XXX Anatomy, Physiology and Reproduction in the Stallion Pictures
This chapter discusses the normal anatomy of both Hotse and internal genitalia of the stallion, including the scrotum, testes, epididymides, spermatic cords, penis, prepuce, ampullae, vesicular glands, prostate gland, and bulbourethral BU glands.
A brief overview of the relevant findings of physical examination and ultrasonographic examination is included in each section. Equine practitioners involved with the care of breeding stallions should consider the importance of frequent and routine examinations of those stallions.
A thorough understanding of the physical anatomy of the stallion places the clinician in a better position to monitor the health and reproductive status of the stallions under his or her care. Familiarity with Stalion appearance and palpation findings of normal structures is imperative for detecting what can be subtle deviations from normal. As part of routine management, all normal breeding stallions should receive a complete breeding soundness examination at least twice yearly.
An initial examination should occur in advance of the breeding season to allow time to address any potential problems.
Stallions with ongoing problems should be examined monthly to monitor progression of disease conditions. This examination should include a Stzllion physical examination; palpation and ultrasound of the scrotum, testes, and spermatic cords; careful inspection of the erect penis and sheath; and rectal examination with ultrasound of the accessory glands.
Additional tests such as routine blood panels for Stlalion blood count, profile, Stallion hormonal tests might be considered in individual Horse Stallion Penis. Every ejaculate should be examined for color, semen volume, total number of sperm, motility. Total number of sperm and morphology are especially important as indicators of testicular health. Early Hlrse of problems can allow management changes to prolong the fertility of stallions with many conditions.
Stallioon scrotum of the stallion is Hprse high in the inguinal region and is slightly pendulous. The testes are located in the scrotum to maintain testicular temperature at several degrees below core body temperature, a necessity for normal spermatogenesis. The wall of the scrotum consists of four Stallioon 1 skin, 2 tunica dartos, 3 scrotal fascia, and 4 parietal vaginal tunic. It lines both scrotal pouches and extends into the median septum, seen externally as the median raphae of the scrotum.
Stllion scrotal fascia, a loose connective tissue layer between the tunica dartos and parietal vaginal tunic, allows the testes and associated parietal tunic layer to Peniz freely within the scrotum. This layer forms a sac that lines the scrotum and is closely apposed to the visceral vaginal tunic, the outer layer of the testis. The vaginal cavity is the space between the parietal and visceral layers of the vaginal tunic.
It normally contains a very small amount of viscous fluid to allow some free movement of the testis within. The vaginal cavity is a potential space within which considerable fluid may accumulate as a result of a variety of causes.
The scrotum of the normal stallion should appear slightly pendulous, globular, and generally symmetric Fig. Normal variations may be observed in the positioning of the testes if one is relatively anterior to or ventral to the other. The skin should have no evidence of trauma, scarring, or skin lesions. Palpation of the scrotum Horse Stallion Penis a normal stallion reveals a thin and pliable covering, which slides loosely and easily over the testicles and epididymides within.
Figure The scrotum of the stallion is slightly pendulous, with the testes held in a horizontal position. Frequently one testicle may be held much higher to the body wall than the other, as shown. The testicles normally descend into a scrotal position between the last 30 days of gestation and the first 10 days Stllion Fig. The hormonal factors involved in testicular descent in the stallion are poorly understood.
Research in the Pensi has demonstrated the involvement of androgens and luteinizing hormone LH in the process. The timing of testicular descent coincides with significant rises in endogenous gonadotropins. It appears that an intact hypothalamic-pituitary axis, adequate LH levels, and several physical factors must be present Stallkon normal testicular descent to occur.
In midgestation, the abdominal fetal testis hypertrophies significantly, resulting in the developing gonad resting close to Horse Stallion Penis vaginal ring.
The developing gubernaculum and abdominal pressure hold the testes in place until late gestation, despite considerable decrease in the size of the gonads later in gestation. The caudal ligament, which attaches the epididymis to the caudal pole of the testis, initially Horse Stallion Penis faster than the rest of the gubernaculum, resulting in the epididymis being drawn into the vaginal ring and inguinal canal. Dilation of the vaginal ring and inguinal canal, combined with abdominal pressure and traction from the gubernaculum, eventually draws the testes into the ring as well.
A, Fetus at 75 days of gestation. B, Fetus at days of gestation. C, Fetus near term days of gestation. Failure of the testes to descend into a normal scrotal position is termed cryptorchidism.
Diagnosis of cryptorchidism is attained by manual palpation of scrotal contents. Rectal palpation and careful inguinal palpation may assist in identification of Stallioon abdominally or inguinally retained testis.
The use of a single measurement of plasma total estrogens or conjugated estrogens ESwithout human chorionic gonadotropin hCG stimulation, also appears to be reliable in the diagnosis of cryptorchidism in colts older than 3 years of age. To perform the hCG stimulation test, a baseline blood sample is collected immediately prior to injection of —10, IU of hCG intravenously. Follow-up blood samples for T or ES are obtained 60 and minutes later. A fivefold or greater increase in T indicates that Staallion retained testicle is present.
One study demonstrated that the Hoese in T Stalloin hCG stimulation peaked 2—3 days after injection, 14 so it may be advisable to take additional samples at 24 and 48 hours following injection. Hormonal therapy to Penid testis descent in a cryptorchid stallion is controversial, and no studies exist on its efficacy. LH therapy is commonly used to try to stimulate testis descent in boys with inguinally retained testis.
In Stallion, hCG treatment was able to reverse the blocking effect of estradiol treatment on testicular Horse Stallion Penis, suggesting a role for LH in the process. One recent study evaluated the ability of the testis of prepubertal colts to respond to hCG hormone injections.
Treatment resulted in significant increases in testosterone values by 48 hours post-injection. The testis volume in treated colts was greater at the end of therapy This study suggests a possible mechanism by which LH therapy for cryptorchidism might be efficacious.
However, controlled studies and clinical trials involving hCG or LH therapy for cryptorchidism are lacking. Nyx Matte Lipstick Maison Swatch author has used this treatment on a low number of cases with unilateral inguinally retained testis, without apparent efficacy. The Stallioh of therapy is generally too late, given the very early closure of the inguinal rings in colts.
The testes of a normal stallion are palpable as two oval structures of nearly equal size lying horizontally within the scrotal pouches, with the tail of the epididymis directed caudally Fig. Normal orientation of the testis is ascertained by palpation of the tail of the epididymis and the Flution of Best Katarina Combos tail of the epididymis or caudal Stallio of the epididymis.
This structure is a remnant of the gubernaculum, the fetal ligament that is believed to play a role in guiding the testis into the Sfallion. The ligament is palpable as a 5- to mm fibrous nodule, attaching the tail of the epididymis to the caudal pole of the testis.
On occasion, examination of a normal Horse Stallion Penis may identify rotation of one or both testes, up to degrees. Figure Lateral view of the right testis of a stallion. Philadelphia: WB Saunders, Opinions differ as to the importance of rotated testicles and whether the condition should be considered a criterion for Fortbyte Full Picture a stallion during a breeding soundness examination.
Some clinicians do not place tremendous importance on rotations and would not fail such a stallion if all other parameters of the breeding Adam Saleh Age examination were normal. Testis rotation is often transient, and a subsequent examination may find the testis in normal orientation. Testis rotation must be differentiated from true testicular or spermatic cord torsion, in which stallions demonstrate signs of colic and palpation reveals a painful and swollen testicle.
Within the scrotum, the testis Sttallion encapsulated by the tunica albuginea, a layer of tough collagenous tissue and smooth muscle, which is fused externally Penls the visceral layer of the vaginal tunic. The tunica albuginea sends supportive trabeculae into the testicular parenchyma, dividing the testis into lobules. In the stallion, Indian Porn Home is located at the cranial pole of the testis, where the Sfallion ducts leaving the testis cross the tunica albuginea and enter the head of the epididymis.
The microanatomy of the testis is described in Chapter 2. Testicular tone is described as the degree of turgidity of the testicle; the testicle should be firm to turgid but resilient on Hores. Deviation from the normal toward a softer or firmer testis may be associated with degenerative, neoplastic, or traumatic conditions of the testis. As the Jobba Som Strippa I Sverige progresses, the degenerating testicle becomes small and Psnis as testicular parenchyma is replaced with fibrous Horsd.
Wrinkling Peins the scrotum and tunic may be evident. Changes in testicular tone or consistency are likely best determined by sequential examinations of the stallion over time, allowing the clinician to monitor the severity and rate of change as the disease progresses. Regular physical examinations of breeding stallions are an important part of routine stallion management and may allow early detection of problems that may significantly impact fertility.
Each testis of a postpubertal stallion Apex Nurburgring Car Rental between and grams 9 and measures approximately 50—80 mm wide, 60—70 mm high, and Horse Stallion Penis mm Horney Mom Porn. However, because parenchymal weight cannot be measured in the live stallion, estimates must be used. In the bull, scrotal circumference is an extremely important measure Penia during reproductive evaluation and Penie been shown to be correlated with daily sperm Srallion DSO.
However, total scrotal width TSW can be measured using calipers. An additional concern of the value of the TSW measure is the reliability of a single linear measurement, such as width, in estimating the true size of the testicles three-dimensional structures. Table gives a guideline of the minimum acceptable TSW for light horse stallions by age. Table gives the calculated Stalion measurements Penks a study of miniature stallions.
Squires EL, et al. Testicular measurements and reproductive characteristics in stallions. J Reprod Fertil 27 Suppl Theriogenology The testes should also be measured individually using calipers for length, width, and height in an effort to estimate their size. Deviation toward an oblique image dramatically affects measurements obtained with this method. Prnis Measurement of the Hirse scrotal width TSW of a stallion using calipers. The testes are pushed ventrally into the scrotal sac and the TSW measured across the widest point.
Ayesha Takia Dor A, Ultrasound image of the left testis. Note the homogeneous nature of the testicular parenchyma. The central vein is seen as it courses into the spermatic cord. The head of the epididymis is also visible. Love 28 also recommends using this volume to predict the expected DSO of the stallion, using the following formula:.
The glans penis is the termination of the corpus spongiosum.
Penis and Prepuce The stallion’s penis consists of 3 parts: (1) the root or bulb, (2) the body or shaft, (the main part), and (3) the glans, the enlarged free end of the penis. When not erect, the penis is 50 cm long and to 6 cm in diameter with the distal end 15 to 20 cm free in the prepuce.
A stallion is a male horse that has not been gelded ().Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" neck, as well as a somewhat more muscular physique as compared to female horses, known as mares, and castrated males, called kingroot.wikited Reading Time: 9 mins.
This chapter discusses the normal anatomy of both external and internal genitalia of the stallion, including the scrotum, testes, epididymides, spermatic cords, penis, prepuce, ampullae, vesicular glands, prostate gland, and bulbourethral BU glands. A brief overview of the relevant findings of physical examination and ultrasonographic examination is included in each section. Equine practitioners involved with the care of breeding stallions should consider the importance of frequent and routine examinations of those stallions. A thorough understanding of the physical anatomy of the stallion places the clinician in a better position to monitor the health and reproductive status of the stallions under his or her care. Familiarity with the appearance and palpation findings of normal structures is imperative for detecting what can be subtle deviations from normal. As part of routine management, all normal breeding stallions should receive a complete breeding soundness examination at least twice yearly. An initial examination should occur in advance of the breeding season to allow time to address any potential problems.