Hemicastration and castration in the beagle dog; the effects on libido, peripheral plasma testosterone concentrations, seminal characteristics and testicular function

Hemicastration of five beagle dogs had no effect on their libido, and in four dogs the total seminal volume and sperm concentration of the second fraction was unchanged; sperm output immediately fell in these four animals. Plasma testosterone concentrations in the peripheral circulation were largely unaffected by hemicastration but following complete castration the value fell rapidly and remained low. The first ejaculates, collected 5 days after complete castration, were aspermic. There was no evidence of compensatory changes in the histological structure in those testes which were removed 41 to 44 days after the first gonad. Evidence of the maturation of spermatozoa with migration and subsequent detachment of the cytoplasmic droplet was observed in stained smears of epididymal semen.     

Unsuccessful laparoscopic castration in a cryptorchid Frisian stallion

A 2-year-old unilateral inguinal cryptorchid Frisian stallion was castrated by bilateral laparoscopic intra-abdominal spermatic cord transection. Because blood testosterone levels were still high on postoperative day 7, both testicles were removed using an open approach. Pathology revealed the presence of vital Leydig-cells in both testes. Failure of the laparoscopic castration in this horse was attributed to an alternate blood supply to the testes by vessels derived from the cremaster and/or external pudendal artery.     

Concentrations of oestradiol and testosterone in peripheral and spermatic venous blood of dogs with unilateral cryptorchidism

Plasma testosterone and oestradiol concentrations were measured in peripheral and spermatic venous blood of 13 dogs with unilateral inguinal cryptorchidism, 9 dogs with unilateral abdominal cryptorchidism, and in a control group of 36 mature normal dogs. The hormone concentrations were similar in the three groups, both in the peripheral and in the spermatic venous blood. The weight of the testes in the control group was correlated with the body weight and there was no significant difference between the weight of the right and the left testes. The weight of the abdominal testes was lower than that of the inguinal testes, and there was no compensatory enlargement of the contralateral scrotal testis. The cryptorchid testes showed little or no histological evidence of spermatogenesis, and spermatogenesis was usually normal in the scrotal testes.     

Effect of Short‐Term Scrotal Hyperthermia on Spermatological Parameters,Testicular Blood Flow and Gonadal Tissue in Dogs

The objective was to assess the effect of a short‐term scrotal hyperthermia in dogs on quantitative and qualitative ejaculate parameters, testicular blood flow and testicular and epididymal histology. After a control period, the scrotum of seven normospermic adult beagle dogs was insulated with a self‐made suspensory for 48 h. Nine weeks later, two animals were castrated, while in five animals, scrotal hyperthermia was repeated. Dogs were castrated either 10 or 40 days thereafter. In each phase of scrotal insulation, average scrotal surface temperature increased by 3.0°C. Semen was collected twice weekly throughout the experiment. Total sperm count did not change after the first hyperthermia, but it slightly decreased after the second (p < 0.05). Profiles of sperm morphology and velocity parameters (CASA) rather indicated subtle physiological variations in sperm quality than effects of a local heat stress. Chromatin stability of ejaculated spermatozoa as indicated by SCSA remained constant throughout the experiment. Perfusion characteristics of the gonads, that is, systolic peak velocity, pulsatility and resistance index at the marginal location of the testicular artery, did not change due to hyperthermia (p > 0.05). Histological examination of excised testes and epididymides for apoptotic (TUNEL and activated caspase‐3) and proliferating cells (Ki‐67 antigen) indicated only marginal effects of scrotal insulation on tissue morphology. In conclusion, a mild short‐term scrotal hyperthermia in dogs does not cause substantial changes in sperm quantity and quality. In contrast to other species, canine testes and epididymides may have a higher competence to compensate such thermal stress.     

Function of contralateral testis after artificial unilateral cryptorchidism in dogs

The effects of a cryptorchid testis on the contralateral testis were investigated after artificially producing unilateral cryptorchidism in 8 beagle dogs. Bilateral testicular biopsy and collection of spermatic vein blood and peripheral vein blood were performed at the time of the operation to produce the cryptorchidism and 52 weeks later. The testicular tissue was used for histological examination by light microscopy and measurement of the testicular transferrin (Tf) concentration by enzyme immunoassay. Plasma testosterone (T), estradiol-17 beta (E2), and luteinizing hormone (LH) levels were measured by radioimmunoassay. Semen was collected weekly and its quality was examined. No spermatogenesis was observed in the cryptorchid testes at 52 weeks after the operation, and the number of germ cells in the contralateral testes had decreased but the number of Sertoli cells did not change. The Tf concentration in both testes had also decreased. The mean total number of sperm between 48 and 52 weeks after the operation (194 x 10(6)) was less than half the number before the operation (510 x 10(6)). Mean spermatic vein plasma T levels (51 ng/ml) in the cryptorchid testes 52 weeks after the cryptorchid operation were significantly lower than before the operation (91 ng/ml; P < 0.05). By contrast, spermatic vein plasma E2 levels (80 pg/ml) were significantly higher than the values before the operation (51 pg/ml P < 0.05). The peripheral plasma LH levels decreased. These findings indicate that a large quantity of E2 secreted by the cryptorchid testis inhibits the endocrine and spermatogenic functions of the contralateral testis in the dog. In particular, it is assumed that dysfunction of the contralateral testis is associated with Sertoli cell dysfunction suggested by the low Tf concentration.     

Influence of local anaesthesia on pain and distress induced by bloodless castration methods in young lambs

Behavioural and cortisol responses of lambs were used as indicators of pain and distress to assess short- and long-term effects of bloodless castration methods with and without local anaesthesia. Eighty lambs, aged 2-7 days, were control handled or castrated by crushing- Burdizzo- or rubber ring method with and without local anaesthesia. Either 4 mg/kg diluted lidocaine, or corresponding volumes of physiologic sodium chloride solution were distributed in both spermatic cords and the scrotal neck. The serum cortisol response was monitored for 48 h, behavioural- and clinical traits over a 3-month period. The crushing castration method was excluded from the study after 10 lambs had been castrated, since this method showed severe local reactions. Local anaesthesia significantly reduced behavioural and cortisol responses after rubber ring castration and tendentially after Burdizzo castration. Prolonged or chronic pain after rubber ring castration with anaesthesia was not evident. If combined with local anaesthesia, both the rubber ring and the Burdizzo method are acceptable methods for castration of lambs up to one week of age.     

Effect of local anaesthesia on short- and long-term pain induced by two bloodless castration methods in calves

Behavioural and cortisol responses of calves were used as indicators of pain to assess short- and long-term effects of bloodless castration methods with and without local anaesthesia. Seventy calves, aged 21-28 days, were control handled (20) or castrated using the Burdizzo (25) or rubber ring technique (25). Either 10 mL lidocaine or NaCl were distributed in both spermatic cords and the scrotal neck. The plasma cortisol response was recorded for 72 h, and behavioural and clinical traits monitored over a three month period. Local anaesthesia reduced the level of indicators of acute pain after both the Burdizzo and rubber ring techniques. It did not, however, result in a totally painless castration. As there was evidence of chronic pain lasting for several weeks after rubber ring castration, the Burdizzo method is judged to be preferable to the rubber ring technique.     

Influence of local anaesthesia on pain and distress induced by two bloodless castration methods in young lambs

To assess short- and long-term effects of bloodless castration methods with and without local anaesthesia, behavioural and cortisol responses of lambs were used as indicators of pain and distress. Seventy lambs, aged 2-7 days, were control-handled or castrated by Burdizzo or rubber ring methods with and without local anaesthesia. Either 5 mL of diluted lidocaine (4 mg/kg) or physiological sodium chloride solution was distributed in both spermatic cords and the scrotal neck. The serum cortisol response was monitored for 48 h, and behavioural and clinical traits were followed for three months. Local anaesthesia tended to reduce behavioural and cortisol responses after Burdizzo castration and provided a significant reduction after rubber ring castration. Prolonged pain after rubber ring castration with anaesthesia was not evident. If combined with local anaesthesia, both the rubber ring and the Burdizzo methods are acceptable methods for castration of lambs up to one week of age.     

Pathological Conditions of the Reproductive Organs of Male Stray Dogs in the Tropics: Prevalence, Risk Factors, Morphological Findings and Testosterone Concentrations

The objective of this study was to estimate the prevalence of and risk factors for pathological conditions of the reproductive organs in stray dogs under tropical conditions. Three hundred and eighteen dogs were examined post-mortem in the period from 1 July 2002 to 30 June 2003. Before killing, a blood sample (from the cephalic vein) for testosterone assay was taken. Pathological conditions of the reproductive organs were found in 135 of the dogs (42.5%) and in 175 of the testes (64.8%). The most frequent pathologies found were testicular degeneration, cryptorchidism, testicular hypoplasia and testicular tumours (in 15.1%, 6.6%, 6.6% and 5.4% of the dogs and 15.1, 4.6, 6.0 and 3.5 of the testes, respectively). Transmissible venereal tumour (TVT) was seen in 5.4% of the dogs. Testicular degeneration was more common in old dogs and underweight dogs (p < 0.05). Testicular tumours were 14.3 times more common in cryptorchid dogs. Age was another important factor for the development of testicular tumours (p < 0.05). Lower levels of testosterone concentration (p < 0.05) were observed in dogs with advanced testicular degeneration (0.7 +/- 0.8 nM), dogs with hypoplastic testicles (0.8 +/- 0.9 nM) and dogs with one degenerated and one retained testis or with bilateral cryptorchidism (1.2 +/- 0.9 nM) compared to dogs with one or two normal testes (7.0 +/- 5.5 nM). Testicular volume and weight were significantly lower in degenerated, hypoplastic and retained testes compared with the contralateral normal testis. Some spermatogenic activity was found in three of the retained testes, producing oligozoospermic smears with a high percentage of sperm abnormalities. No comparable epidemiological data about male pathological conditions of the reproductive organs in the dog is available. The prevalence found in this study, yet, appears high.     

Influence of local anaesthesia on short- and long-term pain induced in calves by three bloodless castration methods

Behavioural and cortisol responses of calves were used as indicators of pain to assess short- and long-term effects of three bloodless castration methods with and without local anaesthesia. Eighty calves, aged 21 to 28 days, were control handled (20) or castrated by Burdizzo (25), rubber ring (25), or crushing technique (10). Either a total volume of 10 ml of Lidocaine or NaCl was distributed in both spermatic cords and the scrotal neck. The plasma cortisol response was monitored for 72 hours, and behavioural and clinical traits over a three-month period. Castration success was assessed by degree of atrophy and histological tissue examination. The crushing technique cannot be recommended due to incomplete castration success, and the evaluation was stopped after 10 animals. Local anaesthesia reduced the level of indicators of acute pain after Burdizzo and rubber ring technique. It did, however, not result in a totally painless castration. When castration is performed at the age of 3 to 4 weeks, the rubber ring but not the Burdizzo method showed evidence of chronic pain lasting for several weeks.     

Evaluation of ‘Section‐Ligation‐Release (SLR)’ Technique Devised for Castration in the Stallion

A novel technique [Section‐Ligation‐Release (SLR)] was evaluated for castration in the horse. Clinical traits, serum testosterone concentrations after challenge with human chorionic gonadotrophin (hCG), and histopathological changes of the testicular tissue were assessed. Five stallions, aged 24–48 months, were castrated using SLR technique under general anaesthesia. Both spermatic cords in each stallion were exposed at the scrotal neck by two 5‐cm long incisions, followed by sharp dissection through the parietal vaginal tunic. Both vascular and non‐vascular structures in the cords were triple clamped, transected and ligated. Both testes were left in situ. Serum testosterone concentrations were measured pre‐operatively and at 2 months after castration following IV administration of 1 × 10⁴ IU of hCG. Both testes from each castrate were collected at 2 months for histopathologic examination. SLR castration was successfully achieved. Moderated scrotal and preputial swelling was the only experienced short‐term complication. Serum testosterone concentrations were significantly lower than basal pre‐operative levels at 2 months after castration, and did not respond to hCG. On histopathology, hyalinization of the seminiferous tubules and loss of testicular interstitial tissue were indicative of complete avascular necrosis. This novel primary closure castration technique of stallion is a simple practical method, with minimal post‐operative complications; and could be safely advocated as an alternative to the traditional castration techniques allowing for second intention healing of scrotal wounds.     

Effect of body condition score on the testicular biometrical measures,semen characteristics and testosterone level in jackass

This study was undertaken to evaluate the effect of body condition score (BCS) on testicle and epididymis biometrics, semen characteristics and testosterone level in Egyptian Jack. This study was conducted on 50 mature Jacks divided according to their body condition score into four groups: Poor (G1), moderate (G2), good (G3) and fat (G4). The complete testis was collected immediately after execution in the Giza Zoo abattoir; then, the epididymis was carefully dissected at the testicular junction. Biometrical measures including length, weight and volume were determined for the right and left testis and epididymis. Also, epididymal sperm was collected from all examined animas and evaluated for sperm concentration, progressive motility, viability and sperm abnormalities. Serum samples were collected for determination of total testosterone level. Results showed that the body condition score of the examined animal affects their biometrical measure of testicles and epididymis. There is a significant decrease (p < .05) in biometrical measures for the testicles and epididymis, sperm concentration, motility, viability and testosterone level in poor BCS animals (G1). The highest values were recorded in Good BCS (G3) Jacks. Conclusion: Jacks with good BCS (G3) should be selected for breeding activity in donkey.     

The influence of duration of photoperiod and hemicastration on growth and testicular and endocrine functions of boars

Yorkshire boars were used to evaluate the influence of duration of photoperiod and hemicastration on growth and testicular and endocrine functions. At 10 wk of age, 5 hemicastrate (HC) and 5 intact (I) boars were assigned to either 8 or 16 hr of light daily until 6 mo of age. Body weights were recorded biweekly throughout the experiment. Venous cannulae were placed in all boars at 6 mo of age, and serum was collected at 30 min intervals from 0800 to 2000 hr. Gonadotropin releasing hormone (GnRH) was infused at 2000 hr (50 micrograms) and at 2030 hr (250 micrograms), and samples of serum were collected until 2400 hr. The following day, all boars were castrated, and the weights and sperm content of the testes and epididymides were determined. At castration, all pigs were given implants containing testosterone. Two weeks later, pigs were again canulated, and serum was obtained at 15 min intervals for 2 hr. Growth of boars was not significantly affected by duration of photoperiod or number of testes. Duration of photoperiod did not affect weight or sperm content of testes or epididymides. Hemi-castrated boars had greater testicular (P less than .01) and capita-corpora (C-C) epididymal weights (P less than .05) and more testicular and C-C sperm (P less than .01) per testis. Neither average concentrations of luteinizing hormone (LH) nor number and amplitude of pulses of LH were affected by photoperiod treatment. However, HC boars had greater average concentrations of LH (P less than .05) than I boars (.71 +/- .05 vs .52 +/- .05 ng/ml). Hemicastrated boars in 16 hr light daily had greater concentrations of FSH in serum (P less than .05) than 8I, 8HC, and 16I boars. Intact and HC boars had similar concentrations of prolactin (PRL) and testosterone. Similarly, concentrations of PRL and testosterone were not affected by duration of photoperiod. Secretion of LH and testosterone after treatment with GnRH was not significantly affected by duration of photoperiod. In general, HC boars released more LH in response to GnRH treatment than I boars. Concentrations of LH were greater (P less than .05) in HC than I boars at .5, 1, 2, and 3 hr after GnRH and tended (P less than .10) to be elevated at 1.5, 2.5, 3.5 and 4 hr after GnRH. The FSH response to GnRH was greater (P less than .05) for 16HC than 8I, 8HC, or 16I boars.(ABSTRACT TRUNCATED AT 400 WORDS)     

Castration of lambs: a welfare comparison of different castration techniques in lambs over 10 weeks of age

Seventy male lambs over 10 weeks of age were castrated using Burdizzo, rubber rings, or surgery to assess the acute and long-term effects of castration. All castrations were performed under local anaesthesia. The surgically castrated lambs were additionally sedated with xylazine and the sedation reversed with tolazoline. The frequency of abnormal postures and immediate behavioural responses indicated that surgically castrated lambs were most distressed; the lambs castrated using Burdizzo and rubber rings were not dissimilar to those of the control group. Between 1.5 and 9 h after castration, signs of pain and distress were at a lower level in lambs anaesthetised with bupivacaine compared with those treated with lidocaine. Due to the markedly faster wound healing, Burdizzo castration seemed to be preferable (fewer signs of long-term pain) when compared to the rubber ring technique. It was concluded that local anaesthesia with bupivacaine, followed by the Burdizzo method is the preferable technique for the castration of lambs older than 10 weeks of age.     

Effect of divergent selection for testosterone production on testicular morphology and daily sperm production in boars

The objective of this study was to characterize correlated responses in testicular morphology and daily sperm production to divergent selection for testosterone production. Duroc boars from high and low lines (HTL and LTL, respectively) divergently selected over 10 generations for testosterone production in response to a GnRH challenge followed by random selection were used. Testicular tissues were sampled from all available males of generation 20 (HTL, n = 46; and LTL, n = 13). Volume densities for Leydig cells, seminiferous tubules, and Sertoli cells were estimated along with sperm production. The HTL boars had greater volume densities of Leydig cells than did LTL (P < 0.01). Volume density of seminiferous tubules tended to differ between lines (P < 0.07), but Sertoli cell volume densities did not differ (P < 0.27). Sperm production traits, adjusted for age, did not differ significantly between lines. Body, testicular, and epididymal weights were recorded for boars from HTL (n = 82) and LTL (n = 44) from generations 20 and 21. After adjustment for BW, average paired testicular weights for HTL and LTL were 417 and 457 g (P < 0.01), respectively. Epididymal weights, adjusted for BW, were heavier for HTL (P < 0.01) than for LTL. To demonstrate that the selection lines still differed for testosterone production, lines were evaluated in generation 21. Endogenous testosterone production of the HTL (n = 54) and LTL (n = 44) testosterone production line averaged 49.0 ng/mL and 27.8 ng/mL (P < 0.01), respectively. Plasma FSH concentrations did not differ between lines (P < 0.30). Selection for testosterone production in response to a GnRH challenge was an effective method of changing testosterone concentrations, testicular size, epididymal weight, and volume density of Leydig cells. However, daily sperm production per gram of testes was unchanged. Based on the results of this study, selection for testosterone production is not recommended as a method of increasing sperm production in pigs.     

Laparoscopic sterilization of Sardinia donkeys using an endoscopic stapler

OBJECTIVE: To describe a laparoscopic technique for sterilization of the male donkey using an endoscopic linear stapler (ELS). STUDY DESIGN: Clinical report. ANIMALS: Male Sardinia donkeys (n=6), aged 24-36 months. METHODS: Laparoscopic sterilization was performed under standing sedation or recumbent under general anesthesia. An endoscopic linear stapler was used to transect, and control hemorrhage of, the spermatic cord. Serum testosterone concentrations were measured preoperatively and at 3, 6, and 12 months after sterilization. One testis from each of 2 donkeys was collected at 12 months for histologic examination. RESULTS: Sterilization was successfully achieved. The only minor intraoperative complication experienced was hemorrhage from 1 spermatic cord stump, which was re-stapled. No other major short- or long-term complications occurred. Serum testosterone concentrations were < 15 ng/dL at 3, 6, and 12 months after surgery in all donkeys. Testicular atrophy without evidence of revascularization was observed in the 2 testes examined histologically. CONCLUSIONS: Sterilization of descended testes by intraabdominal laparoscopic transection of the spermatic cord is a simple practical method, with minimal intraoperative or postoperative complications. Testicular revascularization did not occur. CLINICAL RELEVANCE: Laparoscopic sterilization in donkey can be performed using an endoscopic linear stapler as an alternative to scrotal castration.     

A local pathway for increased testosterone supply from the testis to the epididymis, vas deferens and accessory genital glands of the rat

Radiolabeled testosterone (3H-T) was infused into the testes or left and right mesofuniculus (106 dpm) or injected into a testes (2 x 10(6) dpm). The 3H-T concentration was estimated 15 or 10 min after 3H-T infusion or injection, respectively, in the tissue samples collected from the prostate, seminal vesicles, caput and cauda epididymides, vasa deferentia and the mesofuniculi. The abdominal aorta and posterior vena cava were cannulated, and the posterior part of the body perfused with blood (at blood pressure 70-140 or 260-300 mm Hg in abdominal aorta) was used to study 3H-T transfer from the testes to venous blood and other male genital organs. The concentration of 3H-T found in the accessory genital glands, epididymes and vasa deferentia was affected by blood pressure in the abdominal aorta. The reduced blood pressure and partial blocking of blood supply to the genital organs (after ligation of both testicular arteries or the terminal part of the abdominal aorta) increased the concentration of 3H-T in accessory genital glands, vasa deferentia and epididymes. The removal of the mesofuniculi and vasa deferentia with their mesoducti reduced 3H-T concentration in the prostate, seminal vesicles and cauda epididymides. Both arterial trunks, testicular arteries and common iliac arteries, were shown to be connected by anastomoses in target organs so effectively, that supplying the male genital organs with blood by only one of them assures the transfer of testosterone from the testes to the epididymes, vasa deferentia, mesofuniculi as well as prostate and seminal vesicles. It was concluded that lymphatic vessels of the mesofunicules and of the spermatic cords as well as venous and arterial vasculature of the mesofunicules create a recently unknown pathway for the increase of testosterone supply from the testes to the epididymes, vasa deferentia and accessory genital glands of rats.     

Effect of chorionic gonadotropin administration on the concentration of testosterone in the blood of boars]

In intact boars, intravenous administration of 100 to 6000 I. U. chorionic gonadotropin elicited a pronounced rise in the plasma level of testosterone, depending on the time interval from the administration of chorionic gonadotropin and on the size of the administered dose. In the blood of castrated boars such an application of choronic gonadotropin did not influence the concentration of testosterone. It was inferred that the rise in the levels of blood testosterone in boars after administration of chorionic gonadotropin was specific for testicular incretion and indicated the endocrine reserve of the testes. There is a discussion concerning the importance of the functional testing of the incretion capacity of testes for differential diagnosis different forms o incretion hypogonadism.     

Lectin-binding characteristics and capacitation of canine epididymal spermatozoa

Cross sections of the testes and the caput, corpus and cauda epididymides removed from 12 dogs were stamped on glass slides, and the sperm on the slides were stained with 6 different FITC-lectins (Con A, DBA, PNA, PSA, SBA, and WGA) to examine the characteristics of the surface glycoproteins (GPs) on canine epididymal sperm. The corpus epididymal sperm were washed three times by centrifugation, and their lectin-binding characteristics were investigated. The washed sperm from the corpus and cauda epididymides were incubated for 24 hr, and the fertilizing capacity of the sperm was evaluated by calculating the percentages of actively motile sperm (%MO), hyperactivated sperm (%HA), and acrosome-reacted sperm (%AR), and the number of canine zona-pellucida (ZP)-binding sperm. The testicular sperm did not stain with SBA lectin, but the SBA lectin fluorescence was observed on the surface of the entire heads of the caput epididymal sperm. Although all of the entire heads or acrosomal regions of the corpus epididymal sperm stained with all 6 FITC-lectins, the heads and acrosomal regions of the cauda epididymal sperm did not stain with DBA or SBA lectins. Washing the sperm from the corpus epididymis resulted in loss of the fluorescence of the FITC-DBA and -SBA lectins. The mean %MO, %HA, %AR, and ZP-binding number of the cauda epididymal sperm after 24 hr of incubation were higher than the values for the corpus epididymal sperm. All of the mean values for the washed sperm from the corpus and cauda epididymides were higher than the values for the unwashed sperm from the corpus and cauda, and with the exception of %AR, the values from the washed sperm from the corpus epididymis were significantly higher (P<0.05, 0.01). The results indicate that DBA- and SBA-lectin-binding GPs on the surface of canine epididymal sperm are associated with the fertilizing capacity and may be decapacitation factors.     

Avian infectious bronchitis virus: a possible cause of reduced fertility in the rooster

The formation of epididymal stones in the rooster epididymis is a widespread problem that has detrimental effects on sperm production and fertility. The cause of epididymal stones is unknown, but an infectious agent, the avian infectious bronchitis virus (AIBV), has been implicated. The goal of this study was to determine if administering the live attenuated AIBV vaccine to male chicks increases the incidence of stones in the epididymal region of the adult rooster. Specific pathogen free (SPF) Leghorn roosters were divided into two groups: a vaccine-free group (n = 7) and a group vaccinated with AIBV (n = 12). The vaccine was administered orally at 2, 4, 10, and 14 wk of age. Blood was drawn weekly to monitor antibodies to AIBV. At 26 wk of age, blood was obtained to determine testosterone concentrations, and reproductive tracts were removed to analyze daily sperm production and to detect epididymal stones. Nine of 12 vaccinated roosters developed stones, whereas those not given the vaccine did not develop stones. Serum testosterone concentrations were significantly (P < 0.05) reduced in vaccinated roosters with epididymal stones (3.6 +/- 0.30 ng/ml) when compared with nonvaccinated roosters that did not have epididymal stones (7.0 +/- 1.63 ng/ml). Testis weight was significantly (P < 0.05) reduced in vaccinated roosters with epididymal stones (12.1 +/- 0.76 g), as compared with nonvaccinated roosters without epididymal stones (15.2 +/- 0.81 g). Daily sperm production was significantly (P < 0.05) decreased in vaccinated roosters with epididymal stones (5.03 +/- 0.31 x 10(8) sperm/testis/day) when compared with nonvaccinated roosters without epididymal stones (7.43 +/- 0.52 x 10(8) sperm/testis/day). Comparing daily sperm production on a per gram basis, vaccinated roosters with epididymal stones had 4.38 +/- 0.14 x 10(7) sperm/g of testis, which was significantly (P < 0.05) smaller than nonvaccinated roosters without epididymal stones, which had 5.17 +/- 0.17 x 10(7) sperm/g of testis. We conclude that the use of a live attenuated AIBV vaccine increases the incidence of epididymal stones in roosters, resulting in decreased sperm production and decreased serum testosterone concentrations.