Effect of hemicastration on the level of testicular steroids and growth in bulls and boars

Ten, bull calves of the Norwegian Red breed were hemicastrated at the age of 1 1 2 -3 months . Ten, normal bull calves of similar age served as controls. No significant differences were found in plasma testosterone levels or in weight between the two groups during the ensuing seven-month test period. Eight, male pigs were hemicastrated at 1-2 months of age. Eight, normal male pigs served as controls. Plasma testosterone, androstenone, and body weight were measured fortnightly in all pigs until the age of 6-7 months. Androstenone in adipose tissue was measured from 4-5 months of age. No significant differences were found between normal and hemicastrated animals in any monthly interval. However, when combining the measurement at 5-6 and 6-7 months of age for plasma testosterone and 5alpha-androstenone and 5alpha-androstenone in fat, the normal pigs had significantly higher values than the hemicastrates (p<0.05). The weight of the single testis from the hemicastrated pigs at slaughter nearly equalled the combined weight of both testes from the controls. Thus, hemicastration did not appear to have any significant effect on the level of testicular steroids in plasma in bulls or growth rate in bulls and boars, but did have a slight effect on testicular steroids in plasma in pigs at 5-7 months of age.     

Variations in testicular androgen receptors and histology of the lamb testis from birth to puberty

Changes in testicular androgen receptor numbers were studied in lambs from 25 to 100 days of age. During this period, cytoplasmic receptors increased from 5 to 80 pmol/testis and nuclear receptors from 1 to 12 pmol/testis, while the total volume of Leydig cells increased 7-fold. The total number of Sertoli cells doubled between 25 and 40 days of age. From 40 days onward their number remained constant while their cellular and nuclear sizes increased by a factor of 3 and 1.5 respectively. Cytoplasmic receptor concentration was positively correlated with the number of Sertoli cells per section of seminiferous tubule, and negatively correlated with the number of germinal cells per cross section. One explanation for these results could be that Sertoli cells are the main androgen target cells in lamb seminiferous tubules.     

The effects of feed restriction and realimentation on the growth and reproductive function of Bokoloji bulls

A group of Bokoloji bulls (n=36), consisting of 18 young bulls (12 to 18 mo old) and 18 old bulls (24 to 30 mo old) were used to study the effects of feed restriction and realimentation on reproductive function. The bulls were placed either on a low (L). medium (M) or high (H) plane of nutrition during the 3 treatment periods. At the low and medium feeding levels, the animals received approximately 25 and 45%, respectively, of the intake of the bulls on the high plane diet. All the bulls were fed a low (L) plane of nutrition for 90 d in the first treatment period. The 3 treatments were designated as LL, LM and LH for the mid-period, and as LLH, LMH and LHH for the final period, according to the prescribed level of feeding. Body measurements and scrotal circumference were taken for all bulls before slaughter. A total of 18 bulls was slaughtered at the end of the mid-period, while the remaining 18 bulls were slaughtered at the end of the final period. Testicular weights as well as gonadal and epididymal sperm reserves were determined. At the end of the mid period, the bulls on a high plane of nutrition had significantly (P<0.05) higher live weights and chest girths than bulls on the medium and low planes of nutrition. Gonadal sperm/spermatid reserves of 5.2 x 10(9) and epididymal sperm reserves of 2.4 x 10(9) in bulls on the high plane of nutrition were significantly (P<0.05) higher than the sperm reserves for the bulls on either the low or the medium plane of nutrition. At the end of the final period, ho significant differences existed among the LHH, LMH and LLH treatments in liveweight, chest girth, scrotal circumference and sperm reserves (P>0.05). It is concluded that bulls which have undergone feed restriction for 90 d are capable of regaining their body growth and reproductive function if such bulls are placed on an adequate plane of nutrition.     

Contribution of the scrotum,testes, and testicular artery to scrotal/testicular thermoregulation in bulls at two ambient temperatures

The objective of this study was to determine the contribution of the scrotum, testes, and the testicular artery to scrotal/testicular thermoregulation in bulls at two ambient temperatures. Crossbred beef bulls, 1.5 years of age, were placed in controlled environment chambers at ambient temperatures of 15°C (n = 5) or 25°C (n = 6). The distal lateral aspects and entire ventral part of the scrotum was incised under caudal epidural anaesthesia (xylazine, 0.07 mg kg⁻¹). Both testes were withdrawn from the scrotum and then replaced and maintained by clamping the scrotal incisions with towel clamps. One testis was randomly chosen to be the exposed testis and was withdrawn prior to temperature measurements. Surface and internal temperatures were measured with infrared thermography and needle thermocouples, respectively. Temperature gradients (°C; difference in temperature from top to bottom at 15 and at 25°C) were: scrotal surface (with testis), 1.5 and 1.3; scrotal surface (without testis), 2.1 and 1.6; surface of exposed testis, −0.6 and 0.0; sub-tunic of exposed testis, −2.2 and −0.6; intratesticular (covered testis), 0.0 and 0.4; and intratesticular (exposed testis), −1.3 and 0.4. The scrotum markedly affects testicular temperature but the testes have limited influence on scrotal surface temperature. The bovine scrotum and testes have opposing temperature gradients that complement one another, resulting in a relatively uniform intratesticular temperature. These temperature gradients are attributed in part to the testicular artery, which goes from the top of the testis to the bottom, divides into several branches and ramifies dorsally and laterally before entering the testicular parenchyma. Intra-arterial temperatures (measured with needle thermocouples) were lower (P < 0.05) where the artery entered the testis than at both the bottom and top of the testis for both the covered (31.7, 33.4 and 34.3°C) and exposed testis (29.6, 32.0 and 32.5°C) at an ambient temperature of 15°C. Temperature differences were similar, but less pronounced, at 25°C (covered testis, 34.8, 36.3 and 36.5°C; exposed testis, 32.4, 33.5, 33.9°C). Results supported the hypothesis that blood within the testicular artery has a similar temperature at the top of the testis (just ventral to the testicular vascular cone) compared with the bottom, but subsequently cools before entering the testicular parenchyma.     

Effect of protected protein supplements on some testicular traits in Brahman cross bulls

Differences in a number of testicular traits were examined in 12 Brahman cross (F₂ generation $\text{1}\text{2}$ and $\text{3}\text{4}$ BX) bulls fed either poor-quality native pasture (NP) hay or NP hay with a protected protein supplement. Supplementation for 60 days significantly (P < 0.05) increased roughage dry matter intake (7.7 $\text{v}$ 5.6 kg/head/day), enabling maintenance of liveweight, whereas control animals lost 40 kg. There were significant (P < 0.05) decreases in scrotal circumference (1.5cm) and testicular consistency (0.8 score) in the control group, in which testes weights at slaughter were significantly (P < 0.05) less (373 g $\text{v}$ 459 g), with corresponding lower epididymal weights (37.4 g $\text{v}$ 43.5 g). Estimates of daily sperm production per gram (DSPG) were similar for both groups, and testis daily sperm production (DSP) was somewhat but not significantly (P>0.05) lower in the control group (4.3 × 10⁹$\text{v}$ 6.0 × 10⁹) as a result of lower testis weights. Total epididymal sperm storage capacity was also lower in control bulls (17.2 × 10⁹$\text{v}$ 27.0 × 10⁹), but only significantly (P < 0.05) in relation to cauda sperm reserves (8.5 × 10⁹$\text{v}$ 13.6 × 10⁹). Luteinizing hormone (LH) and testosterone responses to gonadotrophin releasing hormone (GnRH) treatment were similar for both groups, although LH responses to GnRH were greater in $\text{1}\text{2}$ BX than in $\text{3}\text{4}$ BX bulls.     

Early prepubertal testis criteria, seminiferous epithelium and hormone concentrations as related to testicular development in beef bulls

The present study was conducted to evaluate testis size, spermatogenesis and hormone concentrations before and when peripheral testosterone reached 1 ng/ml as related to further gonad development of beef bulls (n=28). Blood samples were taken weekly starting at 10 weeks (wk) and when testosterone reached 1 ng/ml (AGE1), the left testis was surgically excised. From AGE1 until 54 wk, blood samples were collected to follow basal and GnRH-stimulated hormone profiles. At 54 wk, the second testis was removed. Testosterone reached 1 ng/ml at 20±0.6 wk and, at this developmental state, the seminiferous tubules occupied 57±1.1% of the testis parenchyma. At this phase, 79.3±1.4% of tubule sections had no germ cells and only 2.4±0.3% of the remaining tubules had spermatocytes as the most advanced germ cell type. Also at AGE1, testis size was correlated with the number of Sertoli cells per testis (r=0.67; P<0.05), but not (P>0.05) with the percentage of tubules with germ cells. There was a consistent increase in body weight and testis size throughout the study showing that hemicastration did not impair the development of the bulls. At 54 wk, seminiferous tubules represented 76±0.7% of the testis parenchyma and 72.3±1.7% of tubule sections were found with either round or elongated spermatids. Quantitative criteria of spermatogenesis in the second testis (excised at 54 wk) were not correlated (P>0.05) with the percentage of seminiferous tubules with germ cells in the first testis (excised at AGE1). As determined by regression analysis, testis diameter measured between 30 and 44 wk (AVTD) was associated with AGE1 and testis diameter averaged at 12 wk and AGE1 (R(2)=0.77; P<0.01). Also, AVTD was related to AGE1, testis diameter at 12 wk and concentrations of 17β-estradiol (estradiol; basal+GnRH-stimulated) averaged between 10 wk and AGE1 (R(2)=0.79; P<0.01). Yearling testis weight, in turn, was linked to AGE1 and testis weight at AGE1 (R(2)=0.49, P<0.01). In conclusion, early detection of 1 ng of testosterone/ml, larger testis size and greater estradiol before and at that developmental period positively relate to future testis attributes. When testosterone reached 1 ng/ml, the seminiferous tubules had Sertoli cells, spermatogonia and a few spermatocytes and events occurring before and at that phase are potential markers of testis growth and sperm-producing capacity of sires.     

Fine needle aspiration of the testis. Correlation between cytology and histology

OBJECTIVE: To determine the diagnostic value, reliability, safety and patient discomfort of testicular fine needle aspiration (FNA) as a cytologic sampling technique. All cases were divided into three groups: group A (control group), 15 patients with normal testes undergoing orchiectomy for prostatic carcinoma treatment; group B, 17 cases who had presented with oligoazoospermia for evaluation of male infertility; group C, 20 cases who had presented mainly with scrotal swelling with or without pain. The patients' ages ranged between 22 and 83 years. Older patients entered group A. Younger patients entered group B. A wide range in age occurred in group C. STUDY DESIGN: Fine needle aspirates from 98 testes in 52 patients, 46 bilaterally punctured, were assessed. RESULTS: All fine needle results on group A and most on B and C were correlated with histologic results of biopsy specimens. In 88.5% of cases an excellent correlation was found between the results of the two methods, and the cytologic diagnosis was absolutely precise. The specificity and sensitivity of the method were 100% in this series. CONCLUSION: The procedure was well tolerated, reliable and simple, with no serious complications. Testicular FNA is a useful and safe investigative modality in the evaluation of testicular function and disease.     

Heritability estimates and adjustment factors for the effects of bull age and age of dam on yearling testicular size in breeds of bulls

Scrotal circumference, testicular length and body weight were measured in 3,090 yearling bulls of 12 breed groups finishing growth performance tests during a 5 yr period. Breeds were Limousin, Hereford, Charolais, Angus, Red Poll, Simmental, Pinzgauer, Brown Swiss, Gelbvieh and three crossbred breed groups. All bulls were born during a 60-d calving season starting in late March of each year and were subjected to similar management and environmental influences during the study. The bulls were the progeny of 307 sires averaging approximately 26 sires per breed group and 10 sons per sire. Breed group, sire within breed group, year and age-of-dam effects were important (P<0.01) for all testicular traits at both a constant age (354 d) and constant body weight (418 kg). Paternal half-sib estimates of heritability were 0.41 +/- 0.06 for ageconstant scrotal circumference, 0.34 +/- 0.06 for testicular length and 0.37 +/- 0.06 for calculated paired testicular volume, respectively. Age-constant genetic correlations between yearling body weight and testicular traits were small, indicating that testicular growth and body growth rates are largely independent, regardless of breed. Testicular size of bulls from 2-yr-old dams was smaller than that of bulls from older dams. Most of these age-of-dam effects on testicular size were removed when testicular size was adjusted for the effects of body weight, suggesting that age-of-dam effects on testicular size are primarily the result of age-of-dam effects on body weight. Age adjustment factors for yearling scrotal circumference did not differ (P>0.20) among breed groups and averaged 0.032 cm per day of age. Adjustment factors for age of dam were +1.3, +0.8, +0.4, and +0.0 cm for sons of 2-, 3-, 4- and 5-yr-old dams, respectively.     

Effect of continuous light and darkness on the testicular histology of toad (Bufo melanostictus)

Continuous darkness decreases spermatogenesis as well as Leydig cell function whereas continuous illumination suppresses spermatogenesis along with increased Leydig cell activity.     

Induction of meiosis in fetal mouse testis in vitro by rete testis tissue from pubertal mice and bulls.

To test whether a meiosis-inducing substance (MIS) is responsible for the induction of meiosis in the testis at puberty, pubertal mouse rete testis was grown with (1) fetal undifferentiated mouse testis attached to the other side of a filter and (2) the used medium obtained from culture of the rete testis of a pubertal bull for 2 days. In both systems meiosis was induced in the fetal testis showing that MIS is not species specific. No meiosis-preventing effect was seen and it is concluded that meiosis in the testis is triggered at puberty as a result of the activity of the MIS concomitant with decreased activity of the meiosis-preventing substance.     

Fibrotic lesions in the testis of bulls and relationship to semen quality

Ultrasonography of the testes was done in bulls at three locations in western Canada (n = 325) and one in Argentina (n = 387) to determine the prevalence of fibrotic lesions and to examine the relationship between fibrotic lesions and location, age, breed, right compared with left testes, testis size and semen quality. Fibrotic lesions were common in the testes of bulls raised under intensive rearing conditions in western Canada as well as in the more extensive rearing conditions of Argentina. Fibrotic lesions appeared as early as 5–6 months of age and the number of cases continued to increase until at least 12–14 months of age. The severity of lesions increased in some cases during this period; however, it appears that the development of lesions occurred during a finite period of pubertal development. It is unlikely that the prevalence of lesions is influenced by breed, right compared with left testes or testis size. The cause of the lesions is unknown, but there was an association between the development of fibrotic lesions and an outbreak of BRSV disease in Argentina in one group of bulls. There was some indication that during the active process that leads to fibrosis spermatogenesis is adversely affected; however, the presence of a large number of fibrotic lesions that may occupy as much as 50% of the testis parenchyma did not preclude the production of a greater percentage of sperm with normal morphology.     

Effect of nickel on testicular nucleic acid concentrations of rats on protein restriction

The nucleic acids (DNA and RNA) and total protein concentration in testes were estimated in male Wistar strain rats treated intraperitorally with nickel sulfate (2.0 mg/100 g body weight) on alternate days for 10 dosages. In both normal (18% casein) and protein-restricted (5% casein) experimental animals, the nucleic acids and total protein concentration were found to decrease significantly compared to the corresponding controls. Sperm count and sperm motility were also reduced in both experimental groups of animals. The results indicate that nickel influences the expression of genetic information by reducing testicular nucleic acids and protein concentration in both dietary experimental groups.     

Exocrine function of testis with germinal testicular tumour.

Semen collected immediately before or soon after therapeutic unilateral orchidectomy from 86 men with germinal tumours of the testis was analysed. The mean sperm count was 65.6 +/- SEM 10.3 X 10(6) per ejaculate. This was significantly different from that in a control population, in whom the mean was 165.2 +/- 12.9 X 10(6) per ejaculate. The difference appeared to be due to a subpopulation of 32 patients with counts of 20 X 10(6) per ejaculate; the distribution of counts in the remaining patients was similar to that in the controls. The cause of this abnormality of exocrine function is unknown: it may either be due to the tumour or its treatment, or both, or, alternatively, it may predate the events of the malignant transformation, possibly even acting as an inducing or promoting factor.     

Effects of androgen deprivation on the histology of adult chimpanzee testis

Until primate sperm are exposed to the unique microenvironment of the epididymis, they are not capable of fertilization or vigorous motility. Many of the proteins that contribute to the unique microenvironment of the primate epididymis, and thus to sperm maturation, are dependent on androgens to induce their synthesis and secretion. GnRH antagonists have proved effective in suppressing LH and testosterone synthesis and secretion, and thus in maintaining a state of androgen deprivation or functional hypogonadotropism. We report here the effects of GnRH antagonist-induced androgen-deprivation on the histology of the testicular interstitium and seminiferous epithelium of the adult male chimpanzee. After only 21 days of androgen-deprivation, chimpanzee testicular tissues exhibit specific atrophic changes, including the loss of contact between developing spermatocytes and between Sertoli cells and their developing spermatids, alterations in cell development resulting in missing maturation steps (elongating Sc and structurally complete Sd2 spermatids) and inappropriate cell associations, varying degrees of cytoplasmic degradation in germ cells, Sertoli cells, and Leydig cells, and a tubular lumen obscured by masses of sloughed primary and secondary spermatocytes and what appear histologically to be Sb1 and Sd1 spermatids.