Peterson & Smith Equine Hospital

To establish racing prognosis in Thoroughbred yearlings with proximal sagittal ridge osteochondral lesions and compare them to dorsoproximal and palmar/plantar first phalanx osteochondral lesions. A total of 47 horses had proximal sagittal ridge lesions, 34 had palmar/plantar first phalanx lesions, and 115 had dorsoproximal first phalanx lesions. Retrospective case series. Medical records of Thoroughbred yearling racing prospects treated arthroscopically for fetlock osteochondral lesions were reviewed. Data were collected from a public database, including the ability to train and race, earnings, starts, wins, and placed races. Racing prognosis was analyzed and compared between three lesion locations. Of the proximal sagittal ridge group, 76.6% raced, 65.71% of the palmar/plantar first phalanx group, and 74.58% of the dorsoproximal first phalanx group. Career length was similar for all lesions. A lower number of "starts" in the group "five years old and older" was found for the dorsoproximal first phalanx group compared to the cohort with proximal sagittal ridge lesions. Mares had more "earnings" at two years old but fewer "starts" at "five years old" compared to colts and geldings. Forelimb lesions were predictive for fewer total career starts. Proximal sagittal ridge lesions had similar prognoses to dorsoproximal and palmar/plantar first phalanx lesions. In older horses, there was an increase in the number of starts for the proximal sagittal ridge group compared to the dorsoproximal first phalanx group. Mares and forelimb lesions were associated with decreased racing starts. These findings aid in prognostication for Thoroughbreds with osteochondral lesions removed arthroscopically in the fetlock joint.

Genetic testing is required for the registration of foals of most equine breeds. To describe two clinical cases of marked delayed embryonic development or delayed fertilisation in pregnancies generated by embryo transfer. Case report. Donor mares were inseminated with semen from one stallion during one oestrous cycle and semen from a different stallion on the subsequent oestrous cycle. Embryo(s) were collected 8 days after ovulation during the second oestrous cycle and transferred into synchronised recipient mares. Genetic testing was performed to determine parentage of the two foals. For both foals, DNA parentage testing excluded the second stallion as the genetic sire and confirmed that the first stallion, whose semen was inseminated on the previous oestrous cycle, was the actual genetic sire. Rare event in horses; two clinical cases are described. It is hypothesised that either marked delayed embryonic development or extended sperm survival occurred in the donor mares. Without genetic testing, parentage assignment based solely on breeding records would have been incorrect.

To describe the effects of distal limb immobilization and remobilization in the equine metacarpophalangeal joint. Randomized, prospective experimental study. Eight healthy, skeletally mature horses. One forelimb of each horse was immobilized in a fiberglass cast for 8 weeks; this was followed by 12 weeks of a treadmill-based training program after the cast had been removed. Clinical examinations, radiography, computed tomography (CT), nuclear scintigraphy, MRI, and histomorphometry were used to examine the third metacarpal (MC3), proximal phalanx, proximal sesamoid bones, and associated soft tissues in each horse. Serum and synovial fluid were collected for biomarker analyses. Distal limb immobilization resulted in persistent lameness (P < .001), effusion (P = .002), and a decreased range of motion (P = .012) as well as radiographically visible fragments (P = .036) in the cast forelimb. Bone density was decreased (P < .001) in MC3 according to CT, and trabecular bone fluid was increased (P < .001) according to MRI in the cast forelimb. The cast forelimbs had a change (P = .009) in the appearance of the deep digital flexor tendon according to MRI immediately after removal of the cast. Numerous clinical, radiographic, CT, and MR abnormalities were visible at the end of the study period. Eights weeks of cast immobilization induced changes in bone, cartilage, and periarticular soft tissues that were not reversed after 12 weeks of remobilization. Cast application should be used judiciously in horses with musculoskeletal injuries, balancing appropriate stabilization with potential morbidity secondary to cast placement.

Summary The objective of the study was to describe a modified Heineke–Mikulicz pyloroplasty for the treatment of pyloric stenosis in foals due to gastric ulceration and assess the short‐ and long‐term outcome of foals receiving the pyloroplasty. Medical records of foals undergoing a modified Heineke–Mikulicz pyloroplasty due to gastric outflow obstruction secondary to a pyloric stenosis were included in this retrospective case series. The pyloroplasty consisted of an oral to aboral full thickness longitudinal incision on the ventral aspect of the pylorus and proximal duodenum, which was sutured closed with 0 polydioxanone in a transverse orientation, thereby, enlarging the pyloric lumen diameter. Long‐term outcome was obtained from medical and race records. The pyloroplasty was successfully performed in three foals with a surgical time of 95–121 min, with immediate return to nursing and hospital stay of 4–14 days. Complications included a small intestinal volvulus and intra‐abdominal adhesions in a foal that did not survive. Another foal had an incisional infection. Two of the three foals went on to race. It was concluded that the pyloroplasty procedure is an acceptable option for the treatment of pyloric stenosis and secondary gastric outflow obstruction due to gastric ulceration. The limited amount of bowel manipulation with no change in intestinal flow, along with the successful outcomes achieved, make this another surgical option available for the correction of pyloric stenosis in foals.

Reasons for performing studyBiaxial fracture of the proximal sesamoid bones (PSB) is the leading cause of fetlock failure resulting in euthanasia in Thoroughbred racehorses in California, Kentucky and Hong Kong. Identifying alterable risk factors to reduce biaxial PSB fractures could have a significant impact on reducing the occurrence of catastrophic failure of the fetlock (CFF).ObjectivesWe hypothesised that standing MRI (sMRI) would identify a greater degree of bone change in Thoroughbred racehorses with CFF from biaxial PSB fracture when compared to controls.Study designRetrospective cohort study.MethodsBone changes from Florida Thoroughbred racehorses with CFF due to biaxial fracture of the PSB (n = 21) were compared to controls (n = 53) using the sMRI. Data for control limbs were Florida racehorses that were subjected to euthanasia for reasons other than CFF (enteritis, pneumonitis, etc.). All forelimb fetlocks underwent sMRI imaging within 72 h of euthanasia. Bone scores were assigned to the subchondral bone (SCB) on the distal palmar aspect of the lateral and medial condyle of the third metacarpal bone (McIII) and the lateral and medial PSB. All information for analysis from sMRI images for cases and controls for all Thoroughbred racehorses was reviewed and collected by the lead author. The association between the dichotomous outcomes of PSB fracture with independent variables was assessed using bivariable and multivariable logistic regression analysis with significance set at P&lt;0.05.ResultsThe proportion of cases with &gt;75% sclerosis of the ipsilateral lateral PSB (43%, 9/21) was significantly greater than that among controls (6%, 3/53). The proportion of cases with SCB lesion grade &gt;3 of the contralateral palmar lateral condyle (29%, 6/21) was significantly greater than that among controls (0%, 0/53).ConclusionsThe sMRI identified a significantly greater degree of bone change in racehorses with PSB fracture compared to control horses. These identified changes may be useful as a screening tool to identify horses at increased risk of fetlock fracture during racing.Ethical animal research: Explicit owner informed consent for participation in this study was not given but permission for post mortem examination was given by the Racing Authority. Sources of funding: None. Competing interests: No competing interests have been declared.

To describe a tenosynoviotomy technique for treatment of sepsis of the digital flexor tendon sheath (DFTS) in horses and report long-term outcome. Case series. Horses (n = 9). Horses were positioned in lateral recumbency with the affected limb uppermost. A linear incision was made just lateral to the mesotenon beginning 5 cm proximal to the apices of the proximal sesamoid bones, extending 2 cm distal to the bifurcation of the superficial digital flexor tendon (SDFT). The incision was continued through the skin, subcutaneous tissue, palmar/plantar annular ligament, and DFTS. Tenotomy of the distal lateral branch of the SDFT was also performed. The site was thoroughly debrided, lavaged, and packed with gauze and allowed to heal by second intention. Follow-up was obtained via owner telephone interview. Mean surgery time was 32 minutes (range, 10-64 minutes). Systemic antibiotics were administered postoperatively (range, 11-46 days; mean, 23 days). Mean hospitalization was 11 days (range, 0-49 days). Follow-up was available for 7 (70%) horses. One year postoperatively, 5 (71%) horses were serviceable for their intended use, and 2 (29%) had been euthanatized. Of 5 survivors, 3 returned to ridden exercise, 1 was retired as a broodmare, and 1 was a broodmare. All owners were satisfied with the cosmetic appearance of the surgery site. Open drainage via tenosynoviotomy, performed as a salvage procedure, represents a feasible treatment for DFTS sepsis.

SummaryA one‐year‐old, Thoroughbred colt presented for evaluation due to a one month history of fever of unknown origin and progressive weight loss. On initial presentation, the horse was febrile and showed signs localised to the respiratory tract. These included bilaterally increased bronchovesicular sounds and a moderate, diffuse interstitial pattern on thoracic radiographs. A transtracheal wash yielded mucopurulent debris, culture of which grew small numbers of Staphylococcus epidermidis and Aspergillus spp. The horse was discharged with a diagnosis of bronchointerstitial pneumonia and placed on antibiotic therapy. Ten days after initial presentation, he developed abdominal pain that was unresponsive to on‐farm treatment. The horse was febrile, displayed increased respiratory rate and effort, and showed moderate signs of abdominal pain. On rectal examination, a firm, 8–10 cm mass was palpated on midline. The colt was admitted to the hospital and scheduled for exploratory laparotomy, but died a short time later before surgery could be performed. This report describes the clinical, diagnostic and histopathological findings of a case of alimentary lymphoma in a yearling colt.

Three captive-born (5-day-old, 8-day-old, and 4-yr-old) Asian elephants (Elephas maximus) and one captive-born 22-yr-old African elephant (Loxodonta africana) from three private elephant facilities and one zoo in the United States presented with depression, anorexia, and tachycardia as well as gastrointestinal signs of disease including abdominal distention, decreased borborygmi, tenesmus, hematochezia, or diarrhea. All elephants showed some evidence of discomfort including agitation, vocalization, or postural changes. One animal had abnormal rectal findings. Nonmotile bowel loops were seen on transabdominal ultrasound in another case. Duration of signs ranged from 6 to 36 hr. All elephants received analgesics and were given oral or rectal fluids. Other treatments included warm-water enemas or walking. One elephant underwent exploratory celiotomy. Three animals died, and the elephant taken to surgery was euthanized prior to anesthetic recovery. At necropsy, all animals had severe, strangulating intestinal lesions.

To determine proinflammatory gene expression, endothelial adhesion molecule gene expression, and matrix metalloproteinase (MMP) concentrations in laminar specimens at 1.5 hours after administration of black walnut extract (BWE) and to compare these values with later time points. 25 horses. After nasogastric administration of BWE, anesthesia was induced at 1.5 hours in early time point (ETP) horses (n = 5), between 3 and 4 hours in developmental time point horses (5), and between 9 and 10 hours in acute onset of lameness time point horses (5). Anesthesia was induced at 3 and 10 hours after nasogastric administration of water in 2 groups of control horses (3-hour control group, n = 5; 10-hour control group, 5). Real-time quantitative PCR assay was performed on laminar specimens from control and ETP horses for cyclooxygenase (COX)-1, COX-2, interleukin (IL)-1beta, tumor necrosis factor-alpha, IL-6, IL-8, IL-10, MMP-2, and MMP-9 gene expression; and on laminar specimens from all groups for endothelial adhesion molecules, intercellular adhesion molecule (ICAM)-1, and E-selectin gene expression. Leukocyte emigration was assessed via CD13 immunohistochemistry, and gelatinase accumulation was determined by gelatin zymography. Laminar concentrations of IL-1beta, IL-6, IL-8, COX-2, ICAM-1, and E-selectin mRNA were significantly increased in ETP horses, compared with control horses. Concentrations of IL-1beta, IL-8, ICAM-1, and E-selectin mRNA peaked at 1.5 hours. In ETP horses, leukocyte emigration was present in 3 of 5 horses and pro-MMP-9 was detected in 2 of 5 horses. Results indicated that endothelial activation and laminar inflammation are early events in laminitis; MMP accumulation likely is a downstream event.