6-year-old horses. There was no difference in the rate of falls or lameness between tracks. This study provides a benchmark against which ongoing improvements in welfare can be assessed.

Activated carbon biochar from municipal waste as a sorptive agent for the removal of polyaromatic hydrocarbons (PAHs), phenols and petroleum based compounds in contaminated liquids.

Wastewater (WW) sludge cake is problematic to dispose of with treatment unable to remove organic pollutants. Typical disposal options include landfill or deposition on agricultural land, at considerable expense and environmental impact. Pyrolysis can recycle this waste to biochar however, additional unwanted organic pollutants are generated, differing in composition and volume according to the feedstock. These pollutants can be captured in solvent impingers or 'scrubbers' to avoid environmental release but lead to alternative waste. Both activated carbon and biochar are proven clean-up methods for organic pollutants with pine wood biochar showing changes in extraction selectivity with preparation temperature. Activated carbon biochar (ACB) from pine wood has also been successfully compared as a substitute at reduced cost and improved efficacy. To our knowledge, ACB from sludge cake has remained untested along with its application to clean-up solvent scrubbers. We have investigated this material from two WW treatment plants (UK and Ghana) as a sorbent, generated at 400 and 700 °C, to minimise contamination of liquids from pyrolysis and, petrochemicals in the event of a spill. This study confirmed the use and selective production of ACB for preferential clean-up of specific pollutants. Despite high temperature pine wood ACB proving most effective in removing petrochemical mixtures (>76%) extractions of equivalent repeatability and reasonable recovery were achieved with low temperature sludge cake ACB. This re-use of waste sludge cake offers improved thermochemical (recycling) and WW process efficiency, limiting the environmental impact and overall operational costs, minimising waste for disposal.

Paediatric intensive care and neonatal intensive care airway management in the United Kingdom: the PIC-NIC survey.

In 2011, the Fourth National Audit Project (NAP4) reported high rates of airway complications in adult intensive care units (ICUs), including death or brain injury, and recommended preparation for airway difficulty, immediately available difficult airway equipment and routine use of waveform capnography monitoring. More than 80% of UK adult intensive care units have subsequently changed practice. Undetected oesophageal intubation has recently been listed as a 'Never Event' in UK practice, with capnography mandated. We investigated whether the NAP4 recommendations have been embedded into paediatric and neonatal intensive care practice by conducting a telephone survey of senior medical or nursing staff in UK paediatric intensive care units (PICUs) and neonatal intensive care units (NICUs). Response rates were 100% for paediatric intensive care units and 90% for neonatal intensive care units. A difficult airway policy existed in 67% of paediatric intensive care units and in 40% of neonatal intensive care units; a pre-intubation checklist was used in 70% of paediatric intensive care units and in 42% of neonatal intensive care units; a difficult intubation trolley was present in 96% of paediatric intensive care units and in 50% of neonatal intensive care units; a videolaryngoscope was available in 55% of paediatric intensive care units and in 29% of neonatal intensive care units; capnography was 'available' in 100% of paediatric intensive care units and in 46% of neonatal intensive care units, and 'always available' in 100% of paediatric intensive care units and in 18% of neonatal intensive care units. Death or serious harm occurring secondary to complications of airway management in the last 5 years was reported in 19% of paediatric intensive care units and in 26% of neonatal intensive care units. We conclude that major gaps in optimal airway management provision exist in UK paediatric intensive care units and especially in UK neonatal intensive care units. Wider implementation of waveform capnography is necessary to ensure compliance with the new 'Never Event' and has the potential to improve airway management.

Risk factors in equine transport-related health problems: A survey of the Australian equine industry.

BACKGROUND: Transportation can affect equine health and is a potential source of economic loss to the industry. OBJECTIVES: To identify journey (duration, vehicle, commercial or noncommercial) and horse (sex, age, breed, use, amateur or professional status) characteristics associated with the development of transport-related health problems in horses. STUDY DESIGN: Cross-sectional online survey. METHODS: An online survey was conducted targeting amateur and professional participants in the Australian equine industry; eligible respondents were required to organise horse movements at least monthly. Respondents provided details of the last case of a transport-related health problem that had affected their horse(s). Associations between type of health problem, journey and horse characteristics were examined with multivariable multinomial regression analysis. RESULTS: Based on 214 responses, health problems were classified as injuries, muscular problems, heat stroke, gastrointestinal and respiratory problems, and death or euthanasia. Respiratory problems were reported most frequently (33.7%), followed by gastrointestinal problems (23.8%) and traumatic injuries (16.3%). The type of health problem was associated with journey duration (P<0.001) and horse breed (P = 0.001). Injuries were more likely to occur on short journeys, whereas more severe illnesses (gastrointestinal and respiratory problems, and death or euthanasia) were more likely to occur on long journeys. Using Standardbreds as the reference group, Thoroughbreds, Arabians and Warmbloods were more likely to experience a severe illness than an injury. MAIN LIMITATIONS: Self-selected participation in the study and the self-reported nature of transport-related problems. CONCLUSIONS: Horses undertaking journeys of longer than 24 h are at greater risk for the development of severe disease or death. Further studies on long-haul transportation effects are required to safeguard the welfare of horses moved over long distances.

Feasibility and Preliminary Efficacy of an Internet Support Group for Parents of a Child with Neurofibromatosis Type 1: a Pilot Study.

This pilot study investigated the feasibility and preliminary efficacy of an Internet Support Group (ISG) for parents of children with NF1. Eligible parents were recruited by email and completed baseline questionnaires assessing social support, self-efficacy, depression, and anxiety. The ISG involved eight weekly 90-min chat sessions and a discussion forum open 24 h/day for 8 weeks. Follow-up measures were completed immediately post-intervention and 3 months later. Parents from 33 families (29 mothers, 4 fathers) completed baseline measures. Over half of parents (52 %) rated their child's disease severity as mild, 33 % moderate, and 15 % severe. Among 21 parents who completed post-intervention measures, ratings of perceived emotional (p = .0008) and informational (p = .0003) support increased. There were no significant changes in self-efficacy, depression, or anxiety (ps > .05). The mean satisfaction rating was moderately high (7.6/10; range 4-10). Some parents commented that the chat sessions were at inconvenient times, which may have limited participation. Preliminary evidence in this small sample of parents suggests that ISGs may be a feasible and potentially efficacious method of providing support to parents of children with NF1. Having multiple weekly chat sessions held at various days and times may improve accessibility and participation. Clinicians are encouraged to help parents access online support resources.

Survey of horse transportation in Australia: issues and practices.

OBJECTIVE: To survey amateur and professional participants on equine transportation management, practices and outcomes in Australia. METHODS: An online survey targeting people who organised horse movements at least monthly was made available to a broad cross-section of amateur and professional equine associations. Respondents were invited to provide demographic details and information relating to their routine transportation management practices and their experiences of issues relating to the transportation of horses. RESULTS: Of 797 usable responses involving approximately 17,000 horses and 313,000 individual horse transport events, transport-related behavioural problems were reported by 38% of respondents, particularly at loading. Transport-related health problems had been experienced during or after transportation by horses in the care of 67% of respondents. The most common problems reported were traumatic injuries (45.0%), diarrhoea (20.0%), muscular problems (13.0%), respiratory problems (12.3%), overheating (10.5%) and colic (10.3%). In the 2 years reviewed in the survey, 9.4% of participants reported at least one case of transport-associated pneumonia and 35 horses had died, most commonly from fractures, colic or pneumonia. Although respondents identifying as amateurs transported horses less frequently and over shorter distances, the incidence of transport-related problems was similar between amateurs and professionals. Respondents reported specific precautions before, during and after transportation, although management was often not compliant with the Australian Code of horse transportation. CONCLUSIONS: Responses indicated that there remains a substantial risk of adverse welfare and health outcomes for horses transported in Australia and management practices reported may not be compliant with current recommendations for transportation.

Exercise induced pulmonary hemorrhage in horses: American College of Veterinary Internal Medicine consensus statement.

BACKGROUND: Published studies of exercise-induced pulmonary hemorrhage (EIPH), when assessed individually, often provide equivocal or conflicting results. Systematic reviews aggregate evidence from individual studies to provide a global assessment of the quality of evidence and to inform recommendations. OBJECTIVES: Evaluate evidence to determine: if EIPH adversely affects the health, welfare or both of horses; if EIPH affects the athletic capacity of horses; the efficacy of prophylactic interventions for EIPH; and if furosemide affects the athletic capacity of horses. ANIMALS: None. MATERIALS AND METHODS: Systematic review. A panel of 7 experts was formed to assess evidence in the peer reviewed literature addressing each of the 4 objectives. Methodology followed that of the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE). Publications were assessed for quality of evidence by working groups of the panel, and a summary of findings was presented in tables. Recommendations were based on quality of evidence and were determined by a vote of the panel. RESULTS: Much of the evidence was of low to very low quality. Experimental studies frequently lacked adequate statistical power. There was moderate to high quality evidence that EIPH is progressive, is associated with lung lesions, that it adversely affects racing performance, that severe EIPH (Grade 4) is associated with a shorter career duration, that furosemide is efficacious in decreasing the incidence and severity of EIPH, and that administration of furosemide is associated with superior race performance. CONCLUSIONS AND CLINICAL SIGNIFICANCE: Strong recommendation that EIPH be considered a disease and a weak recommendation for use of furosemide in management of racehorses with EIPH.

The use of a portable breath analysis device in monitoring type 1 diabetes patients in a hypoglycaemic clamp: validation with SIFT-MS data.

Monitoring blood glucose concentrations is a necessary but tedious task for people suffering from diabetes. It has been noted that breath in people suffering with diabetes has a different odour and thus it may be possible to use breath analysis to monitor the blood glucose concentration. Here, we evaluate the analysis of breath using a portable device containing a single mixed metal oxide sensor during hypoglycaemic glucose clamps and compare that with the use of SIFT-MS described in previously published work on the same set of patients. Outputs from both devices have been correlated with the concentration of blood glucose in eight volunteers suffering from type 1 diabetes mellitus. The results demonstrate that acetone as measured by SIFT-MS and the sensor output from the breath sensing device both correlate linearly with blood glucose; however, the sensor response and acetone concentrations differ greatly between patients with the same blood glucose. It is therefore unlikely that breath analysis can entirely replace blood glucose testing.

Heritability of epistaxis in the Australian Thoroughbred racehorse population.

Post exercise epistaxis, the manifestation of a severe form of exercise-induced pulmonary haemorrhage (EIPH), has been observed in many equine racing populations. Although multiple analyses have suggested that non-genetic factors may lead to the development of this condition, relatively little consensus has been reached regarding its genetic aetiology. The objective of this study was to provide insight into both genetic and non-genetic factors that may contribute to the expression of epistaxis in the Australian Thoroughbred racing population. Racing records and reported epistaxis occurrences were acquired for 117,088 horses entered in races and official barrier trials from 1 August 2000 until 22 February 2011. Heritability was estimated using two different logistic generalised linear mixed models (lifetime epistaxis risk h(2) = 0.27 and individual race epistaxis risk h(2) = 0.50). Sex, age, and year of birth were shown to be significant; however, trainer, jockey, race distance, condition of the track (i.e. 'going'), racecourse, track surface, number of race starters, year and month of race were not significant. Evidence suggests genetic and non-genetic links to EIPH expressed as epistaxis.

Handedness of whip use by Australian Jockeys.

OBJECTIVE: To compare handedness of whip use by Australian jockeys in Melbourne (where racing is counterclockwise) and Sydney (where racing is clockwise). METHODS: Photographs of finishes of Thoroughbred horse races in Melbourne and Sydney were examined. Where whip use was clearly visible, the venue, the hand in which the whip was held and the names of the jockey and the horse were determined. Comparisons of whip hand use between cities were made using the Chi-squared test. RESULTS: A total of 771 identifications were made, 328 from Melbourne and 443 from Sydney, representing 78 jockeys and 506 horses. Right-handed whip use was identified in 244 (74.39%) photographs of Melbourne races and in 313 (70.65%) photographs of Sydney races. There was no difference between right-handed whip use in Melbourne and Sydney (P = 0.53), nor in the handedness of whip use by individual jockeys (P = 0.74). Predominantly right-handed jockeys demonstrated significantly stronger dominance (84.51 ± 14.03%) compared with left-hand dominant riders (71.07 ± 9.40%; P = 0.01). A total of 84 horses were identified being ridden by the same jockey in different races. In 64 of the 84 cases, the whip was used in the same hand in all photographs. In the remaining instances, the whip was observed to be used in both hands by the one jockey. CONCLUSION: The findings support the view the whip can be used as an aid to steering during races.

Changes in sexual inhibition and excitation during PDE5I therapy.

The aim of this longitudinal study was to assess possible changes in sexual inhibition and excitation (measured using the Sexual Inhibition and Sexual Excitation Scales (SIS/SES)) in men being treated with PDE5 inhibitors (PDE5I) for ED. Established PDE5I users diagnosed with psychogenic ED completed the SES/SIS questionnaire at recruitment and 3 months later. On the basis of International Index of Erectile Function scores at recruitment, subjects were divided into two groups - mildly affected (M) and mild-to-moderately affected (MM). SES scores were significantly lower, and SIS1 scores were significantly higher in Group MM at recruitment and at 3 months (P<0.001). In Group M, SES scores increased (P<0.005) and SIS1 (P<0.001) and SIS2 (P=0.01) scores decreased over the 3 months of the study. In Group MM, ongoing decreases in SES and increases in SIS1 scores were observed (P<0.001). The results of multiple linear regression showed that SIS/SES variables were of little value in predicting erectile function (EF) at recruitment, or changes in EF during the study period. The results for Group M showed that men whose EF scores increased were more likely to experience increased SIS2 and decreased SES scores.

Circulating insulin-like factor 3 (INSL3) in healthy and infertile women.

STUDY QUESTION: How does insulin-like factor 3 (INSL3) concentration in blood vary across the menstrual cycle in women? SUMMARY ANSWER: INSL3 is secreted by the theca interna cells of growing antral follicles and is phasic in its expression. WHAT IS KNOWN ALREADY: The relaxin-like hormone INSL3 is known to be expressed in follicles of several mammal species, and was recently shown in cows to be specifically secreted into the bloodstream by growing antral follicles, corresponding to follicular waves. In males INSL3 is known to be acutely independent of the hormones of the hypothalamic-pituitary-gonadal axis, suggesting that in women INSL3 might be a novel biomarker for antral follicle recruitment and development. STUDY DESIGN, SIZE, DURATION: Two cohorts of women were studied. First, 18 healthy women of reproductive age were followed longitudinally for one and a half cycles, with blood sampling and hormone measurement every 2-3 days. A second cohort comprised a cross-sectional study of 909 women attending an infertility clinic, with a single blood sample taken at entry, together with other clinical and hormonal parameters. PARTICIPANTS/MATERIALS, SETTING, METHODS: Blood samples from both retrospective cohorts were analyzed for INSL3 using a highly sensitive time-resolved fluorescent immunoassay, and data were analyzed in comparison with other clinical and hormonal parameters. MAIN RESULT AND THE ROLE OF CHANCE: For young healthy women of reproductive age, we showed a phasic expression of INSL3 corresponding to antral follicle growth in both the follicular and luteal phases of the cycle, which was significantly (P < 0.05) elevated compared with that during menses. For women attending an infertility clinic, those with diagnosed polycystic ovarian syndrome indicated significantly (P < 0.0005) greater circulating INSL3 levels and those with low ovarian reserve showed significantly (P < 0.002) decreased INSL3 values. LIMITATIONS, REASONS FOR CAUTION: These were retrospective studies and the results were obtained from natural cycles only, with their inherent variability. WIDER IMPLICATIONS OF THE FINDINGS: We show for the first time that INSL3 in women does vary across the menstrual cycle, and appears to reflect the number of growing antral follicles recruited within both follicular and luteal phases. STUDY FUNDING/COMPETING INTEREST(S): The present retrospective study was largely supported by departmental funds. There were no competing interests.

Epistaxis in racehorses: risk factors and effects on career.

OBJECTIVE: To profile Thoroughbreds that incurred a ban under Australian Rule of Racing 53A on New South Wales racetracks between August 1999 and July 2008, determine the effect on their careers and identify the factors that predict whether these horses would race again or experience a recurrence of epistaxis. METHODS: Differences between horses that did or did not return to racing and did or did not suffer recurrent epistaxis were determined. Backwards stepwise logistic regression was used to identify variables predicting a return to racing and recurrence of epistaxis. RESULTS: The mean (± SD) age at the first episode of epistaxis was 4.90 ± 1.28 years. Males that bled were older, had more career starts and were more likely to race again than females. Horses that were retired from racing after the first episode of epistaxis were older than horses that continued to race. Variables that were significant predictors of retirement were: age at the first episode of epistaxis, sex, percentage of winning starts before the first episode of epistaxis, percentage of placed starts before the first episode of epistaxis and number of starts in the preparation before the first episode of epistaxis. The significant predictors of recurrence of epistaxis were: change in distance between previous start and start at which the second episode occurred and a change in percentage of winning starts, although the odds ratios were low (0.98-0.99). CONCLUSIONS: Females experience epistaxis at a younger age than males. No readily applicable predictors of the recurrence of epistaxis were identified.

The perceptions of young rural drivers in NSW, Australia of speeding and associated risk: a mixed methods study.

The study, using mixed methodology, examined perceptions of risk associated with speeding in young rural people. Focus groups discussions (age range 16-24) in which speeding was identified as often being an involuntary driving behaviour, informed the development of a survey instrument. The survey was conducted with two groups of young people, one rural (n=217) and another semi-rural (n=235). The results from both the focus groups and surveys indicate that young rural drivers had specific attitudes to speeding, when compared with other risk factors for crashing. Speeding behaviour was viewed as both acceptable and inevitable. Males and those from a rural area viewed speeding, and reducing trip time when compared to that of a peer, to be less risky than did females and those who lived in a semi-rural area. Speeding was considered to be less risky than drink driving. These perceptions of speeding may contribute to the crash rates on rural roads involving young, local drivers and need to be considered in interventions or educational programmes which aim to reduce the rural road crash rate.

The association of age at first start with career length in the Australian Thoroughbred racehorse population.

REASONS FOR PERFORMING STUDY: Studies of Thoroughbred racing populations have provided evidence of a positive effect on racing careers for horses that commence racing as 2-year-olds. Currently, research investigating the presence of this effect in the Australian Thoroughbred racing population is limited. OBJECTIVES: To investigate the association between age at first start and career length in the Australian Thoroughbred population and estimate the risk of racing retirement for horses racing in Australia based on age at first start, career earnings, number of starts as a 2-year-old and distance raced. METHODS: Data were collected for Thoroughbreds, born on or after 1 January 1998, that had raced between 1 August 2000 and 22 February 2011 in Australia. A Kaplan-Meier survival curve, stratified by age group, was produced for career length. A Cox proportional hazard model was fitted to assess factors influencing the risk of retirement from racing. The model included sex, age at first start, career earnings, number of starts as a 2-year-old, distance raced and appropriate interaction terms. RESULTS: The study population included 117,088 horses. Geldings had significantly (P<0.001) longer careers than females and intact males, and females had significantly (P<0.001) longer careers than intact males. Risk of retirement from racing decreased with a younger age at first start, a higher number of starts as a 2-year-old, and a longer average distance raced. For intact males, the risk of retirement from racing increased as earnings increased, while for females and geldings the risk of retirement from racing decreased as earnings increased. CONCLUSIONS AND POTENTIAL RELEVANCE: The introduction of young Thoroughbreds to racing appears to have no apparent adverse effects on these horses racing in Australia. The impact of some risk factors associated with retirement from racing varied between sexes and should be considered when evaluating career outcomes.

The effect of exogenous gonadotropins on ovarian function in goats actively immunized against inhibin.

The aim of this investigation was to compare the ovarian response to superovulatory treatments in does before and after inhibin immunization, with a view to optimizing the superovulatory potential of the caprine ovary. To avoid interference by the ovarian cycle, the experiment was conducted out-of-season. At the onset of the experiment 48 does were subjected to treatment with an sc implant of the progestogen norgestomet, combined with a gonadotropin; eight does each received a single injection of 1200 IU eCG, 400 IU eCG or 2 mL physiological saline (control) or six injections (at 12 h intervals) constituting 16 or 5.4 AU pFSH. The does were mated and subjected to embryo collection 6 to 7 d later. Throughout the experiment ovarian function (by ultrasonography) and plasma levels of inhibin antibodies and progesterone were monitored. Of 40 does treated during the first part of the experiment, 48% showed estrus. The ovarian response in does treated with a high or low dose of eCG or a low dose of pFSH was barely in excess of the ovarian response in the saline-treated controls, whereas a superovulatory dose of pFSH (16 AU) gave a satisfactory response of, on average, 14.5 ovulations (yielding 8.8 flushed ova and embryos). Immediately after the does had been subjected to embryo collection they were actively immunized against inhibin by administering two injections of a recombinant α-subunit of ovine inhibin at four week intervals. All immunized does produced antibodies with the maximal titer reached two weeks after the second injection. Groups of immunized does were subjected to the same gonadotropin treatments as before (avoiding allocation of individuals to the same treatments). This time all does showed estrous symptoms. The ovulatory response to the various treatments, including the saline controls, was virtually identical, the overall average being 21.8 follicles and 9.1 ovulations. The average embryo yield per doe was 5.7. The results imply that inhibin acted as the key factor in determining the ovulatory response since no impact of any of the supplementary gonadotropins was noted in inhibin-immunized does. This finding gives rise to the notion that inhibin antibodies may act primarily by an intraovarian paracrine action rather than by reducing the suppressive action of inhibin on pituitary FSH release. Further, these findings confirm earlier reports that eCG is less suitable than FSH for inducing superovulation in goats, and indicate that active immunization against inhibin may be considered a viable alternative to using exogenous gonadotropin for inducing superovulation in goats.

Age at first start and racing career of a cohort of Australian Standardbred horses.

OBJECTIVE Compare the career profiles of a cohort of Standardbred horses that first raced as 2-year-olds with those that started their racing careers at a later age. METHOD Retrospective analysis of the racing records of all foals born in New South Wales in the 2000 foaling season. RESULTS The career records of 999 horses were analysed. Almost half (43.9%) first raced as 2-year-olds and one-third (33.9%) as 3-year-olds. The median career duration for horses that first raced as 2-year-olds was 2.93 years (interquartile range (IQR) 2.70-3.16), which was significantly greater than the median for horses that first raced at 3, 4 or ≥5 years old (P < 0.001). Males, and horses that first raced as 2-year-olds, earned significantly more prize money than females or horses that started racing aged ≥3 years (P < 0.001). The population median number of career starts was 28.0 (IQR 8-64). Males, and horses that first raced as 2-year-olds, had significantly more career starts than females or horses that started racing aged ≥3 years (P < 0.001). CONCLUSION This study found no evidence suggesting that racing as a 2-year-old had a deleterious effect on a horse's racing career.