Male Reproduction



9-9-02

Male Reproduction in Llamas and Alpacas                          PART I
David E Anderson, DVM, MS, DACVS
Daniel Linden, BS
International Camelid Institute
www.internationalcamelidinstitute.org


Camelid Male
F       Birth:   -       testicles normally present in or near scrotum at birth
F       Maturation:   -       phenotypic maturity 24 to 36 months
-       breeding soundness:
u       frenulum usually absent by 12 months
u       may start breeding as early as 18 months
-       not usually "mature" until 24 to 36 months

Camelid Male
F       Normal Features:   -       Testicles: Minimum standard
u       Alpacas                 2 cm x 2.5 cm
u       Llamas                  2.5 cm x 3.5 cm
                                       -       Accessory Sex Glands
u       Bulbourethral gland:    1 cm diameter
u       Prostate:                       1.5 cm diameter
u       Seminal Vesicles:               Absent

Abnormal Conditions

Infertility - Male
F       Congenital defects
-       e.g. cryptorchidism
F       Maturity
F       Libido
F       Special Senses and Function
-       Hearing
-       Sight
-       Musculoskeletal soundness
-       Reproductive Tract
F       Aquired defects

Testicular Abnormalities
F       CONGENITAL DEFECTS:
-       hypoplasia (most common ~ 10 %)
-       cryptorchidism (~ 8%, predominantly left side)
-       ectopic testes (~ 2.5 %)
-       cystic structures (~ 14.5 %)
F       Sumar, 1983

Infertility - Male
F       Maturity
-       18 to 36 months
-       > 3 years abnormal

Libido
F       Behavior
F       Hypotestosteronism?
-       Testicular hypoplasia
F       Abuse
-       dominant female
F       Owner overintervention

Testicular Abnormalities
F       ACQUIRED DEFECTS
-       testicular trauma = fighting injury
u       hemi-castration by a fighting male
u       testicle bruise / abscess / sperm granuloma
-       non-reproductive tract
u       heat stress
u       illness

Infertility - Male
F       Musculoskeletal
-       Lameness
-       Back Pain
u       arthritis
u       myositis

Penile Trauma
F       Urolithiasis
F       Penile hematoma
F       Penile adhesions
F       Penile lacerations
-       fighting injury

Preputial Trauma
F       Preputial laceration
F       Peri-preputial abscess
-       caused penile thrombosis, sloughing in a young alpaca

Heat Stress
F       testicular degeneration
F       temporary infertility


       

                                                                        PART II
                                    Cryptorchidism in Camelids: The How's and Why's
Daniel Linden, BS
David E Anderson, DVM, MS, DACVS
International Camelid Institute
www.internationalcamelidinstitute.org

What is Cryptorchidism?

.       Cryptorchidism is a congenital defect that causes retention of one or both testes in the male animal.
.       Kryptos: Greek for hidden, secret, or covered
.       Orchi: Greek for testes.
.       Cryptorchid = "hidden testicle"
.       Unilateral: retention of only one testicle in the body cavity
.       Bilateral: retention of both testicles.

CONGENITAL DEFECTS:
-       hypoplasia (most common ~ 10 %)
-       cryptorchidism (~ 8%, predominantly left side)
-       ectopic testes (~ 2.5 %)
-       cystic structures (~ 14.5 %)
Sumar, 1983

Cryptorchidism

F       Uncommon (< 10 %)
F       Usually left sided
F       More difficult to locate than horses, cattle, pigs
-       possibly because of varied location and ectopic locations

Causes of Cryptorchidism:

.       Cause for the retention of testes not known.
.       Hormone analysis of human men, pigs, & dogs show that hormones are not completely responsible.
.       May be genetically transmissible in an unknown way. Possibly through maternal side.
.       Heavily linebred dogs show more cases than open bred dogs.


Diagnosis of Cryptorchidism

F       Diagnosis in hemi-castrate
-       Basal Testosterone
-       GnRh stimulation test (10 mg) - poor response
-       hCG stimulation test (up to 5000 IU) - test of choice
u       testosterone response in 30 minutes to 18 hours
Other Diagnostic tests
Laparoscopy:  probably THE definitive test
Estrone sulfate: - probably not useful in llamas and alpacas

Diagnostic testing for Cryptorchidism:

GnRH:
.       Released from the hypothalamus and stimulates the release of FSH and LH.
.       Recent studies at Ohio State University by Dan Linden and David Anderson showed that the plasma levels of testosterone were raised by 467.9% 12 hours after administering GnRH in an intact male, 184.9% in a bilateral male, 108.4% in a unilateral male, and 107.3% in a castrate.

HCG:
.       Placental hormone used to regulate normal pregnancies.
.       Recent studies at Ohio State University by Dan Linden and David Anderson shows that testosterone plasma levels were at unmeasurable levels in an intact male, but increased by 102.1% in a bilateral male, decreased to only 74.3% of time 0 in a unilateral male, and increased to 107.3% in a castrate.

What Does it All Mean?

.       The study was conducted to see if testosterone plasma levels would be increased by 3-400% after the two hormones were injected in separate trials.
.       GnRH had better and more consistent results than HCG, even though it only caused a near 200% increase in a bilateral male, and negligible increases in a unilateral and a castrated male. HCG caused negligible increases in an intact male and in a bilateral male. It caused a decrease in the unilateral and castrated male.

Cryptorchidism

F       Basal Testosterone Serum Concentrations
-       alpacas and llamas > 2 years old:
u       testosterone > 1 ng/ml
u       diurnal variation of up to two-fold concentration
-       Gelded camelids
u       testosterone < 0.2 ng/ml

Cryptorchidism
F       Surgical Correction
-       inguinal approach
-       parainguinal approach
-       laparoscopy

Battling Cryptorchidism.

Bilateral cryptorchids are generally infertile due to thermal suppression of spermatogenesis.
Unilateral cryptorchids are generally fertile since the descended testicle is low enough from the body to have only normal thermal suppression. There is a marked depression in the plasma levels of testosterone in cryptorchids. Unilaterals are lower than an unaffected male and bilaterals are lower still.

Is Cryptorchidism an Problem For Herdsmen?

.       Cryptorchidism is not a very common occurrence.
.       Out of 2916 alpacas inspected during a preshipment examination for exporting from South America only two animals had cryptorchidism. Another four animals had other testicular problems, mainly unequal size issues, that disqualified them for exporting.

What Can Be Done?

.       The sheep industry found that by removing all unilateral cryptorchids from breeding programs, they had a 18-28% reduction of cryptorchidism occurrences.
.       This would lower the genetic availability of the gene if it is in fact a genetically transmitted problem.
.       Many researchers are looking at hormonal markers to test possible cryptorchids. The hormones in question are GnRH and HCG.


Summary

.       Cryptorchidism is a congenital defect with a high risk of heritability in offspring of cryptorchid males.

Cryptorchids are undesirable breeding animals.

Testicles can be hard to find, but should be present at birth. We recommend close inspection of crias at weaning because the testicles are more obvious at that time.




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