Sutureless Technique for Surgical Castration in Adult Boars: A Feasibility Study

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animals Article Sutureless Technique for Surgical Castration in Adult Boars: A Feasibility Study Stella Maria Teresa Romeo, Sarah Morrone , Toufic Akl, Antonio Scanu and Nicolò Columbano * Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy * Correspondence: ncolumbano@uniss.it Simple Summary: The use of boars for breeding purposes is common on small farms in rural regions of Italy. These animals are butchered at the end of their reproductive life for the production of charcuterie. In this regard, orchiectomy is required to remove boar taint caused by testosterone metabolites. The purpose of this study is to validate the efficacy of a safe, rapid and inexpensive castration procedure. To accomplish this objective, 91 boars were orchiectomised using the suture lig- ation technique. Following castration, characteristics of the severed ductus deference were evaluated in order to understand how much force would be required to tie knots without breaking the deferens and achieving proper haemostasis. After identifying a correlation between tensile strength and the age and weight of boars, a sutureless technique was successfully applied to 20 animals. Abstract: The heterogeneity of Italian manufacturing processes results in the production of a large variety of pork products. In Sardinia, boars are raised and butchered to produce charcuterie. These animals are castrated before slaughter as androstenone would otherwise taint the meat, rendering it unfit for human consumption. However, to date, the literature concerning surgical orchiectomy in adult boars is limited. The goal of this study is to assess whether a sutureless swine orchiectomy procedure is feasible. Additionally, this study aims to determine the appropriate traction force needed to tie

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whether a sutureless swine orchiectomy procedure is feasible. Additionally, this study aims to determine the appropriate traction force needed to tie knots in the deferens duct of pigs of different weights and ages. Two groups were created: the first (n = 91) underwent orchiectomy by suture ligation; the second (n = 20) was castrated using the sutureless technique. Deferens ducts of animals in the first group (n = 182) were collected Citation: Romeo, S.M.T.; Morrone, S.; following castration, and their tensile strength was measured. Pearson’s linear correlation was used Akl, T.; Scanu, A.; Columbano, N. to determine the relationship between the maximum traction force and weight and age groups. A Sutureless Technique for Surgical Castration in Adult Boars: A correlation of 0.99 and 0.96 was shown between traction force and age and traction force and weight, Feasibility Study. Animals 2023, 13, respectively. In accordance with these results, sutureless castration was performed on 20 animals, 407. https://doi.org/10.3390/ calibrating the pulling force needed according to the age and weight of the boars. No complications ani13030407 were observed during the feasibility study, thus validating sutureless orchiectomy in adult boars. Academic Editor: Lysimachos Keywords: boars; surgical castration; swine; orchiectomy; sutureless technique; feasibility; field Papazoglou conditions Received: 23 December 2022 Revised: 22 January 2023 Accepted: 23 January 2023 Published: 26 January 2023 1. Introduction Pork is the most consumed meat in the European Union (EU), and the pig sector is one of its most economically significant farming industries. Furthermore, the EU is the world’s second-largest producer of pork after China and the world’s largest exporter of Copyright: © 2023

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rming industries. Furthermore, the EU is the world’s second-largest producer of pork after China and the world’s largest exporter of Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. pork products [1]. Germany, Spain, France, and Italy account for approximately 50% of the This article is an open access article EU’s overall production [2]. According to the National Institute of Statistics (ISTAT), the distributed under the terms and Italian pork sector is valued at roughly EUR 1.7 billion, of which processed pork makes conditions of the Creative Commons up 85% [3]. Ham, bacon, guanciale, and many other products are omnipresent in Italian Attribution (CC BY) license (https:// traditional culinary culture, and some, like prosciutto di Parma (DOP) and prosciutto San creativecommons.org/licenses/by/ Daniele (DOP), are exported all around the globe. The significance of pork products in 4.0/). Italy is reflected by the importance of its pig farming industry, consisting of numerous Animals 2023, 13, 407. https://doi.org/10.3390/ani13030407 https://www.mdpi.com/journal/animals Animals 2023, 13, 407 2 of 9 small farms commonly found in rural areas of the country. Sardinia, known for being one of Italy’s biggest agricultural areas, is one such region. In this context, the castration of mature boars is often required since farmers mainly rely on natural reproduction through mating. At the end of their reproductive term, such boars are castrated in order to avoid boar taint caused by the presence of androstenone making the meat unfit for human consumption [4,5]. Whereas the surgical castration of young piglets is a standard routine procedure, the castration of adult boars is more complex and less described [6]. The latter usually requires general

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ung piglets is a standard routine procedure, the castration of adult boars is more complex and less described [6]. The latter usually requires general anesthesia since large boars are rather dangerous to handle and restrain. More importantly, orchiectomy of adult boars entails the use of haemostatic measures such as the ligation of the spermatic cord with surgical sutures or the crushing of the cord with an emasculator. Both these actions involve the introduction of foreign objects to the surgical site, as well as excessive manipulation, increasing the risk of hemorrhage and surgical contamination and, therefore, infection and abscess, which are the most common complications of orchiectomy [7]. In light of this, a novel sutureless castration technique was devised that does not require the use of foreign objects. This technique was inspired by the castration method for tomcats and consists of an open castration where haemostasis is achieved by splitting the vas deferens from the testis and tying several simple knots using the deferens duct and the testicular vasculature. This study aims to assess the viability of this sutureless technique as well as identify possible correlations between animal age/weight and technical surgical effectiveness. 2. Materials and Methods The study was conducted in Sardinia during activities of the Mobile Clinic organized by the Veterinary Medicine Department of the University of Sassari between October 2020 and December 2021. 2.1. Animals Ninety-one boars (group 1) were subjected to conventional orchiectomy by suture ligation. In order to determine the tensile strength of the ductus deferens according to the age and weight of the animals, 182 deferens were removed and measured. Following this, 20 boars (group 2) were castrated employing the

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ccording to the age and weight of the animals, 182 deferens were removed and measured. Following this, 20 boars (group 2) were castrated employing the newly developed sutureless technique. All animals included in the study were older than 12 months and had mated at least once. Procedures were performed on site (farms) after the preparation of a clean and sanitized ad hoc surgical area. Informed consent was acquired from all breeders for the performance of the novel sutureless procedure. 2.2. Anesthesia Identical anesthetic protocols were applied for all boars included in this study. Animals scheduled for castration were fasted for 12 h prior to the surgery and isolated from the rest of the pigs on the farm in order to facilitate capture and restraint at the time of the intervention. Boars were restrained using a snout snare passed caudally of the superior canine teeth and over the dorsal surface of the snout. Peripheral intravenous (IV) administration of sedative and anesthetic drugs was achieved through the auricular veins, as seen in Figure 1. The weight of the animals was measured using a professional electric scale with a hook (PCE-CS 500, Ziboni Technology S.r.l., Rogno (BG), Italy). Animals 2022,13, Animals2023, 12,407 x 33 of of 99 Figure 1. IV accessFigure for the1.administration IV access for of theanesthetic drugs was administration achieved through of anesthetic theachieved drugs was auricularthrough veins. the auricu- lar veins. Sedative and anesthetic drugs were administered in a single IV bolus. Sedation was achieved withand Sedative 1 mg/kg of Azaperone anesthetic (Stresnil, drugs were Elanco S.p.A. administered singleSesto in a Italia, Fiorentino IV bolus. (FI), Sedation Italyachieved was ) and 0.01withmg/kg1 mg/kg of Azaperone of detomidine (Stresnil,

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stered singleSesto in a Italia, Fiorentino IV bolus. (FI), Sedation Italyachieved was ) and 0.01withmg/kg1 mg/kg of Azaperone of detomidine (Stresnil, (Detonervin, Elanco Italia Ecuphar Italia, S.p.A.S.r.l., Fiorentino Sesto (MI), Milano Italy); (FI), Italy) general and 0.01 mg/kg anesthesia of detomidine was induced with a dose(Detonervin, of 5 mg/kgEcuphar Italia S.r.l., Milano(Zoletil of tiletamine/zolazepam (MI), Italy); general anesthesia was induced with a dose of 5 mg/kg of tiletamine/zolazepam 50/50, Virbac Italia, Milano (MI), Italy). The sedative and anesthetic medication adminis- (Zoletil tered was 50/50, VirbactoItalia, sufficient Milano maintain (MI), Italy). an adequate The level ofsedative anesthesia andforanesthetic the entiremedication duration of administered the procedurewas sufficient (which did not toexceed maintain 5–10anmin adequate levelstarting in all cases of anesthesia from the forfirst theincision entire duration of the procedure of the pre-scrotal area and(which endingdid nothe with exceed 5–10ofmin excision the in all cases second starting testis). Afterfrom the sedation first incision of the pre-scrotal area and ending with the excision of and the induction of anesthesia, animals were positioned in dorsal recumbency, and thethe second testis). After surgical and sedation site the wasinduction prepared,ofallowing anesthesia, some animals time for were deep positioned anesthesia in dorsal recumbency, to initiate. This was and done by first washing the whole area with antibacterial soap (DOC SCRUBinitiate. the surgical site was prepared, allowing some time for deep anesthesia to PVP-IODIO,This was done by first washing the whole area with antibacterial soap (DOC GARDENING S.r.l., Genova (GE), Italy) to eliminate large contaminant

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-IODIO,This was done by first washing the whole area with antibacterial soap (DOC GARDENING S.r.l., Genova (GE), Italy) to eliminate large contaminant particles, followed SCRUB PVP-IODIO, GARDENING by scrubbing S.r.l.,with Genova (GE), Italy)solution povidone-iodine to eliminate (10%) large for contaminant a few minutes. particles, followed The testis was by scrubbing with povidone-iodine solution (10%) for a few minutes. pushed cranially into the inguinal area, and a variable dose of 5–20 mL (according to theThe testis was pushed length ofinto cranially thethe inguinal incision) of area, and a variable 2% lidocaine solutiondosewasof 5–20 injected (according to the(SC) mL subcutaneously length of along the incision) of 2% lidocaine solution was injected subcutaneously (SC) the incisional line to achieve local anesthesia. In no instance did the dose of lidocaine ex-along the incisional line ceed tothe achieve dose local of 15 anesthesia. mg/kg [8]. In no instance did the dose of lidocaine exceed the dose of 15 mg/kg [8]. 2.3. Surgery 2.3. Surgery All boars were castrated by open castration. A 4- to 10-cm longitudinal incision was All boars were castrated by open castration. A 4- to 10-cm longitudinal incision was made with a scalpel over the skin covering the inguinally displaced testis. The incision made with a scalpel over the skin covering the inguinally displaced testis. The incision was continuedthrough wascontinued through thethe underlying underlying tissue, tissue, andand the the parietal parietal tunica tunica vaginalis vaginalis was in- was incised. cised. The testis was freed from its attachment to the tunica vaginalis by digitally The testis was freed from its attachment to the tunica vaginalis by digitally breaking the breaking the ligament ligament of

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ca vaginalis by digitally The testis was freed from its attachment to the tunica vaginalis by digitally breaking the breaking the ligament ligament of theoftail theoftail theofepididymis, the epididymis, and theandspermatic the spermatic cordmanually cord was was manually stripped stripped from from the parietal tunic as proximally as possible to the inguinal ring. According the parietal tunic as proximally as possible to the inguinal ring. According to the treatment to the treatment assigned to assigned each animal,to each animal, performed the surgeon the surgeon performed either either one of the one of techniques. following the following techniques. 2.3.1. Classical Castration (Group 1) 2.3.1.Animals Classical Castration assigned (Group to group 1) = 91) were castrated using the previously described 1 (n Animals spermatic cord assigned to group and ligation technique 1 (n underwent = 91) were castrated using the previously surgical procedures comparabledescribed to those spermatic cord ligation technique and underwent surgical procedures comparable to Animals 2023, 13, 407 4 of 9 currently described in the scientific literature [9] (with the exception of the decubitus posi- tion: dorsal instead of lateral). Castration was performed by placing a ligature around the vascular portion of the spermatic cord and the vas deferens using absorbable polyglactin 910 sutures. The suture USP size used was determined according to the respective weight of each boar, with USP 2 (Vicryl Plus, Ethicon Inc., Lamonea Medical Products, Ancona (AN), Italy) being used for animals over 100 kg, USP 1 for animals between 50 and 100 kg, and USP 0 for animals under 50 kg. The ligature was placed proximally to the spermatic cord; the spermatic cord was then transected distally of the ligatures

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0 for animals under 50 kg. The ligature was placed proximally to the spermatic cord; the spermatic cord was then transected distally of the ligatures and was inspected for the presence of hemorrhage before being placed back into the tunica vaginalis. Finally, co- agulated blood particles were removed from the scrotal pouch, and the surgeon proceeded to castrate the contralateral testis using the same technique described above. 2.3.2. Tensile Strength Measurements The age and weight of each animal were recorded prior to the surgery. After the excision of the testis, the diameters of the deferens duct (in mm) of the left and right testis of each animal in both groups were measured at the transection level using grid paper. Additionally, the tensile strength (N) of the left and right deferens ducts was measured using a KOP 24387 (KeenOptics, London, UK) digital dynamometer. For that purpose, a portion of the excised deferens duct was sampled. A standardized length of 4 cm for boars less than 9 months and 5 cm for boars older than 8 months of age (measured with grid paper) was used. Each end of the sampled vas deferens portion was clamped with a straight Klemmer haemostatic forceps. One end was attached to the dynamometer, while the second end was gradually pulled on with increasing force until the deferens duct tore. This procedure was performed by the same individual during the whole study in order to eliminate the risk of error arising from interindividual variability. The tensile strength of each deferens duct was recorded (Newtons). After determining the force necessary to tie a knot between the spermatic funiculus and the ductus deferens without rupturing the latter, the surgeon proceeded with the sutureless technique in the experimental group, as described in the

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d the ductus deferens without rupturing the latter, the surgeon proceeded with the sutureless technique in the experimental group, as described in the following chapter. 2.3.3. Sutureless Castration (Group 2) Animals assigned to group 2 (n = 20) were castrated by applying the novel sutureless technique. Prior to the surgery, the age and weight of each animal were recorded. Following extraction of the testis from the vaginal process and stripping of the spermatic cord from the parietal tunic up to the level of the inguinal ring, the deferens duct was manually detached from the tail of the epididymis and freed from the testis spermatic cord. The latter was then divided into a spermatic portion comprised of the deferens duct and a vascular portion consisting of the testicular artery and vein. These two portions were then tied together with 4 to 6 simple knots. The first knot was set as proximally as possible to the internal inguinal ring, while the following knots were placed about 2 cm distally from the first. The force applied to tie the knots was calibrated using the tensile strength results obtained from group 1. After tying an appropriate number of knots, both portions of the spermatic cord were aligned and transected distally from the knots, and the remaining part of the spermatic cord was inspected for hemorrhage before placing it back within the tunica vaginalis. If continuous dripping of blood was observed from the remnant spermatic cord, a double ligature was placed, and the sutureless technique was considered unsuccessful in that particular case. In addition, accidental rupture of the funiculus before the placement of a sufficient number of knots, and thus before adequate haemostasis was achieved, was also deemed a surgical failure. Similarly to the preceding

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ent of a sufficient number of knots, and thus before adequate haemostasis was achieved, was also deemed a surgical failure. Similarly to the preceding group, the deferens duct was collected and measured to assess tensile strength. Finally, after the removal of coagulated blood particles, the surgeon proceeded to castrate the contralateral testis using the same technique as described above. The different steps applied in the sutureless castration technique are illustrated in Figure 2. the incision and the surrounding area were disinfected with povidone-iodine and sprayed with antibacterial chlortetracycline hydrochloride spray (CycloSpray, Dechra Veterinary Products S.r.l). Prophylactic systemic antibiotic treatment was given in the form of an in- tramuscular (IM) injection of 30 mg/kg of long-acting oxytetracycline (ENGEMICINA Animals 2023, 13, 407 D.D., MSD, MSD Italia S.r.l., Roma (RM), Italy). In addition, a subcutaneous (SC) admin- 5 of 9 istration of 300 μg/kg ivermectin (Ivomec., Boehringer Ingelheim Animal Health Italia S.p.A., Milano (MI), Italy) was performed in order to prevent any parasitic complications. Figure 2. Illustration of orchiectomy using the sutureless technique: Initiate by making a Figure 2. Illustration of orchiectomy using the sutureless technique: Initiate by making a skin incision skin incision in the prescrotalin area the prescrotal area with a scalpel with blade. a scalpel Continue theblade. incisionContinue theunderlying through the tissue andthe incision through underlying parietal tunicatissue and parietal vaginalis tunicathe and exteriorize vaginalis and testis (A). exteriorize Digitally thethe rupture testis (A). Digitally ligament of the tail rup- of the epididymis and strip the spermatic cord from the tunica vaginalis up to the

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ally thethe rupture testis (A). Digitally ligament of the tail rup- of the epididymis and strip the spermatic cord from the tunica vaginalis up to the level of the the ture the ligament of the tail of the epididymis and strip the spermatic cord from tunica inguinal canal (B,C)up vaginalis to the before level detaching manually of the inguinal canal the deferens (B–from duct C) before manually the epididymis, detaching splitting the def- the spermatic erens ducta spermatic cord into from the andepididymis, splitting vascular portion (D).the Tiespermatic both portionscord into ausing together spermatic and vascular 4 to 6 simple knots portion (D). Tie both portions together using 4 to 6 simple knots (E – F). Place the (E,F). Place the first knot as proximally as possible to the internal inguinal ring (G) and the following first knot asknots proximally as possible to the internal inguinal ring (G) and the following about 2 cm distally to the first (H). Finally, align the spermatic and vascular portions of theknots about cm distally 2spermatic cordtoand thetransect first (H). Finally, using align scalpel theNo blade spermatic 22. Assess and vascular that portions ofofthe correct haemostasis sper- blood matic vesselscord and transect is achieved (I). using a scalpel blade No 22. Assess that correct haemostasis of blood vessels is achieved (I). In both groups, the surgical incision was left open to allow for second-intention heal- ing, providing better drainage of the surgical site in the postsurgical period. The site of the incision and the surrounding area were disinfected with povidone-iodine and sprayed with antibacterial chlortetracycline hydrochloride spray (CycloSpray, Dechra Veterinary Products S.r.l). Prophylactic systemic antibiotic treatment was given in the

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rial chlortetracycline hydrochloride spray (CycloSpray, Dechra Veterinary Products S.r.l). Prophylactic systemic antibiotic treatment was given in the form of an intramuscular (IM) injection of 30 mg/kg of long-acting oxytetracycline (ENGEMICINA D.D., MSD, MSD Italia S.r.l., Roma (RM), Italy). In addition, a subcutaneous (SC) admin- istration of 300 µg/kg ivermectin (Ivomec., Boehringer Ingelheim Animal Health Italia S.p.A., Milano (MI), Italy) was performed in order to prevent any parasitic complications. Animals 2023, 13, 407 6 of 9 2.3.4. Follow-Up At the conclusion of the surgical operation, a veterinarian observed each animal’s awakening until it achieved a stable quadrupedal station. The next day, each farmer was called by telephone to obtain information on the period between recovery and resum- ing feeding. 2.4. Statistical Analysis All data were entered in an Excel sheet. The Shapiro–Wilk test was used to verify the normal distribution of the data. The mean and standard deviation of each variable for each group was calculated using Stata 17 software (StataCorp, College Station, TX, USA). The correlation between age and tensile strength (CA-T) and weight and tensile strength (CW-T) was calculated using the Pearson linear correlation coefficient R. Results were considered significantly different for a p-value lower than 0.05. 3. Results All 111 animals included in this study were successfully castrated through either classical or sutureless castration. No boars from group 2 required the sutureless procedure to be replaced by conventional castration. No complications were recorded during the surgery or the immediate postsurgical period in both groups. The age of boars from group 1 ranged between 5 and 36 months, with an average of 18.22 months (sd.10.65), and

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iate postsurgical period in both groups. The age of boars from group 1 ranged between 5 and 36 months, with an average of 18.22 months (sd.10.65), and the age of boars ranged between 4 and 60 months with an average of 17.97 months (sd. 12.80) in group 2. Further results, including weight and the tensile strength and diameter of the deferens duct are shown in Table 1. Table 1. Average and standard deviation of variables recorded for groups 1 and 2; R: right; L: left; DD: deferens duct. Tensile Tensile Right DD Tensile DD Tensile Age Weight Left DD Group 1 Strength R Strength L DD Strength R Strength L (months) (kg) Diameter (kg) (kg) Diameter (N) (N) Average 18.22 211.75 2.35 2.46 3.67 3.64 22.42 23.76 standard deviation 10.65 78.90 1.16 1.16 1.72 1.71 10.42 10.20 Group 2 Average 17.97 192.72 2.22 2.40 4.05 4.02 22.17 23.56 standard deviation 12.80 93.85 1.14 1.30 1.62 1.67 10.83 12.75 Correlation The castration technique was not taken into account during the evaluation of the relationship between tensile strength and age/weight, and thus all animals were considered part of a single group. In fact, since the variable of interest was the tensile strength of the vas deferens, the observational unit became the vas deferens instead of the boar itself, and therefore each deferens duct (i.e., left or right) was considered as a single observation. Accordingly, the average and median tensile strength, including standard deviation and confidence intervals, were calculated for the totality of the animals (Table 1). Pearson’s linear correlation was used to determine any possible correlation between the deferens duct’s tensile strength and the age and weight of each animal. The correlation coefficient R for tensile strength and age was very close to 1, with R = 0.99 with p <

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strength and the age and weight of each animal. The correlation coefficient R for tensile strength and age was very close to 1, with R = 0.99 with p < 0.05; a strong correlation between weight and tensile strength was found as well (R = 0.96) (Figure 3). Animals 2022, 13, Animals 2023, 12, 407 x 77 of of 99 Figure 3. The left graph shows the correlation between age and tensile strength in the pooled sam- Figure 3. The left graph shows the correlation between age and tensile strength in the pooled sample; ple; the right graph shows the correlation between weight and tensile strength in the pooled sample. the right graph shows the correlation between weight and tensile strength in the pooled sample. A A significantly strong correlation was found (R = 0.99 and R = 0.96, respectively (p < 0.05)). significantly strong correlation was found (R = 0.99 and R = 0.96, respectively (p < 0.05)). 4. Discussion 4. Discussion Sutureless orchiectomy Sutureless orchiectomy is is widely widely applied applied for for the the castration castration of of tomcats tomcats and and was was also also reported to reported to be successful in be successful in young young lambslambs of of 44 to to 66 days days old old [10] [10] and and pediatric pediatric and and juvenile juvenile dogs [11]. This technique has the potential to be less expensive dogs [11]. This technique has the potential to be less expensive than traditional orchiectomy than traditional orchiec- tomy and to result in fewer post-operative complications, and to result in fewer post-operative complications, such as infections [12–14]. Another such as infections [12–14]. An- other advantage of the sutureless procedure is the duration advantage of the sutureless procedure is the duration of surgery, which is significantly of

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ther advantage of the sutureless procedure is the duration advantage of the sutureless procedure is the duration of surgery, which is significantly of surgery, which is signifi- cantly shorter. shorter. Various Various castrationcastration methods methods for piglets for piglets are described are described in the in the current current scien- scientific tific literature literature [15,16], [15,16], whilewhile the understanding the understanding of surgical of surgical castration castration techniques techniques for adultfor boars adult boars is is lacking. lacking. The prescrotal The prescrotal approach approach employed employed in thiswas in this study study was actually actually found to found to be be poorly poorly described described for adult for adultInboars. boars. fact, aInscrotal fact, aincision scrotal is incision is most commonly most commonly adopted, adopted, with the incision incision with the being being made made ventrally ventrally in orderintoorderallow tofor allow for proper proper drainage drainage [17]. The [17].useTheof use a of a prescrotal prescrotal incision incision for the fororchiectomy the orchiectomy of adult of adult boarsboars has only has only beenbeen described described once,once, and this this approach and approach is thought is thought to allowto allow even better even better drainage,drainage, given given the ventral the ventral positioning positioning of the of the incision incision [9]. Possible [9]. Possible complications complications arisingarising from applying from applying a prescrotal a prescrotal incision incision includein- a clude arisk higher higher risk of evisceration of evisceration in the case in of theancase of an hernia inguinal inguinal andhernia andofthe the risk risk of awound a surgical surgi- infection cal

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of evisceration in the case in of theancase of an hernia inguinal inguinal andhernia andofthe the risk risk of awound a surgical surgi- infection cal woundeveloping into peritonitis infection developing into given the close peritonitis givenproximity the close of the surgical proximity of the site to the surgical inguinal canal, which can act as a route for ascending infections site to the inguinal canal, which can act as a route for ascending infections [18]. The pur- [18]. The purpose of this study pose ofwas thistostudy assesswas the to feasibility assess the and validity and feasibility of sutureless validity of orchiectomy in adult boars, sutureless orchiectomy in adultthe and mainand boars, objective the main was objective to successfullywas to perform this procedure. successfully perform this All 20 animals within procedure. All 20 group animals 2 were within successfully group 2 were castrated using the successfully sutureless castrated using method without any the sutureless method postsurgical without complications any postsurgical or death (same as or complications fordeath group(same1: classical as forcastration). The most group 1: classical critical aspect castration). The of applying the sutureless technique proved to be the tightening most critical aspect of applying the sutureless technique proved to be the tightening of of simple knots between the spermatic simple and vascular knots between portions of the spermatic andthevascular spermatic cord. At portions of this stage, the vas the spermatic cord. deferens At this may stage, the vas deferens may break, leading to surgical failure. For this purpose,several break, leading to surgical failure. For this purpose, it was decided to evaluate it was variables decided toofevaluate the deferens several duct

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veral break, leading to surgical failure. For this purpose, it was decided to evaluate it was variables decided toofevaluate the deferens several duct during of variables orchiectomies the deferens performed duct duringinorchiectomies group 1, including performedtheir in group and diameter tensile strength. 1, including The latter their diameter andwas correlated tensile strength. withThe and weight age latter of the animals was correlated with in order to determine the maximum traction force to be age and weight of the animals in order to determine the maximum traction force to be applied for each boar. Although applied for eachitboar. has been hypothesized that deferens duct tensile strength is directly Although it hasand proportional to age been weight, to the best hypothesized ofdeferens that our knowledge, duct tensileno studies strength is directlythese correlating pro- variables portional to age and weight, to the best of our knowledge, no studies correlating small have previously been conducted in pigs. In this study, with a relatively these sample variables size andpreviously have variable age andconducted been weight, a more in pigs.homogeneous In this study, sample withwas considered a relatively by small conducting the correlation analysis on a pooled sample. sample size and variable age and weight, a more homogeneous sample was considered As expected, a strong correlation was found between by conducting age and tensile the correlation analysis strength on a pooled(R = 0.99 sample. withAsp expected, < 0.05), asawell strong as correla- weight and tensile strength (R = 0.96 with p < 0.05) (Figure 3). According to these results, tensile tion was found between age and tensile strength (R = 0.99 with p < 0.05), as well as weight strength is minimal in young

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ing to these results, tensile tion was found between age and tensile strength (R = 0.99 with p < 0.05), as well as weight strength is minimal in young boars and increases progressively with age and weight. and tensile strength (R = 0.96 with p < 0.05) (Figure 3). According to these results, tensile strength is minimal in young boars and increases progressively with age and weight. Animals 2023, 13, 407 8 of 9 Thanks to the identification of these correlations, successful sutureless castration (100% success rate) was performed on 20 boars, calibrating the force needed for optimal nodal tightness without inducing vas deferens rupture. No post-operative complications were recorded in either group, and animals resumed feeding 5 h after complete recovery from anesthesia. The next step in the validation of sutureless orchiectomy in adult boars will be to perform short-, medium- and long-term follow-ups of animals. 5. Conclusions Due to its potential advantages, including being simple to execute and master, the su- tureless technique can potentially be considered a valid method for adult boar orchiectomy. The most critical step in sutureless castration corresponds to the execution of the nodes between the ductus deferens and the spermatic funiculus in order to achieve the proper haemostasis of the vessels. The force required to tie these knots is directly proportional to the age and weight of the animals. This study has laid the cornerstone needed to proceed with large-scale clinical studies on the sutureless castration of adult boars. Future research is needed in order to explore other essential aspects of this technique, such as wound healing, postsurgical recovery, and the occurrence of short and long-term complications. An in-depth investigation of the occurrence of

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such as wound healing, postsurgical recovery, and the occurrence of short and long-term complications. An in-depth investigation of the occurrence of postsurgical complications was left to the next stage of research, which will consist of a large-scale clinical study based on the findings of this study. Author Contributions: Conceptualization, N.C.; methodology, N.C., A.S. and S.M.T.R.; formal analysis, S.M.; data curation, S.M.T.R.; writing—original draft preparation, T.A. and S.M.; writing— review and editing, N.C. and S.M.; visualization, A.S.; supervision, N.C. All authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Institutional Review Board Statement: The animal study protocol was approved by the Ethics Committee of the University of Sassari (protocol code 139037). Informed Consent Statement: Informed consent was obtained from all the owners involved in the study. Data Availability Statement: Not applicable. Acknowledgments: Not applicable. Conflicts of Interest: The authors declare no conflict of interest. References 1. Bellini, S. The pig sector in the European Union. In Understanding and Combatting African Swine Fever: A European Perspective; Wageningen Academic Publishers: Wageningen, The Netherlands, 2021; pp. 639–648. 2. Popescu, A. Trends in pork market in the European Union and in its main producing countries in the period 2007–2018. Sci. Pap. Ser. Manag. Econ. Eng. Agric. Rural Dev. 2020, 20, 475–488. 3. Bonazzi, G.; Camanzi, P.; Ferri, G.; Manghi, E.; Iotti, M. Economic sustainability of pig slaughtering firms in the production chain of denomination of origin hams in Italy. Sustainability 2021, 13, 7639. [CrossRef] 4. Tajet, H.; Andresen, Ø. Estimation of genetic

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tor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.