Radiographic changes in Thoroughbred yearlings in South Africa

Abstract

This study involves the evaluation of pre-purchase radiographic studies of South African Thoroughbred yearlings. Radiographic changes were recorded and compared with similar international studies. The study differs from other studies in that a lower prevalence of pedal osteitis (1.26 %), dorsal osteochondral fragmentation of the metatarsophalangeal joint (1.60 %), distal metacarpal sagittal ridge changes (15.7 %), ulnar carpal bone lucencies (8.33 %), carpal osteophytes (1.19 %), distal intertarsal and tarsometatarsal joint radiographic changes (9.92 %), tarsal osteochondrosis lesions (4.40 %) and stifle osteochondrosis lesions (0.4 %) was found. The prevalence of dorsal osteochondral fragments in the metacarpophalangeal joint was similar to other studies (1.60 %). A higher prevalence of vascular channels as well as irregular borders and lucencies was evident in the proximal sesamoid bones. There was a higher prevalence of palmar metacarpophalangeal and plantar metatarsophalangeal osteochondral fragments (2 % and 7.10 % respectively). Palmar metacarpal disease, metacarpal supracondylar lysis, proximal sesamoid bone fractures and carpal osteochondral fragmentation were absent in the current study. Additional findings recorded in the current study were proximal interphalangeal joint hyperextension (left front 15.13 %, right front 18.91 %), the solar angle (right front 2.38°, left front 2.79°), the prevalence of carpal bone 1 (30.95 %) and carpal bone 5 (1.59 %). Management, nutrition and genetics in the various groups of Thoroughbred yearlings should be further investigated in order to explain the reasons for the differences recorded in the current study.

Fragmentation of the dorsal distal aspect of the talus on weanling survey and pre‐sale radiographs of juvenile Thoroughbreds: prevalence and 2‐ and 3‐year‐olds racing performance

“…The prevalence of FDDT is similar to that of OCD of the LTR and/or MTR of the talus, and of OCD of the medial malleolus of the tibia in previous studies. 4,6,[7][8][9][10][11]13 The prevalence of OCD of the DIRT in the current study (5.01%) was 7.95-fold greater than that of FDDT lesions and was similar to that previously reported in Australian yearlings 7,9,11 and in yearling populations in the USA, 4,13 France, 14 South Africa, 8 New Zealand 6 and Japan. 10 However, the true prevalence is likely to be underestimated in studies in which surgical removal of lesions before repository examination is not reported.…”

“…3 Studies have assessed the prevalence of some of these findings in juvenile Thoroughbreds [3][4][5][6][7][8][9][10][11] and their association with race performance 5,10,12-14 although evaluation of uncommon lesions has been limited by the low power of some studies. With expert interpretation, these examinations can highlight abnormalities that may affect sale, soundness and performance.…”

“…Radiographic changes are often detected and may represent normal variations in the appearance or development of bones or result from congenital, acquired or developmental abnormalities. 3 Studies have assessed the prevalence of some of these findings in juvenile Thoroughbreds [3][4][5][6][7][8][9][10][11] and their association with race performance 5,10,[12][13][14] although evaluation of uncommon lesions has been limited by the low power of some studies. 1,15 Osteochondrosis (OCD) is the most common lesion identified in the tarsus on yearling sale radiographs, most frequently affecting the distal intermediate ridge of the tibia (DIRT) and less commonly the lateral trochlear ridge of the talus (LTR), medial malleolus of the tibia and the medial trochlear ridge of the talus (MTR).…”

Prevalence, radiographic resolution and outcomes of slab fractures of the third and central tarsal bones in juvenile Thoroughbred horses

“…Veterinarians are required to interpret the significance of radiographic findings for sale, soundness and future racing performance . Studies have assessed the prevalence of some of these radiographic changes and their association with subsequent performance, although limitations associated with these studies, including the low power of those that have evaluated less common lesions, have been recognised …”

A retrospective study of radiographic abnormalities in the repositories for Thoroughbreds at yearling sales in Japan

“…Because radiographic abnormalities can decrease the contract price and sometimes these abnormalities are needed medical management of a horse, the prevalence of these abnormalities and the effects of these abnormalities on their future performances should be investigated. The prevalence of radiographic abnormalities at the time of yearling sales has already been reported in the U.S.A. [ 9 ], Australia [ 8 ], New Zealand [ 13 ] and South Africa [ 6 ], but not in Japan.…”