Introduction:

Reduced infertility in male may be due to hereditary or may originate from psychic disturbances, hormonal imbalances, nutritional deficiencies or environmental factors. Even though semen characteristics may be satisfactory, fertility may be adversely affected as a result of poor libido. Nutritional deficiencies denotes delay onset of puberty and depress production and characteristics of semen. Ration deficient in vitamin A, proteins and minerals may reduce sex drive. Young bulls are mostly affected by protein deficiency. Dietary vitamin A deficiency leads to testicular degeneration in all farm male animals. Iodine deficiency also leads to poor libido. Plant estrogens exert adverse effect on male accessory organs. Overfeeding and obesity reduce libido and sexual activity in male animals. A management and psychic factors also affects the libido like young males may be slow at service due to inexperience while lack of exercise and proper training also leads to poor sex drive.

Psychic factors play an important role in altering the sex drive of males of low genetic makeup. Injuries during semen collection are usually remembered by the bulls and may inhibit the sex drive and abusive handling of bull during semen collection. Size and colour of dummy also affect the libido of male animals. A chronic and acute debilitating disease like tuberculosis, john’s disease, pneumonia, severe mange, actinomycosis etc seriously affects the libido. Climatic factors like high temperature especially during summer reduces libido. Hormones like thyroxine, testosterone and gonadotrophins deficiency reduced sexual desire.

Impotentia Coeundi:

Bull may have normal or slightly decreased libido but is unable to copulate. Inability to copulate may be due to following conditions like joint, muscle, nerve, bone and tendon injuries.

Gonitis:

Gonitis is common in bulls, characterized by a short, stiff gait and distention and enlargement of the capsule of the stiffle joint. Rupture of anterior cruciate ligament of stiffle occurs commonly in smaller breeds of dogs.

Coxitis:

Coxitis is common in dogs and boars, characterized by a short stride and adduction of the limb. Rupture of round ligament may be observed in bulls with degenerative coxitis. Other conditions like overgrown claws or hooves, suppurative pododermitis, interdigital granuloma tendonitis, suppurative arthritis of coffin joint, myositis or rupturing of muscles like gastrocnemius or large gluteal and also hip dislocation are responsible for the reduce libido. In spastic syndrome, crampiness or stretches in bulls, severe acute attacks may interfere with or prevent copulation due to prolonged spasms of the skeletal muscles of the rear limbs and back. It is observed most commonly in HF and Guernsey breeds.

Affections of penis and prepuce:

Short penis:

This is a heritable and can cause infertility because of the difficulty in the copulation.

Short retractor penis:

The short retractor penis prevents penile extension. Diagnosis is by feeling a tight band at erection where the retractor penis muscle is situated. A short unilateral retractor penis results in a bulge unilaterally by the scrotum on erection.

Balanoposthitis:

Balanitis is an inflammation of glans penis and posthitis is an inflammation of prepuce. When inflammation of penis and prepuce are involved together, it is called balanoposthitis. Balanoposthitis is a relatively common condition of the male sheep, in which it is colloquially known as pizzle-rot. The condition may be due to infectious or non-infectious causes. Infections of the penis and prepuce are common in the dog, bull and ram, occasional in the stallion, and rare in the boar and cat. Severe balanoposthitis can cause pain, unwillingness to mate, preputial stenosis, adhesions between penis and prepuce, and peripenile adhesions. Occasionally, a canine herpesvirus causes a more severe balanoposthitis which is characterised by ulceration of the penis and unwillingness to copulate¹. Bulls are also susceptible to granulomatous formation on the penis, which is a non-transmissible and usually asymptomatic condition². Tuberculous balanoposthitis has been described in areas where the disease is epizootic³. The most serious cause of balanoposthitis in the stallion is the notifiable disease of dourine^4,5. Prognosis is depending upon severity of trauma or infection. Prognosis is good in mild cases and guarded in chronic cases with severe adhesions in between penis and prepuce. In mild cases, douching the prepuce can be done with antiseptics (1:2000 acriflavin or potassium permanganate solution, 1% H₂O₂ solution) or antibiotics. Application of oily preparation of antiseptics and antibiotics are also helpful. Systemic antibiotics given in severe cases and sexual rest require during treatment.

Phimosis:

Phimosis or stenosis of the prepucial orifice leads to prevention of normal protrusion of penis and thus male is unable to perform coitus. The main causes are congenital (especially in dog, cat and horse) and acquired due to injuries, wounds and infections. In dogs, particularly in the German shepherd and Golden retriever breeds are suspected. Prognosis is guarded and depends upon extent of trauma, necrosis and promptness to handling of case. Phimosis of congenital origin may be corrected by surgical operation. Severely congenitally affected puppies may be unable to urinate adequately, with the consequential balanoposthitis leading to septicaemia and death⁶. In stallions, prolapse of the penis is the sequel to many conditions. For example, it generally occurs transiently after the administration of phenothiazide tranquillisers^7,8.

Paraphimosis:

Inability of penis to retracted back into prepuce after protrusion resulting into swelling, oedema and balanoposthitis. Inability to withdraw the penis into the prepuce results from congenital or acquired structures of the prepuce, paralysis of the penis due to spinal diseases. The condition is most common in the dog and stallion. Paraphimosis following copulation or spontaneous erection is relatively common in the dog. It may also occur when the preputial opening becomes constricted by a band of hair, thereby preventing return of the penis to the prepuce. Prognosis is guarded and depends upon degree of trauma, degree of necrosis and promptness of treatment. Removal of necrotic tissue and over it uses of broad spectrum antibiotic ointments. Cold pack may help reduce swelling. Sometime, surgically enlarge the prepucial opening in order to replace the penis. Penis should be wrapped with gauze and penis with its gauze dressing should be replaced inside sheath. Support of prolapsed penis and sheath using tight suspensory bandage would help minimize the oedema. In severe case, amputation of penis is recommended.

Priapism:

Persistent erection in absence of sexual stimulation occurs most often in dogs. Consequences are generally similar to those of paraphimosis and as irreversible damage to the penis may rapidly occur. Penile amputation is only feasible treatment.

Phallocampsis or Deviations of the penis:

Ventral or Rainbow deviation:

It is less common. Ventral deviation prevents intromission and occurs when the dorsal ligament is thin and stretched to the point that it is incapable of holding up the distal portion of the penis during erection.

Lateral deviation:

It may occur due to secondary to trauma of the penis or prepuce. Scars or adhesions of the elastic tissue pull the penis to one side or the other.

Spiral or corkscrew type:

The most common deviation observed in bulls between 2 ½ and 5 years of age. Spiral deviation occurs at the peak of erection. The spiral configuration is caused by the dorsal apical ligament slipping off to the left hand side of the penis resulting in a counter clockwise spiral as viewed from the rear. Up to 50 per cent of normal bulls have been shown to develop spiral deviation during copulation. The condition is often noticed in normal bulls during masturbation, following intromission and when erection is produced by an electro ejaculator. Spiral deviation may be due to deficiency of the dorsal apical ligament of the penis⁹. Spiraling of the tip of the penis is a normal part of the process of ejaculation in the bull, occurring after intromission, during the ejaculatory thrust^10-14. The onset of the condition may be at any age, although it is least common in yearlings and most common in animals in their second or third season of use¹⁵. It is not considered pathologic until its occurrence is observed on repeated natural breeding trials in which it occurs prior to entrance into the vulva and thereby prevents intromission.

S-shaped deviation:

It is relatively rare deviation and usually occurs in older bulls with an excessively long penis. The apical ligament is sufficient in strength but insufficient in length and the S-shape results during erection.

Persistent penile frenulum:

This condition is characterized by a fibrous band attaching the prepuce to the free portion of the penis along the median raphe immediately caudal to the glans. It manifests as a marked ventral deviation of the bull's penis during attempts at coitus. It is noted chiefly in Angus and Shorthorn bulls (also reported in Brangus, Santa Gertrudis, Beef Master and Hereford). The anomaly is congenital and suspected to be a heritable condition. Persistence of the penile frenulum is most frequently encountered in young bulls, in which it either limits the amount of penis that can be protruded or causes the protruded penis to be deviated ventrally^16,17. Transecting the frenulum after ligating the frenular blood vessels (if they are sufficiently prominent) gives a good prognosis for the recovery of breeding ability¹⁸. Persistence of the penile frenulum has also been occasionally reported in boars and dogs¹⁹. This condition prevents intromission in Bos taurus breeds but may not interfere with breeding in Bos indicus bulls due to the length of the prepuce. The epithelial surfaces of the penis and prepuce of bulls are fused at birth. At approximately 4 months, the penis and prepuce begin to separate under the influence of male hormones. Separation should be complete by 8 to 11 months of age. The frenulum normally ruptures during separation of the penis from the prepuce. If such failure of growth is confined to the sigmoid flexure, it may be impossible to exteriorise the penis¹. Although treatable by myectomy, this condition like so many others affecting the bovine penis is probably inherited²⁰.

Ruptured or broken penis:

Ruptured or broken penis with secondary hematoma is most commonly observed in young bulls. It also occurs sporadically in boars and rams. The condition has many names likes rupture of the CCP (Corpus Cavernosum Penis), ruptured penis, fractured penis or broken penis. Rupture occurs most commonly either in the region of the insertion of the retractor penis muscle, or on the dorsal aspect of the distal sigmoid flexure where the trabeculae of the CCP are relatively weak. Rupture of the tunica albuginea occurs spontaneously if pressures within the CCP rise substantially above the pressures achieved during normal copulation^21,22. The injury usually occurs at the time of coitus when cow suddenly goes down or suddenly falls under the weight of bull or the erected penis is bended due to strike on abnormal site on cow at the movement of bull thrust. The site of rupture of penis is generally behind the attachment of retractor penis muscle.

Hematoma of the penis:

Hematoma of the penis occurs during coitus when the cow slips or goes down under the weight of the bull or when the penis is thrust against the escutcheon of the cow during breeding attempts. Penile hematoma results from a tear of the tunica albuginea into the CCP. The tear usually occurs on the dorsum of the penis at the distal sigmoid flexure opposite the insertion of the retractor penis muscles; the tunica albuginea is thinner in this area. The swelling due to hematoma is a result of blood from the CCP being forced into the peripenile tissues.

Adhesions of the penis and prepuce:

Adhesion in the region of sigmoid flexure may be due to horn injuries in bull and ram. Due to these adhesions normal penile protrusion is prevented. Vigorous thrust during semen collection with artificial vagina may produce injury or even tear the prepuce or injure the circumference of the penis. Subsequent infections may produce abscesses and may even produce adhesion. Surgical treatment of the adhesion leads to more severe form of adhesion. Treatment with antibiotics both locally in oily base as well as by parenteral route along with complete sexual rest is given.

Preputial trauma or Laceration or Prolapse:

Habitual prolapse of the prepuce is common especially in the breeds like Brahman, Angus and Polled Hereford. The predisposition to preputial prolapse probably involves four anatomic features; pendulousness of the sheath (prepuce below the carpus, low preputial angle), length of the prepuce, size of the preputial orifice and presence of retractor prepuce muscles (frequently absent in polled breeds - 1/3 of all polled bulls lack these small paired muscles). The sheath and prepuce of bos indicus bulls are more pendulous averaging 5.5 cm longer than bos taurus breeds. In cattle, intermittent protrusion of varying lengths of preputial mucosa is a normal occurrence, which normally coincides with non-erectile movement of the penis within the sheath^23-25. It is most commonly observed in naturally polled members of breeds with a pendulous prepuce^26-28. Preputial prolapse and trauma often occurs one of two ways. First, Bulls which frequently have some prepuce exposed may develop abrasions and lacerations of the prepuce from exposure to environmental factors (including frostbite). This may lead to oedema, further prolapse, more trauma, abscess and eventually fibrosis of the preputial tissue. Second, laceration of the prepuce during breeding may occur which usually leads to preputial prolapse. Lacerations of this type occur when there is a bunching of excess preputial tissue immediately prior to the breeding. Because of the elastic layers and retraction of the penis there is a marked tendency for healing to occur in a transverse manner which shortens the effective length of the prepuce as it heals. The traumatic injury results in edema formation and preputial prolapse.

Preputial avulsion:

Preputial avulsion usually occurs during semen collection with an artificial vagina. If the artificial vagina is too tight, a transverse or oblique laceration may occur at the dorsum of the preputial ring or fornix. These injuries should be sutured immediately using 2-0 vicryl in an interrupted pattern. Allow 60 to 90 days of sexual rest.

Retropreputial abscess:

Retropreputial abscess is frequent sequelae to preputial laceration in Bos taurus bulls. The bull retracts the prepuce into the preputial cavity after injury. Drainage is impaired causing abscess formation and the abscess dissects into the elastic layers. Prognosis is guarded; there is less than 30 per cent chance of return to service. Conservative approaches include 6 months pasture rest and re-examination; abscesses will occasionally effectively heal on their own. More aggressive treatment is drainage of the abscess into the preputial cavity followed by antiseptic flushes. If the abscess is drained through the skin, adhesions almost always develop which will eventually prevent penile extension. Actinomyces pyogenes is most frequently isolated from such abscesses; therefore, penicillin is the antibiotic of choice. Regardless of the method of treatment, possible complications include stricture formation and adhesion formation resulting in a useless breeding animal.

Penile neoplasia:

Fibropapilloma of the penis is common and is caused by the Bovine papilloma virus. The penile integument, particularly its terminal 5 cm, is a common site for such tumors, which may be single or multiple. Tumors can be found in intact and castrated animals, but rarely persist beyond 3 years of age. The condition occurs as a result of homosexual tendencies of young bulls (1 to 3 years) housed together. The virus gains entrance into the skin through wounds and causes neoplastic growth of fibroblasts. There is no associated metastasis or local invasion. The warts may be single or multiple and usually occur on the glans and free portion of the penis. Penile papillomata also occur in the dog but, unlike those of the bull, are generally ulcerative, locally keratinized and poorly circumscribed²⁹. The tumor develops in response to the carcinogenic properties of the smegma that accumulates around the penis of geldings³⁰. A fetid, bloody preputial discharge may be present and, on exteriorisation of the penis, characteristic fleshy, greyish red, nodular masses are observed³¹. Clinical effects vary according to the size and the morphology of the lesions. Hemorrhage and ulceration are the most common sequelae, the pain caused by the ulceration sometimes being sufficiently severe to impair libido. Large tumors can lead to either paraphimosis or phimosis. The papillomas are removed by dissecting through the epithelium at the base of the growth. Penile carcinomata are best treated by radical amputation of the penis, with an urethrostomy on the penile stump within the sheath or directly to the preputial skin³². Administration of an autogenous tissue vaccine markedly reduces the incidence of recurrences³³. Sexual rest is provided for 2 to 4 weeks after surgery. Recurrence is common if the bull is in an active stage of the disease. Administration of a wart vaccine (commercial or autogenous) may reduce recurrence.

Impotentia Generandi:

It is characterized by normal sexual desire and normal ability to copulate but the fertility is either subnormal or absent. Impotentia generandi may be of following types; a) Impotentia generandi associated with production of apparently normal semen. It may be due to either infectious diseases or inherited sperm defects, and b) Impotentia generandi associated with production of semen, which is abnormal in morphology, concentration, motility and other qualities.

A) Impotentia generandi associated with production of apparently normal semen:

Infectious diseases:

The sperm ejaculate of bulls infected with brucellosis, campylobacteriosis, trichomoniasis and IBR-IPV etc. may be normal in motility, concentration, and morphology but such samples result in embryonic/fetal death, abortion and signs of infertility.

Inherited sperm defects:

Diadem defect:

It is eversion of galea capitis and crater shaped depressions in the nucleus or nucleus pouch formation defect. The bulls are infertile or nearly sterile through the semen has normal motility and concentration of spermatozoa. This defect is sign of the severe disturbance in spermatogenesis. Feulgen stain and phase contrast microscopy are helpful in revealing this defect.

Knobbed spermatozoa:

This is an acrosomal defect and there is accentrically placed thickening of the acrosome. It is an inherited autosomal recessive, sex linked defect related to defective spermiogenesis involving golgi apparatus. This defect has been noted in bulls, boars and dog. The semen samples have normal spermatozoa motility and concentration but are associated with infertility. The defect can be seen after staining with Eosin-B, Fast green or with phase contrast microscopy.

Gene or chromosomal defects:

Gene or chromosomal defects may occur at the time of meiosis resulting in infertility with semen appearing good to excellent. The decline in fertility is due to intrachromosomal aberrations. Greater the number of genes involved in translocation and inversion, greater are the chances of infertility or sterility.

Inherited enzymatic disturbances:

That may cause early death of the spermatozoa in the female genital organs.

Atypical basic nuclear proteins:

It may be formed due to defect in sperm cell chromatin which occurs during spermiogenesis. The semen picture is revealed as normal. The atypical basic nuclear proteins possibly interfere with activation of ova and/or penetration of sperm into ova.

B) Impotentia generandi associated with production of apparently abnormal semen:

This type of infertility may be associated with pathology of testes, epididymis, vas deferens and accessory sex glands or may be associated with abnormal semen production due to congenital or hereditary causes or due to acquired causes.

Affections of testis

Cryptorchidism:

Cryptorchidism occurs when the normal process of testicular descent is impaired, such that one or both testes fail to complete their descent into the scrotum. Spermatogenesis is generally markedly impaired or absent in testes that are not scrotal, due to high intratesticular temperature. Cryptorchidism occurs most commonly in the stallion³⁴, the boar³⁵ and in some breeds of dog³⁶. Animals that have a single cryptorchid testis are usually fertile, although the inhibition of spermatogenesis in retained testes means that the sperm density is often below expectation for the species. Where both testes are cryptorchid, the ejaculate is either aspermic or very severely oligospermic. Testosterone secretion is unaffected by a cryptorchid position, so the libido of affected animals is normal.

Testicular hypoplasia:

Testicular hypoplasia is unilateral or bilateral condition noted at the time of puberty or later. The condition is commonly noted in bulls, rams, boars and stallions. In bull, the incidence is up to 23 per cent of the testicular pathology cases. Testicular hypoplasia is a congenital and hereditary condition caused by single recessive autosomal gene with incomplete penetration. The condition is due to lack of marked reduction in spermatogonia in the gonad during the fetal life. There may be failure of germ cells to develop in the yolk sac, failure of germ cell to migrate to the gonad, failure of the germ cell to multiply in the gonad, and extensive degeneration of the germ cells after they reached the gonads. Left side testicular hypoplasia is more common (66.70%) compared to right side testicular hypoplasia. Klinefelter’s syndrome (karyotype XXY) is a sporadic cause of testicular hypoplasia in bulls³⁷ and has been reported in rams, boars and dogs^38-40. Symptoms are varying greatly depending upon degree of testicular hypoplasia. Lowered conception rate are associated with bilateral testicular hypoplasia. Only in bilateral complete testicular hypoplasia, animal is sterile. The affected testes are reduced in size and usually firmer. The affected bulls have small and firm epididymis indicating reduction in spermatogenesis as well as gonadal sperm reserves. Semen evaluation of affected animals resulted in to low concentration of spermatozoa, low motility, high incidence of proximal protoplasmic droplets and abnormal spermatozoa. In bilateral cases, the semen is usually clear and watery with only few or no spermatozoa. Giant cells and medusa cells from efferent tubules may be observed in ejaculate. Histologically the seminiferous tubules are very much underdeveloped with only the basal layer of the cells being present. Diagnosis of testicular hypoplasia should not be done before 2 years of age in bulls and horses and before 1 year of age in boar, ram, dog and cat, unless male is well grown. Prognosis in testicular hypoplasia is poor since the condition is hereditary. The affected animal should not be used for breeding purpose. Treatment of testicular hypoplasia is not successful and the animals should be culled.

Testicular degeneration:

It is estimated that 75 to 80 per cent of testicular pathology is related to testicular degeneration. Generalized disease processes bring about bilateral testicular degeneration and local testicular lesions bring about unilateral testicular degeneration. Testicular degeneration is very rapid (may be within hours or days) but testicular regeneration process is very slow and it may take several weeks to several months for recovery. Epithelium of testis is most sensitive to any adverse influence.

Thermal influence:

Prolonged elevated body temperature as in certain infectious diseases, prolonged high environmental temperature, direct heating of scrotum, and increase in scrotal temperature due to any other cause e.g. irritants, dermatitis, cryptorchidism. Summer infertility in exotic bulls and rams is common phenomenon.

Vascular lesions of the testes:

Torsion of testes leads to impaired circulation in testis. Presence of strongyle larvae in testicular artery of horse and varicoceles of spermatic vein may cause infarction.

Irradiation:

Spermatocytes are the most sensitive and leyding cells and sertoli cells are quite resistant to radiation. Increase in number of abnormal spermatozoa and decrease in concentration of spermatozoa.

Hormonal causes:

Tumors of anterior pituitary gland or hypothalamus interfere with production of gonadotrophic hormones. This is seen most commonly in dog. In dog, this tumor is also associated with testicular atrophy and degeneration and with obesity and is referred to as dystrophia adiposogenatilis. Leyding cell tumors produce excessive amount of testosterone and estrogen. Excessive steroids suppress production of FSH.

Age effects:

Generally old age e.g. dogs over 10 years of age, cat over 12 years of age and bulls over 8 to 10 years of age affected the most.

Trauma, Stress or Diseases:

Severe fatigue, traumatic gastritis, internal abscesses, severe arthritis, laminitis, foot rot and traumatic lesions of testis and scrotum are also responsible causes.

Localized or systemic infectious diseases:

Infection causing orchitis or epididymitis by Brucella abortus, Mycobacterium tuberculosis, Corynebacterium pyogenes, Actinomyces bovis, IBR-IPV virus, Epivag virus, Canine distemper virus etc. Inflammatory process produces heat, oedema and congestion leads to alteration in physiological environment of testis and epididymis.

Nutrition:

Underfeeding and malnutrition producing debility and loss of body weight suppress the release of gonadotrophic hormone from anterior pituitary gland. Severe vitamin A deficiencies produce testicular degeneration. High feeding levels and obesity generally do not affect semen quality in males but it does affect willingness to mount.

Poisons:

Dipping of rams in arsenic solutions cause degeneration of seminiferous tubules. Antimony compounds (for treating heart worms) in dog causes temporary infertility. Chlorinated naphthalene produces testicular degeneration in bulls and rams. Testicular degeneration occurs in response to raised intratesticular temperature, toxins, endocrine disturbances and infection^41,42. In rams, raised scrotal temperature can result from excessive amounts of wool over the scrotum, or from leaving animals unshorn during the summer⁴³. Excessive deposition of fat in the scrotum, such as occurs in rapidly grown bulls and rams, can prevent heat loss from the scrotum and result in infertility⁴⁴. Conversely, scrotal frostbite can also result in testicular degeneration⁴⁵. Testicular size is usually reduced because of atrophy of seminiferous tubules. Consistency of testes is generally soft. In acute cases, there is tense swelling and enlargement with pain and heat. In chronic cases may show fibrosis and calcification. Sex drive is usually not affected except in painful conditions or in severe debilitating conditions. Semen may be watery and translucent with azoospermia and oligozoospermia. Sperm motility is reduced because of increased percentage of abnormal cells, dead cells and poorly viable cells. There is an increase in abnormal heads, middle piece and tails abnormalities. The occurrences of large number of primary abnormalities are more indicative of testicular degeneration. Giant or multinucleated cells are increased. Fertility may vary from only slight reduction in conception rate to severe infertility.

Prognosis is variable depending upon the causative factor, duration, degree of degeneration and age of animal. In young animal, in slight and mild cases and correctable causes, the prognosis is fair to good. Prognosis is poor in chronic cases. Severe testicular degeneration leads to fibrosis and calcification and recovery is never possible. Correction of causative factors and gives sexual rest. Balanced diet supplemented with vitamin A and quality proteins. Exercise require in some cases. Air conditioning and cooling may recommended for exotic bulls and rams in tropical climate. Use of hormones has not been found satisfactory. Testosterone, FSH preparation and thyroxin have not been found to be of therapeutic value in cases of testicular degeneration. Cold packs may be applied. In case of acute orchitis, sexual rest and broad range antibiotics together with glucocorticoids may used. If orchitis is unilateral, affected testes may be removed to hasten recovery and to save breeding life of valuable animals.

Orchitis:

Inflammation of testis caused mostly by bacterial infections (e.g. Brucella abortus) and some viral agents (e.g. Epivag virus). Orchitis can arise from a primary infection or by haematogenous spread of bacteria into the testis superinfecting pre-existing traumatic viral or parasitic damage. Orchitis is more commonly unilateral than bilateral and may involve the epididymis. In acute cases, scrotum becomes hot, painful and oedematous. Brucella species cause orchitis in many domestic animals like Brucella abortus, Brucella canis, brucella melatensis and Brucella suis affecting bulls, dogs, goats and boars, respectively. However, the majorities of isolates from cases of orchitis are both non-specific bacteria and mycoplasma, or are the particular pyogenic organism for the animal species (e.g. Actinomyces pyogenes in cattle). Ascending infection from the urinary tract is postulated, but haematogenous spread seems more probable. Treatment includes dressing with antiseptics and application of ice packs. Sexual rest is given to affected animals. Broad range antibiotics with glucocorticoids may give through parenteral routes. Brucella infected bulls should never be used on Brucella free herds either naturally or through artificial insemination.

Testicular fibrosis:

Testicular fibrosis is usually the end result of testicular inflammation and testicular degeneration. In testicular fibrosis, the leyding cells and seminiferous tubules are replaced by fibrous tissue. Areas of necrosis, calcification and lymphocytic infiltration observed. The ejaculates are watery and contain few or no sperms.

Testicular tumors or Testicular neoplasia:

It is rare in the bull, ram and boar, although common in dogs. Usually tumors are observed in older age. The large tumors may cause testicular degeneration either due to their compressing effect or due to excess of steroids produced by interstitial or sertoli cell tumors. Testicular tumors may originate from interstitial cells, sertoli cells and from germinal epithelium. Interstitial cell tumors are the most common tumor of the dog, and are recorded occasionally as incidental findings in aged bulls. They are very rare in stallions. Seminomas, the next most common canine testicular tumor, are also occasionally found in bulls (and stallions), while Sertoli cell tumors rarely occur in species other than the dog.

Interstitial cell tumor:

It seen mainly in dogs and bulls. It may or may not produce androgens or estrogens. It looks tan yellow, soft and nodular and prone to haemorrhage and necrosis. Polygonal cells with eosinophilic vacuolated cytoplasm like leyding cells.

Sertoli cell tumor:

It is usually benign, rarely malignant, but often produces estrogen and feminizing effects. Prostate may also be enlarged. It appears firm to hard, white and lobulated mass. Cells form tubular structures surrounded by abundant connective tissue.

Seminoma:

It seen mainly in dogs and horses and prevalent in cryptorchid testis. It is a firm and white mass like lymphoid tissue. Cells are large, polyhedral and in sheets with little or no stroma. Giant cells and mitotic figures are common, but tumor is benign in dogs and produces no hormones. In case of horses, it is often malignant.

Lesions of epididymis and mesonephric duct Epididymitis:

Inflammation of epididymis usually occur secondary to orchitis. It can also occur as a primary infection or by spread from an infected testis. Orchitis in the associated testis can also occur following a primary epididymitis. The general signs of epididymitis are similar to those of orchitis, like heat, swelling and pain of the affected organ. Any inflammation of the epididymis causes obstruction of the single, highly convoluted tube of which the organ is composed, so a loss of function takes place. Unilateral epididymitis results in reduced fertility, whereas bilateral obstruction results in sterility. Epididymitis can also occur as a primary infection or by spread from an infected testis⁴¹. Furthermore with orchitis, unilateral epididymitis causes temperature induced degeneration in the contralateral testis, so early removal of the affected epididymis and its associated testis should be recommended.

Spermiostasis:

Spermiostasis caused by blind rudimentary mesonephric tubules. These defective tubules are attached to rete testis or epididymis and produce lesions mainly in head of epididymis. The condition is common in bucks and rams, less common in bulls and rare in other domestic animals. The condition is probably genetic in origin. No treatment for this condition and because of hereditary nature of this condition, the affected animals should be culled.

Aplasia of the mesonephric ducts:

Segmental aplasia of the mesonephric ducts are most commonly manifested as an absence of parts of the epididymis. In the bull, the condition is probably inherited. The body and tail or all the epididymis and even part of the vas deferens may be missing. In majority cases, the condition is unilateral and the bull is fertile. The bilateral cases are sterile and semen is watery with no sperm. Absence of the head or tail of epididymis can be determined relatively easily by careful palpation of the scrotum, but the medially sited epididymal body is rarely palpable. There is no treatment and the affected animals should not be used in breeding programmes as the condition is hereditary.

Spermatocele:

It is an obstruction of epididymis after infection and inflammatory changes in epididymis, will lead to obstruction and enlargement of epididymis. It is common in ram, boars and male goats, but infrequent in others. The condition may be unilateral or bilateral. On cross section of affected part, cavities up to 1 cm in diameter containing thick suspension of spermatozoa and cellular debris are found.

Lesions of the accessory glands Seminal vesiculitis:

Inflammation of vesicular glands may caused by variety of organisms including specific pathogens (like Brucella, Chlamydia, Mycoplasma, Mycobacterium bovis, Mycobacterium paratuberculosis, Epivag and IBR-IPV virus) and nonspecific opportunistic pathogens (like Streptococci, Staphylococci, Actinobacilli, Corynebacterium etc.) Seminal vesiculitis occurs most commonly in young bulls of less than 2 years old and in aged bulls. Seminal vesiculitis may be acute or chronic. In acute seminal vesiculitis, affected glands may enlarged and firm and pain on palpation. Purulent exudate is present in semen consistency. In chronic cases, enlargement, fibrosis and loss of lobulations from the gland may found. Pain on palpation is usually absent. The main consequence of infection of the vesicular gland is a decline in semen quality, decrease in motility, elevated pH, low fructose concentrations and presence of polymorphonuclear leucocytes. In moderate or severe cases, the semen may appear overtly purulent and may be tinged brownish, due to the presence of degenerating blood from the damaged gland. Prognosis in seminal vesiculitis may be fair to poor depending upon duration and severity of infection. Broad range antibiotics may give for 2 to 3 weeks. Massage of gland may helpful. In chronic cases, affected gland may be removed surgically.

Prostatitis:

Prostatitis is uncommon in animals except in dogs. Prostatitis in dog above 5 years of age is common and often associated with hyperplasia of the gland. It may occur as ascending or descending infections or from haematogenous infections. Organisms responsible for this condition are Brucella canis, E. coli, Streptococci and Proteus species. Leucocytes are frequently found in urine. Condition may be characterized by stiff gait in rear limbs, elevated temperature and pulse rate, constipation, anorexia and vomiting. Prostatitis frequently respond to broad range antibiotics for prolong period. Prostatitis due to Brucella canis does not respond to treatment.

Prostatic hyperplasia:

Prostatic hyperplasia is reported in dogs above 5 years of age that have not been castrated. The condition is probably due to an altered androgen-estrogen ratio with an excess of testosterone secreted causing hyperplasia of the prostate gland. The enlarged gland may contain small cysts and cyst may be calcified. Dogs with prostatic hyperplasia are usually constipated. Diagnosis can be done by per rectal examination and by abdominal palpation of prostate gland. The size, location and contour of prostate can also be evaluated by caudal abdominal radiography. The most effective treatment for prostatic enlargement is castration. In hormonal treatments, diethylstilbestrol may give orally as dose of 1 mg per day for 5 days or estradiol cypionate as 0.1 mg per kg with maximum dose of 2 mg may be given intramuscularly.

Future prospect and conclusions:

Fertility is a fragile parameter that may vary temporarily or be permanently depressed. The ability to maintain body condition and the existence of conformational abnormalities may alter fertility. Abnormalities of the external genitalia may directly affect the ability to copulate or may alter the quality of semen. Testicular disease alters semen quality, sometimes transiently and other times permanently. The fertility prognosis for testicular problems can be judged on the basis of repeated examinations.

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Received on 12.05.2016 Modified on 21.05.2016

Research J. Science and Tech. 2016; 8(2):113-121

DOI: 10.5958/2349-2988.2016.00015.2