งานนำเสนอเรื่อง: "NON-SURGICAL CASTRATION IN MALE DOGS POSSIBILITY, AVAILABILITY AND HUMANITY Suppawiwat Ponglowhapan DVM (Hons), MS, MSc, PhD Department of Obstetrics Gynaecology."— ใบสำเนางานนำเสนอ:
NON-SURGICAL CASTRATION IN MALE DOGS POSSIBILITY, AVAILABILITY AND HUMANITY Suppawiwat Ponglowhapan DVM (Hons), MS, MSc, PhD Department of Obstetrics Gynaecology and Reproduction, Faculty of Veterinary Sciences Chulalongkorn University
1970’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”. 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.
Introduction In 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 estimated 8-10 millions dogs and cats enter shelters each year 4.5 millions of them are euthanized
Introduction How many stray dogs in Mexico city? 1962: 460,000 dogs 1974: 900,000 dogs 2006: 3,000,000 dogs
Introduction How many stray dogs in Bangkok? 254025422548 Family dogs580,000523,000- Stray dogs-110,000823,000
Pet overpopulation 1. Social problem 2. Hygiene problem 3. Health problem: zoonosis Texas (1977): stray dogs can produce 94,950 gallons of urine and 38.6 tons of feces per day.
Control of pet overpopulation The complexity of pet overpopulation Human-animal bond Pet owner responsibility Animal sterilization/neutering Non purpose-bred dogs must be neutered!
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)reproductive organ sterilizing Sterilizing (sterilize = to perform a medical operation on someone in order to make them unable to have children) Female Female; spaying (removal of the ovaries) OVH ovariectomy / ovariohysterectomy OVH Male Male; neutering, castration (removal of the testicles)
Castration Surgical VS Non-surgical (Permanent VS temporary)
Surgical Castration Traditional neutering of male dogs Surgical removal of the testicles of a male animal or human Removing or inhibiting the function or development of the testes Dog testicles Spermatozoa Testosterone
Surgical Castration Spermatozoa Testosterone Sterility Loss of testosterone- dependent characteristics libido, roaming, urine spraying, aggression, etc.
Vasectomy Cooper (1930) : first experimental vasectomy on a dog Vasectomy & Castration
Surgical Castration Not all owners prefers to have their pets surgically sterilized. In Brazil (Soto et al., 2005) 56.5% of owners (adopted shelter dogs) against surgical sterilization - Compassion (58.1%) - Unnecessary procedure (11.4%) - Cost (9.5%) - Behavioral change (4.8%)
Surgical Castration In Thailand (Swangchan-uthai et al., 2005) 38.3% against contraception in dogs and/or cats (170/446) - Breeding purpose - Able to confine male dogs - Not necessary to have males neutered - Behavioral and physical change, i.e. obesity - Unsafe procedure - กลัวว่าตัวเองหรือแฟนจะเป็นหมัน... บาป !!! 61.7% prefer to have their pets neutered (276/446) - 13.7% males, 39.8% females, 46.5% both - 72.5% orchiectomy, 19.8% vasectomy, 7.7% reversible hormone implant
Non-Surgical Castration No scalpel castration Chemical castration Expectations for non-surgical castration As effective as gold standard (bilateral orchiectomy) No adverse effects (short-term and long-term) Safe Inexpensive Quick (can be applied to large-scale population) Reversible (?)
Hormonal treatment Exogenous hormone Down regulation Temporary suppression of fertility
Hormonal treatment Steroid Hormone In early 1930, isolated and determined structure of steriods In 1937, reported progesterone inhibits ovulation in rabbits No 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 Hormone GnRH agonist Suprelorin (Deslorelin, Virbac) Gonazon implant (Nafarelin, Intervet)
Clinical use in the bitch Control of oestrus (suppression/prevention) Pseudopregnancy Hypoluteoidism Clinical use in the dog Antisocial behaviour Epilepsy Benign Prostatic Hyperplasia Contraception (+/-) Circum-anal adenoma
Progestogen: female Prevention of anoestrus Medroxyprogesterone Perlutex Perlutex 2.5-3 mg/kg at 5 mth interval Promone-E Promone-E 50 mg/bitch at 6 mth intervalProligestone Covinan Covinan 10-33 mg/kg - early proestrus - a series at 3, 4 and 5 mth intervals Side effects : type of hormone, dose, duration of repeated treatment, treatment regimen, stage of oestrus cycle and age of the animal
Progestogen: female Side effect Selman et al., 1994 glucose intolerance diabetes mellitus mammary tumors (50%) in treated OVH-bitches Use with Cautions Type of hormone Type of hormone Route of administration Route of administration Dosage Dosage Duration of repeated treatment Duration of repeated treatment Stage of the cycle at initiation of the treatment Stage of the cycle at initiation of the treatment Age of the animal Age of the animal
Progestogen: male LH/FSH Spermatogenesis progestogen
Progestogen: male England, 1997 ProgestogensDosageRouteDurationResults Megestrol acetate2 mg/kgPO7 dNo change in semen quality Megestrol acetate4 mg/kgPO7 dMinor sperm abnormalities MPA10 mg/kgSC-No change in semen quality MPA20 mg/kgSC-Rapid decline in sperm motility, morphology and output No change in plasma LH concentration was detected as seen in females !!! MPA; medroxyprogesterone acetate Megestrol acetate The male dog appears to differ in the sensitivity of hypothalamo-pituitary response to progestogen feedback
Progestogen: male Not recommended for contraception in the male dog 1. ineffective 2. adverse effects Selman et al., 1994 glucose intolerance diabetes mellitus
Androgen AndrogensDosageResultsReferences Mixed testosterone ester5 mg/kgDecline in sperm motility (wk 3-15 post injection) England, 1997 Methyltestosterone50 mg (90 d) Decreased daily sperm output Freshman et al., 1990
In 1953 In 1953, Freund et al. Aspermatogenesis in the guinea pig induced by the testicular tissue and adjuvants. J Exp Med. 97:711-26. sclerozing/necrotizing agents aspermatogenic orchitistissue sclerosisinfertility Injection of sclerozing/necrotizing agents into the testes to induce aspermatogenic orchitis and tissue sclerosis resulting in infertility Local inflammatory response Autoimmone response
Different Sites of injection Intratesticular injection Intraepididymal injection Vas deferen injection
Intratesticular injection Sclerosing agents o Zinc gluconate (Levy et al., 2008) o 20% hypertonic saline (Emir et al., 2008) o Glycerol (Immegart et al., 2000) o 1.5% chlorhexidine gluconate in 50% DMSO (Pineda et al., 1977) o Calcium chloride (Jana and Samanta, 2007)
Intratesticular injection Active ingredientDogs treatedDosage/RouteResultsReferences Zinc arginine2-3.5 yr, n = 10 50mg (0.5mL)/Caudal epididymal injection azoospermia in 90 days post- injection Fahim et al., 1993 Balanced zinc solutionAdults, n = 5Intratesticular injection azoospermia in 4 out of 5 dogs beginning between Day 26-51 post-injection Tepsumethanon et al., 2005 Zinc gluconate with or without 0.5% DMSO Adults, n=25 13.1 or 26.2mg/ Intratesticular injection azoospermia, oligozoospermia, asthenospermia depending on dosage used and the presence of DMSO Soto et al., 2007 Zinc gluconate neutralized in physiological vehicle 8 mo to 4 yr, n = 10 2.6 – 13.1 mg depending on testicular width/ Intratesticular injection Histological changes including degeneration, vacuolation, fewer germ cells, lack of spermatid in atrophic seminiferous tubules Oliverira et al., 2007 Zinc-based solution
Neutersol/Esterilsol Zinc gluconate neutralized by arginine Recommendations 1. Labeled for chemical castration via intratesticular injection in the male dog 2. Age 3-10 months (puppy) 3. Predetermined amount of zinc solution based on scrotal width into each testis 4. Sedation is recommended Range of testicular width (cm)mL per testisMg Zinc 10-120.22.6 13-150.33.9 16-180.56.6 19-210.79.2 22-240.810.5 25-271.013.1
Neutersol/Esterilsol Neutersol injection Atrophy of the testis, epididymis, seminiferous tubles and prostate gland Scar tissue formation Prevention of sperm movement from seminiferous to epididymis 3-10 mth old puppies: 99.6% success (223/224)
Intratesticular injection Recommendations 1. Information 2. Family dog / stray dog 3. Large scale control population 4. Skill 5. Animal identification 6. National policy Non-surgical castration in male dogs Possibility, availability and humanity