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

Introduction Dr. Patricia N Olson

Introduction 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

Introduction How many stray dogs in Bangkok? 2540 2542 2548 Family dogs 580,000 523,000 - Stray dogs 110,000 823,000

Introduction

Introduction In some countries, such as Sweden and Norway, pet overpopulation is not a problem and neutering pets is UNCOMMON. Pet owners: responsibilities > rights

Pet overpopulation Year Cat 1 12 2 67 3 376 4 2,107 5 11,801 6 66,088 370,092 8 2,072,514 Year Dog 1 16 2 128 3 512 4 2,048 5 12,288 6 67,000 www.spayusa.com

Pet overpopulation Social problem Hygiene problem 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) 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 OVH Male; neutering, castration (removal of the testicles)

Castration Surgical VS Non-surgical (Permanent VS temporary)

Surgical Castration  Spermatozoa  Testosterone 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  Spermatozoa  Testosterone Dog testicles

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

Vasectomy

Vasectomy

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 (?)

Non-Surgical Castration Hormonal treatment Progestogens, Androgens, GnRH analogues (agonist/antagonist) Intratesticular/intraepididymal injection Immunocontraception Ultrasound testicular ablation

Hormonal treatment

Hormonal treatment

Hormonal treatment Steroid hormone (Progestogens, Androgens) Non-steroid hormone (GnRH analogues) Progestogen Androgens GnRH

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)

Progestogen

Progestogen 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 2.5-3 mg/kg at 5 mth interval Promone-E 50 mg/bitch at 6 mth interval Proligestone 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 glucose intolerance diabetes mellitus Selman et al., 1994 glucose intolerance diabetes mellitus mammary tumors (50%) in treated OVH-bitches Use with Cautions Type of hormone Route of administration Dosage Duration of repeated treatment Stage of the cycle at initiation of the treatment Age of the animal

Progestogen: male LH/FSH progestogen Spermatogenesis

Progestogen: male England , 1997 Progestogens Dosage Route Duration Results Megestrol acetate 2 mg/kg PO 7 d No change in semen quality 4 mg/kg Minor sperm abnormalities MPA 10 mg/kg SC - 20 mg/kg Rapid decline in sperm motility, morphology and output No 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 feedback Megestrol acetate MPA; medroxyprogesterone acetate

Progestogen: male Not recommended for contraception in the male dog 1. ineffective 2. adverse effects Selman et al., 1994 glucose intolerance diabetes mellitus

Androgen Androgens Dosage Results References Mixed testosterone ester 5 mg/kg Decline in sperm motility (wk 3-15 post injection) England, 1997 Methyltestosterone 50 mg (90 d) Decreased daily sperm output Freshman et al., 1990

GnRH analogues Agonists Antagonists Suprelorin (Deslorelin, Virbac) Gonazon implant (Nafarelin, Intervet) Antagonists Acyline (Merrion Pharmaceuticals)

Oestrogen Testosterone Deslorelin implant Hypothalamus Anterior pituitary Ovary, Testis GnRH LH, FSH Oestrogen Testosterone

Deslorelin implant

Deslorelin implant

Deslorelin implant 15 d pre-implant 15 d post-implant recovery

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

Deslorelin implant 50% in 3rd week 40% in 16th week 40% in 4th week Castration 50% in 3rd week 70% in 9th week (Barsanti and Finco, 1995) Finasteride 40% in 16th week (Sirinarumitr et al., 2001) Deslorelin 40% in 4th week (Ponglowhapan et al., 2010)

14-day post treatment of Deslorelin implant SAMSON Golden retriever 7 years old Urination difficulty BPH Before and 14-day post treatment of Deslorelin implant

Deslorelin implant Prostatic volume [(L x W xD)/2.6] + 1.8 (Kamolpatana et al., 2000) Before = 42.0 cm3 14-d after = 38.5 cm3

Intratesticular injection

Intratesticular injection In 1953, Freund et al. Aspermatogenesis in the guinea pig induced by the testicular tissue and adjuvants. J Exp Med. 97:711-26. 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 Vas deferen injection Intraepididymal injection Intratesticular injection

Intratesticular injection Sclerosing agents Zinc 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)

Intratesticular injection Zinc-based solution Active ingredient Dogs treated Dosage/Route Results References Zinc arginine 2-3.5 yr, n = 10 50mg (0.5mL)/Caudal epididymal injection azoospermia in 90 days post-injection Fahim et al., 1993 Balanced zinc solution Adults, n = 5 Intratesticular 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

Neutersol/Esterilsol FDA approved in 2003

Neutersol/Esterilsol Zinc gluconate neutralized by arginine Recommendations Labeled for chemical castration via intratesticular injection in the male dog Age 3-10 months (puppy) Predetermined amount of zinc solution based on scrotal width into each testis Sedation is recommended Range of testicular width (cm) mL per testis Mg Zinc 10-12 0.2 2.6 13-15 0.3 3.9 16-18 0.5 6.6 19-21 0.7 9.2 22-24 0.8 10.5 25-27 1.0 13.1

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)

Neutersol/Esterilsol Spermatocyte necrosis Giant cell

Surgical castration vs Intratesticular injection Surgical Method Intratesticular Injection เทคนิคและบุคคลากร ต้องการเทคนิคและอุปกรณ์การผ่าตัด และต้องการสัตวแพทย์ผู้ชำนาญการผ่าตัด ไม่ต้องการเทคนิคมาก ใช้บุคลากรน้อย ไม่จำเป็นต้องมีทักษะการผ่าตัด การวางยาสลบ ต้องวางยาสลบ (General Anesthesia) ไม่จำเป็นต้องวางยาสลบ แต่ FDA (USA) แนะนำให้ใช้ยาซึมก่อนการฉีด ความเจ็บปวด สามารถวางแผนระงับความเจ็บปวดได้อย่างมีประสิทธิภาพ เกิดความเจ็บปวดจากการบวมอักเสบ ภายหลังการฉีด ร้อยละในการคุมกำเนิด 100% 99.6%

Surgical castration vs Intratesticular injection Surgical Method Intratesticular Injection ระยะเวลาที่เริ่มมีผลในการคุมกำเนิด 7 วัน 60 วัน สำหรับการใช้ Neutersol ลักษณะและจำนวนอสุจิ Azoospermia Oligozoospermia Asthenospermia Azoosspermia ฮอร์โมน ไม่สามารถผลิต Testosterone สามารถผลิต Testosterone เนื่องจากยังมี Leydig’s cell เหลืออยู่บางส่วน พฤติกรรม ไม่มีพฤติกรรมทางเพศ ยังมีพฤติกรรมทางเพศ

Surgical castration vs Intratesticular injection Surgical Method Intratesticular Injection ร้อยละของปัญหาแทรกซ้อน (Levy et al., 2008) 3.4 3.9 ลักษณะของปัญหาแทรกซ้อน และการแก้ไข แผลแตก : ทำแผล เย็บซ่อม แผลหายเร็ว เนื้อตาย แผลรูเปิด ติดเชื้อรุนแรง : รักษาภาวะติดเชื้อ ผ่าตัดเอาอัณฑะออกเย็บตกแต่ง แผลหายช้า ลักษณะภายนอก ไม่เห็นอัณฑะที่อยู่ภายในถุงหุ้ม อัณฑะในถุงหุ้มมีขนาดเล็กลง และอาจไม่เท่ากัน Identification required* ค่าใช้จ่าย 800 – 2,000 บาทโดยประมาณราคาในประเทศไทย 1,651 บาท โดยคิดจาก Neutersol หนึ่งโดสต่อตัว 49.95 เหรียญสหรัฐอเมริกา

Intratesticular injection Recommendations Information Family dog / stray dog Large scale control population Skill Animal identification National policy Non-surgical castration in male dogs Possibility, availability and humanity