1 Non-surgical castration in male dogs Possibility, availability and humanity Suppawiwat PonglowhapanDVM (Hons), MS, MSc, PhDDepartment of Obstetrics Gynaecology and Reproduction,Faculty of Veterinary SciencesChulalongkorn University
3 Introduction1970’s First awakening to pet over population at animal care & control facilities“ … hundreds of dogs seems to have been euthanized due to some horrific diseases that was not one we have been taught about in veterinary school !” and “most of them are young and look healthy”.
4 Introduction“ How would the veterinary community respond to a disease that resulted in the death of between 10-25% of all dogs and cats each year? ” a vet student asked.
5 IntroductionIn USA, over half of all households own a dog or cat (1:3 in UK,1:4 in BKK)The human society of the United Stated estimated8-10 millions dogs and cats enter shelters each year4.5 millions of them are euthanized
6 Introduction How many stray dogs in Mexico city? 1962: 460,000 dogs
7 Introduction How many stray dogs in Bangkok? 2540 2542 2548 Family dogs580,000523,000-Stray dogs110,000823,000
9 IntroductionIn some countries, such as Sweden and Norway, pet overpopulation is not a problem and neutering pets is UNCOMMON.Pet owners: responsibilities > rights
10 Pet overpopulation Year Cat 1 12 2 67 3 376 4 2,107 5 11,801 6 66,088 370,09282,072,514YearDog1162128351242,048512,288667,000
11 Pet overpopulation Social problem Hygiene problem Health problem: zoonosisTexas (1977): stray dogs can produce 94,950 gallons of urine and 38.6 tons of feces per day.
12 Control of pet overpopulation The complexity of pet overpopulationHuman-animal bondPet owner responsibilityAnimal sterilization/neuteringNon purpose-bred dogs must be neutered!
13 Neuter Neuter (Latin) = Neither (neither masculine or feminine) adjective = The German word for 'book', 'das Buch', is neuter.verb = Has your dog been neutered?Neutering is the removal of an animal's reproductive organ, either all of it or a considerably large part. It is the most drastic surgical procedure with sterilizing purposes. (Wikipedia)Sterilizing(sterilize = to perform a medical operation on someone in order to make them unable to have children)Female; spaying (removal of the ovaries)ovariectomy / ovariohysterectomy OVHMale; neutering, castration (removal of the testicles)
14 CastrationSurgical VS Non-surgical(Permanent VS temporary)
15 Surgical Castration Spermatozoa Testosterone Traditional neutering of male dogsSurgical removal of the testicles of a male animal or humanRemoving or inhibiting the function or development of the testes Spermatozoa TestosteroneDog testicles
16 Surgical Castration Spermatozoa Testosterone Sterility Loss of testosterone-dependent characteristicslibido, roaming, urine spraying, aggression, etc.
17 Vasectomy Cooper (1930) : first experimental vasectomy on a dog Vasectomy & Castration
20 Surgical CastrationNot all owners prefers to have their pets surgically sterilized.In Brazil (Soto et al., 2005)56.5% of owners (adopted shelter dogs) against surgical sterilizationCompassion (58.1%)Unnecessary procedure (11.4%)Cost (9.5%)Behavioral change (4.8%)
21 Surgical Castration In Thailand (Swangchan-uthai et al., 2005) 38.3% against contraception in dogs and/or cats (170/446)Breeding purposeAble to confine male dogsNot necessary to have males neuteredBehavioral and physical change, i.e. obesityUnsafe procedureกลัวว่าตัวเองหรือแฟนจะเป็นหมัน ... บาป !!!61.7% prefer to have their pets neutered (276/446)13.7% males, 39.8% females, 46.5% both72.5% orchiectomy, 19.8% vasectomy, 7.7% reversible hormone implant
22 Non-Surgical Castration No scalpel castrationChemical castrationExpectations for non-surgical castrationAs effective as gold standard (bilateral orchiectomy)No adverse effects (short-term and long-term)SafeInexpensiveQuick (can be applied to large-scale population)Reversible (?)
27 Hormonal treatment Exogenous hormone Down regulation Temporary suppression of fertility
28 Hormonal treatment Steroid Hormone In early 1930, isolated and determined structure of steriodsIn 1937, reported progesterone inhibits ovulation in rabbitsNo new products for control of reproduction in the dog and cat have been introduced during the last two decades, other than revised formulations and new brands of progestogens.Non-steroid HormoneGnRH agonistSuprelorin (Deslorelin, Virbac)Gonazon implant (Nafarelin, Intervet)
30 Progestogen Clinical use in the bitch Control of oestrus (suppression/prevention)PseudopregnancyHypoluteoidismClinical use in the dogAntisocial behaviourEpilepsyBenign Prostatic HyperplasiaContraception (+/-)Circum-anal adenoma
31 Progestogen: female Prevention of anoestrus Medroxyprogesterone Perlutex mg/kg at 5 mth intervalPromone-E 50 mg/bitch at 6 mth intervalProligestoneCovinan mg/kg- early proestrus- a series at 3, 4 and 5 mth intervalsSide effects : type of hormone, dose, duration of repeated treatment, treatment regimen, stage of oestrus cycle and age of the animal
32 Progestogen: female Side effect glucose intolerance diabetes mellitus Selman et al., 1994glucose intolerancediabetes mellitusmammary tumors (50%) in treated OVH-bitchesUse with CautionsType of hormoneRoute of administrationDosageDuration of repeated treatmentStage of the cycle at initiation of the treatmentAge of the animal
34 Progestogen: male England , 1997 Progestogens Dosage Route Duration ResultsMegestrol acetate2 mg/kgPO7 dNo change in semen quality4 mg/kgMinor sperm abnormalitiesMPA10 mg/kgSC-20 mg/kgRapid decline in sperm motility, morphology and outputNo change in plasma LH concentration was detected as seen in females !!!The male dog appears to differ in the sensitivity of hypothalamo-pituitary response to progestogen feedbackMegestrol acetateMPA; medroxyprogesterone acetate
35 Progestogen: male Not recommended for contraception in the male dog 1. ineffective2. adverse effectsSelman et al., 1994glucose intolerancediabetes mellitus
36 Androgen Androgens Dosage Results References Mixed testosterone ester 5 mg/kgDecline in sperm motility(wk 3-15 post injection)England, 1997Methyltestosterone50 mg (90 d)Decreased daily sperm outputFreshman et al., 1990
41 Deslorelin implant15 d pre-implant15 d post-implantrecovery
42 Deslorelin implant Deslorelin Suprelorin 4.7 mg implant for dogs has been licensed in EU.Indication:For the induction of infertility in healthy, non-castrated, sexually mature male dogs
43 Deslorelin implant 50% in 3rd week 40% in 16th week 40% in 4th week Castration50% in 3rd week70% in 9th week(Barsanti and Finco, 1995)Finasteride40% in 16th week(Sirinarumitr et al., 2001)Deslorelin40% in 4th week(Ponglowhapan et al., 2010)
44 14-day post treatment of Deslorelin implant SAMSONGolden retriever7 years oldUrination difficultyBPHBefore and14-day post treatment of Deslorelin implant
45 Deslorelin implant Prostatic volume [(L x W xD)/2.6] + 1.8 (Kamolpatana et al., 2000)Before = 42.0 cm314-d after = 38.5 cm3
47 Intratesticular injection In 1953, Freund et al. Aspermatogenesis in the guinea pig induced by the testicular tissue and adjuvants. J Exp Med. 97:Injection of sclerozing/necrotizing agents into the testes to induce aspermatogenic orchitis and tissue sclerosis resulting in infertilityLocal inflammatory responseAutoimmone response
48 Different Sites of injection Vas deferen injectionIntraepididymal injectionIntratesticular injection
49 Intratesticular injection Sclerosing agentsZinc gluconate (Levy et al., 2008)20% hypertonic saline (Emir et al., 2008)Glycerol (Immegart et al., 2000)1.5% chlorhexidine gluconate in 50% DMSO (Pineda et al., 1977)Calcium chloride (Jana and Samanta, 2007)
50 Intratesticular injection Zinc-based solutionActive ingredientDogs treatedDosage/RouteResultsReferencesZinc arginine2-3.5 yr, n = 1050mg (0.5mL)/Caudal epididymal injectionazoospermia in 90 days post-injectionFahim et al., 1993Balanced zinc solutionAdults, n = 5Intratesticular injectionazoospermia in 4 out of 5 dogs beginning between Day post-injectionTepsumethanon et al., 2005Zinc gluconate with or without 0.5% DMSOAdults, n=2513.1 or 26.2mg/ Intratesticular injectionazoospermia, oligozoospermia, asthenospermia depending on dosage used and the presence of DMSOSoto et al., 2007Zinc gluconate neutralized in physiological vehicle8 mo to 4 yr,n = 102.6 – 13.1 mg depending on testicular width/ Intratesticular injectionHistological changes including degeneration, vacuolation, fewer germ cells, lack of spermatid in atrophic seminiferous tubulesOliverira et al., 2007
52 Neutersol/Esterilsol Zinc gluconate neutralized by arginineRecommendationsLabeled for chemical castration via intratesticular injection in the male dogAge 3-10 months (puppy)Predetermined amount of zinc solution based on scrotal width into each testisSedation is recommendedRange of testicular width (cm)mL per testisMg Zinc10-120.22.613-150.33.916-180.56.619-210.79.222-240.810.525-271.013.1
53 Neutersol/Esterilsol Neutersol injectionAtrophy of the testis, epididymis,seminiferous tubles and prostate glandScar tissue formationPrevention of sperm movement from seminiferous to epididymis3-10 mth old puppies: 99.6% success (223/224)
58 Intratesticular injection RecommendationsInformationFamily dog / stray dogLarge scale control populationSkillAnimal identificationNational policyNon-surgical castration in male dogs Possibility, availability and humanity