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A 7-year-old Friesian stallion with a history of oesophageal stenosis, weight loss, inappetence, and recurrent hyperthermia was referred for gastroscopy. The stomach mucosa surrounding the oesophageal opening showed a large, necrotic, and ulcerated mass. On post-mortem examination, a very large, cauliflower-like neoplasm was seen, affecting non-glandular gastric mucosa. Nodular lesions were observed, scattered on the omentum, the spleen, and the liver. Microscopic findings allowed the diagnosis of gastric squamous cell carcinoma with abdominal metastasis. Biomolecular investigations demonstrated the presence of EcPV-2 genes in neoplastic lesions, thus supporting the role of EcPV-2 in the ethiology of equine gastric cancer.

Background: Capsulitis leads to the release of inflammatory mediators into the joint causing capsular fibrosis and osteoarthrosis (OA). Strain elastosonography (SE) measures the elasticity of tissue evaluating its strain to an operator-dependent deformation. Aims of the study were to assess the feasibility of SE for evaluating the distal attachment of the joint capsule (DJC) of fore fetlocks in sound horses and in horses with fetlock OA and to evaluate differences in their elastosonographic aspect. After a whole lameness examination, fore fetlocks DJC were assigned to Group S and Group P and examined by two operators using SE. The inter-rater reliability (IRR), the intraclass (intra-CC) and interclass (inter-CC) correlation coefficients were used to compare colour grading scores, repeatability, reproducibility of elasticity index (EI) and strain ratio (SR). The same parameters were compared between groups. Findings were significant for P < 0.05. Results: Forty-one horses were included, 11 in Group S, 30 in Group P (16 with bilateral OA, 8 left and 6 right OA). IRRs ranged from good to excellent. For transverse and longitudinal scans, the EIs of Group S were 0.57-0.51, SRs were 0.32-0.28. Inter-CC and intra-CC were always > 0.8. In Group P, EI was 1.09-0.89, SRs was 0.78-0.72 with intra-CC and inter-CC >0.57. Significative differences of EI and SR were detected between groups, and between Group S and the affected limb of Group P.Conclusions: SE is a useful technique for evaluating the DJC, with good repeatability and reproducibility. DJC appears softer in sound horses.

Pain management is necessary for all surgical procedures. Little scientific evidence about drug efficacy in donkeys is available. The aim of this study was to evaluate the analgesic effect of butorphanol in donkeys undergoing orchiectomy under total intravenous anaesthesia with guaifenesin-ketamine-detomidine. A randomized blinded prospective clinical trial (Protocol n. 2021/0000338), was carried out on 18 clinically healthy donkeys undergoing bilateral orchiectomy. Patients were assigned to Group D (n = 8) or Group DB (n = 10) if receiving intravenous detomidine or detomidine-butorphanol respectively, before induction of general anaesthesia with ketamine-diazepam. Intraoperative muscle relaxation, nystagmus, palpebral reflex, heart and respiratory rate, and non-invasive blood pressure were evaluated every 2 min, time to prepare the patient, duration of surgery and anaesthesia and recovery score were recorded. Group D had significantly longer surgical time, higher heart rate, higher systolic and mean blood pressure (p &lt, 0.05, repeated measure ANOVA), increased muscle rigidity and expression of palpebral reflex (p &lt, Mann–Whitney U test) than group DB. Top-ups with thiopental were statistically higher in Group D. Butorphanol and detomidine together produced a more stable anaesthetic plan. The low dosage of opioid and alpha-2-agonists and reduced rescue anaesthesia are responsible for a safer and more superficial anaesthesia, which is mandatory under field conditions.

Equine sinonasal myxomas (SNM) are very rare; only a few cases/small case series are reported in veterinary literature. The purpose of this report is to describe the diagnostic and surgical procedure adopted to approach the neoplastic mass in a case of equine SNM. A 5 year old, Murgese gelding was presented with mild serous nasal discharge, minimal facial swelling, decreased airflow from the right nostril, and dull frontal sinus percussion. Diagnostic imaging, including endoscopy, revealed a pale mass in the caudal portion of the right middle meatus, which developed inside the right conchofrontal sinus and nasal cavity and deviated the nasal septum to the left side. A large frontonasal bone flap was created with the horse in general anesthesia, aiming to remove the lesion and perform further diagnostic investigation. The mass had the shape of a small orange, the caudodorsal and rostral part having a hard wall, whereas the ventral part being friable; the inside was hollow, containing a viscous and transparent liquid. Surgical excision was broad but incomplete, and therefore after surgery, a standing transendoscopic diode laser irradiation and photoablation of small residual lesions per nasum were performed. Microscopically, the mass consisted of spindle-shaped cells, loosely arranged within an abundant, light blue myxoid matrix. On the basis of clinical and pathologic findings, the diagnosis of sinonasal myxoma was made. Although benign and slowly growing, myxomas usually tend to infiltrate the surrounding tissues; as a consequence, recurrence is very likely after surgical excision. In the case described herein, the combination of a surgical excision, transendoscopic diode laser irradiation, and photoablation provided a positive outcome, until at least 14 months after surgery.

Simple Summary The equine prepuce is characteristic for having two infoldings that allow for substantial accommodation of the penis during detumescence and permit erection. Segmental posthetomy of the equine prepuce is a well described technique indicated for penile sheath injuries or lesions (neoplasms, granulomas, or scar tissue) that do not involve the underlying penile tunics. This surgical technique can be performed with variable extent of excision (i.e., the Adam’s procedure or subtotal posthetomy). The authors describe their experiences and results with different levels of preputial resection for treating four Equidae stallion patients with different preputial/pathologies. Abstract Segmental posthetomy, also referred to as circumcision, reefing or posthioplasty, consists of removing a circumferential segment of the internal preputial lamina (internal preputial fold) followed by end-to-end anastomosis of skin edges. The purpose of this case series is to describe the successful outcome of segmental posthetomy for treating different diseases involving the internal or/and external preputial fold, while restoring the normal telescopic function. In this paper, we report the first case of complete degloving injury of the equine penis in the literature (case 1) and describe three different common lesions of the equine prepuce/penis (preputial scar tissue in case 2, preputial sarcoid in case 3 and penile/preputial wound in case 4). The amount of prepuce (safe minimums) that can be removed from a stallion without disrupting the proper telescopic function of the internal/external preputial fold and normal copulatory ability, has not been established. In this case series, all Equidae stallions maintained the telescopic function after preputial surgical resection. However, the surgeon must carefully evaluate every single case, especially when performing the Adam’s procedure.

Mules are hybrids bred from the mating of a jack donkey and a horse mare, known for their strength and resistance and still used to work in agriculture. Although they have been for long considered sterile, evidence of estrus cycle has been demonstrated together with abnormal behavior related to ovarian activity. In this study, a bilateral standing laparoscopic ovariectomy technique using the LigaSure technology was applied in 10 mare mules for treating unwanted behavioral patterns. The technique was effectively performed on these animals avoiding the risk of general anesthesia, and the use of the LigaSure technology allowed good hemostasis and reduced surgical time. Owners declared to be satisfied with the resolution of the behavior.

The healing of wounds located on the equine distal limbs can often be impaired, which can result in exuberant granulation tissue and its associated aesthetic alteration and functional failures. Although a number of therapies have been developed and assessed, the treatment of these wounds still presents challenges. This report describes the treatment of exuberant granulation tissue in a horse using an intra-lesional injection of 4% formaldehyde solution. The successful outcome of this treatment suggests that further investigations are required in order to better evaluate its efficacy, as well as the incidence and the severity of any adverse reaction.

Objective To analyse the effectiveness of intrafunicular lidocaine and intravenous flunixin for reducing pain and signs of stress in lambs undergoing surgical castration. Design Randomised controlled trial. Setting One university teaching hospital in Italy. Participants 30 healthy male lambs, 9–12 weeks old. Intervention Allocation to five groups: a control group (C), undergoing general anaesthesia but not castration; a surgery group (S), undergoing orchiectomy without analgesic treatment; a surgery-lidocaine group (SL), undergoing orchiectomy and receiving intrafunicular 2 per cent lidocaine solution; a surgery-flunixin group (SF), undergoing orchiectomy and receiving intravenous flunixin; a surgery-flunixin-lidocaine group (SFL), undergoing orchiectomy and receiving both intrafunicular lidocaine and intravenous flunixin. Main outcome measures Nociception and stress were assessed through intraoperative indicators, serum cortisol concentration, glycaemia, behaviour, immune response and clinical evaluation of the heart rate (HR), respiratory rate and rectal temperature after surgery. Results Groups S and SL showed increased values of intraoperative HR, mean arterial pressure and postoperative cortisol concentration. In group SFL, cortisol values were similar to those of group C. No other difference could be detected. Conclusions The combination of intravenous flunixin and intrafunicular lidocaine reduced the pain and discomfort of lambs castrated under general anaesthesia. Intrafunicular lidocaine alone did not prevent pain or discomfort associated with castration. Trial registration number 30/2012/CEISA/COM.

Objectives This study evaluated synovial and systemic plasma pharmacokinetic variables of marbofloxacin after a single intravenous regional limb perfusion (IVRLP) performed using two different tourniquets in clinically healthy, standing, non-sedated dairy cows. The authors hypothesised that the type of tourniquet used for IVRLP would influence the synovial fluid concentration of marbofloxacin in the perfused distal limb. Design The study had a randomised parallel-group design. Methods Ten adult dairy cows were included. Unilateral hindlimb IVRLP through the dorsal common digital III vein was performed in two groups of five cows (group 1: wide rubber tourniquet; group 2: manual pneumatic tourniquet) using 0.67 mg/kg of marbofloxacin. The tourniquet was applied proximal to the tarsus and maintained for 30 minutes. Samples of jugular blood and synovial fluid from the tibiotarsal joints of the perfused limb were obtained before and at intervals after IVRLP. All samples were analysed for drug concentrations using liquid chromatography tandem mass spectrometry. Pharmacokinetic parameters were determined to establish the influence of tourniquet types. Differences were considered significant at P≤0.05. Results No adverse effects from the procedure or marbofloxacin were observed in any animal. Significant differences in synovial concentrations and pharmacokinetic parameters were measured. The mean ± sd areas under the concentration versus time curve from time 0 to 24 hours were 178.98±58.08 µg hour/ml for group 2 and 21.11±9.93 µg hour/ml for group 1. The mean ± sd maximum marbofloxacin concentrations were 75.50±10.19 µg/ml for group 2 and 6.35±1.47 µg/ml for group 1. Conclusions Performing IVRLP using the dorsal common digital III vein and a manual pneumatic tourniquet set at 300 mmHg above the tarsus in standing cows resulted in significantly higher marbofloxacin concentrations in the tibiotarsal joint compared with those with the wide rubber tourniquet. Trial registration Local ethical committee (number 41/2012/CEISA).

This study aimed to evaluate the analgesic effect of intrafunicular lidocaine during orchiectomy in isoflurane-anesthetized donkeys. For this purpose, 10 adult healthy donkeys were chosen from Martina Franca donkey population. Each donkey underwent two surgical procedures of monolateral orchiectomy under general anesthesia. Starting isoflurane vaporizer setting was 1.5% to maintain a light plane of anesthesia. Regional anesthesia was performed by injecting 10 mL of 2% lidocaine plus adrenalin or an equivalent volume of saline solution into the spermatic cord. According to what was injected into the funiculus before the surgical procedure, each donkey was once assigned to the group L (lidocaine) and once to the group S (saline). End-tidal isoflurane and standard physiological parameters were measured. Compared with groups, monolateral orchiectomy increased mean heart rate in group S; during surgical procedure, the end-tidal isoflurane was significantly lower in group L. No differences were found regarding mean arterial blood pressure, respiratory rate, recovery quality, and metabolic parameters between groups during procedures. In isoflurane-anesthetized donkeys, intrafunicular injection of lidocaine before castration appears to decrease intraoperative nociception and significantly reduces the concentration of the volatile agent to obtain a sufficient surgical anesthesia.

This case report describes surgical treatment of 3 cases of septic chronic tenosynovitis of the tarsal sheath with fragmentation of the sustentaculum tali in 3 horses. Diagnosis was based on clinical signs, radiographic and ultrasonographic findings, synovial fluid cytology, and bacteriology. In each case, treatment consisted of tenovaginoscopy of the tarsal sheath performed with the horse under general anesthesia and regional intravenous perfusion of antibiotics. Follow-up data obtained between 12 and 46 months after surgery reported a good outcome, with a good cosmetic appearance in all cases described. Two horses returned to their intended use at 44 and 46 months, and 1 horse reportedly showed a remarkable functional improvement after 12 months. Despite the poor prognosis associated with the chronicity of the lesions, the presence of adhesions and the degree of involvement of the lateral digital flexor tendon, tenovaginoscopy of the tarsal sheath and regional antimicrobial therapy were successful therapeutic options for treating septic tenosynovitis of the tarsal sheath with fragmentation of the sustentaculum tali.

A rapid LC-MS/MS method for the determination of marbofloxacin in plasma and synovial fluid is presented in this study. The method uses a rapid sample preparation which only requires an ultrafiltration step with centrifugal filter devices. The optimized procedure allows a minimal need of sample (175 μL), particularly useful for synovial fluid samples which amount is rather limited; it is simple, rapid and easily applicable providing anyhow a satisfactory clean up, demonstrated by post-infusion experiments. On the other hand to maximize the speed of the analysis an ultrafast chromatographic separation has been obtained by selecting a column of 20 mm; the reduced run-time is suitable for processing numerous samples on a daily basis. Linearity was assessed in the range 5-2500 ng mL(-1); ofloxacin was used as internal standard. LOD and LOQ were respectively 1 and 5 ng/mL. The method was successfully applied to a set of samples generated during an experimental veterinary study.

A 15-year-old gelding was referred for a florid, cauliflower-like ulcerated mass, enclosing penis and prepuce together with penile urethra showing a malodorous purulent and blood-stained discharge and larvae infestation.En blocextensive resection of the penis and prepuce, without penile retroversion or pexy to ventral abdomen associated with a permanent perineal urethrostomy, was performed. Histology of the mass revealed a squamous cell carcinoma of penis and prepuce. The surgical technique that was adopted is a modified version of that already described that allows a more proximal resection of the penile body and is a valid option for treating advanced SCC lesions involving the penis. Early postsurgical complications (mild strangury, haemorrhage from the urethrostomy site and its partial dehiscence, and infection of the abdominal wound) were managed with a medical treatment and resolved within 5 to 12 days. Three years after surgery the horse is in good body condition and does not show any sign of recurrence or disorders related to the surgery.

Objective To report laparoscopic-assisted cystotomy and inguinal cystostomy for treating bladder urolithiasis in a gelding. Study Design Clinical report. Animals Twelve-year-old Appaloosa gelding. Methods A laparoscopic approach was used to locate and grasp the bladder, which was exteriorized through an enlarged instrument portal for cystotomy to remove the calculus. During withdrawal, the calculus fragmented into multiple pieces. To avoid urethral occlusion and facilitate elimination of these fragments, an inguinal cystostomy was created. The seromuscular layer of the bladder was circumferentially secured to the abdominal fascia and bladder mucosa margins were sutured to the skin. Results At 2-year follow-up, the gelding was in good condition with mild urine scald of the left ventral abdomen. Conclusion Laparoscopic-assisted cystotomy was used for calculus removal and inguinal cystostomy for successful fragment elimination.

An experimental protocol was designed to study the survival and behaviour of an allograft of amniotic epithelial cells (AECs) in an ovine model. The study was conducted on three healthy adult sheep. A core lesion was created in both calcaneal tendons under ultrasound (US) guidance by injecting 400 UI of Type 1A collagenase diluted in 0.6 ml saline. The AECs were obtained from a 60-80-day-old fetus and cultured under standard conditions. After 15 days of collagenase treatment, 2 x 10(6) AECs stained with a vital membrane fluorescent probe (PHK26) were injected under US guidance in 500 microl saline solution into the lesion of one limb. The contralateral untreated limb was used as a control. Animals were euthanatized 7 (1) and 30 (2) days later. Histological analyses performed on explanted tendons clearly demonstrate that AECs survived for at least 1 month inside the lesion without any adverse reactions. The damaged tissue of the treated tendons showed a high number of reparative cells in active proliferation that were accumulating collagen within the extracellular matrix. In addition, after 1 month, the neo-collagen began to be organized into parallel arrays of fibers oriented along the longitudinal axis of the tendon.

The ovine foetus is an ideal model for preclinical medical studies of cell therapies. It allows us to follow the behaviour of repairing cells inserted into a favourable physiological microenvironment in an animal species more closely related to humans than the rat or rabbit. In addition, the preimmune foetus is able to support cell engraftment by eliminating the problems of tissue rejection. Labelled fibroblasts were transplanted into the myocardium of preimmune foetuses, injecting through a disposable bowed mouth pipette into the left ventricular apex. Two weeks later, foetuses were isolated by laparotomy and each heart was collected and morphologically analyzed. No cases of abortion or postoperative complications in mothers or foetuses occurred. Macroscopically, the isolated hearts did not display any abnormality apart from a small petechia at the injection site. Tissue sections did not show any sign of acute tissue inflammation and viable labelled cells were easily identified among myocardiocytes. This model system guarantees a reduced damage in the engrafted tissue, a high survival and easy retrieval of the injected cells. The direct injection of cells into the preimmune ovine foetus myocardium can be satisfactorily performed to control tissue delivery and to reduce the risk of cell loss and dispersion.

Dental implant prostheses cannot preclude a correct and stable implant osseointegration, which is still a challenge and greatly depends on biomaterial-cell interface. Titanium (Ti) coating using polyelectrolyte poly-L-lysine (PLL) may represent an interesting and simple approach, to provide a charged surface net able to improve cell adherence. However, in vitro and in vivo effects of Ti coated with PLL have been poorly investigated. The aims of the present study are (1) to obtain and characterize, chemically and physically, Ti disks coated with PLL (TiPLL); (2) to perform in vitro studies on osteoblast cell lines' cytocompatibility and functionality (alkaline phosphatase [ALP] activity, calcium deposition, proinflammatory interleukin 6 production); (3) to obtain in vivo evidence of osseointegration, using a sheep animal model. XPS, AFM, and contact-angle analyses demonstrated that the Ti disk was successfully covered with PLL, providing higher hydrophilicity to the Ti disk. No cellular toxicity, enhanced calcium deposition, and a decreased tendency toward interleukin-6 production were observed in the osteoblast seeded onto TiPLL. In vivo experiments showed cortical bone microhardness at 3 months significantly improved in the presence of the PLL coating. PLL coating on Ti implants seemed to safely enhance calcium deposition and implant early osseointegration in animals, suggesting promising evidence to optimize the surface properties of dental implants.

To report laparoscopic-assisted cystotomy and inguinal cystostomy for treating bladder urolithiasis in a gelding.Clinical report.Twelve-year-old Appaloosa gelding.A laparoscopic approach was used to locate and grasp the bladder, which was exteriorized through an enlarged instrument portal for cystotomy to remove the calculus. During withdrawal, the calculus fragmented into multiple pieces. To avoid urethral occlusion and facilitate elimination of these fragments, an inguinal cystostomy was created. The seromuscular layer of the bladder was circumferentially secured to the abdominal fascia and bladder mucosa margins were sutured to the skin.At 2-year follow-up, the gelding was in good condition with mild urine scald of the left ventral abdomen.Laparoscopic-assisted cystotomy was used for calculus removal and inguinal cystostomy for successful fragment elimination.

Jaagsiekte sheep retrovirus (JSRV) is a unique oncogenic virus with distinctive biological properties. JSRV is the only virus causing a naturally occurring lung cancer (ovine pulmonary adenocarcinoma, OPA) and possessing a major structural protein that functions as a dominant oncoprotein. Lung cancer is the major cause of death among cancer patients. OPA can be an extremely useful animal model in order to identify the cells originating lung adenocarcinoma and to study the early events of pulmonary carcinogenesis. In this study, we demonstrated that lung adenocarcinoma in sheep originates from infection and transformation of proliferating type 2 pneumocytes (termed here lung alveolar proliferating cells, LAPCs). We excluded that OPA originates from a bronchioalveolar stem cell, or from mature post-mitotic type 2 pneumocytes or from either proliferating or non-proliferating Clara cells. We show that young animals possess abundant LAPCs and are highly susceptible to JSRV infection and transformation. On the contrary, healthy adult sheep, which are normally resistant to experimental OPA induction, exhibit a relatively low number of LAPCs and are resistant to JSRV infection of the respiratory epithelium. Importantly, induction of lung injury increased dramatically the number of LAPCs in adult sheep and rendered these animals fully susceptible to JSRV infection and transformation. Furthermore, we show that JSRV preferentially infects actively dividing cell in vitro. Overall, our study provides unique insights into pulmonary biology and carcinogenesis and suggests that JSRV and its host have reached an evolutionary equilibrium in which productive infection (and transformation) can occur only in cells that are scarce for most of the lifespan of the sheep. Our data also indicate that, at least in this model, inflammation can predispose to retroviral infection and cancer., Author Summary The identification of cells that give origin to cancer is critical in order to design effective therapeutic strategies. To this end, the early stages of cancer are the most informative but they are seldom associated with clinical symptoms and therefore pass unnoticed in human patients. Studies on animal tumors are invaluable to this research area. In this study, we determined the cells originating an infectious lung cancer of sheep (ovine pulmonary adenocarcinoma, OPA) that is similar to some forms of human pulmonary adenocarcinoma. OPA is caused by a virus known as Jaagsiekte sheep retrovirus (JSRV). We show that OPA is caused by JSRV infection of proliferating type 2 pneumocytes (lung alveolar proliferating cells, LAPCs). We show that young animals possess abundant LAPCs and are highly susceptible to JSRV infection while healthy adult sheep exhibit a relatively low number of LAPCs and are resistant to OPA induction. However, adult sheep were susceptible to JSRV infection when the presence of LAPCs was stimulated by induction of a mild injury to the respiratory epithelium. Thus, our study identifies the cells originating lung adenocarcinoma in OPA and shows that inflammation to the respiratory epithelium can predispose to retrovirus infection and cancer.

Goats were infected experimentally with a mycoplasma (the "Irbid" strain) isolated previously from a goat with contagious agalactia in northern Jordan. The strain was unusual in that, although it had been identified by molecular methods as Mycoplasma mycoides subsp. mycoides LC/Mycoplasma mycoides subsp. capri, it showed no inhibition of growth by any of the hyperimmune rabbit antisera conventionally used to speciate members of the Mycoplasma mycoides cluster. Animals were infected either intratracheally or by aerosol and placed "in-contact" with other goats. After 2 weeks, those infected intratracheally became febrile, showing a nasal discharge and slight conjunctivitis, followed a week later by respiratory distress and polyarthritis; lesions seen at necropsy included coagulative necrotic pneumonia, fibrinous pleurisy with pleural exudate, and inflammatory exudates, necrosis and fibrosis in the joints. Animals infected by aerosol showed much milder clinical signs, including nasal discharge and occasional swollen joints. In the "in-contact" goats, seroconversion was first seen after 7 weeks, accompanied by coughing and laboured respiration; lesions in this group consisted of fibrinous pneumonia with focal areas of necrosis and abundant pleural exudate.

Background Several diseases affect bone healing and physiology. Many drugs that are commonly used in orthopaedics as "analgesics" or anti-inflammatory agents impair bone healing. Stressful conditions are associated with decreased serum osteocalcin concentration. High endorphin levels alter calcium metabolism, blocking the membrane channels by which calcium normally enters cells. The consequent decrease of intracellular calcium impairs the activities of calcium-related enzymes. Naloxone is a pure opioid antagonist. Morphine-induced osteocalcin inhibition was abolished when osteoblasts were incubated with naloxone. Naloxone restored the altered cellular and tissue physiology by removing β-endorphins from specific receptors. However, this is only possible if the circulating Ca concentration is adequate. The aim of the present study was to evaluate the efficacy of parenteral naloxone administration in inducing fast mineralization and callus remodelling in a group of sheep with a standardised bone lesion. Methods Twenty ewes were randomly assigned to 4 treatment groups. Group A acted as control, group B received a solution of calcium gluconate, group C a solution of naloxone, and group D a solution of calcium gluconate and naloxone. A transverse hole was drilled in the left metacarpus, including both cortices, then parenteral treatment was administered intramuscularly, daily for four weeks. Healing was evaluated by weekly radiographic examination for eight weeks. For quantitative evaluation, the ratio of the radiographic bone density between the drill area and the adjacent cortical bone was calculated. After eight weeks the sheep were slaughtered and a sample of bone was collected for histopathology Results Group D showed a higher radiographic ratio than the other groups. Sheep not treated with naloxone showed a persistently lower ratio in the lateral than the medial cortex (P < 0.01). Histopathology of bone samples showed more caverns and fewer osteoblasts in group D than in the other groups (P ≤ 0.001). Conclusion A low-dose parenteral regimen of naloxone enhances mineralization and remodelling of the callus in healing cortical defects in sheep, especially if associated with calcium gluconate.

THE term ‘monorchidism’ has been used to describe the absence of a descended testicle but should, more strictly, be used to describe the complete absence of one testicle (Parks and others 1989, Santschi and others 1989, Cox 1993, Strong and others 1997). This condition may result from unilateral testicular agenesis or may follow a unilateral vascular accident. ‘Cryptorchidism’ is the correct term to define the retention of a testicle that does not descend into the scrotum (Parker and others 1997). The presurgical evaluation and surgical approach to cryptorchid and monorchid horses are complex diagnostic and surgical challenges (Schumacher 1992). A definitive diagnosis can only be made after surgical exploration of the abdomen, removal of the other testis and then hormonal testing. The human chorionic gonadotropin (hCG) stimulation test in horses over 18 months of age is the most reliable indicator for the presence of vital testicular tissue (Silberzahn and others 1989, Searle and others 1999). This short communication describes the evaluation and treatment of a case of monorchidism in an appaloosa stallion. An eight-year-old appaloosa stallion was referred to the Department of Veterinary Clinical Sciences of the University of Teramo for castration, with no history of previous surgery. Clinical examination showed the absence of the left testicle in the scrotal or inguinal regions. Laparoscopy in dorsal recumbency and under general anaesthesia was planned to diagnose left abdominal cryptorchidism or monorchidism. The horse was fasted for 36 hours and water was withdrawn 12 hours before surgery. Preoperative intravenous flunixin meglumine (1·1 mg/kg), 20,000 iu/kg bodyweight intramuscular penicillin and 6 mg/kg intravenous gentamicin were administered. Premedication with 0·01 mg/kg acepromazine intramuscularly 30 minutes before induction was followed by general anaesthesia induced with 1·1 mg/kg xylazine intravenously and 2·2 mg/kg ketamine intravenously. Anaesthesia was maintained with isoflurane in oxygen. Laparascopic examination according to the technique of Fischer (2002) did not identify the left testicle or vaginal ring, but a cylindrical structure, approximately 1 cm wide, was seen ending near the left internal inguinal ring. It was connected to the peritoneal surface by a short fibrous band. A piece of this structure was collected for histopathological examination. A left parainguinal laparotomy was then performed for inspection of the left dorsal and sublumbar abdominal region, but no testicle was found. Thereafter the right testicle was removed. Histopathology showed the sample from the cylindrical structure to be dense fibrous tissue with no signs of testicular tissue or scarring, suggesting the infarction of a testis. Postoperative therapy included tetanus prophylaxis, and 20,000 iu/kg bodyweight penicillin G given intramuscularly every 12 hours, 6 mg/kg gentamicin administered intramuscularly every 24 hours, and 1·1 mg/kg flunixin meglumine administered intravenously every 24 hours for three days. Eight days after surgery, a hCG stimulation test was performed to determine whether functional testicular tissue was present. This test was repeated 60 days later. Blood samples were collected for determination of plasma testosterone concentration before and one and 24 hours after intravenous administration of 10,000 iu hCG (Searle and others 1997). The blood was stored in sterile vacutainers containing lithium heparin (Venoject; Terumo), and plasma was obtained after centrifugation for 10 minutes at 1200 g. The plasma was then put into Eppendorf tubes at 20°C. A testosterone assay was performed with a radioimmunological assay technique using a commercial kit (Direck RIA; Sorin Biomedica) with an analytical sensitivity of 0·02 ng/ml (Arighi and Bosu 1989, Strong and others 1997). Table 1 shows the values of plasma testosterone before and after hCG administration. Following the testosterone results monorchidism was definitively diagnosed, and six months after surgery the horse showed no stallion-like behaviour. The tubular, fibrous structure detected during laparoscopy may have been the distal part of the undifferentiated ductus deferens, or, more likely, the gubernaculum testis in a stallion with testicular agenesis. It was decided to use a hCG stimulation test rather than the simple measurement of conjugated oestrogens as suggested by Schumacher (1992) to avoid the possibility of false positive results. The basal hormonal values for oestrogens and androgens would be expected to be high in the stallion soon after castration. However, according to Silberzahn and others (1989), the production of oestrogen is almost unresponsive to hCG treatment, and it was therefore decided to use the stimulation test to evaluate the changes in the androgen levels. The first hCG stimulation test was performed eight days after the orchiectomy, as suggested by Santschi and others (1989) and Strong and others (1997). The basal value of the testosterone was considered relatively high, despite the decrease seen one and 24 hours after the administration of hCG. The high basal value during the first test may have been due to the short time after orchiectomy. However, eight weeks after castration, the basal level of androgens was low, and it is suggested that at least this time should be allowed between surgery and testing to achieve the maximum accuracy of any hormonal test. As previously mentioned, a definitive diagnosis of monorchidism in the horse can be achieved only after a complex procedure. Moreover, laparoscopic examination of the abdomen in dorsal recumbency cannot be exhaustive because, even using the Trendelenburg position, dorsal abdominal structures cannot be thoroughly inspected (Galuppo 2002). After removal of the descended testicle, the only reliable way to make a diagnosis is to determine the blood testosterone level and before one and 24 hours after stimulation with 10,000 iu hCG (Arighi and Bosu 1989). In horses with no vital testicular tissue, there should be no increase above basal testosterone concentrations (Searle and others 1997).