Breeding Soundness Examination in the Male Camelid
Stacey Poskarbiewicz, Veterinary Student
David E Anderson, DVM, MS, DACVS
What is a Breeding Soundness Examination?
A breeding soundness examination (BSE) is an integral part of any successful reproduction business. It looks beyond performance records and pedigrees, to include all things that can affect fertility. The reproductive function of males depends on a variety of characteristics, including sexual desire, or libido, mating ability, capability of forming semen, etc. These all need to be taken into consideration in the BSE. An all-inclusive BSE should include a physical examination, examination of the reproductive tract, evaluation of mating desire (libido), and semen evaluation.
A physical examination is one of the most important aspects of the BSE. It will reveal conditions that could be detrimental to reproduction, but would not be picked up if one were only evaluating the reproductive aspects. A physical exam will identify circumstances that can affect the males' ability to locate dams in heat (if pasture breeding) or affectively mount and mate the female. Body Condition Scoring (BCS) is important to the overall health of all animals; but, also can be detrimental to reproductive success. Emaciated animals will not have the energy to perform, while obese males will not only lack the vigor, but also more importantly, it affects the thermoregulation of the testicles and therefore decreases semen quality. Feet and legs need to be considered, as the male will be unable to mount or stay mounted for an extended period of time if there is a problem. Previous injuries, length of toenails, and osteoarthritis are a few troubles that could be recognized in a possibly unsound male. The importance of a thorough examination of the reproductive tract is obvious. The testicles need to be palpated and measured. The testicles should be firm, but not hard or soft. They should be freely moveable, symmetrical, and contain no lumps, or enlargements. The size should be measured with either calipers or ideally via ultrasound. The size and shape of the bulbourethral and prostate glands also need to be determined. This is also done by ultrasound examination. The glands should be homogenous in echotexture. The penis and prepuce should be inspected for any signs of inflammation, abscesses, adhesions, or deviations. (The average sizes of normal testicles, bulbourethral and prostate glands can be found in figures 1 and 2.)
Evaluation of mating desire can be observed while obtaining a specimen for semen evaluation. A male that is unarousable by a receptive female is likely infertile and the cause needs to be identified. A serum testosterone level would then be evaluated and a normal value should be >1000pg/mL in a sexually mature male. A male with a good libido will begin to orgle, smell under her tail to check fertility and receptivity, then approach her from behind in order to persuade her to cush for the act of mating (Stamberg, 2000). If electroejaculation is being utilized for semen collection, the libido will not be noted; however, this is usually used when the libido is known to be adequate. Semen can be retrieved from the vagina after ejaculation or an electroejaculator can be used. A disadvantage of collecting from the vagina is that it often does not provide an adequate representation of the true motility/morphology of sperm as they can be damaged in the retrieval. Electroejaculation on the other hand, requires sedation and can often become contaminated with urine (Tibary, 2000). The use of an artificial vagina along with receptive females appears to be the most efficient method, IF the camelid is trained to mount. The semen is then evaluated for volume, consistency, color and most importantly motility and morphology of the sperm. Normal motility of semen collected by electroejaculation is moderate; whereas, that collected by vaginal aspiration is slow (0-50%). Normal morphology from electroejaculation collection has not been noted, while vaginal aspiration shows normal from 10-78% (Bravo, 2002). "The proportion of normal spermatozoa ranges between 60 and 90%, and as in other livestock species, it varies" (Bravo, 2002). Abnormalities of sperm noted upon microscopic examination include abnormal heads, midpiece defects, cytoplasmic droplets, detached heads, and tail defects.
At The Ohio State University
A retrospective study conducted in August of 2005 looked at the results of BSE performed on 45 male camelids in order to identify the most common reasons that they fail to be sound breeders. 28% of the males were diagnosed with testicular degeneration, 20% with testicular hypoplasia and 3% with cryptorchidism. 22% of the males were found to be likely normal satisfactory breeders. (4% were obese, the effects of which were discussed earlier).
Testicular degeneration is a progressive disease that can be caused by a variety of diseases but is most commonly associated with heat stress, prolonged weight loss, or prolonged fever. Testicular degeneration is where the function of the testicle deteriorates and the production of sperm is decreased. This is likely the most common cause of infertility of old males (Tibary, 2000). "Specific causes for testicular degeneration include elevated temperatures, frostbite, systemic infections, nutritional factors, toxins, hormonal deficiencies and excesses, vascular occlusions, obstruction to testicular atrophy, autoimmunity and age" (Buergelt, 2005). This can often be palpated as softer and smaller than usual testicles. The definitive diagnosis is reached through a biopsy of the testicular tissue. The biopsy will reveal absence or abnormality of spermatogenesis of the seminiferous tubules and spermatogonia. Treatment of degeneration is feasible only if an underlying cause for the disease is identified, which is often not the case. With the biopsies submitted to the pathology department at OSU, the underlying origin often was not determined. Medical treatments currently used attempting to treat this condition includes GAGS (glycosaminoglycans, such as Adequan), NSAIDS, vitamin E and sexual rest. The average cycle of spermatogenesis is 60 days. Therefore, after an initial adverse event (such as heat stress), the time for sperm production to return to normal is after that time frame. Reevaluations are scheduled at the end of that period to note if production has in fact returned. If the cause of the degeneration is idiopathic, the condition is not responsive to medical therapy.
"Testicular hypoplasia is a congenital pathologic condition which manifests itself at puberty" (Buergelt, 2005). It is the reduction or complete lack of spermatic tissue in either one or both testes. Sperm production is correlated with size in camelids; therefore, as testicular size decreases, so too does sperm output and fertility (Vaughan, 2003). "Hypoplasia may be bilateral or unilateral, and ranges from mild (varying degrees of spermatogenic activity) to severe (Sertoli cells only) histologically" (Vaughan, 2003). The true underlying cause is unknown, but is suspected to be a developmental disorder in that germinal cells fail to migrate to the fetal testes or are destroyed during development. Diagnosis can be confirmed through ultrasound measurements, testicular biopsy and testosterone values. As these males still have functional Leydig cells they should continue to produce normal levels of testosterone and have normal libidos.
"Cryptorchidism is defined as failure of testicular descent into the scrotum" (Buergelt, 2005). It is a relatively rare condition (10%) in the camelids that is usually unilateral (left sided) but has been identified as bilateral (Anderson, 2002). The cause of the retention is unknown, but is believed to be a heritable defect. Cryptorchids are generally diagnosed by palpation, often then the location of the testicle is found using an ultrasound. "Unilateral cryptocrchids 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. Unilateral are lower than an unaffected male and bilateral are lower still" (Anderson, 2002). Bilateral cryptorchids are completely infertile. Regardless of the number of retained testicles all cryptorchids should be castrated as this renders the males as unsatisfactory breeders that will pass the faulty trait to their offspring.
There are numerous causes of infertility in camelids - male and female. The importance of the breeding soundness examination cannot be stressed enough for both sexes in order to identify these causes. It is recommended that BSE's be performed on all animals prior to purchasing and at any indication that fertility is decreasing. Relying on a thorough BSE performed by a proficient veterinarian should increase the rate of successful breedings on your farm.
Mean testicular size and testosterone concentrations by age in llamas and alpacas
|Llama size |
|Alpaca size |
(Figure adapted from Bravo, 2002 - Chapter 4, page 49)
Mean bulbourethral gland and prostate gland size in the alpaca
(Figure adapted from Bravo, 2002 - Chapter 4, page 51)
- Anderson, D., Linden D. Male Reproduction in Llamas and Alpacas.
International Camelid Institute. RMLA.com. 2002.
- Bravo, Walter. The Reproductive Process of South American Camelids. 2002.
- Buergelt, C.D. Pathology of the Male Reproductive Tract. AFIP.org. 2005.
- Stamberg, G., Wilson, D. Llamapaedia.com. 2000.
- Tibary, A., Anouassi, A. Reproductive Disorders in the Male Camelid.
- Vaughan, J., Galloway, D., Hopkin D. Artificial Insemination in Alpacas (Lam pacos). RIDC.gov.au. 2003.
David E Anderson, DVM, MS, DACVS
Head and Associate Professor of Farm Animal Surgery
Director, International Camelid Initiative
Ohio State University**
College of Veterinary Medicine
601 Vernon L Tharp Street
Columbus, Ohio 43210
** Dr Anderson is no longer with Ohio State University. Please use the following web site: http://www.vet.k-state.edu/depts/ClinicalSciences/faculty/anderson.htm