Breeding Soundness Examination in Goats

Does and bucks should be examined before the breeding season to optimize the likelihood of reproductive success.

• Does should be in marginal body condition (2–3 out of 5) to maximize response to focused feeding programs and to minimize the risk of developing pregnancy toxemia in the last trimester.

• Bucks should be in moderate body condition (3–4 out of 5), because they can lose more than 10% of their body condition throughout the breeding season.

Breeding animals should be in overall good health. Anemia due to heavy parasite infections and chronic debilitating diseases, such as pneumonia, can lead to loss of libido and/or infertility.

Foot abnormalities, such as overgrown hooves, hoof rot, or severe laminitis, should be treated appropriately to ensure the ability of bucks to mount and does to be able to stand for mounting.

Bucks with caprine arthritis and encephalitis (CAE) virus infection may have painful, enlarged stifles, and, if they are even able to mount, are usually reluctant to ejaculate because of pain. Does infected with CAE may have mastitis and should be culled.

A complete breeding soundness examination should be performed routinely on all bucks before the breeding season to prevent undesirable reproductive outcomes. Occasionally, a post-breeding examination may be needed in bucks when pregnancy rates are found to be lower than expected. However, does are usually only assessed if they do not conceive after several attempts.

Palpation of the penis and prepuce of bucks during a physical examination is performed to ensure there are no masses or lesions that may prevent protrusion, intromission, or ejaculation. The penis can be assessed during electroejaculation or via manual exteriorization. The buck may be placed on its rump or laid on its side with pressure applied to the sigmoid flexure by an assistant while the prepuce is stabilized for penis exteriorization.

Shearing wounds (especially in Angoras), prior balanoposthitis (ie, pizzle rot), old fly-strike wounds, and scarring around the prepuce may make protrusion of the penis impossible, and animals should be culled if severely affected. Persistent penile frenulum may also prevent exteriorization in young bucks and should be surgically corrected before breeding.

It is worth noting that persistent penile frenulum is thought to be a genetic condition, and affected bucks should only be bred if their kids are not intended to be used for breeding. While the presence of a urethral process at the tip of the penis is a normal anatomic variation of the goat, prior amputation to treat or prevent urethral obstruction is common and has no apparent deleterious effect on breeding ability.

Cryptorchidism occurs infrequently in bucks and is usually genetic. Therefore, a thorough reproductive examination in young breeding bucks should include confirmation that both testicles have descended completely. Cryptorchid males should be castrated entirely to prevent any unwanted pregnancies and eliminate undesirable buck behavior. Castration usually involves abdominal surgery to remove the retained testis, which may be cost-prohibitive. Alternatively, these males could be vasectomized or epidectomized to use as teasers, but the retained testicle should still be removed to prevent unwanted breeding.

The testicles should be evaluated for size (scrotal circumference), consistency, and symmetry. Testicular hypoplasia occurs rarely and is mostly associated with intersex condition; however, it may also be a manifestation of chronic malnutrition, so history and body condition score should be considered.

Scrotal circumference is positively correlated with semen production capacity and should be > 25 cm in mature bucks (> 14 months old) (1). Pygmy and dwarf breeds may be smaller, so it is more important to focus on individual animal trends in testicular size as well as consistency and semen quality. Additionally, scrotal circumference can vary by season and decrease by as much as 3 cm outside the breeding season.

The testicles and epididymides should be symmetric and slightly firm on palpation. Any asymmetry or changes in tone may indicate infection or injury and can adversely affect fertility.

Bucks with evidence of orchitis (testicular infection) or epididymitis (infection of the epididymides) should be first tested for infectious diseases (see orchitis and epididymitis images).

Orchitis, goat

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Bilateral orchitis in a breeding buck presented for poor reproductive performance. Ultrasonographic examination of the testes (right) showed hyperechoic nodules and several pockets of fluid in both testicles. Fine-needle aspiration and microbial culture of specimens from the lesions revealed Corynebacterium pseudotuberculosis infection.

Courtesy of Dr. Jamie Stewart and the Diagnostic Imaging Department, University of Illinois at Urbana-Champaign.

Epididymitis, goat

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Unilateral epididymitis in a buck presented for routine semen collection and analysis. Ultrasonographic examination of the testes confirmed the presence of hyperechoic material in the cauda epididymis. Subsequent cytological analysis of the sample revealed severe suppurative inflammation, and microbial culture yielded a mixture of Actinomyces honkongensis and Escherichia coli.

Courtesy of Dr. Jamie Stewart.

Outside of the US, Brucella melitensis is a common concern in bucks with orchitis and epididymitis, because bred does will be at risk of stillbirth and abortion. Other infectious causes of orchitis and epididymitis in bucks include Corynebacterium pseudotuberculosis (causative agent of caseous lymphadenitis), Trueperella pyogenes, and Actinobacillus seminis.

Testicular ultrasonography can aid in the diagnosis of epididymitis and orchitis and assist with determining the need for additional diagnostics, such as fine-needle aspirate, biopsy, or semen culture.

Spermatic granulomata and calcification of the testicles are common sequelae of epididymitis and orchitis and will reduce or eliminate the buck’s fertility. Therefore, bucks with clinical orchitis or epididymitis usually need to be culled.

In cases where an infectious origin of epididymitis or orchitis is not suspected (such as trauma), ultrasonography may be used to determine whether one or both testicles are affected and if hemicastration is an option to preserve breeding potential of valuable males.

Sperm evaluation is another crucial component of the buck breeding soundness examination. Semen collection can be performed using either an artificial vagina (AV) or an electroejaculator. Collection with an AV yields a higher-quality sample, which is useful when semen is being collected for freezing; however, it also typically requires the presence of a doe in heat to perform. Electroejaculation is more convenient; thus, it is used more commonly for semen collection in breeding soundness examinations.

Once semen is obtained, it should be maintained at 37°C (98.6°F) and evaluated as quickly as possible. Grossly, the semen should be cloudy, white, and free from urine, blood, pus, or dirt. Occasionally, semen with an off-yellow color may be normal, although it should be examined closely for urine contamination.

Semen should be evaluated microscopically for sperm motility, morphology, and presence of WBCs.

Gross sperm motility can be measured by placing a drop of undiluted semen on a warmed slide and examining it microscopically on low magnification (typically 100X). A satisfactory sample can exhibit anywhere from general oscillation to vigorous swirling on gross motility assessment. Sporadic oscillation usually indicates poor semen viability, though it may also be due to low concentration.

Individual and progressive sperm motility should also be assessed at higher magnification (400X) by diluting the semen with prewarmed isotonic diluent (eg, 0.9% saline) or extender. Sperm cells are counted to determine the percentage of progressively motile sperm, with a minimum of 30% considered acceptable.

Sperm morphology should also be assessed microscopically at a magnification of 1,000X (oil immersion) to assess percentage of normal cells versus those with head, midpiece, or tail defects. Morphologic analyses can be performed with light microscopy by preparing a slide with eosin-nigrosin staining of sperm cells or with a phase-contrast microscope by preparing a wet-mount slide of formalin-killed sperm.

Parameters for morphologic assessment are extrapolated from those used in bulls, with a minimum of 70% normal being acceptable when counting a minimum of 100 sperm cells (2). (Also see Breeding Soundness Examination of the Male.) Sperm with distal droplets have been reclassified as normal sperm cells in bulls and may be considered normal in bucks, too, because these defects do not appear to affect fertility in ruminants.

Bucks with questionable sperm morphology may be deferred and rechecked in 7 weeks, after a full spermatogenic cycle has passed. Notably, semen quality can be affected by photoperiod, so bucks evaluated outside the breeding season should always be deferred and rechecked in the autumn.

Breeding soundness examinations in does are typically performed only after discovering the doe did not become pregnant during the breeding season.

The external genitalia of doelings should be examined for abnormalities, such as an enlarged clitoris, hypotrophic vulva, or increased urogenital distance that suggests intersex, a condition common in homozygous polled females, especially in Alpine, Saanen, and Toggenburg breeds. Intersex goats are sterile and should be culled.

Examination of external genitalia may also help to detect adhesions or rectovaginal fistulas in multiparous does that had a previous dystocia (see ano-vulvar fistula image. These conditions may be surgically corrected in valuable does; however, does are more commonly culled because treatment may be unrewarding.

Ano-vulvar fistula, goat

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A doe with an ano-vulvar fistula, found incidentally at time of artificial insemination. The doe likely had a difficult birth previously and was subsequently culled because of poor prognosis for fertility.

Courtesy of Dr. Jamie Stewart.

A speculum can be used to examine the walls of the vagina, vestibules, and cervix to search for lesions in does with fertility issues. Transabdominal and/or transrectal ultrasonography can be used to examine the uterus and ovaries for cysts, hydrometra (pseudopregnancy), or other abnormalities.

Occasionally, a doeling may have a shortened vagina, no cervix, or segmental aplasia of various parts of the tract that warrant culling. In valuable breeding does, surgical laparoscopy or laparotomy may be performed to check for causes of infertility, such as oviductal blockage, tumors, adhesions, or segmental aplasia, that may not be visible on speculum examination or via ultrasonography.