A retrospective evaluation of the surgical management of equine carpal injury

SUMMARY: Records of 220 thoroughbred horses presented to the Randwick Equine Centre or the University of Queensland Veterinary Teaching Hospital for surgical management of carpal injury were reviewed. Details of racing performance were obtained, enabling evaluation of racing success following surgery. Age and sex matched control horses not known to have suffered carpal injury were selected from the Australian Stud Book and the Australian Racehorse Register. Control and treated populations were compared in terms of overall career racing success.
Radiographs or xeroradiographs from 198 horses were available for evaluation. The dorsomedial aspects of the distal articular surface of the radial carpal bone and the proximal articular surface of the third carpal bone were the most commonly observed locations of osteochondral fracture. Bilateral carpal injury was found to be sufficiently common to warrant routine radiographic examination of both limbs. The dorsolateral-palmaromedial oblique, flexed lateral and dorsoproximal-dorsodistal oblique (skyline) projections were the most useful views for evaluation of carpal degenerative joint disease. Surgical removal of osteochondral fractures by arthrotomy or arthroscopy was found to be a suitable method of treatment.
Arthroscopy was associated with a significantly shorter convalescent period than arthrotomy. Seventy-six percent of the treated population returned to racing following surgery. Average earnings following surgery were 20 000. However, the median value was only 1400 and 48% of the treated population failed to earn more than 1000. Male horses in both the treated and control groups performed significantly better than females. Treated horses performed significantly better than the randomly selected control population.     

Prevalence and risk factors for medical events following exercise at Australian Greyhound race meetings

Aim

A prospective, observational study to determine the prevalence of post‐exercise conditions at Australian Greyhound race meetings and to assess association with race performance and other environmental, race‐ and dog‐related factors was undertaken.

Methods

A total of 4020 starters were observed (2813 Greyhounds, 1009 trainers, 536 races, 52 race meets, 48 race dates and 11 race tracks) following a race. The presence of diaphragmatic flutter (DF), ataxia, seizure, collapse or sudden death was recorded. Risk factors were screened by univariable logistic regression prior to multivariable backward stepwise model building.

Results

In this study, 962 starters (n = 768 dogs) had DF (23.9%), 16 starters were ataxic (0.4%) and there were no observed cases of collapse, seizure or sudden death. Race track location, increasing race distance, race grade based on increasing 1st place prize value, lower (earlier) race number at the meeting, age, a previous observation of DF at the last start, females, colour (white) and better finishing position were all associated with an increased risk of a Greyhound being observed with DF. However, when logistic regression assessing the random effect of dog was performed, the presence of previous DF was not significant. In this cohort, DF was common following strenuous exercise in Greyhounds and on its own does not appear to result in reduced performance or distress to the animal.

Conclusion

The incidence of ataxia was low and collapse, seizure and sudden death were not observed. However, even though uncommon, ataxia has welfare concerns for racing Greyhounds that warrants further investigation.     

Development of Procedures for Sex-sorting Frozen–Thawed Bovine Spermatozoa

Dairy bull sperm may be sex‐sorted, frozen and used to artificially inseminate heifers with acceptable fertility if the herd is well‐managed. One drawback to the technology is that donor bulls must be located within a short distance of the sorting facility in order to collect semen, which limits the number of bulls from which sorted sperm are available. A successful method used to overcome this limitation in sheep is sex‐sorting from frozen–thawed semen and refreezing for artificial insemination. This technique is attractive to the dairy industry, and therefore a series of three experiments was designed to investigate the optimal methods to prepare, sex‐sort and re‐freeze frozen–thawed bovine sperm. Sperm were prepared for sorting by density gradient separation in either PureSperm^® or BoviPure?, followed by staining in one of three diluents (Androhep^®, Bovine Sheath Fluid + 0.3% BSA or TALP buffer). Sperm were sorted and collected into Test yolk buffer, and frozen in an extender containing 0, 0.25, 0.375 or 0.5% Equex STM Paste. Frozen–thawed sperm were better orientated (p = 0.006) and had fewer damaged membranes (8.7 ± 0.6% vs 19.5 ± 2.4%; p = 0.003) after centrifugation in PureSperm^® rather than BoviPure? gradients. Sperm orientation (p < 0.05) and motility (69.9 ± 3.0 vs 55.6 ± 4.0; p < 0.001) were highest after staining in Androhep^® rather than in TALP buffer. Sperm were more motile (58.2 ± 4.7 vs 38.7 ± 3.5; p < 0.001) and had better acrosome integrity (74.3 ± 2.9 vs 66.8 ± 2.0; p < 0.001) after freezing in an extender containing 0.375% Equex STM Paste than in extender without Equex. Hence, a protocol has been developed to allow frozen–thawed bull sperm to be sex‐sorted with high resolution between the sexes, then re‐frozen and thawed with retention of motility and acrosome integrity.     

Repair of a type IV Monteggia fracture in a foal

A Monteggia fracture is a humero-radial luxation combined with a fracture of the ulna. It is a rare injury, infrequently reported in the horse. This case report describes the surgical repair of such a fracture in a 4-month-old filly.     

Translational efficiency of bovine pyruvate carboxylase 5' untranslated region messenger ribonucleic acid variants

The bovine pyruvate carboxylase (PC) gene is expressed as 6 alternatively spliced variants that share a common open reading frame but that differ within their 5' untranslated regions (UTR). The PC 5' UTR variants (A through F) contain 6 combinations of 5 exons and are 68, 253, 363, 89, 226, 178 bp in length, respectively. The objective of this experiment was to determine whether or not the bovine PC mRNA variants exhibit different translational efficiencies. Each bovine PC 5' UTR variant was linked to the firefly luciferase coding region, and the resulting constructs were transcribed and translated in a rabbit reticulocyte lysate assay. All constructs resulted in synthesis of luciferase protein. The abundance of luciferase protein synthesized from the UTR of bovine PC 5' D was greater (P < 0.05) than synthesis from either PC 5' UTR C or E, and the abilities of UTR D, A, B, and F to drive protein translation were similar. The disproportionate contribution to protein synthesis of the PC 5' D UTR compared with UTR variant C or E indicates a complexity of control for PC enzyme synthesis in the bovine that is dependent on the profile of PC variants. These observations are consistent with differences in PC variant expression that have been observed in vivo and indicate that when PC mRNA is elevated, the pattern of variants directs an increase in PC activity through augmented PC enzyme synthesis.     

Mepivacaine local anaesthetic duration in equine palmar digital nerve blocks

REASONS FOR PERFORMING STUDY: Perineural analgesics are used for lameness diagnosis but the duration of effect, knowledge of which would provide valuable information when performing subsequent blocks, is unknown. OBJECTIVE: To evaluate the duration of a palmar digital nerve block using force plate measurements. METHODS: Ten horses diagnosed with unilateral navicular syndrome were trotted at range of 3 +/- 0.15 m/sec over a force plate to record ground reaction forces for 5 trials of each forelimb. Data were recorded before nerve block, and then at 15 mins, 1, 2 and 24 h post nerve block. RESULTS: Before nerve block, peak vertical force (mean +/- s.e.) was significantly higher in the contralateral forelimb (CL = 5345 +/- 188 N) than in the lame forelimb (L = 4256 +/- 204 N; P<0.05). At 15 mins post nerve block there was no significant difference between the 2 forelimbs (CL = 5140 +/- 184 N; L = 5126 +/- 129 N), and this remained the case for 1 h. By 2 h, the mean score for the lame leg had decreased (L = 4642 +/- 182 N) but was still greater than preblock. By 24 h, vertical forces had returned to preblock values. CONCLUSIONS: The palmar digital nerve block was fully effective between 15 mins and 1 h. The analgesic effect began to subside between 1 and 2 h but sufficient analgesia persisted to affect gait characteristics beyond 2 h. POTENTIAL RELEVANCE: When using a palmar digital nerve block, it is important to perform lameness evaluations between 15 mins and 1 h to be sure of effective nerve blockade.     

INDEPTH Wide-Angle Reflection Observation of P-Wave-to-S-Wave Conversion from Crustal Bright Spots in Tibet

Three-component wide-angle seismic data acquired in southern Tibet during Project INDEPTH show strong P-to-S converted reflections from reflectors that are aligned at a depth of approximately 15 kilometers beneath the northern Yadong-Gulu rift. These converted reflections are locally higher in amplitude than the corresponding P-wave reflections. Modeling of reflection mode conversion as a function of incidence angle indicates that this condition obtains for a reflector that is a solid over fluid interface; it is not typical of a solid-solid interface. The likely candidates for a fluid trapped within the crystalline crust of southern Tibet are granitic magma and water (brine).