TABLE OF CONTENTS

Breeding Soundness Evaluation (BSE) in Bulls

Breeding soundness evaluation (BSE) in bulls is a standardized procedure conducted by veterinarians to assess a bull’s ability to breed and impregnate females successfully.

A regular Breeding Soundness Examination (BSE) of breeding bulls is required for the following reasons:

A significant number of bulls used for breeding either in AI programme or in natural service are infertile, sub fertile or unable to copulate.
Evaluation of breeding soundness of a bull by crossing with fertile cows is time consuming and expensive.

Interpretation of results requires knowledge of animal health and physical status, a careful examination of libido, reproductive system and an examination of semen:

A veterinarian who is experienced and competent should conduct the examination.
A general evaluation of the bull should be conducted including historical information and observation of locomotion in the unrestrained bull.
The bull’s external reproductive genitalia should be thoroughly examined and scrotal circumference should be recorded. A seminal ejaculate should be collected and evaluated.
A seminal ejaculate should be collected and evaluated.
A signed report should be prepared defining the standard results.

*Breeding Soundness Evaluation (BSE) in Bulls*

Breeding soundness examination consist of:

Physical examination of the animal
Examination of reproductive organs
Measurement of scrotal size
Evaluation of semen

In addition the following tests or procedures may be included:

Libido and mating ability
Pelvic measurement
Trichomonas testing

1. Physical Examination

Weight and Body Condition

Bulls should not be fat but should carry some extra weight going in to the breeding pasture, because they can be expected to lose weight during the breeding season.
Over fat animals may have poor libido.
At the same time bulls should not be thin. If the bull starts too thin, he may not be in good enough condition later on to breed cows.

Rear Leg Conformation

Sound rear legs are vital to the breeding capacity of bulls.
A bull whose legs are hurt may not find cows in estrus nor mount them successfully, which might result in reduced conception rates.
Bulls should be evaluated for mobility and rear leg soundness prior to being restrained in a chute.
Interdigital fibromas and foot abscesses can be detected with careful examination.
Need for trimming feet results from faulty rear conditions.
Hooves of structurally sound bulls wear evenly under normal conditions.
Prognosis for structural unsoundness is poor.
Breeders should be warned that structural faults of the rear legs are heritable.

Vision and Teeth

Good sight is important to the breeding bull.
Common eye problems are pink eye, scars and squamous cell carcinoma.
Scars resulting from infectious keratitis seldom obscure a bull’s vision enough to impair breeding ability.
However, detection of early cancer eye should be reason for slaughter or surgery because these lesions can develop rapidly, reduce salvage value and interfere with bulls breeding value.
Oral examination to detect oral deficiencies.
A bull that has lost teeth is unable to chew properly and will lose weight rapidly during the breeding season, resulting in impaired reproductive performance.

Libido

Bulls must be observed under natural breeding conditions or special tests must be applied using restrained heifers to evaluate libido and mating.
In ‘one bull method’, a bull is allowed to a restrained heifer for 10-15 minutes to mount the heifer.
A bull should mount at least once. If he does not mount, he should fail and be tried again.
The ‘multiple bull method’ uses 4 heifers and 5 bulls on a pen perimeter.
Each bull should serve at least 3 times in 40 min.

Mating Ability

Mating ability may be impaired due to deviations and loss of innervation of the penis, problems of musculoskeletal system, unsoundness of the rear legs and lower back.
Observation of the bull as he walks may be helpful to diagnose the inability to mate due to arthritis, injuries or other lameness.
All bulls should be turned with estrus females and be observed by the veterinarian or owner to detect deficiencies in libido or mating ability.
Ventral and lateral deviations, the corkscrew configuration, persistent frenulum and injuries of the penis can all be observed in affected bulls during attempts at natural service.

2. Examination of Reproductive Organs

Testes

Testis should be carefully palpated and evaluated during the examination.
Restrained bull should be approached from behind to palpate the testes to reduce risk of injury.
Size, shape, form and consistency should be assessed.
The testes should be freely moveable within the scrotum and the testes should be symmetric.
The testes may rotate 40 degrees normally and the ‘scrotal ligament’ may cause the testes to be pulled dorsal and caudal, but this has little apparent affect on fertility.
Normal testes are almost always symmetrical; any deviation from balance and symmetry should be evaluated carefully before a prognosis is given.
The size of the testes is correlated with sperm production in the bull and age of puberty in the offspring.
Variations of normal scrotal conformation: Elongated testes, rounded testes, rotated testes and distinctly cleaved testes.
Abnormal scrotal conformation: Testes held too close, unilateral hypoplasia, scrotal hernia and incomplete descent.
Bulls with abnormalities of the testes should not be used for breeding because most of these defects are heritable.

Epididymis

Epididymis consists of three anatomic parts; the head, body and tail.
Attention should be given to alterations in their size, form and consistency.
Gross alterations in the epididymis are fairly rare.
Hypoplasia / aplasia may occur-heritable, affected bulls should be classified as unsatisfactory potential breeders.
Head of the epididymis should be carefully palpated for nodular enlargement indicating sperm granulomas, which may cause occlusion of the epididymal duct.
Affected bulls should be rejected for breeding purpose.

Internal Genital Organs

Internal genital organs should be evaluated by rectal palpation.
For orientation, the pelvic portion of the urethra should be located.
It lies on the floor of the pelvis and feels like a cylinder, 3-4 cm in diameter. It is firm and slightly flattened on top.
The body of the prostate is located on the anterio-dorsal end of the pelvic urethra at about wrist depth.
It forms a transverse ridge that is easy to locate and palpate which serves as a landmark for location of the ampullae and vesicular glands.
They empty into the pelvic urethra at the colliculus seminalis, which is located just beneath the body of the prostate in the pelvic urethra.
The ampullae and vesicular glands can be stroked several times to prime them for effective electro ejaculation at the time of palpation.

Vesicular Glands

Vesicular Glands are lobulated-paired organs that lie in the pelvis.
Vesicular gland adenitis (Vesiculitis) one of the most common pathological conditions, often found in young and very old bulls.
Vesiculitis is usually diagnosed by palpation changes in gland size, shape and consistency.
Vesiculitis characterized by enlargement, induration and loss of lobulations and is often associated with decreased semen quality.
If a physical examination is not done, the first indication of vesiculitis may be the presence of leukocytes in the semen.
Findings of rectal examination should be correlated with the presence of increased numbers of leukocytes in the semen to verify the diagnosis.
Inflamed vesicular glands usually indicate inflammation of other sex organs as well.
Fairly common sequelae to vesiculitis are peri orchitis, orchitis, epididymitis and ampullitis.
Otherwise normal bulls with vesiculitis should be classified as questionable and the course of the disease monitored by repeated examinations.

Ampullae and Prostate

Ampullae lie between the vesicular glands.
Enlargement from ampullitis can sometimes be palpated, but is not usually apparent.
Clinically diagnosed abnormalities of the prostate alone have not been reported.

Internal Inguinal Rings

Contains the spermatic cords.
Herniation of the viscera in to the rings can be palpated but rarely occurs.

Penis

Penis of the bull should be examined for indications of injury or diseases.
Penis can be manually exteriorized, but in most cases should be examined at the time of collection of semen sample.
Penile deviations can be evaluated accurately only when the male mounts a teaser animal or breeds a female.
Electro ejaculator stimulation often produces deviations or other abnormal configurations in the normal penis so these defects must be evaluated by observing natural mating.
Persistent frenulum, tumors, abscess, balano-posthitis etc., should be ruled out.

Prepuce

The structural faults in the prepuce lead to injury to breeding organs and loss of bull use.
Palpation of the prepuce allows one to determine whether or not adhesions are present.
A fibrotic preputial orifice may become strictured enough to increase the risk of phimosis or paraphimosis.

3. Scrotal Circumference

Scrotal circumference is an indirect measure of testicular mass, it is associated with sperm production, and it is associated with parenchymal health of the testicular tissues.
Is an indicator of a bull’s potential to produce semen?
Scrotal circumference, testis size and semen production are highly correlated, especially in young bulls.
Scrotal circumference measurements should be made at the time the testes are palpated on physical examination.
Bulls with large scrotal circumference have more semen, a higher prevalence of normal spermatozoa, and increased sperm motility than those with small testes.
We can classify a bull as having very good, good or fair scrotal circumference.
The scrotal circumference is measured at the widest point of the scrotum.
To measure scrotal circumference, the testes are pulled firmly in to the lower part of the scrotum by encircling its base with the hand and pulling down on the testes.
The thumb and fingers should be located on the side of the scrotum rather than the front to prevent separation of the testes which results in inaccurate measurements.
The circumference reading is taken in cm, using a special tape constructed for this purpose.
The scrotal tape is formed in to a loop and slipped upward around the scrotum then tightened snugly around its greatest diameter.
SC measurements taken in this manner is highly repeatable.
Special care to be taken when weather is cold to pull the testes down in to the scrotum, otherwise results in faulty measurements.

3. Examination of Semen Quality

If the bull is satisfactory on general physical examination and complete exam of the internal and external reproductive organs, a semen sample is collected and evaluated under the microscope. Semen collected by an artificial vagina or electro ejaculator method should be assessed for its quality by estimating the following parameters.