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Hess RA, Park CJ, Soto S, Reinacher L, Oh JE, Bunnell M, Ko CJ. Male animal sterilization: history, current practices, and potential methods for replacing castration. Front Vet Sci 2024; 11:1409386. [PMID: 39027909 PMCID: PMC11255590 DOI: 10.3389/fvets.2024.1409386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Accepted: 06/10/2024] [Indexed: 07/20/2024] Open
Abstract
Sterilization and castration have been synonyms for thousands of years. Making an animal sterile meant to render them incapable of producing offspring. Castration or the physical removal of the testes was discovered to be the most simple but reliable method for managing reproduction and sexual behavior in the male. Today, there continues to be global utilization of castration in domestic animals. More than six hundred million pigs are castrated every year, and surgical removal of testes in dogs and cats is a routine practice in veterinary medicine. However, modern biological research has extended the meaning of sterilization to include methods that spare testis removal and involve a variety of options, from chemical castration and immunocastration to various methods of vasectomy. This review begins with the history of sterilization, showing a direct link between its practice in man and animals. Then, it traces the evolution of concepts for inducing sterility, where research has overlapped with basic studies of reproductive hormones and the discovery of testicular toxicants, some of which serve as sterilizing agents in rodent pests. Finally, the most recent efforts to use the immune system and gene editing to block hormonal stimulation of testis function are discussed. As we respond to the crisis of animal overpopulation and strive for better animal welfare, these novel methods provide optimism for replacing surgical castration in some species.
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Affiliation(s)
- Rex A. Hess
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Epivara, Inc, Champaign, IL, United States
| | - Chan Jin Park
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Epivara, Inc, Champaign, IL, United States
| | | | | | - Ji-Eun Oh
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Mary Bunnell
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - CheMyong J. Ko
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Epivara, Inc, Champaign, IL, United States
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Hamed MA, Amin YA, Mohamed RH, El-Adl M, Bazeed SM, Elnegiry AA, Shawki HH, Al-Lethie ALA. Evaluation of chemical castration using intra-testicular injection of zinc gluconate into the testis of the male donkey versus surgical castration: antimullerian hormone as an endpoint marker. BMC Vet Res 2023; 19:140. [PMID: 37660034 PMCID: PMC10474774 DOI: 10.1186/s12917-023-03694-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 08/17/2023] [Indexed: 09/04/2023] Open
Abstract
BACKGROUND Chemical castration of male animals is an alternative to surgical castration for inducing azoospermia, consequent sterility. Intra-testicular injection of zinc gluconate has been used for chemical castration in several animal species. However, its application to equine species, such as donkeys, has yet to be reported. This study aimed to evaluate the use of zinc gluconate for the chemical castration of male donkeys and to compare its effectiveness relative to routine surgical castration. For this purpose, investigations of serum testosterone and anti-Müllerian hormone levels, testicular ultrasonographic echogenicity, and histopathological findings were performed. METHODS Fourteen clinically healthy adult male donkeys were randomly and equally divided into two groups. The donkeys in group I (n = 7) underwent surgical castration. The donkeys in group II (n = 7) received intra-testicular zinc gluconate injections. The donkeys were kept under close clinical observation for 60 days. Abnormalities in donkey behavior and gross alterations in the external genitalia were recorded daily. Serum testosterone and anti-Müllerian hormone (AMH) levels were measured 15 days before the start of the treatment and 15, 30, 45, and 60 days after treatment. The testicles of group II donkeys were evaluated ultrasonographically. At the end of the study, the testes were removed and histologically examined. RESULTS Serum testosterone levels significantly declined compared to pre-castration levels in surgically castrated donkeys (group I), but donkeys exposed to chemical castration (group II) showed a non-significant reduction in testosterone levels. Donkeys in the surgical group had considerably lower serum AMH levels. In contrast, there was a non-significant (p > 0.05) increase in AMH levels in the chemical group compared with the pre-sterilization level. In addition, ultrasonographic examination revealed that the testicular echo-density had changed, as observed by a few scattered hyperechoic regions throughout the entire testis parenchyma. The histopathological investigation confirmed the presence of necrosis of the spermatogenic epithelium, increased thickness of the basement membrane of the seminiferous tubules, marked interstitial fibrosis, and shrinkage of the seminiferous tubules. Furthermore, syncytial giant cells were present in the lumen of seminiferous tubules and were associated with Sertoli cell vacuolation. Donkeys subjected to chemical castration (group II) had orchitis, as confirmed histopathologically. CONCLUSION Intra-testicular injection of zinc gluconate resulted in histopathological and ultrasonographic testicular changes in adult male donkeys, which may affect their reproductive potential. However, it did not significantly alter serum testosterone or AMH levels, indicating that it cannot be used as a substitute for surgical castration in male donkeys.
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Affiliation(s)
- Mohamed A Hamed
- Department of Surgery, Anesthesiology and Radiology, Faculty of Veterinary Medicine, Aswan University, Aswan, Egypt
| | - Yahia A Amin
- Department of Theriogenology, Faculty of Veterinary Medicine, Aswan University, Aswan, Egypt.
| | - Ragab Hassan Mohamed
- Department of Theriogenology, Faculty of Veterinary Medicine, Aswan University, Aswan, Egypt
| | - Mohamed El-Adl
- Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt
| | - Shefaa M Bazeed
- Department of Biochemistry and Chemistry of Nutrition, Faculty of Veterinary Medicine, Badr university, Badr, Cairo, Egypt
| | - Ahmed Abdou Elnegiry
- Department of Cytology and Histology, Faculty of Veterinary Medicine, Aswan University, Aswan, Egypt
| | | | - Al-Lethie A Al-Lethie
- Department of Surgery, Anesthesiology and Radiology, Faculty of Veterinary Medicine, Aswan University, Aswan, Egypt
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Virendra A, Shrivastava O, Shukla S, Shukla M, Bajaj N, Khanam A, Khan F. Evaluation of intratesticular chlorhexidine gluconate for chemical contraception in dogs. ASIAN PACIFIC JOURNAL OF REPRODUCTION 2022. [DOI: 10.4103/2305-0500.356842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Rafatmah D, Mogheiseh A, Eshghi D. Chemical sterilization with intratesticular administration of zinc gluconate in adult dogs: a preliminary report. Basic Clin Androl 2019; 29:12. [PMID: 31388429 PMCID: PMC6670226 DOI: 10.1186/s12610-019-0092-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/09/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Chemical sterilization with zinc gluconate is being developed due to its permanent contraceptive effect in prepubertal dogs. In this study, five healthy adult dogs were selected randomly. Semen samples were collected and analyzed before the study to confirm normal testicular function. Under general anesthesia, pH neutralized zinc gluconate was injected directly into their testes. Testes diameter, ultrasonographic appearance, changes in the percentage of white blood cells, and testosterone concentration were monitored twice a week before and 1 month after the injection. At the end of the study, the dogs were castrated and their testes were removed for histopathological evaluation. RESULTS The general health of all dogs was normal after the injection. The appearance of testicular swelling was limited within 2 days of treatment. The average diameter of left and right testes was 2.48 and 2.03 cm before the injection and reached to diameter 2.12 and 2.15 cm, respectively, at the end of the study. Serum testosterone concentration was 4.2 ng/ml at the start and 4 ng/ml at the end of the study. The percentage of white blood cells at the start and end of the study were within normal ranges reported for dogs. Histopathological analyses indicate a degeneration of germ cells in seminiferous tubules, but Leydig cells retained their structure. CONCLUSIONS Therefore, It is inferred that the injection of pH neutralized zinc gluconate into the adult dogs' testes resulted in the loss of sperm-producing tissue without affecting the production of testosterone and the general health of adult dogs.
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Affiliation(s)
- Dorna Rafatmah
- Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, P.O.Box 71441-69155, Shiraz, Fars Iran
| | - Asghar Mogheiseh
- Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, P.O.Box 71441-69155, Shiraz, Fars Iran
| | - Davoud Eshghi
- Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, P.O.Box 71441-69155, Shiraz, Fars Iran
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Silva RCA, Paranzini CS, Franco LG, Miguel MP, Honsho CS, Souza FF. Calcium chloride combined with dimethyl sulphoxide for the chemical sterilization of dogs. Reprod Domest Anim 2018; 53:1330-1338. [DOI: 10.1111/rda.13252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 06/05/2018] [Indexed: 10/28/2022]
Affiliation(s)
- Renata C. A. Silva
- Hospital School of VeterinaryUniversidade de Franca, UNIFRAN Franca Brazil
| | - Cristiane S. Paranzini
- School of Veterinary Medicine and Animal Science Universidade Estadual Paulista “Júlio de Mesquita Filho”, UNESP Botucatu Brazil
| | - Leandro G. Franco
- Hospital School of VeterinaryUniversidade de Franca, UNIFRAN Franca Brazil
- School of Veterinary and Animal ScienceUniversidade Federal de Goiás, UFG Goiânia Brazil
| | - Marina P. Miguel
- Institute of Tropical Pathology and Public HealthUniversidade Federal de Goiás, UFG Goiânia Brazil
| | | | - Fabiana F. Souza
- Hospital School of VeterinaryUniversidade de Franca, UNIFRAN Franca Brazil
- School of Veterinary Medicine and Animal Science Universidade Estadual Paulista “Júlio de Mesquita Filho”, UNESP Botucatu Brazil
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de Macêdo SRB, de Lima LAR, de Torres SM, de Oliveira VVG, de Morais RN, Peixoto CA, Tenorio BM, Junior VADS. Effects of intratesticular injection of zinc-based solution in rats in combination with anti-inflammatory and analgesic drugs during chemical sterilization. Vet World 2018; 11:649-656. [PMID: 29915504 PMCID: PMC5993773 DOI: 10.14202/vetworld.2018.649-656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/16/2018] [Indexed: 02/02/2023] Open
Abstract
Aim Chemical sterilization is a non-surgical method of contraception based on compounds injected into the testis to induce infertility. However, these injections can cause discomfort and pain able to impair the recovery of animals after this treatment. The objective of this study was to investigate if anti-inflammatories or pain relievers inhibited the sterilizing effect of zinc gluconate-based solution on the testis. Materials and Methods Adult rats were treated in groups: G1 (control), G2 (dimethyl sulfoxide + dipyrone); G3 (dipyrone/zinc); G4 (dipyrone + celecoxib/zinc); G5 (dipyrone + meloxicam/zinc), and G6 (dipyrone + dexamethasone/zinc) in a single dose per day during 7 days. Animals were analyzed at 7, 15, and 30 days after treatments. Results The zinc-induced a widespread testicular degeneration and decreased testosterone levels even in combination with anti-inflammatories or pain relievers. Testis, epididymis, prostate, and seminal vesicle had a weight reduction. The anti-inflammatory effect of dexamethasone interfered in the desired action of zinc gluconate in the 1st 15 days and celecoxib up to 7 days. Conclusion Meloxicam plus dipyrone did not impair the chemical sterilization based on zinc gluconate, and it can be used to reduce nociceptive effects in animals after chemical sterilization.
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Affiliation(s)
| | | | - Sandra Maria de Torres
- Department of Veterinary Medicine, Federal Rural University of Pernambuco, Recife, Brazil
| | | | | | - Christina Alves Peixoto
- Laboratory of Ultrastructure, Aggeu Magalhães Research Center (CPqAM), Recife, Pernambuco, Brazil
| | - Bruno Mendes Tenorio
- Department of Morphology, Federal University of Paraíba, João Pessoa, Paraíba, Brazil
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Paranzini CS, Sousa AK, Cardoso GS, Perencin FM, Trautwein LGC, Bracarense APFRL, Martins MIM. Effects of chemical castration using 20% CaCl 2 with 0.5% DMSO in tomcats: Evaluation of inflammatory reaction by infrared thermography and effectiveness of treatment. Theriogenology 2018; 106:253-258. [PMID: 29096273 DOI: 10.1016/j.theriogenology.2017.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 10/06/2017] [Accepted: 10/07/2017] [Indexed: 11/27/2022]
Abstract
This study used infrared thermography to monitor the immediate inflammatory reaction to an intratesticular injection of 20% (calcium chloride) CaCl2 with 0.5% dimethyl sulfoxide (DMSO) for chemical castration and to provide evidence of the treatment's clinical viability. Six animals received a 0.25 mL intratesticular injection of 20% CaCl2 with 0.5% DMSO in each testis. Thermographic imaging, testicular measurement, penile spine evaluation, electroejaculation, and sperm analysis were performed before the injection. Eighty days post-injection, the cats were evaluated again, then received an orchiectomy followed by histological analysis. Infrared thermography of the testicular area was performed before (M0) and after anesthesia (M0A); after electroejaculation (M0E); 10 min (M1), 1 h, (M2) and 6 h (M3) after the injection for seven consecutive days (M4-10); after 15 (M11) and 30 days (M12); and after 80 days, before and after anesthesia and after electroejaculation (M13, M13A and M13E). No cats had a significant increase in testicular temperature or behavioral changes. All animals were azoospermic and had a 50% reduction in total testicular volume after 80 days. Histologically, the testes showed different degrees of degeneration, necrosis, calcification and replaced connective tissue, as well as Leydig cell hyperplasia in 7/12 of the testes. Infrared thermography efficiently diagnosed and monitored scrotal inflammation caused by intratesticular injection of 20% CaCl2 solution with 0.5% DMSO, and it is suggested that a single injection of this compound can cause azoospermia after 80 days. We concluded by infrared thermography with a clinical exam, that the adverse reactions were minimal and did not interfere with animal welfare.
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Affiliation(s)
- Cristiane Sella Paranzini
- Animal Reproductio Laboratory (REPROA), Veterinary Clinics Department, State University of Londrina, Rodovia Celso Garcia Cid, PR 445 Km 380, Campus Universitário, Cx. Postal 10.011, CEP: 86.057-970, Londrina, Paraná, Brazil
| | - Anne Kemmer Sousa
- Animal Reproductio Laboratory (REPROA), Veterinary Clinics Department, State University of Londrina, Rodovia Celso Garcia Cid, PR 445 Km 380, Campus Universitário, Cx. Postal 10.011, CEP: 86.057-970, Londrina, Paraná, Brazil
| | - Guilherme Schiess Cardoso
- Animal Reproductio Laboratory (REPROA), Veterinary Clinics Department, State University of Londrina, Rodovia Celso Garcia Cid, PR 445 Km 380, Campus Universitário, Cx. Postal 10.011, CEP: 86.057-970, Londrina, Paraná, Brazil
| | - Felipe Montanheiro Perencin
- Animal Reproductio Laboratory (REPROA), Veterinary Clinics Department, State University of Londrina, Rodovia Celso Garcia Cid, PR 445 Km 380, Campus Universitário, Cx. Postal 10.011, CEP: 86.057-970, Londrina, Paraná, Brazil
| | - Luiz Guilherme Corsi Trautwein
- Animal Reproductio Laboratory (REPROA), Veterinary Clinics Department, State University of Londrina, Rodovia Celso Garcia Cid, PR 445 Km 380, Campus Universitário, Cx. Postal 10.011, CEP: 86.057-970, Londrina, Paraná, Brazil
| | - Ana Paula Frederico Rodrigues Loureiro Bracarense
- Preventive Veterinary Medicine Department, State University of Londrina, Rodovia Celso Garcia Cid, PR 445 Km 380, Campus Universitário, Cx. Postal 10.011, CEP: 86.057-970, Londrina, Paraná, Brazil
| | - Maria Isabel Mello Martins
- Animal Reproductio Laboratory (REPROA), Veterinary Clinics Department, State University of Londrina, Rodovia Celso Garcia Cid, PR 445 Km 380, Campus Universitário, Cx. Postal 10.011, CEP: 86.057-970, Londrina, Paraná, Brazil.
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Cavalieri J, Hayes L. Examination of the use of intraovarian administration of CaCl2
and zinc gluconate as potential chemosterilants in Bos indicus
heifers. Aust Vet J 2017; 95:403-415. [DOI: 10.1111/avj.12644] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 02/02/2017] [Accepted: 02/12/2017] [Indexed: 11/30/2022]
Affiliation(s)
- J Cavalieri
- College of Public Health, Medical and Veterinary Sciences; James Cook University; Townsville Queensland 4811 Australia
| | - L Hayes
- College of Public Health, Medical and Veterinary Sciences; James Cook University; Townsville Queensland 4811 Australia
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Araujo-Lima CF, Nunes RJM, Carpes RM, Aiub CAF, Felzenszwalb I. Pharmacokinetic and Toxicological Evaluation of a Zinc Gluconate-Based Chemical Sterilant Using In Vitro and In Silico Approaches. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5746768. [PMID: 28197414 PMCID: PMC5288521 DOI: 10.1155/2017/5746768] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 12/12/2016] [Accepted: 12/26/2016] [Indexed: 11/18/2022]
Abstract
Sclerosing agents as zinc gluconate-based chemical sterilants (Infertile®) are used for chemical castration. This solution is injected into the animal testis, but there are not enough evidences of its safety profiles for the receivers. The present work aimed to establish the pharmacokinetics and toxicological activity of Infertile, using in vitro and in silico approaches. The evaluation at the endpoint showed effects in a dose-dependent manner. Since necrosis is potentially carcinogenic, the possible cell death mechanism could be apoptosis. Our data suggested that Infertile at 60 mM presented risk for animal health. Even though Infertile is a licensed product by the Brazilian Ministry of Agriculture, Livestock and Supply, it presented a high mutagenic potential. We suggest that the optimal dose must be less than 6 mM, once, at this concentration, no mutagenicity or genotoxicity was observed.
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Affiliation(s)
- Carlos F. Araujo-Lima
- Department of Biophysics and Biometry, Rio de Janeiro State University, Boulevard 28 de Setembro, 87 Fundos, 4° Andar, 20551-030 Rio de Janeiro, RJ, Brazil
| | - Rafael J. M. Nunes
- Department of Biophysics and Biometry, Rio de Janeiro State University, Boulevard 28 de Setembro, 87 Fundos, 4° Andar, 20551-030 Rio de Janeiro, RJ, Brazil
| | - Raphael M. Carpes
- Department of Biophysics and Biometry, Rio de Janeiro State University, Boulevard 28 de Setembro, 87 Fundos, 4° Andar, 20551-030 Rio de Janeiro, RJ, Brazil
| | - Claudia A. F. Aiub
- Department of Genetics and Molecular Biology, Federal University of the State of Rio de Janeiro, Rua Frei Caneca, 94 Centro, 20211-040 Rio de Janeiro, RJ, Brazil
| | - Israel Felzenszwalb
- Department of Biophysics and Biometry, Rio de Janeiro State University, Boulevard 28 de Setembro, 87 Fundos, 4° Andar, 20551-030 Rio de Janeiro, RJ, Brazil
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Biosterilant effects of Bacillus thuringiensis kurstaki HD-73 extract on male Wistar albino rats. Theriogenology 2017; 88:73-83. [DOI: 10.1016/j.theriogenology.2016.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 10/01/2016] [Accepted: 10/03/2016] [Indexed: 11/20/2022]
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Vannucchi C, Angrimani D, Eyherabide A, Mazzei C, Lucio C, Maiorka P, Silva L, Nichi M. Effects of intratesticular administration of zinc gluconate and dimethyl sulfoxide on clinical, endocrinological, and reproductive parameters in dogs. Theriogenology 2015; 84:1103-10. [DOI: 10.1016/j.theriogenology.2015.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 06/04/2015] [Accepted: 06/10/2015] [Indexed: 10/23/2022]
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Chemical sterilisation of Bos indicus bull calves following intratesticular injection of zinc acetate: Effects on growth and concentrations of testosterone. Anim Reprod Sci 2015; 159:163-71. [DOI: 10.1016/j.anireprosci.2015.06.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 06/11/2015] [Accepted: 06/15/2015] [Indexed: 11/18/2022]
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13
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Chemical sterilisation of Bos indicus bull calves following intratesticular injection of zinc acetate: Effects on semen quality and testicular changes. Anim Reprod Sci 2015; 156:23-33. [DOI: 10.1016/j.anireprosci.2015.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/30/2015] [Accepted: 02/02/2015] [Indexed: 11/21/2022]
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Vanderstichel R, Forzán MJ, Pérez GE, Serpell JA, Garde E. Changes in blood testosterone concentrations after surgical and chemical sterilization of male free-roaming dogs in southern Chile. Theriogenology 2014; 83:1021-7. [PMID: 25557187 DOI: 10.1016/j.theriogenology.2014.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 11/29/2014] [Accepted: 12/01/2014] [Indexed: 10/24/2022]
Abstract
There is a growing interest in chemical sterilization as an alternative to surgical castration in large-scale sterilization campaigns to control canine populations. An important step toward understanding the short-term and long-term effects of chemical sterilants is to determine their impact on blood testosterone concentrations, particularly as these could influence dog behavior after treatment. A field trial was conducted with 118 free-roaming male dogs in the Chilean Patagonia, where 36 dogs were chemically sterilized using EsterilSol, 39 dogs were surgically castrated, and 43 dogs remained intact as controls. Blood testosterone levels were determined at four time periods: on enrollment 6 months before treatment (t-6m), at the time of treatment (t0, within one hour after surgical castration or chemical sterilization and during a concurrent 2-week period for the control group), four (t+4m), and six (t+6m) months after treatment. Intrinsic and temporal factors were evaluated; age was significantly associated with testosterone, where dogs 2- to 4-year-old had the highest testosterone concentrations (P = 0.036), whereas body weight and body condition scores were not associated with testosterone; testosterone concentration was not influenced by time of day, month, or season. After treatment (t+4m and t+6m), all of the surgically castrated dogs had testosterone concentrations below 1.0 ng/mL. On the basis of this cut point (<1 ng/mL), testosterone remained unchanged in 66% of the chemically sterilized dogs at both t+4m and t+6m; it remained low for 22% of dogs at both t+4m and t+6m; it was unchanged at t+4m but low at t+6m in 9% of dogs; and, it was low at t+4m but reverted back to unchanged at t+6m in one dog (3%). Incidentally, testosterone in chemically sterilized dogs increased dramatically within 1 hour of treatment (t0), more than doubling (131%) the concentration of control dogs at the time of treatment (t0), likely because of severe necrosis of interstitial cells. The use of EsterilSol as a method of sterilizing dogs had a variable effect on blood testosterone concentrations. Approximately, 30% of chemically sterilized dogs had a reduced testosterone concentration (actual maximum, 1 ng/mL) after 6 months, similar to that of surgically castrated dogs. Most chemically sterilized dogs, however, showed no long-term changes in blood testosterone concentrations.
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Affiliation(s)
- R Vanderstichel
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada.
| | - M J Forzán
- Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada
| | - G E Pérez
- Veterinarians without Borders/Vétérinaires sans Frontières Canada, Latin America Regional Office, Ottawa, Ontario; The Global Alliance for Animals and People, Valdivia, Chile
| | - J A Serpell
- Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - E Garde
- Veterinarians without Borders/Vétérinaires sans Frontières Canada, Latin America Regional Office, Ottawa, Ontario; The Global Alliance for Animals and People, Valdivia, Chile
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Forzán MJ, Garde E, Pérez GE, Vanderstichel RV. Necrosuppurative orchitis and scrotal necrotizing dermatitis following intratesticular administration of zinc gluconate neutralized with arginine (EsterilSol) in 2 mixed-breed dogs. Vet Pathol 2013; 51:820-3. [PMID: 24078007 DOI: 10.1177/0300985813505875] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Intratesticular injection of EsterilSol (zinc gluconate neutralized with arginine) is a chemical sterilant for male dogs sometimes used in population control campaigns. Adverse reactions have been reported in 1% to 4% of treated dogs, but detailed histomorphologic descriptions are lacking. During a behavioral study conducted in the Chilean Patagonia in 2012, severe necrosuppurative orchitis and ulcerative dermatitis were observed in 2 of 36 (6%) dogs sterilized with EsterilSol according to the manufacturer's instructions. Reactions were noted on days 8 and 7 postinjection and required scrotal ablation on days 8 and 13, respectively; neither reaction was associated with the injection site. Although self-trauma following administration may have contributed, the cause of the adverse reactions is uncertain. EsterilSol is a relatively uncomplicated method to sterilize male dogs, but the occurrence of severe adverse reactions several days after administration emphasizes the need for the provision of long-term monitoring and veterinary care during sterilization campaigns using this product.
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Affiliation(s)
- M J Forzán
- Canadian Cooperative Wildlife Health Centre, Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
| | - E Garde
- Veterinarians without Borders/Veterinarios sin Fronteras-Canada, Latin America Regional Office, Valdivia, Chile
| | - G E Pérez
- Veterinarians without Borders/Veterinarios sin Fronteras-Canada, Latin America Regional Office, Valdivia, Chile
| | - R V Vanderstichel
- Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE, Canada
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Massei G, Miller LA. Nonsurgical fertility control for managing free-roaming dog populations: a review of products and criteria for field applications. Theriogenology 2013; 80:829-38. [PMID: 23998740 DOI: 10.1016/j.theriogenology.2013.07.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 07/17/2013] [Accepted: 07/19/2013] [Indexed: 10/26/2022]
Abstract
About 75% of dogs worldwide are free to roam and reproduce, thus creating locally overabundant populations. Problems caused by roaming dogs include diseases transmitted to livestock and humans, predation on livestock, attacks on humans, road traffic accidents, and nuisance behavior. Nonsurgical fertility control is increasingly advocated as more cost-effective than surgical sterilization to manage dog populations and their impact. The aims of this review were to 1) analyze trends in numbers of scientific publications on nonsurgical fertility control for dogs; 2) illustrate the spectrum of fertility inhibitors available for dogs; 3) examine how differences between confined and free-roaming dogs might affect the choice of fertility inhibitors to be used in dog population management; and 4) provide a framework of criteria to guide decisions regarding the use of nonsurgical fertility control for dog population management. The results showed that the 117 articles published between 1982 and 2011 focussed on long-term hormonal contraceptives, such as gonadotropin-releasing hormone agonists, immunocontraceptives, and male chemical sterilants. The number of articles published biennially increased from one to five papers produced in the early 1980s to 10 to 20 in the past decade. Differences between confined dogs and free-roaming dogs include reproduction and survival as well as social expectations regarding the duration of infertility, the costs of sterilization, and the responsibilities for meeting these costs. These differences are likely to dictate which fertility inhibitors will be used for confined or free-roaming dogs. The criteria regarding the use of fertility control for dog population management, presented as a decision tree, covered social acceptance, animal welfare, effectiveness, legal compliance, feasibility, and sustainability. The review concluded that the main challenges for the future are evaluating the feasibility, effectiveness, sustainability, and effects of mass nonsurgical sterilization campaigns on dog population size and impact as well as integrating nonsurgical fertility control with disease vaccination and public education programs.
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Affiliation(s)
- Giovanna Massei
- National Wildlife Management Centre, Animal Health and Veterinary Laboratories Agency, Sand Hutton, York YO26 5LE, UK.
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Oliveira E, Fagundes A, Melo C, Nery L, Rêvoredo R, Andrade T, Oliveira-Esquerre K, Kastelic J, Silva V. Intratesticular injection of a zinc-based solution for contraception of domestic cats: A randomized clinical trial of efficacy and safety. Vet J 2013; 197:307-10. [DOI: 10.1016/j.tvjl.2013.01.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 01/13/2013] [Accepted: 01/17/2013] [Indexed: 12/01/2022]
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Franka R, Smith TG, Dyer JL, Wu X, Niezgoda M, Rupprecht CE. Current and future tools for global canine rabies elimination. Antiviral Res 2013; 100:220-5. [PMID: 23871797 DOI: 10.1016/j.antiviral.2013.07.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 07/01/2013] [Accepted: 07/07/2013] [Indexed: 12/25/2022]
Abstract
Even though rabies is almost uniformly fatal, it is readily preventable with currently available tools. Vaccination is highly efficacious for the pre-exposure prophylaxis (PrEP) of rabies in humans and animals, and prompt postexposure prophylaxis (PEP) with vaccine and rabies immune globulin (RIG) can reliably prevent disease in humans. However, access to these tools and knowledge of their proper use are often limited, especially in impoverished, rabies-enzootic countries with the highest disease burden. In the absence of reliable diagnostic capacity and risk assessments, vaccines and RIG are often administered inappropriately, leading to chronic supply shortages and otherwise preventable deaths. Rather than focusing solely on human prophylaxis, it is more cost-effective over the long term to eliminate canine rabies in its natural terrestrial reservoirs. Because more than 99% of human rabies deaths result from dog bites, prevention efforts should focus on dogs. A versatile "One Health" strategy for canine rabies elimination should aim to create sustainable herd immunity in dogs, using proven vaccination strategies at the local level, coupled with community education and humane population management. Such strategies have succeeded in both developed and developing countries, and can be adapted to any locality. Numerous examples in Africa, Asia, and Latin America have shown that community-based, locally guided vaccination and education programs, based on a shared vision and long-term commitment, can eliminate canine rabies. Such programs should have specific goals and measurable outcomes, and should be conducted under the guidance of supportive governments, in collaboration with international partners and nongovernmental organizations. In addition to currently available tools, rabies prevention can be augmented by new dose-sparing human vaccine schedules, alternative routes of vaccine administration, monoclonal antibodies as an alternative to RIG, sensitive and specific point-of-care diagnostics and the development of canine immunocontraceptive methods. Accurate risk assessments of potential human exposures and support for decentralized laboratory capacity will be essential to ensure the most effective utilization of vaccines and RIG until canine rabies has been eliminated.
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Affiliation(s)
- Richard Franka
- Poxvirus and Rabies Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, NE, Mail Stop G33, Atlanta, GA 30333, USA.
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Oliveira EC, Muller PM, Silva FL, Nery LT, de Sá MJ, Guerra MMP, Oliveira-Esquerre KP, Kastelic JP, Douglas RH. Oral administration of an anti-inflammatory does not compromise the efficacy of intra-testicular injection of zinc gluconate as a contraceptive for dogs. Anim Reprod Sci 2012; 132:207-12. [DOI: 10.1016/j.anireprosci.2012.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 04/25/2012] [Accepted: 05/03/2012] [Indexed: 10/28/2022]
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Oliveira EC, Moura MRP, de Sá MJ, Silva VA, Kastelic JP, Douglas RH, Marques AP. Permanent contraception of dogs induced with intratesticular injection of a Zinc Gluconate-based solution. Theriogenology 2012; 77:1056-63. [DOI: 10.1016/j.theriogenology.2011.10.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 09/22/2011] [Accepted: 10/08/2011] [Indexed: 10/14/2022]
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Effects of intratesticular zinc gluconate treatment on testicular dimensions, echodensity, histology, sperm production, and testosterone secretion in American black bears (Ursus americanus). Theriogenology 2011; 75:1444-52. [DOI: 10.1016/j.theriogenology.2010.10.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2010] [Revised: 10/09/2010] [Accepted: 10/28/2010] [Indexed: 11/20/2022]
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