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Topic:Castration
Castration in horses is a surgical procedure that involves the removal of the testicles, primarily performed to reduce aggressive behavior and prevent breeding. This operation, typically conducted on young male horses, or colts, can be done using various techniques, including open, closed, or laparoscopic methods. The procedure is generally carried out under anesthesia and requires post-operative care to minimize complications such as infection, swelling, or hemorrhage. Castration can influence a horse's physiology and behavior, often resulting in calmer temperaments and easier handling. This page offers a collection of peer-reviewed research studies and scholarly articles that explore the methodologies, physiological impacts, and behavioral changes associated with castration in equines.
Survey of equine castration techniques, preferences and outcomes among Australian veterinarians. (1) To collect the perceptions of veterinarians performing equine castrations in Australia on techniques, preferences and outcomes, (2) to investigate veterinarian use and experience with the Henderson castrating instrument and (3) to investigate potential associations between demographics, castration methods and techniques, and complications. Methods: Online survey of members of the Australian Veterinary Association's Special Interest Group, Equine Veterinarians Australia (EVA). Methods: A link to the survey was included in the EVA e-newsletter and practices on the EVA website were contacted ...
Morcellation for testes extraction in horses undergoing standing laparoscopic cryptorchidectomy. The major objective of this study was to describe the use of morcellation for standing laparoscopic cryptorchidectomy in 30 client-owned horses. A second objective was to describe a laparoscopic-assisted standing scrotal technique for removal of a descended testis in unilateral cryptorchids. Morcellation for extraction of abdominal testes is effective, efficient, and well-tolerated. Morcellation enabled safe and straightforward extraction of testes from the abdomen through an approximately 13- to 20-mm incision using a 2-portal technique. No incisional or morcellator-related complications occu...
Evaluation of total intravenous anesthesia with propofol-guaifenesin-medetomidine and alfaxalone-guaifenesin-medetomidine in Thoroughbred horses undergoing castration. Anesthetic and cardiorespiratory effects of total intravenous anesthesia (TIVA) technique using propofol-guaifenesin-medetomidine (PGM) and alfaxalone-guaifenesin-medetomidine (AGM) were preliminarily evaluated in Thoroughbred horses undergoing castration. Twelve male Thoroughbred horses were assigned randomly into two groups. After premedication with intravenous (IV) administrations of medetomidine (5.0 µg/kg) and butorphanol (0.02 mg/kg), anesthesia was induced with guaifenesin (10 mg/kg IV), followed by either propofol (2.0 mg/kg IV) (group PGM: n=6) or alfaxalone (1.0 mg/kg IV) (group AGM...
Open standing castration in Thoroughbred racehorses in Hong Kong: Prevalence and severity of complications 30 days post-castration. Complications following open standing castration (OSC) in Thoroughbred racehorses are well recognised but variation in their prevalence and severity between populations is not well documented. Objective: To describe the prevalence and severity of complications in the 30 days following OSC. Methods: A retrospective cohort study of veterinary clinical records relating to horses that underwent OSC between July 2007 and July 2012. Methods: Complications were graded on a severity score from N, no complications, to C3, severe complications. Additional data were accessed for each horse including age,...
Evaluation of the use of midazolam as a co-induction agent with ketamine for anaesthesia in sedated ponies undergoing field castration. There are limited investigations comparing ketamine to a ketamine-midazolam co-induction. Objective: To compare quality and safety of general anaesthesia induced using ketamine alone with anaesthesia co-induced using ketamine and midazolam. Methods: Randomised, double blinded, placebo controlled trial. Methods: After i.v. detomidine (20 μg/kg) thirty-eight ponies undergoing field castration received either 0.06 mg/kg (0.6 mL/50 kg) midazolam (group M) or 0.6 mL/50 kg placebo (group P) with 2.2 mg/kg ketamine i.v. for anaesthetic induction. Quality of anaesthetic induction, endotracheal intuba...
Do different characteristics of two emasculators make a difference in equine castration? The Serra and Reimer emasculators are frequently used in equine orchiectomy. They differ in jaw profile and the mechanism by which they achieve haemostasis. Objective: To investigate whether the haemostatic capacities of the Reimer and Serra emasculators in open and closed castration differ, to compare the haemostatic capacities of each emasculator in both open and closed castration, and to assess whether the tensile strength of the parietal tunic in closed castration differs according to whether a Reimer or Serra emasculator is used. Methods: Ex vivo randomised study. Methods: Eighty equine c...
Pharmacokinetics of the anti-androgenic drug flutamide in healthy stallions. Alternatives to surgical castration are necessary for controlling the sexual behaviour of stallions with breeding potential in training and competition. Flutamide is a potent selective non-steroidal androgen receptor competitive antagonist that has been used in human beings as an anti-androgenic drug. In this study, the pharmacokinetics and bioavailability of flutamide and its main active metabolite, 2-hydroflutamide, were determined in seven healthy mature stallions. Single doses of flutamide (1mg/kg intravenously, 1mg/kg orally in fasted horses, 5mg/kg orally in fasted horses and 5mg/kg oral...
Two complementary methods to control gonadotropin-releasing hormone vaccination (Improvac®) misuse in horseracing: Enzyme-linked immunosorbent assay test in plasma and steroidomics in urine. Since the availability on the European market of the vaccine Improvac® dedicated to male pig immunological castration, the risk of misuse of this product in horses is now considered as a threat for the horseracing industry. Immunological castration is not allowed by the racing codes (immune system, Article 6). Indeed, this vaccination against the hypothalamic hormone luteinizing hormone-releasing hormone or gonadotropin-releasing hormone (GnRH) will prevent the release from the anterior pituitary of luteinizing hormone and follicle stimulating hormone, which are required for the development a...
Relationship between echotextural and histomorphometric characteristics of stallion testes. The goal of this study was to investigate correlations between objective measures of testicular echotexture and histomorphometric attributes related to the histological composition of stallion testes. Fifty-four scrotal testes were obtained from three groups of stallions during routine castrations: colts 5 yrs old (n = 9). In addition, two scrotal testes with degeneration, 16 retained inguinal and 10 retained abdominal testes were surgically obtained. Cross-sectional and longitudinal ultrasonograms were obtained for each testis. Mean numerical pixel values (NPVs) as well as pixel standard...
Complications and risk factors of castration with primary wound closure: Retrospective study in 159 horses. Castration with primary wound closure reportedly has lower complication rates and shorter recovery periods compared to castration with second intention healing. However, little is known about risk factors associated with complications using primary wound closure. Medical records of 159 horses castrated and having primary wound closure were reviewed. Main short-term complications were: scrotal hematoma in 12 horses (7.6%), signs of colic in 6 horses (3.8%), fever in 4 horses (2.5%), and peri-incisional edema in 3 horses (1.9%). As for long-term complications, 24 out of 105 (23%) horses sustaine...
Castration in the standing horse combining laparoscopic and conventional techniques. Standing laparoscopic castration without orchidectomy has been shown to be a reliable method of castration in animals with abdominal cryptorchidism, but it cannot be recommended as a method of castration in those with inguinal cryptorchidism or normal males. An alternative laparoscopic method for the castration of horses with descended testes was developed. Objective: To report the results of laparoscopy-assisted abdominal transection of the spermatic cord and a modified open method in the standing horse for castration of descended testes in unilateral abdominal cryptorchids. Methods: Descript...
Alfaxalone for maintenance of anaesthesia in ponies undergoing field castration: continuous infusion compared with intravenous boluses. To compare alfaxalone as continuous intravenous (IV) infusion with intermittent IV injections for maintenance of anaesthesia in ponies undergoing castration. Methods: Prospective, randomized, 'blinded' clinical study. Methods: A group of 33 entire male Welsh ponies undergoing field castration. Methods: After preanaesthetic medication with IV detomidine (10 μg kg) and butorphanol (0.05 mg kg), anaesthesia was induced with IV diazepam (0.05 mg kg) followed by alfaxalone (1 mg kg). After random allocation, anaesthesia was maintained with either IV alfaxalone 2 mg kg hour (group A; n ...
Laparoscopic cryptorchidectomy with a vessel-sealing device in dorsal recumbent horses: 43 cases. To document laparoscopic cryptorchidectomy with a vessel-sealing device in dorsal recumbent horses. Methods: Retrospective study. Methods: Forty-three male horses. Methods: Food was withheld for 36 hours before horses were placed under general anesthesia and positioned in dorsal recumbency. One laparoscopic portal and 2 instrument portals were placed for the laparoscopic procedure. A third instrument portal was created in bilateral cryptorchid horses. A vessel-sealing device was used for hemostasis and transection of retained testes. Descended testes were removed via closed castration with pri...
Oxidative stress markers in Thoroughbred horses after castration surgery under inhalation anesthesia. Oxidative stress has been reported to occur during surgery. It is important to reduce intraoperative oxidative stress to improve the postoperative prognosis. However, there are no reports regarding oxidative stress related to surgery in horses. In the present study, we measured pre and postsurgical diacron-reactive oxygen metabolites (d-ROMs) and biological antioxidant potential (BAP); the oxidative stress index (OSI) was then calculated (OSI=d-ROMs/BAP × 100). d-ROMs were not significantly different between the pre and postsurgical periods. However, BAP significantly decreased after surgery ...
Evaluation of chemical castration with calcium chloride versus surgical castration in donkeys: testosterone as an endpoint marker. For the last few years, researchers have been interested in developing a method for chemical sterilization which may be a better alternative to surgical castration. An ideal chemical sterilant would be one that effectively arrests spermatogenesis and androgenesis as well as libido with absence of toxic or other side effects. Calcium chloride in various solutions and concentrations has been tested in many animal species, but few studies have been evaluated it in equines as a chemical sterilant. So, the objective of this study was to evaluate the clinical efficacy of chemical castration with 20%...
Ex vivo comparison of the giant and transfixing knot in equine open and closed castration. In equine castration, application of a ligature on the spermatic cord to prevent complications such as haemorrhage and evisceration has been reported with controversial results. Characteristics of commonly used knots have not been studied. Objective: To compare the modified transfixing and giant knots and the emasculator in open and closed equine castration techniques. Methods: Ex vivo experiment. Methods: A total of 144 testicles were randomly assigned to 2 groups for open or closed castration. Both groups were divided into 3 subgroups of 18 specimens each: emasculator only, emasculator plus ...
Comparison of Chemical and Surgical Vasectomy on Testicular Activity in Free-Roaming Horses (Equus caballus) Free-roaming horse (Equus caballus) management is a complex issue incorporating social, economic, emotional, political, and environmental factors. Currently, few proven field techniques exist for managing free-roaming horse population growth, which can reach 20-25% annually. Although there are several strategies available for sterilizing mares when managing free-roaming horse populations, surgical vasectomy is the only method used in the field for stallions. Some managers believe that surgically vasectomizing dominant stallions would have significant effects on reducing horse populations. Howe...
Anatomical variations in epididymal-testicular fusion in stallions and their possible clinical significance. Fusion anomalies of the epididymis with the testis may be clinically relevant in horses. However, anatomical variations in epididymal-testicular fusion have not been classified, and their clinical significance is unknown. Objective: To describe anatomical variations and clinical significance of epididymal-testicular fusion in stallions. Methods: Anatomical study of testes from castrations, and description of 2 clinical cases with atypical epididymal-testicular fusion. Methods: A total of 104 testes were obtained from equine castrations. Eight patterns of epididymal-testicular fusion were ident...
Sperm DNA quality evaluated by comet assay and sperm chromatin structure assay in stallions after unilateral orchiectomy. Unilateral orchiectomy (UO) may interfere with thermoregulation of the remaining testis caused by inflammation surrounding the incision site, thus altering normal spermatogenesis and consequently sperm quality. Two measures of sperm DNA quality (neutral comet assay and the sperm chromatin structure assay [SCSA]) were compared before UO (0 days) and at 14, 30, and 60 days after UO to determine whether sperm DNA changed after a mild testis stress (i.e., UO). The percent DNA in the comet tail was higher at 14 and 60 days compared to 0 days (P < 0.05) after UO. All other comet tail measures (i....
Characterization of the equine blood-testis barrier during tubular development in normal and cryptorchid stallions. The formation of the blood-testis barrier (BTB) is defined as occurring with the first appearance of spermatocytes at around puberty and is vital for normal spermatogenesis. This barrier between two adjacent Sertoli cells (SCs) consists of a cell junctional protein complex, which includes tight junctions (TJs), adherens junctions, and gap junctions. In many mammalian species, BTB composition has already been investigated, whereas little is known about the equine BTB. In the present study, immunohistochemistry and qualitative Western Blot analysis were used to assess the expression and distribu...
Clinical and pharmacokinetic evaluation of S-ketamine for intravenous general anaesthesia in horses undergoing field castration. Intravenous anaesthetic drugs are the primary means for producing general anaesthesia in equine practice. The ideal drug for intravenous anaesthesia has high reliability and pharmacokinetic properties indicating short elimination and lack of accumulation when administered for prolonged periods. Induction of general anaesthesia with racemic ketamine preceded by profound sedation has already an established place in the equine field anaesthesia. Due to potential advantages over racemic ketamine, S-ketamine has been employed in horses to induce general anaesthesia, but its optimal dose remains und...
Effects of an anabolic steroid (Durateston) on testicular angiogenesis in peripubertal stallions. The aim of this study was to determine the effect of the anabolic steroid testosterone on the testicular vascularization, angiogenesis and expression of angiogenic factors, and their receptors in testes of peripubertal stallions. Seven peripubertal stallions were treated with Durateston and castrated either 4 (treatment group 1 [TG1]) or 12 weeks (TG2) after the last injection. The castration of seven untreated control stallions (control group [CG]) took place within the same time. In the testicular specimens, volume density (VD), numerical density (ND), and area of vessels were determined mor...
Anti-Müllerian hormone as an indicator of hemi-castrated unilateral cryptorchid horses. Anti-Müllerian hormone (AMH), a glycoprotein secreted from the fetal testis, is responsible for regression of the Müllerian duct in the male fetus. The aim of this study was to evaluate the usefulness of serum AMH as a biomarker for diagnosis of cryptorchidism in horses. Serum AMH concentrations were measured in intact stallions, hemi-castrated unilateral cryptorchid stallions, and geldings. In addition, expression of AMH was characterized in cryptorchid testes by immunohistochemistry. Serum AMH was detected in intact stallions (n=11, 13.3 ± 1.8 ng/ml) and in hemi-castrated cryptorchid stal...
Cryptorchidectomy in equids: 604 cases (1977-2010). To evaluate the management of equids undergoing cryptorchidectomy at a referral hospital. Methods: Retrospective case series. Methods: 604 client-owned equids. Methods: Medical records of all equids undergoing surgical treatment of cryptorchidism from 1977 to 2010 were retrospectively reviewed. Analyses of breed, location of retained testes, accuracy of palpation per rectum for determining the location of retained testes, surgical technique, and postoperative complications were performed. Results: The most frequently affected breed was the Quarter Horse (282/604 [47%]), which was significantly...
Dexamethasone acutely regulates endocrine parameters in stallions and subsequently affects gene expression in testicular germ cells. Testicular steroidogenesis and spermatogenesis are negatively impacted by stress-related hormones such as glucocorticoids. The effects of two injections of a therapeutic dose of dexamethasone (a synthetic glucocorticoid, 0.1mg/kg; i.v.) given 24h apart to each of three stallions were investigated and compared to three saline-injected control stallions. Dexamethasone decreased circulating concentrations of cortisol by 50% at 24h after the initial injection. Serum testosterone decreased by a maximum of 94% from 4 to 20h after the initial injection of dexamethasone. Semen parameters of the dexame...
Comparison of midazolam and diazepam as co-induction agents with ketamine for anaesthesia in sedated ponies undergoing field castration. To compare intravenous (IV) midazolam and diazepam administered with ketamine for induction of anaesthesia in ponies, already sedated with detomidine, undergoing field castration. Methods: Prospective, randomised, 'blinded', clinical study. Methods: Twenty Welsh pony yearlings. Methods: After IV injection of detomidine (20 μg kg(-1) ) and phenylbutazone (4.4 mg kg(-1) ) ponies were allocated to receive either IV midazolam (group M) or diazepam (group D) (both 0.06 mg kg(-1) ) with ketamine (2.2 mg kg(-1) ) for induction of anaesthesia. Using simple descriptive scales, quality of sedat...
Buprenorphine provides better anaesthetic conditions than butorphanol for field castration in ponies: results of a randomised clinical trial. A prospective, randomised, blinded, clinical trial in 47 ponies compared butorphanol and buprenorphine administered intravenously with detomidine prior to castration under anaesthesia. Detomidine 12 μg/kg intravenously was followed by butorphanol 25 μg/kg (BUT) or buprenorphine 5 μg/kg (BUP) before induction of anaesthesia with intravenous ketamine and diazepam. Quality of sedation, induction and recovery from anaesthesia, response to tactile stimulation, and surgical conditions were scored. If anaesthesia was inadequate 'rescue' was given with intravenous ketamine (maximum three dose...
Dexamethasone acutely down-regulates genes involved in steroidogenesis in stallion testes. In rodents, livestock and primate species, a single dose of the synthetic glucocorticoid dexamethasone acutely lowers testosterone biosynthesis. To determine the mechanism of decreased testosterone biosynthesis, stallions were treated with 0.1mg/kg dexamethasone 12h prior to castration. Dexamethasone decreased serum concentrations of testosterone by 60% compared to saline-treated control stallions. Transcriptome analyses (microarrays, northern blots and quantitative PCR) of testes discovered that dexamethasone treatment decreased concentrations of glucocorticoid receptor alpha (NR3C1), alpha a...
Control of the misuse of testosterone in castrated horses based on an international threshold in plasma. Testosterone is an endogenous steroid produced primarily in the testes. Trace levels of testosterone are found in urine samples from geldings, as testosterone is also secreted by the adrenal. An international threshold of free and conjugated testosterone in urine (20 ng/mL) was adopted by the International Federation of Horseracing Authorities (IFHA) in 1996 for controlling testosterone misuse in geldings. In view of the recent popularity of using blood in doping control testing, it is necessary to establish a threshold for testosterone in gelding plasma. A liquid chromatography-mass spectro...
