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
1974: 900,000 dogs
2006: 3,000,000 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
Year
Dog
1
12
1
16
2
67
2
128
3
376
3
512
4
2,107
4
2,048
5
11,801
5
12,288
6
66,088
6
67,000
7
370,092
8
2,072,514
www.spayusa.com
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)
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

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 testosteronedependent 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
กลัวว่าตัวเองหรือแฟนจะเป็ นหมัน ... 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
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
Spermatogenesis
progestogen
Progestogen: male
England , 1997
Progestogens
Dosage
Route
Duration
Results
Megestrol acetate
2 mg/kg
PO
7d
No change in semen quality
Megestrol acetate
4 mg/kg
PO
7d
Minor sperm abnormalities
MPA
10 mg/kg
SC
-
No change in semen quality
MPA
20 mg/kg
SC
-
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



Suprelorin (Deslorelin, Virbac)
Gonazon implant (Nafarelin, Intervet)
Antagonists

Acyline (Merrion Pharmaceuticals)
Deslorelin implant
Hypothalamus
GnRH
Anterior pituitary
LH, FSH
Ovary, Testis
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
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)
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
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
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 postinjection
Fahim et al., 1993
Balanced zinc solution
Adults, n = 5
Intratesticular injection
Tepsumethanon et al.,
2005
Zinc gluconate with or
without 0.5% DMSO
Adults, n=25
13.1 or 26.2mg/ Intratesticular
injection
Zinc gluconate
neutralized in
physiological vehicle
8 mo to 4 yr,
n = 10
2.6 – 13.1 mg depending on
testicular width/ Intratesticular
injection
azoospermia in 4 out of 5 dogs
beginning between Day 26-51
post-injection
azoospermia, oligozoospermia,
asthenospermia depending on
dosage used and the presence of
DMSO
Histological changes including
degeneration, vacuolation, fewer
germ cells, lack of spermatid in
atrophic seminiferous tubules
Soto et al., 2007
Oliverira et al., 2007
Neutersol/Esterilsol

FDA approved in 2003
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.
4.
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 และต้องการ
สัตวแพทย์ผชู้ านาญการผ่าตัด
ไม่ตอ้ งการเทคนิคมาก ใช้บุคลากรน้อย ไม่
จาเป็ นต้องมีทกั ษะการผ่าตัด
การวางยาสลบ
ต้องวางยาสลบ
(General Anesthesia)
ไม่จาเป็ นต้องวางยาสลบ แต่
FDA (USA) แนะนาให้ใช้ยาซึมก่อนการฉี ด
ความเจ็บปวด
สามารถวางแผนระงับความเจ็บปวดได้อย่างมี
ประสิ ทธิภาพ
เกิดความเจ็บปวดจากการบวมอักเสบ
ภายหลังการฉี ด
ร้ อยละในการคุมกาเนิด
100%
99.6%
Surgical castration vs Intratesticular injection
Surgical Method
Intratesticular Injection
ระยะเวลาที่เริ่มมีผลในการ
คุมกาเนิด
7 วัน
60 วัน สาหรับการใช้ Neutersol
ลักษณะและจานวนอสุ จิ
Azoospermia
Oligozoospermia
Asthenospermia
Azoosspermia
ฮอร์ โมน
ไม่สามารถผลิต Testosterone
สามารถผลิต Testosterone เนื่องจากยังมี
Leydig’s cell เหลืออยูบ่ างส่วน
พฤติกรรม
ไม่มีพฤติกรรมทางเพศ
ยังมีพฤติกรรมทางเพศ
Surgical castration vs Intratesticular injection
Surgical Method
Intratesticular Injection
ร้ อยละของปัญหาแทรกซ้ อน
(Levy et al., 2008)
3.4
3.9
ลักษณะของปัญหาแทรกซ้ อน
และการแก้ไข
แผลแตก : ทาแผล เย็บซ่อม
แผลหายเร็ว
เนื้อตาย แผลรู เปิ ด ติดเชื้อรุ นแรง :
รักษาภาวะติดเชื้อ ผ่าตัดเอาอัณฑะออก
เย็บตกแต่ง แผลหายช้า
ลักษณะภายนอก
ไม่เห็นอัณฑะที่อยูภ่ ายในถุงหุม้
อัณฑะในถุงหุม้ มีขนาดเล็กลง
และอาจไม่เท่ากัน
Identification required*
ค่าใช้ จ่าย
800 – 2,000 บาทโดยประมาณราคาใน 1,651 บาท โดยคิดจาก Neutersol หนึ่ง
ประเทศไทย
โดสต่อตัว 49.95 เหรี ยญสหรัฐอเมริ กา
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