The effects of abrupt dietary transition on the faecal microbiota of forage-fed horses over a 3-week period were investigated. Yearling Thoroughbred fillies reared as a cohort were exclusively fed on either an ensiled conserved forage-grain diet (“Group A”; n = 6) or pasture (“Group B”; n = 6) for three weeks prior to the study. After the Day 0 faecal samples were collected, horses of Group A were abruptly transitioned to pasture. Both groups continued to graze similar pasture for three weeks, with faecal samples collected at 4-day intervals. DNA was isolated from the faeces and microbial 16S and 18S rRNA gene amplicons were generated and analysed by pyrosequencing. The faecal bacterial communities of both groups of horses were highly diverse (Simpson’s index of diversity >0.8), with differences between the two groups on Day 0 (P<0.017 adjusted for multiple comparisons). There were differences between Groups A and B in the relative abundances of four genera, BF311 (family Bacteroidaceae; P = 0.003), CF231 (family Paraprevotellaceae; P = 0.004), and currently unclassified members within the order Clostridiales (P = 0.003) and within the family Lachnospiraceae (P = 0.006). The bacterial community of Group A horses became similar to Group B within four days of feeding on pasture, whereas the structure of the archaeal community remained constant pre- and post-dietary change. The community structure of the faecal microbiota (bacteria, archaea and ciliate protozoa) of pasture-fed horses was also identified. The initial differences observed appeared to be linked to recent dietary history, with the bacterial community of the forage-fed horses responding rapidly to abrupt dietary change.

Within the lay literature, and social media in particular, there is often debate about the age at which a horse should be started and introduced to racing or sport. To optimize the welfare and longevity of horses in racing and sport, it is important to match exercise with musculoskeletal development and the ability of the musculoskeletal system to respond to loading. The justification for not exercising horses at a certain age is often in contrast to the scientific literature and framed, with incorrect generalizations, with human growth. This review provides a relative comparison of the growth and development of the horse to the descriptors used to define growth and development in humans. Measures of physeal closure and somatic growth demonstrate that the horse completes the equivalent of rapid infant growth by weaning (4–6 months old). At approximately 11 months old, the horse completes the equivalent of the childhood phase of growth and enters puberty. At 2 years old, the horse has achieved most measures of maturity used within the human literature, including the plateauing of vertical height, closure of growth plates, and adult ratios of back length:wither height and limb length:wither height. These data support the hypothesis that the horse evolved to be a precocious cursorial grazer and is capable of athletic activity, and use in sport, relatively early in life.

The aim of the present study was to describe the pattern of flat and jump races and starts, including temporal trends, in Thoroughbred racing in New Zealand. Data on all race starts between 1 August 2005 and 31 July 2011 were supplied by New Zealand Thoroughbred Racing. Descriptive statistics were used to describe the data at both race and start level, stratified by flat and jumps races. In total, 96% of races run were flat races and most races and starts occurred in the Northern region. There was an even distribution of flat races across season of the year, whereas most (60%; 514/863) jumps races were run in winter followed by autumn (21%; 183/863), with no races run in summer. Irrespective of region or season, most flat races were run on Good (37%; 7505/20 091) tracks and most (45%; 384/863) jumps races were run on Heavy tracks. There was no change in the number of horses per race or starts per horse across the years studied, and the median number of starts per trainer was 14 (interquartile range 6–38) for flat races and 3 (interquartile range 2–6) for jumps races. The results showed there is a relatively consistent product offered for Thoroughbred racing in New Zealand, which is primarily focussed on flat racing. The study provided baseline data on the pattern of Thoroughbred racing in New Zealand, which can be used as background for future industry-related studies.