Closure of the Distal Radial Epiphysis and Its Relationship to Unsoundness in Two Year Old Thoroughbreds‡

Radiography of the distal extremity of the manus in the donkey foal: Normal images and quantitative characterization from birth to 2 years of age: A pilot study

“…Earlier closure in fillies than in colts was also seen for Throughbreds, Arabian, Anglo-Arabian and Hucul horses (Luszczynski et al, 2011), as also for Brasileiro de hipismo horse breed horses (Buchmann de Godoy, Vulcano, Santos, & Soares, 2004). Similar results were found by Mason and Bourke (1973), but they did not find statistically significant differences in the time of growth plate closure between both sexes. In contrast, Pasolini et al (2007) and Gabel, Spencer, and Pipers (1977) In addition to genetic factors, diverse exogenous factors may play a significant role in growth rate and growth plate closure (Luszczynski et al, 2011).…”

“…Moreover, it has been observed that increased feeding rations or access to better quality feeds results in a greater and more rapid rate of growth, especially in young horses (Cymbaluk, Christison, & Leach, 1990;Donabedian et al, 2006;Pagan, Jackson, & Caddel, 1996). Different feeding may also contribute to premature closure of metaphyseal growth plates (Glade & Belling, 1984;Mason & Bourke, 1973). In contrast, a low level of feeding may inhibit growth, may cause changes to body conformation and may delay the age of growth plate closure (Ellis & Lawrence, 1978).…”

Inheritance of racing performance of Thoroughbred horses

“…Mason and Bourke (1973) found that trainers had a significant effect on the soundness of 2-year-old horses. Ainslie (1988) stated that the Thoroughbred racehorse reaches peak performance in the middle of its fourth year of age and maintains this peak through its seventh year.…”

“…Subsequently, Bailey et al (1998) reported that the incidence of musculoskeletal injuries in flat, hurdle and steeple races in Thoroughbred horses were 0.29, 1.73 and 2.91% and the corresponding death rates were 0.06, 0.63 and 1.43% respectively. Numerous studies have examined factors that affect career longevity (Mason and Bourke, 1973;Rooney, 1983;Bailey et al, 1997;Williams et al, 2001;Pinchbeck et al, 2004a,b). The factors include conformation, training, environmental conditions, type of competition, age, and sex (Burns et al, 2006).…”

“…High levels of loss occur in the first or second racing seasons (Mason and Bourke, 1973;Mohammed et al, 1991;Bourke, 1995); while lack of ability contributed to this loss, a significant proportion of horses may be retired due to injury or disease associated with training and racing. Several studies have found that the risk of injury increases with age (Robinson and Gordon, 1988;Mohammed et al, 1991;Bailey et al, 1997;Williams et al, 2001), but starting to compete at an older age has a negative impact on career duration (Bourke, 1995;Ricard and Fournet-Hanocq, 1997;Bailey et al, 1999).…”