Review: Abnormalities of the bull - occurrence, diagnosis and treatment of abnormalities of the bull, including structural soundness.

Selecting bulls for reproductive soundness requires that the bull be structurally sound, free of abnormalities that impair his ability to produce adequate numbers of motile, morphologically normal spermatozoa, and be able to successfully complete coitus. This review discusses the diagnosis and etiology of abnormalities of the penis, prepuce as well as common musculoskeletal conditions that prevent normal pasture breeding soundness. A review of testicular and thermoregulation addresses the potential impact of musculoskeletal disorders on normal sperm production.

Initial steps in defining the environment of the prepuce of the bull by measuring pH and temperature.

OBJECTIVE: To determine the baseline pH and temperature of the preputial cavity of bulls. METHODS: We enrolled 55 bulls ranging in age from 15 to 84 months. The preputial temperature and pH were measured by insertion of temperature and pH probes, respectively, into the preputial orifice prior to routine breeding soundness examinations. Information was obtained from owners regarding the diet of each bull and categorised as one of three categories: forage only, grain supplemented or silage supplemented. RESULTS: The average temperature of the prepuce was 37.81°C ± 1.76 and the median pH of the prepuce was 8.45 (6.35-9.46). Preputial temperatures of the bull weakly correlated with ambient temperatures (rs = -0.29, P = 0.028). The preputial pH of silage-fed bulls was significantly lower than that of bulls fed forage only (P = 0.025) or grain-supplemented diets (P = 0.002). The median preputial pH of bulls fed a silage-based diet was 7.6 (6.3-8.9) compared with a median pH 8.7 (7.8-9.1) for bulls fed forage-based diets or a median of 8.5 (7.7-9.4) for those given grain-supplemented diets. CONCLUSION: Diet and ambient temperature can, respectively, affect pH and the temperature in the prepuce. Further studies to describe and understand the microbiota of the prepuce and penis may assist in developing treatments for diseases of the genital tract in bulls.

Immunolocalization of the hyaluronan receptor CD44 in the reproductive tract of the mare.

Hyaluronan (HA), a glycosaminoglycan, is a major component of the pericellular matrix which envelopes mammalian cells. Binding of hyaluronan to one of its specific receptors, CD44, modulates transduction of intracellular signals which direct a variety of processes, including embryogenesis, wound healing, inflammation, and neoplasia. Since regulation of these processes is critical to equine reproductive success, localization of constitutive CD44 expression was evaluated by immunohistochemical methods in ovarian, oviductal, and uterine tissues from healthy mares. Ovarian stroma contained thecal cells with varying CD44 immunopositivity. Follicular and granulosa cells of some antral and atretic follicles were positive for CD44. In the oviduct, the luminal epithelium was variably positive for CD44, with overall decreasing intensity of immunostaining from the infundibulum to the isthmus. The CD44 molecule was expressed strongly by surface epithelial cells of the uterine endometrium, but was present only rarely among cells of uterine glands. In addition, CD44 was expressed by smooth muscle cells of vascular walls, oviduct, and uterus. Since CD44 is known to modulate cell movement and differentiation, and was present at multiple sites in the reproductive tract of normal mares, we inferred there may be an important role for the HA-CD44 signaling pathway in reproductive function and inflammation.

Prevalence of Tritrichomonas foetus in several subpopulations of Alabama beef bulls.

The objective of this study was to estimate the prevalence of Tritrichomonas foetus infections in Alabama (USA) beef bulls through prospective and retrospective surveys. The prospective survey included 240 Alabama beef bulls that were sampled between January 2005 and March 2006. Preputial smegma was collected from the 240 bulls with a dry pipette and cultured in an InPouch TF T. foetus culture pouch (BioMed Diagnostics; White City, OR, USA). The samples were evaluated microscopically once a day for 6 days for growth resembling T. foetus. To avoid false-positives due to fecal trichomonads, all suspect cultures were sent to both the Alabama Department of Agriculture Veterinary Diagnostic Laboratory in Auburn, AL, USA and the Auburn University College of Veterinary Medicine Parasitology Laboratory (Auburn, AL, USA) for polymerase chain reaction (PCR) confirmatory assays. Of the 240 bulls cultured in the prospective survey, 3 (1.25%) cultures were considered suspect on microscopic evaluation. However, PCR-based assays were negative for T. foetus, suggesting that the samples most likely contained fecal trichomonads. The retrospective analysis included 374 T. foetus cultures performed at the Alabama Department of Agriculture Veterinary Diagnostic Laboratory between October 2002 and March 2005. Of the 374 bulls included in the retrospective analysis, only 1 (0.27%) was confirmed positive by a PCR-based assay.

Caliper and ultrasonographic measurements of bovine testicles and a mathematical formula for determining testicular volume and weight in vivo.

This study quantified the relationship between calibrated caliper and ultrasonographic derived measurements of bovine testicles in vivo with actual testicular length, width, volume and weight. The prolate spheroid formula was tested to accurately predict testicular volume and a modification to predict weight. Ten bulls were employed to derive caliper and ultrasound testicle (n = 20) length and width measurements in vivo. Caliper length measurements were more reliable than ultrasound derived lengths, with correlations of r2 = 0.8023; P < 0.05 and r2 = 0.5111; P < 0.05, respectively. Width for both the calipers and ultrasound measurements when compared to actual width measurements were r2 = 0.7313; P < 0.05 and r2 = 0.8310; P < 0.05, respectively. The prolate spheroid formula is reliable in determining testicle (n = 116) volume (r2 = 0.8928; P < 0.05). Testicular volume and weight are highly correlated (r2 = 0.9776; P < 0.05); therefore, a modification of the prolate spheroid formula was used to predict weight (r2 = 0.9084; P < 0.05) against the actual weight. Caliper-derived length and width measurements used in the prediction of volume and weight had correlation coefficients against actual volume and weight of r2 = 0.5497; P < 0.05 and r2 = 0.6340; P < 0.05, respectively. Ultrasound in vivo measurements for prediction of testicular volume and testicular weight had a correlation of r2 = 0.3276; P < 0.05 and r2 = 0.6249; P < 0.05, respectively. A testicular (n = 116) length to width ratio of 1.8:1 (SEM = 0.01) was determined for both slaughterhouse and castrated animals. Caliper measurements are reliable, inexpensive and much simpler to obtain than ultrasound determinations for in vivo testicle length, width, volume and weight. The two-dimensional measurement of length and width would be a more accurate predictor of testicle volume and weight than the one-dimensional measurement of scrotal circumference (SC), especially in bulls with variation in testicular shape.

Blood flow to the corpus cavernosum penis in the bull and goat buck during penile quiescence.

Bulls and bucks were used to study the blood flow into and out of the corpus cavernosum penis (CCP) during the non-erect state of the penis. When contrast medium was injected into the dorsal artery of the penis in a bull cadaver and into surgically implanted catheters of anesthetized bucks, it flowed into the cavernous spaces of the CCP via the penetrating arteries. When contrast medium was injected directly into the CCP of the bull and buck there was no evidence of vascular exits along the body of the penis. The only venous outlets from the CCP were in the crus penis area. In the non-erect penis the vascular pressure within the CCP was 17.8 mm Hg higher in the bull and 8.3 mm Hg higher in the buck at the glans area than the crus area. During the non-erect state of the penis most of the blood flow to the CCP is from the dorsal artery of the penis via the penetrating arteries. The results showed that the pressure gradient provides the means for flow of blood from the glans area toward the base or crus penis area. This flow prevents platelet aggregation and clot formation and provides nutrition to local tissue during the long periods of non-erection.

Testicular shape and its relationship to sperm production in mature Holstein bulls.

This study was conducted to determine the relationship between testicular shape, scrotal circumference (SC) and sperm production. Twenty-seven mature Holstein bulls were evaluated subjectively and objectively for testicular shape as indicated by testicular length and width, then placed in 1 of 3 groups. Group 1 contained 17 bulls with a normal ovoid testicular shape and a length to width ratio of 1.61:1 +/- 0.01 (SEM). Group 2 was composed of 4 bulls with a long, slender testicular shape and a length to width ratio of 1.95:1 +/- 0.06 (SEM). Group 3 was comprised of 6 bulls with spheroid-shaped testicles and a length to width ratio of 1.3:1 +/- 0.03 (SEM). All the groups were statistically different for length to width ratios (P < 0.05). Length measurements from cranial to caudal pole of the testis proper were also different between groups (P < 0.05). Width or testicular diameter was different between Group 2 and Group 3 at P < 0.05; however, there was no difference between Group 1 and Group 2 or between Group 1 and Group 3. Predicted volumes and weights of testicles were not significantly different between groups. Scrotal circumference measurements were significantly different between groups (P < 0.05). Group 1 had an average SC of 43.07 +/- 0.36 cm (SEM), Group 2 of 39.33 +/- 1.18 cm (SEM) and Group 3 of 46.22 +/- 0.69 cm (SEM). Sperm production for a twice daily, 2-day-per-week collection schedule revealed a statistically significant difference for sperm output. A total of 2742 ejaculates was evaluated. A total of 1818 ejaculates was evaluated in Group 1, 440 ejaculates in Group 2 and 484 ejaculates in Group 3. The mean spermatozoal harvest per day for Group 1 bulls was 13.62 +/- 0.09 x 10(9) (SEM). Group 2 bulls with the longer-shaped testicles produced 14.82 +/- 0.18 x 10(9) (SEM) spermatozoa per day, and Group 3 bulls, with the more rounded testicle shape and the significantly larger SC produced 11.72 +/- 0.64 x 10(9)(SEM) sperm cells per day. All 3 groups were statistically different at the P = 0.05 level. The results suggest that prediction of sperm production may be dependent on factors other than SC, testicular volume, or weight. Testicular shape may influence sperm output in mature Holstein bulls.

Erection failure as a sequela to obstructive urolithiasis in a male goat.

A 14-month-old 40-kg Anglo-Nubian buck was referred for erection failure after recurrent bouts of obstructive urolithiasis. Previous episodes of obstructive urolithiasis were treated successfully with amputation of the urethral process, followed by an exploratory celiotomy and insertion of an indwelling Foley catheter into the bladder. The buck had been capable of intromission prior to the most recent episode of urethral obstruction. The results of physical examination and electroejaculation did not reveal any abnormalities, except failure to achieve erection. Contrast radiography of the corpus cavernosum penis (CCP), however, revealed failure of contrast media to migrate proximal to the sigmoid flexure. A diagnosis of obstruction of the CCP caused by cavernositis and fibrosis secondary to urolithiasis was made. A poor prognosis was given for breeding soundness. Although breeding soundness following obstructive urolithiasis may be enhanced by surgical intervention, impotence may result from obstruction of blood flow through the CCP secondary to urethral rupture or urethritis.

Invasive malignant fibrous histiocytoma in a cow.

An invasive malignant fibrous histiocytoma associated with the left cornual process, and causing lysis of the frontal bone, was diagnosed in a cow. The mass compressed the left cerebral hemisphere focally and extended into the frontal sinus and ethmoid and nasal turbinates. It was composed of pleomorphic to spindle-shaped cells with ultra-structural evidence of fibroblastic, myofibroblastic, and fibrohistiocytic differentiation. Trauma and chronic inflammation may be predisposing factors for development of neoplasia in cattle.

Metastatic multicentric neurofibrosarcoma of the lumbosacral plexus in a cow.

A metastatic multicentric neurofibrosarcoma of the lumbosacral plexus in an adult cow is described. The left lumbosacral plexus was obliterated by a mass which extended through the intervertebral foramen into the spinal canal and between the dorsal arches of the fifth and sixth lumbar vertebrae. A closely associated (possibly contiguous) mass extended into and separated the left sacroiliac joint. Multiple similar masses involved peripheral nerves and skeletal muscles of the pelvis, pelvic limbs, and abdominal wall. Metastatic lesions were scattered throughout the lungs. The lumbosacral lesion and all other masses consisted of interwoven bundles of loosely cohesive, elongated cells separated by variable collagenous matrix. Many neoplastic cells were positive for S-100 protein. Ultrastructurally, fibroblastic cells were mixed with scattered cells possessing schwannian characteristics.

Eperythrozoon infection in young bulls with scrotal and hindlimb edema, a herd outbreak.

Young (9 to 10 mo) Aberdeen-Angus bulls (n = 5) in excellent body condition and pastured with approximately 35 other bulls of similar age on a farm in southeastern Alabama had fever, harsh pulmonary sounds, increased respiratory rate and variable amounts of hindlimb and scrotal edema. Bulls had mild microcytic, normochromic anemia. Numerous eperythrozoon organisms were identified on blood smears. Indirect hemagglutination inhibition test results for Eperythrozoon suis antibodies were negative either because E. suis antigens do not cross react with cattle eperythrozoon organism antibodies or blood was collected before there was sufficient time for seroconversion. Bulls had swelling of the scrotal wall, soft testes, and poor semen quality, characterized by low progressive motility and a high percentage of spermatozoa with primary and secondary abnormalities. Some of these abnormalities may be attributed to the age of the bulls. However, loss of scrotal thermoregulation was a major cause of testicular degeneration leading to poor semen quality. Other bulls in the herd had fever, increased respiratory rate, and swollen hindlimbs or scrotum. Subsequent to administration of oxytetracycline, parasitemia resolved rapidly, and clinical signs gradually abated. Four of five bulls successfully passed breeding soundness examinations six months after initial clinical illness. The remaining bull failed twice due to the presence of testicular inflammation.

Hematologic and semen quality changes in bulls with experimental eperythrozoon infection.

Eperythrozoon organisms were isolated from the blood of a young beef bull with scrotal and hindlimb edema. Young beef bulls, managed under conditions closely mimicking those used in organized bull testing programs, were experimentally administered eperythrozoon organisms. Scant to few organisms were identified on blood smears from bulls (5 of 6) for 2 to 4 days starting 12 days after administration. After a second challenge with intravenously administered viable eperythrozoon organisms, the bulls demonstrated immunity by either failing to become parasitemic (4 of 6) or rapidly clearing the organisms from the blood (2 of 6). No bull became anemic, icteric, or hypoglycemic. Increased serum lactate and decreased blood bicarbonate concentrations probably reflected increased glycolytic activity of infected erythrocytes. A cause for azotemia observed late in the study was not determined. The bulls did not develop scrotal or hindlimb edema. Scrotal circumference and texture remained constant throughout the study. Semen quality was minimally altered while the bulls had organisms identified on blood smears. Harsh lung sounds were asculted in bulls during and immediately after organisms were present in the blood. Although the bulls reliably had organisms in the blood, none showed anemia, scrotal or hindlimb edema, or decreased semen quality; therefore, an additional factor or factors, or greater parasite load may be required for the expression of disease.

Comparison of tiletamine-zolazepam-ketamine and tiletamine-zolazepam-ketamine-xylazine anaesthesia in sheep.

The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 +/- 6.9 min with TK and 82.8 +/- 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep.

Sensory nerve conduction velocity of the dorsal penile nerves of bulls.

Mean conduction velocity of sensory axons of the dorsal penile nerves of clinically normal bulls was determined by recording action potentials evoked by cutaneous stimulation. Locations of stimulating and recording electrodes were standardized. Overall mean +/- SD conduction velocity was 55.1 +/- 5.1 m/s. Mean +/- SD velocity recorded from the distal electrode was 53.3 +/- 4.9 m/s; velocity recorded from the middle electrode was 55.3 +/- 5.0 m/s; and velocity recorded from the proximal electrode was 56.7 +/- 5.1 m/s. Differences among means were not significant. Four bulls had mean conduction velocities of 54.0 m/s and 48.4 m/s before and 3 weeks after castration, respectively.

Severe prepartum ketosis in an obese beef cow.

A beef cow was examined to find the cause of decreasing appetite of 2 weeks' duration. The cow was obese (body condition score, 8 of 9), and multiple fetuses were identified on palpation per rectum. Urinalysis revealed > 160 mg of ketones/dl. Abnormal serum biochemical data included high concentrations of bilirubin, creatinine, sodium, and chloride; low concentrations of total CO2 and calcium; and high activity of aspartate transaminase. Treatment included administration of dextrose solution, i.v.; propylene glycol, PO; and insulin, i.v. and SC. The cow's appetite improved gradually over 8 days of treatment. Concentration of ketone bodies in urine decreased to trace amounts by day 4. The cow was discharged on day 10 and gave birth to twins 4 days after discharge (duration of gestation, 279 days). The clinical history of this cow differed from the history of other cattle with ketosis, but mimicked pregnancy toxemia in ewes. Multiple fetuses have not been implicated as a predisposing factor in severe prepartum ketosis of cows.

Congenital maldevelopment of the tibia in two calves.

Two calves were admitted for evaluation of valgus deformity centered at the middiaphysis of the right tibia. Each deformity was observed at the time of attended, unassisted birth. The limbs were stable and the calves were ambulatory. Radiography revealed a thick lateral cortex and radiating trabecular bone pattern. The valgus deformities (75 degrees and 45 degrees) were treated by corrective osteotomy. One of the cows was bred and carried a clinically normal fetus to near term before dying of undetermined causes. The angular limb deformities appeared to be attributable to in utero bending stress and bone remodeling early in gestation.

Infertility associated with Eperythrozoon wenyonii infection in a bull.

A 16-month-old Charolais bull was examined because of acute onset of scrotal and hind limb edema, fever, tachycardia, tachypnea, anorexia, and lethargy. Scrotal circumference on initial examination was 48 cm. Clinicopathologic abnormalities included microcytic, normochromic anemia and numerous Eperythrozoon organisms in blood smears. Results of immunohistochemical staining of a skin biopsy specimen suggested that the edema was the result of an Arthus-type reaction. Semen quality deteriorated rapidly, and the bull was aspermic within 7 days. The bull was treated with oxytetracycline, and the anemia and edema gradually subsided. Eperythrozoon organisms were not detected in blood smears after 3 days. Six months after initial examination, results of physical examination and semen evaluation were normal. We hypothesize that scrotal edema caused failure of testicular thermoregulation, resulting in transient production of abnormal sperm and infertility.