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Newmarket, United Kingdom

Lane E.,University College Dublin | Bijnen M.,University College Dublin | Osborne M.,Forenaghts Stud | More S.,University College Dublin | And 3 more authors.
Reproduction in Domestic Animals | Year: 2016

Contents: To evaluate factors contributing to fertility of thoroughbred mares, data from 3743 oestrous periods of 2385 mares were collected on a large thoroughbred farm in Ireland. Fourteen stallions (mean age 8.3 years; range 4-15 years) had bred 2385 mares (mean age 9.4 years; range 3-24 years). Maiden mares accounted for 12%, mares with a foal at foot for 64%, and barren, slipped or rested mares for 24% of the total. The mean pregnancy rate per cycle was 67.8% (68.6% in year 1 and 66.9% in year 2). Backward stepwise multivariable logistic regression analysis was utilized to develop two models to evaluate mare factors, including mare age, reproductive status, month of foaling, dystocia, month of cover, foal heat, cycle number, treatments, walk-in status and stallion factors including stallion identity, stallion age, shuttle status, time elapsed between covers and high stallion usage on the per cycle pregnancy rate and pregnancy loss. Old age (p < 0.001) and cover within 20 days post-partum (p < 0.003) were associated with lowered pregnancy rates. High mare age (p < 0.05) and barren, slipped or rested reproductive status (p = 0.05) increased the likelihood of pregnancy loss. Uterine inflammation or infection, if appropriately treated, did not affect fertility. Only high usage of stallions (used more than 21 times in previous week) was associated with lowered (p = 0.009) pregnancy rates. However, shuttle stallions were more likely to have increased (p = 0.035) pregnancy survival, perhaps reflecting a bias in stallion selection. In conclusion, mare age exerted the greatest influence on fertility; nonetheless, thoroughbreds can be effectively managed to achieve high reproductive performance in a commercial setting. © 2016 Blackwell Verlag GmbH.

Jacklin B.D.,Newmarket Equine Hospital | Jacklin B.D.,Lane College | Minshall G.J.,Newmarket Equine Hospital | Wright I.M.,Newmarket Equine Hospital
Equine Veterinary Journal | Year: 2014

Reasons for performing study: Surgical management for overriding spinous processes of the thoracolumbar vertebrae (SPs) is often favoured when conservative therapies have failed, pathology is severe, or in competition horses constrained by drug withdrawal periods. Objectives: To evaluate whether subtotal (cranial wedge) ostectomy represents an effective treatment for overriding SPs, with short surgery time and low complication rates, maintains the contour of the spine and produces a functionally and cosmetically better outcome than previously reported surgical techniques for management of overriding/impinging SPs. Study design: Retrospective study. Methods: A new technique is described and records were retrieved for 25 cases that had undergone the procedure at Newmarket Equine Hospital between 2009 and 2011. Case records were evaluated for anamnesis, clinical findings and details of surgical and post operative management. Outcome of surgery was assessed by telephone questionnaire with owners, relating to both functional and cosmetic results. Results: Of cases treated using the described technique, 78.9% had resolution of clinical signs and returned to full work and a further 18.2% were improved. Outcome was unrelated to number of SPs resected or mean radiographic grade of impingement. Cosmetic outcome was described as excellent in 81.8% and good in the remainder. Surgery time ranged from 20 to 70 (median 30) min and there were no intra- or post operative complications. Conclusions: In contrast to previously described amputation techniques, subtotal (cranial wedge) ostectomy removes only impinging portions of SPs. General anaesthesia and lateral recumbency facilitate access and enable a short surgery time. The procedure maintains the contour of the back and has fewer complications, but produces functional outcomes similar to more invasive procedures. © 2013 EVJ Ltd.

Smith M.R.W.,Newmarket Equine Hospital | Wright I.M.,Newmarket Equine Hospital
Equine Veterinary Journal | Year: 2014

Reasons for performing study: Fractures of the proximal phalanx are generally considered to result from monotonic supraphysiological loads, but radiological observations from clinical cases suggest there may be a stress-related aetiology. Objectives: To determine whether there are radiologically identifiable prodromal changes in Thoroughbred racehorses with confirmed parasagittal fractures of the proximal phalanx. Study design: Retrospective cross-sectional study. Methods: Case records and radiographs of Thoroughbred racehorses with parasagittal fractures of the proximal phalanx were analysed. Thickness of the subchondral bone plate was measured in fractured and contralateral limbs, and additional radiological features consistent with prodromal fracture pathology documented. Results: The subchondral bone plate was significantly thicker in affected than in contralateral limbs. Evidence of additional prodromal fracture pathology was observed in 15/110 (14%) limbs with parasagittal fractures, and in 4% of contralateral limbs. Conclusions: The results of this study are not consistent with monotonic loading as a cause of fracture in at least a proportion of cases, but suggest a stress-related aetiology. Increased thickness of the subchondral bone plate may reflect (failed) adaptive changes that precede fracture. Potential relevance: Better understanding of the aetiology of fractures of the proximal phalanx may help develop strategies to reduce the risk of fracture. The Summary is available in Chinese - see Supporting information. © 2013 EVJ Ltd.

Wright I.M.,Newmarket Equine Hospital | Minshall G.J.,Newmarket Equine Hospital
Equine Veterinary Journal | Year: 2014

Reasons for performing study: Osteochondritis dissecans (OCD) of the distal sagittal ridge of the third metacarpal bone (McIII) has not previously been described in the literature. Objectives: To describe the clinical, radiological and arthroscopic features of OCD of the distal sagittal ridge of the McIII and to report outcome in a series of cases. Study design: Retrospective case series. Methods: Case records and images of horses with OCD of the distal sagittal ridge of the McIII admitted to a single referral centre between February 2006 and February 2013 were reviewed. Follow-up information was obtained by telephone questionnaire and/or racing performance. Results: Osteochondritis dissecans of the distal sagittal ridge of the McIII was found in 16 lame horses; 9 unilaterally and 7 bilaterally. Lesions were consistently identified with flexed lateromedial radiographs and in 21 joints in dorsopalmar projections also. These were arthroscopically accessible from the dorsal compartment with metacarpophalangeal joints maximally flexed. This permitted fragment removal and lesion debridement. Thirteen of 14 horses with follow-up of ≥12 months post surgery performed athletically including 11 of 12 Thoroughbreds that raced. Conclusions: Unlike more proximal lesions, OCD of the distal sagittal ridge appears to affect the McIII preferentially. Lesions were identified on dorsopalmar and flexed lateromedial radiographs only and are amenable to arthroscopic surgery. Clinicians should be aware of the potential for OCD to affect the distal sagittal ridge of the McIII together with the radiographic projections needed to identify its presence. A modified arthroscopic approach to the dorsal metacarpophalangeal joint is necessary in order to access lesions. © 2013 EVJ Ltd.

Minshall G.J.,Newmarket Equine Hospital | Wright I.M.,Newmarket Equine Hospital
Equine Veterinary Journal | Year: 2014

Reasons for performing study: Accurate radiological and ultrasonographic descriptions of frontal plane fractures of the accessory carpal bone (ACB) are lacking, and implications of these fractures for the carpal sheath and its contents have not previously been reported. Objectives: Aims were as follows: 1) to describe the location and radiological features of frontal plane fractures of the ACB; 2) to document communication of displaced fractures with the carpal sheath and consequent injury to the deep digital flexor tendon (DDFT); 3) to describe ultrasonographic identification of lesions; and 4) to report tenoscopic evaluation and treatment. Study design: Retrospective case series. Methods: Analysis of frontal plane fractures of the ACB referred to a single hospital between 2006 and 2012, including review of radiographic, ultrasonographic and tenoscopic images. Results: Nine fractures were identified, of which 8 displaced fractures all communicated with the carpal sheath. Comminuted fragments and/or protruding fracture margins lacerated the lateral margin of the enclosed DDFT. This was identifiable ultrasonographically and confirmed at tenoscopy in 7 cases. Treatment in these horses consisted of removal of torn tendon tissue together with fragmentation and protuberant fracture edges, and 7 of 7 cases returned to work. One horse with a nondisplaced fracture was managed with immobilisation; the fracture healed, and the horse returned to work. One horse with a displaced fracture was retired to stud. Conclusions: Frontal plane fractures of the ACB occur palmar to the groove in its lateral margin for the tendon of insertion of ulnaris lateralis. Comminuted fragments can displace distally within the carpal sheath to a mid-metacarpal level or abaxially to lie extrathecally, lateral to the parent bone. Displaced fractures communicate with the carpal sheath and traumatise the DDFT. © 2013 EVJ Ltd.

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