Changes in testicular size, echotexture, and arterial blood flow associated with the attainment of puberty in Dorper rams raised in a subtropical climate

Ultrasonography of Testicular Maturation and Correlation with Body Growth and Semen Evaluation in Beagle Dog Model

This prospective study investigated the ultrasonographic appearance of the canine testis from birth to adulthood. Eight purpose-bred laboratory Beagle-breed dogs were monitored from 4 to 40 weeks of life. The following parameters were evaluated every two weeks: bodyweight and height, scrotal and testicular volume, ultrasonographically measured testicular volume, echogenicity, heterogeneity, blood-flow score, ratio of the grayscale intensity value of the testis to the capsule, ejaculate volume, motility, viability, and number of spermatozoa. A correlation analysis was carried out between the various measurements obtained. Fertility was achieved in the 36th week of life. The echogenicity of the testicular parenchyma increased with age, and subsequently to the 30th week of life remained constant. The heterogeneity of the testicular parenchyma, as was evaluated by the standard deviation of the values of grayscale intensity of the parenchyma, also increased with age and was >19 at the onset of fertility. The ratio of grayscale intensity of testicular parenchyma had values < 200 at maturity. A colour Doppler evaluation first detected blood flow in the testis in the 22nd week. After the 32nd week, distinct signals were visible. In the 36th week, >80% of the testes imaged had visible vessels. A significant correlation was found between all the evaluation methods. The findings of the study may help clinicians detect the onset of fertility in dogs, especially when semen evaluation is not feasible; however, their applicability in all breeds or individuals might possibly vary due to genetic, physiological, and developmental differences. In summary, the study ultrasonographically explores the testicular maturity in dogs, with the aim to improve clinical assessments and health management in these animals.

Does Size Matter? Testicular Volume and Its Predictive Ability of Sperm Production in Rams

Over the years, testicular volume has been used to evaluate the reproductive capacity of rams and the effects of different factors related to reproductive performance. The aim of this study was to determine the most suitable tool and formula to calculate testicular volume under field conditions to guarantee a more accurate determination of sperm production. First, testicles from 25 rams (n = 50) were measured in vivo and postmortem using calipers and ultrasonography during the breeding season (BS). The accurate testicular volume (ATV) was calculated through water displacement. In addition, the sexual status of donor rams was evaluated during a period of four years in a reproduction center, and the three most crucial groups in terms of genetic value and seminal collections were studied in the second part of this experiment: ER-NBS (Elite rams during the non-breeding season), ER-BS-S (Elite rams with a standard frequency of seminal collection), and ER-BS-O (Elite rams with a high frequency of seminal collection). The total testicular volume (TTV), testosterone (T), and total spermatozoa obtained from two consecutive ejaculates in the same day (SPERM) were measured, and the relationship between SPERM and TTV and T was analyzed to predict SPERM. Although all published formulas revealed statistically significant differences (p ≤ 0.05) from the ATV, our proposed formula (ItraULE) (Testicular volume = L × W × D × 0.61) did not show significant differences. In the second part of the study, in the ER as a model donor ram for its high genetic value and high demand from farmers, TTV and T showed strong positive correlations with SPERM (r = 0.587, p = 0.007 NBS; r = 0.684, p = 0.001 BS-S; r = 0.773, p < 0.0001 BS-O). Moreover, formulas were established to predict SPERM in these practical scenarios. In conclusion, the use of ultrasonography and a new formula adapted to rams could improve the prediction of SPERM considering crucial factors such as season and semen collection frequency.

Ovine fertility by artificial insemination in the breeding season could be affected by intraseasonal variations in ram sperm proteomic profile

It is important to note that seasonality could affect ram reproductive parameters, and therefore, fertility results after artificial insemination. In this work, 1) we assessed fertility rates after cervical artificial insemination of 11,805 ewes at the beginning (June 21st to July 20th) and at the end (November 20th to December 21st) of the reproductive season in the Assaf breed for the last four years, and 2) we aimed to identify male factors influencing the different reproductive success obtained depending on the time at the mating season in which ovine artificial insemination was performed. For this purpose, we evaluated certain ram reproductive and ultrasonographical parameters as well as we performed a multiparametric and proteomic sperm analysis of 6-19 rams at two very distant points in the mating season (July as Early Breeding Season -EBS- and November as Late Breeding Season -LBS-). Rutinary assessments carried out in the ovine reproduction centers (testicular volume, libido, sperm production and mass motility) showed non-significant differences (P ≥ 0.05) between both studied times, as well as the ram ultrasonographic evaluation (Resistive and Pulsatility Index as Doppler parameters; and pixels mean gray level, and hypoechoic areas percentage and density as echotexture parameters). However, at level of sperm functionality, although sperm quality appeared non-significantly lower (P ≥ 0.05) in the EBS, we identified a significantly different (P < 0.05) sperm proteomic profile between the seasonality points. The following proteins were identified with the lowest abundance in the EBS with a fold change > 4, a P = 2.40e-07, and a q = 2.23e-06: Fibrous Sheath-Interacting Protein 2, Disintegrin and Metalloproteinase Domain-Containing Protein 20-like, Phosphoinositide-Specific Phospholipase C, Tektin 5, Armadillo Repeat-Containing Protein 12 Isoform X3, Solute Carrier Family 9B1, Radial Spoke Head Protein 3 Homolog, Pro-Interleukin-16, NADH Dehydrogenase [Ubiquinone] 1 Alpha Subcomplex Subunit 8, Testis, Prostate and Placenta-Expressed Protein, and Acyl Carrier Protein Mitochondrial. In conclusion, while our basic analyses on male and sperm quality showed similar results between the beginning and the end of the breeding season, on a proteomic level we detected a lower expression of sperm proteins linked to the energy metabolism, sperm-oocyte interactions, and flagellum structure in the EBS. Probably, this different protein expression could be related to the lower fertility rate of Assaf ewes after cervical artificial insemination at this time. More importantly, sperm proteins can be used as highly effective molecular markers in predicting sperm fertilization ability related to intraseasonal variations.

Coat color affects the resilience against heat stress impacts on testicular hemodynamics, reproductive hormones, and semen quality in Baladi goats

Drastic climatic changes threaten animal productivity and prolificacy, whose adaptability is governed by its pheno- and genotypic traits. This study was aimed at investigating the effect of coat color on the adaptability of goat bucks under heat stress conditions from the perspectives of testicular blood flow (TBF) and biometry, reproductive hormones, and semen quality. Twenty bucks (Capra hircus) bearing different coat colors were selected from a large flock and divided into four equal groups (n = 5 each) as follows: black coat (BC; 100% black), brown coat (BrC; 100% dark brown), white coat (WC; 100% white), white-black coat (WBC; 50-60% white). Bucks were examined for TBF [Doppler ultrasonography and serum nitric oxide (NO)], testosterone (T) and luteinizing hormone (LH), seminal plasma oxidative biomarkers [catalase (CAT), total antioxidant capacity (TAC), and malondialdehyde (MDA)], and sperm traits percentages [progressive motility (PM), viability (SV), normal morphology (NM), and sperm concentration (SC) once a week for seven consecutive weeks (W1-W7) in the summer season (temperature humidity index = 88.4-92.2). Specifically, at W3-W7, darker bucks (BC and BrC) testicular volume, testicular colored area, T, NO, CAT, TAC, PM, SV, NM, and SC (W7 only) differed significantly (P < 0.05) by decrease than the lighter ones (WC and WBC). Both Doppler indices and serum MDA concentrations were elevated (P < 0.05) at W3-W7 in the BC and BrC bucks compared to WC and WBC groups. In conclusion, bucks with lighter coats were more resistant to the negative effects of HS on TBF, seminal oxidative biomarkers, and semen quality.

Testicular alterations and semen quality in a selected group of breeding buffaloes

Testicular ultrasound enables the evaluation of changes in the testicular parenchyma. This study aimed to report the occurrence of hypoechogenic testicular alterations and their relationship with semen quality in five breeding buffaloes. Two buffaloes presented with hyperechoic points characteristic of fibrosis and anechoic density content between the parietal and visceral tunica. The two bulls without ultrasonographic changes showed higher average trajectory speed, linear velocity, curvilinear velocity, amplitude of lateral displacement of the spermatic head, total motility, progressive motility, fast speed, and acrosomal membrane values within the normal range. The number of spermatozoa with major and total defects was higher in the group of animals without alterations. The three buffaloes that presented with testicular alterations produced semen within established freezing standards.

Seasonal Alterations in Testicular Hemodynamics and Echotexture in Relation to Semen Quality in Buffalo Bulls

The present study is aimed at investigating the usefulness of the pulsed-wave Doppler ultrasonography for the characterization of testicular blood flow in buffaloes during the nonbreeding and breeding seasons. Ten Egyptian buffalo bulls were evaluated for changes in the blood flow (Doppler’s indices: resistive index (RI) and pulsatility index (PI)) at the levels of supratesticular (STA) during the breeding (winter) and nonbreeding season (summer). The alterations in testicular parenchyma echotexture (pixel intensity (PIX) and echotexture heterogeneity (EH)) were assessed by computer analysis software. Circulating testosterone and nitric oxide (NO) concentrations and total antioxidant capacity (TAC) were measured colorimetrically. Sperm parameters including total and progressive motility %, viability %, morphology %, and concentrations were assessed. Results revealed lower values ( $p<0.05$ ) of RI ( $0.55\pm 0.02$ ) and PI ( $0.82\pm 0.03$ ) within the STA in the breeding period compared to the nonbreeding period (RI: $0.67\pm 0.03$ ; PI: $0.99\pm 0.01$ ). Higher ( $p<0.05$ ) PIX and EH were found in the nonbreeding season (PIX: $72.09\pm 1.81$ ; EH: $14.99\pm 1.37$ ) compared to the breeding season (PIX: $60.95\pm 1.51$ ; EH: $11.75\pm 0.63$ ). Concentrations of testosterone and TAC were not significantly changed. However, the concentrations of NO were greater ( $p<0.05$ ) during the breeding season ( $78.21\pm 0.87$ ) compared to those of the nonbreeding one ( $59.74\pm 2.97$ ). Total motility %, progressive motility %, viability %, and sperm concentrations were higher during the breeding season compared to that during the nonbreeding season ( $p<0.05$ ). In conclusion, seasonality alters testicular hemodynamics and echotexture, NO concentrations, and sperm quality in buffaloes without alterations in the testosterone and TAC levels.

Application of ultrasound technique to evaluate the testicular function and its correlation to the sperm quality after different collection frequency in rams

The frequency of semen collection is a crucial factor to consider in the rams performance inside breeding centers workout. To evaluate this factor, ram Breeding Soundness Evaluation could include sperm quality evaluation and new predictive and non-invasive tools such as ultrasound technique. In this work, an advanced ultrasonography technology, analyzing the testicular volume, echotexture, and vascular function, was used in three different frequencies of semen collection (abstinence frequency, AF; standard frequency, SF; and intensive frequency, IF). Semen samples were cooled (15°C, 6 h) and evaluated in terms of production, motility, viability, apoptosis, and content of reactive oxygen species. Correlation coefficients were calculated between ultrasonography measurements of echotexture and blood flow and sperm quality parameters. Our results showed an increase in the testicular echotexture when the frequency of semen collection was intensified. Doppler parameters (PSV, RI, PI, TABF) increased (P ≤ 0.05) when the frequency of semen collection was intensified. The sperm motility and functionality decreased in the samples of IF (P ≤ 0.05), evidencing the frequency of semen collection's influence. Moreover, moderate positive correlations were established among echotexture and different Doppler parameters with motility parameters in SF. Furthermore, the influence of abstinence days on AI success was analyzed in a field assay. The highest fertility rates were obtained when males had two to five abstinence days. To conclude, frequency of semen collection could be influenced in terms of semen quantity and sperm quality, showing changes in parenchyma echotexture and testicular vascularization. The standard semen collection frequency was the most adequate option. In addition, ultrasonography may be a predictive tool for estimating variations in the sperm quality of donor rams subjected to different frequencies of semen collection in reproduction centers.

An updated insight on testicular hemodynamics: Environmental, physiological, and technical perspectives in farm and companion animals

In all organs, control of blood flow is important but might be particularly critical for testicular functions. This is because of the very low oxygen concentration and high metabolic rate of the seminiferous tubules, the physiological temperature of the testis, and its location outside the abdominal cavity. Many factors affect the characteristics of TBF in farm and companion animals, such as environment (thermal and seasonal effects) and physiological (species, breeds, age, body weight, and sexual maturity). Thermal environment stress has detrimental effects on spermatogenesis and consequently has more serious impacts on both human and animal fertility. Numerous studies have been performed to assess TBF in different animal species including bulls, rams, bucks, alpacas, stallions, and dogs with varied results. Hence, assessment of TBF by Doppler ultrasonography is of great importance to estimate the effect of high environment temperature on testicular functions. Also, differences observed in the TBF may result from different technical aspects such as the identification of the segment of the testicular artery to be examined. In the current review, we focused on the imperative roles of TBF in various animal species. Besides, we discussed in detail various factors that could affect TBF. These factors can significantly modify the TBF and thus should be considered when establishing reference values in farm animals for better clinical diagnosis. The information provided in this review is valuable for researchers and veterinarians to help them a better understanding of testicular hemodynamics for the proper evaluation of breeding soundness examination in males.

Diurnal rhythms in testicular blood flow, testicular morphometry and reproductive hormones in Shiba goats

Context Testicular blood flow (TBF) is crucial for testicular function. The pattern of TBF in Shiba goats indicates seasonal variations. Aims This study aimed to investigate the effect of diurnal variations on TBF, testis volume (TV), testicular echogenicity, and reproductive hormones in goats over a 24-h period. Methods In three trials that went for three consecutive days each, 12 bucks were scanned using Triplex ultrasonography to assess the TV, pixel intensity of testicular echotexture (PIX), and Doppler indices of TBF (resistive index: RI and pulsatility index: PI) in four-time points a day (at 6.00, 12.00, 18.00, and 00.00 h). Concomitantly, the changes in circulating FSH, LH, inhibin, testosterone (T), estradiol (E2), cortisol, and melatonin were assessed. Key results Results revealed diurnal alterations in the calculated RI of TBF and the PIX of testicular parenchyma (P < 0.05). Lower RI values of the TBF were observed at 6.00 h compared to other time points. There were significant diurnal alterations in the levels of FSH (P < 0.05), LH (P < 0.05), T (P < 0.0001), E2 (P < 0.0001), cortisol (P < 0.0001), and melatonin (P < 0.0001). FSH attained a higher concentration at 18.00 h compared to 12.00 h. Concentrations of LH were significantly higher at 06.00 h compared to those at 18.00 h. Concentrations of T were significantly higher at 6.00 compared to other time points. E2 showed higher concentrations at 6.00 h and 00.00 h compared to 12.00 h and 18.00 h. On the contrary, concentrations of cortisol were significantly higher at 12.00 h and 18.00 h compared to 06.00 h and 00.00 h. The highest concentrations of melatonin were observed at 00.00 h compared to other time points, while the lowest concentrations were at 12.00 h. Conclusions Diurnal rhythm induces significant changes in TBF, testicular PIX, and circulating FSH, LH, T, E2, cortisol, and melatonin over the 24-h day. Implications The outcomes of the study are reflected in the advisability of monitoring the TBF at a fixed time a day to avoid the circadian rhythm effect.

Coenzyme Q10 Supplementation enhances testicular volume and hemodynamics, reproductive hormones, sperm quality, and seminal antioxidant capacity in goat bucks under summer hot humid conditions

Oxidative stress (OS) is brought on by heat stress (HS), which weakens antioxidant defense and initiates OS. Since mitochondria are the primary source of reactive oxygen species (ROS), HS-mediated OS may be lessened by targeting mitochondria with particular antioxidants. The purpose of this study was to investigate the effect of oral coenzyme Q10 (CoQ10) supplementation on the reproductive performance of goat bucks under HS conditions. Ten mature bucks were randomly separated into two groups and housed in an environment with a high-temperature humidity index (THI: 88.3 to 94.8; summer season). The first group (n = 5) got the baseline diet while the second group (n = 5) received supplemental oral CoQ10 (3 mg/kg BW; CoQ10 group) daily for six weeks. Testicular blood flow parameters (TBF), testicular volume (TV) and echogenicity (TE), nitric oxide (NO), seminal alanine aminotransferase (ALT) and catalase (CAT) activities, total antioxidant capacity (TAC), malondialdehyde (MDA) content, and semen quality traits were all measured. The examinations started a week before (W-1), on the first supplementation day (W0), and weekly for eight consecutive weeks (W1-W8). There were marked (P < 0.05) increases in TBF (W3-W6) and TV, and a decrease in TE (W3-W5) in the CoQ10 group compared to the CON group. Similarly, testosterone (T) and NO levels (W3-W5) in the CoQ10 group were higher (P < 0.05) than those of the control group. The CoQ10 group demonstrated significant (P < 0.05) increases in seminal CAT (W4-W8) and TAC (W2-W6) activities and decreases in ALT (W4-W7) activity and MDA (W5-W8) concentration as compared to the control group. The CoQ10 group showed improvements (P < 0.05) at W3-W6 for sperm progressive motility, viability, and normal morphology and at W6-W8 for sperm concentration. In conclusion, oral CoQ10 supplementation improved testicular hemodynamics, testosterone production, semen quality, and antioxidant capacity in goat bucks during summer heat stress conditions.

Morphological and ultrasonographic characterization of the three zones of supratesticular region of testicular artery in Assaf rams

To fully understand the histological, morphometrical and heamodynamic variations of different supratesticular artery regions, 20 mature and healthy Assaf rams were examined through ultrasound and morphological studies. The testicular artery images of the spermatic cord as shown by B-mode analysis indicated a tortuous pattern along its course toward the testis, although it tends to be less tortuous close to the inguinal ring. Doppler velocimetric values showed a progressive decline in flow velocity, in addition to pulsatility and vessel resistivity when entering the testis, where there were significant differences in the Doppler indices and velocities among the different regions. The peak systolic velocity, pulsatility index and resistive index were higher in the proximal supratesticular artery region, followed by middle and distal ones, while the end diastolic velocity was higher in the distal supratesticular region. The total arterial blood flow and total arterial blood flow rate reported a progressive and significant increase along the testicular cord until entering the testis. Histological examination revealed presence of vasa vasorum in the tunica adventitia, with their diameter is higher in the proximal supratesticular zone than middle and distal ones. Morphometrically, the thickness of the supratesticular artery wall showed a significant decline downward toward the testis; meanwhile, the outer arterial diameter and inner luminal diameter displayed a significant increase distally. The expression of alpha smooth muscle actin and vimentin was higher in the tunica media of the proximal supratesticular artery zone than in middle and distal ones.

Exogenous L-carnitine Administration Ameliorates the Adverse Effects of Heat Stress on Testicular Hemodynamics, Echotexture, and Total Antioxidant Capacity in Rams

Heat stress (HS) diminishes the testicular antioxidant defense systems, which adversely affect the testicular blood perfusion. Improving the testicular hemodynamics during HS conditions is of a great impact on the whole reproductive performance in rams. This study aimed to evaluate the ameliorative effects of L-carnitine (LC) on the testicular blood flow and echotextures and also on the total antioxidants (TAC) and nitric oxide (NO) concentrations in the serum during HS conditions in rams. Testicular blood flow was evaluated through scanning of the supra-testicular artery (STA) spectral patterns through pulsed Doppler ultrasonography [peak systolic velocity (PSV), end-diastolic velocity (EDV), time average maximum velocity (TAMAX), resistive index (RI), and pulsatility index (PI)], while the echotexture assessment of testicular parenchyma was performed by a computerized software program. Moreover, TAC and NO concentrations were assayed colorimetrically using the spectrophotometer. There were significant decreases (P &lt; 0.05) in values of PSV at 48 and 168 h (23.45 ± 0.39 and 23.37 ± 1.41 cm/s, respectively), and TAMAX at 1, 48, and 168 h (17.65 ± 0.95, 17.5 ± 0.13, and 16.9 ± 1.05 cm/s, respectively) after LC administration compared to just before administration (31.92 ± 1.13 and 21.58 ± 0.92 cm/s, respectively). Values of RI and PI of the examined STA significantly decreased, especially at 1 h for RI (0.45 ± 0.02) and 1 and 48 h for PI (0.66 ± 0.06 and 0.65 ± 0.05, respectively) after LC treatment to 0 h (0.55 ± 0.03 and 0.84 ± 0.06, respectively). The EDV values did not show any significant (P &lt; 0.05) changes in all the experimental time points. There were significant (P &lt; 0.05) increases in the values of pixel intensity of the testicular parenchyma, especially at 1 and 168 h (78.71 ± 2.50 and 88.56 ± 4.10, respectively) after LC administration, compared to just before administration (69.40 ± 4.75). Serum NO levels tend to increase after LC administration (P = 0.07) concerning just before administration. While TAC values showed significant gradual increase and reached the highest values at 168 h (2.75 ± 0.58 mM/l) after LC administration, compared to 0 h (1.12 ± 0.05 mM/l). In conclusion, exogenous LC administration ameliorates testicular hemodynamic disruptions, as measured by spectral Doppler ultrasonography, via augmentation of the rams' total antioxidant capacity under HS conditions.

Testicular Ultrasound Analysis as a Predictive Tool of Ram Sperm Quality

Simple Summary

In animal production, the prediction of male fertility is vital for the success of specific techniques such as artificial insemination. Thus, testicular ultrasound, a non-invasive diagnostic procedure, could be a useful tool. Moreover, recent ultrasound-video analysis and software developments allow the visualization of tissue at the microscopic level. The objective of this work was to establish a possible correlation between testicular ultrasonography and semen quality in rams. For this purpose, the testicles of nine rams were evaluated and the semen was analyzed for one year. The results revealed that the number of white and grey pixels correlated with sperm parameters indicating poor seminal quality. On the other hand, the increase in the seminiferous-tubule density or the lumen area of these tubules was related to a rise in seminal quality. Therefore, ultrasound-video analysis could be a good tool for evaluating the fertility of rams, either for artificial insemination or on the farm.

Abstract

Testicular ultrasound is a non-invasive technique that could be very useful for predicting ram seminal quality. Recent software developments allow macroscopic and microscopic evaluation of testicular parenchyma. Thus, the aim of this study was to evaluate the testicular echotexture using ultrasound-video analysis and investigate its possible correlation with semen quality. Nine rams were evaluated for one year using a portable ultrasound scanner and the echotexture was analyzed with ECOTEXT^® software. The number of black (Ec1), white (Ec2), and grey pixels (Ec3), tubular density (TD), lumen area (LA), and lumen diameter (LD) were analyzed. Semen was collected by an artificial vagina the same day and the sperm concentration, morphology, motility, viability, phosphatidylserine (PS) translocation, reactive-oxygen-species (ROS) levels, DNA damage and capacitation state were evaluated. Ec2 and Ec3 correlated positively with “bad quality” sperm parameters (the percentage of spermatozoa with high ROS levels, with PS translocation and proximal cytoplasmic droplets), and negatively with motility. In contrast, TD and LA showed a positive correlation with “good quality” parameters (motility or normal morphology) and a negative correlation with spermatozoa with high ROS levels, with DNA fragmentation, and proximal or distal cytoplasmic droplets. Thus, echotexture analysis by ultrasound-video analysis could be a valuable tool for assessing ram fertility.

Semen quality, testosterone values, and testicular and accessory gland parameters in rams receiving sustained stimulation with low doses of buserelin

ContextThe use of buserelin, a gonadotropin-releasing hormone (GnRH) agonist, can improve semen quality. Nevertheless, the appropriate dosage, and frequency and time of application, remain to be established owing to the subsequent negative feedback on endogenous production of testosterone described so far.AimsThis study aimed to propose a new buserelin application protocol for sperm improvement in Santa Inês rams.MethodsFifteen Santa Inês rams were divided into two experimental groups: the first group (n=8) received 2.5μg buserelin acetate; and the second group (n=7) received saline solution. Treatments were applied for 21 days at intervals of 6h, totalling four hormonal or saline applications per day. In all animals, macroscopic and microscopic seminal characteristics and freezability, plasma testosterone, pixels of testicular parenchyma, and biometric analysis of testicular and accessory sex glands by ultrasound were evaluated throughout the period of hormonal application and for a further 7 days.Key resultsRams receiving buserelin showed a peak of testosterone after the first week (Day 7) of application, with a drop in values at Day 14, followed by negative feedback at Day 21 and return to basal concentrations at Day 28. They also showed improvement of kinetics parameters such as straight line velocity (μm/s: +buserelin 51.5±1.5 &gt; control 46.6±1.6) and linearity coefficient (%: +buserelin 53.5±1.8 &gt; control 47.5±1.9). Ultrasound parameters, pixels of testicular parenchyma, and freezability were not affected by treatment.ConclusionsThe administration of buserelin was able to improve some sperm kinetics parameters of Santa Inês rams.ImplicationsLow doses of this GnRH analogue can be used; however, further adjustments to the hormonal protocol are needed to obtain an effective improvement in sperm quality.

Ageing affects plasma steroid concentrations and testicular volume, echotexture and haemodynamics in rams

The objective was to determine the effect of ageing on plasma steroid concentrations and testicular volume, echotexture and haemodynamics in Ossimi rams. Twenty-four rams were allocated, by age, into three groups: young (1 year; 32.00 ± 0.78 kg, n = 6); mature (2.5 years; 48.00 ± 1.02 kg, n = 9) and aged (7.5 years; 65.00 ± 1.10 kg, n = 9). Aged rams had the highest (p ˂ 0.05) plasma testosterone concentrations 3.90 ± 0.75 ng/ml (three-fold the other groups), whereas in young rams, plasma estradiol-17β concentrations (5.85 ± 0.34 pg/ml) were approximately one-quarter (p ˂ 0.05) of other groups. Regarding pulsed-wave Doppler indices values of the (resistive index RI; and pulsatility index PI) were lower (p ˂ 0.05) in the mature (0.32 ± 0.04 and 0.36 ± 0.03, respectively) and aged (0.51 ± 0.03 and 0.77 ± 0.06) rams compared to young rams (0.62 ± 0.03 and 0.98 ± 0.07). In the young group, testicular pixel intensity was highest (p ˂ 0.05) but values of coloured area/pixels were lowest (p ˂ 0.05) compared to the other groups. In conclusion, these parameters indicate that aged rams (7.5 years) are likely to be suitable for breeding ahead of the younger aged groups (1 and 2.5 years) examined, but a final decision would need to be tempered by consideration of other parameters in the breeding soundness examination (BSE), such as physical soundness and semen characteristics. Of the parameters studied, testicular pixel intensity could be most readily incorporated in a BSE for deciding a ram's breeding efficiency.

Melatonin improves testicular haemodynamics, echotexture and testosterone production in Ossimi rams during the breeding season

The objective was to determine effects of a single parenteral dose of melatonin on testicular blood flow indices, testicular echogenicity and plasma testosterone concentrations in rams during the physiological breeding season. We hypothesized that melatonin enhances testicular blood flow, echogenicity and plasma testosterone concentrations during the breeding season in rams. During the breeding season, 12 sexually mature Ossimi rams were randomly allocated to either a melatonin group (n = 8) that received 18 mg of melatonin in 1 ml of corn oil (injected SC) or a control group (n = 4) that received 1 ml corn oil only. Blood collection and ultrasonographic assessment of the testes and supratesticular arteries were conducted immediately before treatment (W0) and once weekly for 6 weeks after melatonin injection (W1-W6). Mean plasma testosterone concentrations were greater (p < .05; at least 1 ng/ml) in the melatonin-treated group compared to the control group from W4 to W6 after treatment. A decrease (p < .05) in both resistive index (RI) and pulsatility index (PI) began 1 week after melatonin injection (W1) and persisted until the end of the experiment, with mean RI and PI values in the melatonin group lower (p < .05) than those in the control group on W3 and W4. Furthermore, plasma testosterone concentrations in melatonin-treated rams were inversely correlated to both RI and PI (r = -.7 and -.6, respectively, p < .01). Testicular echogenicity decreased (p < .05) 1 week after melatonin injection (W1) and remained lower (p < .05) in the melatonin-treated group compared to the control group until the end of the study (W6). In conclusion, melatonin administration significantly altered testicular blood flow and echogenicity and increased plasma testosterone concentrations in Ossimi rams during the breeding season.

Exogenous oxytocin administration improves the testicular blood flow in rams

The current research aimed to examine the effects of single-dose oxytocin administration on testicular blood flow measurements peak systolic velocity (PSV), end-diastolic velocity (EDV), resistive index (RI) and pulsatility index (PI) and plasma steroid (testosterone and oestradiol-17β) concentrations in rams. In the treated group, eight mature Ossimi rams during the breeding season were injected intravenously (iv) with 20 IU oxytocin, while the other eight male rams were administered normal saline (2 ml) iv as a control group. Venous blood samples and testicular blood flow in the left and right testes were examined immediately before (0) and 5, 30, 60 and 120 min after injections. The control group did not show significant changes in the variables examined (p > .05), except for the EDV (p < .05). In the treated group, the administration of oxytocin led to a significant decrease in RI and PI values starting 5 min after oxytocin administration until 60 min after its application (p < .05). The plasma concentrations of testosterone and oestradiol-17β raised from 5 to 30 min after oxytocin injection (p > .05) and then declined significantly until 120 min (p < .05). In conclusion, oxytocin is a potent testicular vasodilator affecting the testicular vascular tone and steroid concentrations in rams.

Ageing changes testes and epididymis blood flow without altering biometry and echodensity in dogs

Senescence leads to deleterious effects in testicular function, sperm quality and fertility in dogs. There, however, are no consistent results of vascular changes in the testes and epididymis during natural ageing in dogs. The aim of this study, therefore, was to compare testes and epididymis blood flow, biometry and echodensity between young and senile dogs. Ten young dogs (1-4 years) and eight senile dogs (over 7 years) were selected and assigned to two experimental groups: Young Group and Senile Group. Dogs were evaluated using testicular and epididymis B-mode (dimensions and echodensity) and Doppler ultrasonography (tissue perfusion parameters and blood flow velocity of the testicular artery). There were no differences between experimental groups for the echographic evaluation of testicular and epididymis parenchyma and biometric variables. The dogs in the Young Group had greater (P = 0.02) testes vascularization score and greater (P = 0.06) testicular artery blood flow velocity than those in the Senile Group. Furthermore, the older dogs had a greater (P = 0.06) pulsatility index of the testicular artery than those in the Young Group. Ageing, therefore, seems to cause natural hemodynamical changes to the testicular artery, resulting in reduced blood flow (ischemia) and tissue damage. Testes and epididymis vascular characteristics, therefore, may represent the causal factors for changes in spermatogenesis and, as a consequence, negatively affect the sperm quality of older dogs. In conclusion, senescence alters testicular artery blood flow and vascularization of the testes, without changing testicular and epididymis ultrasonographic dimensions and echodensity in dogs.

Salmon oil supplementation in dogs affects the blood flow of testicular arteries

The administration of fish oils is known to cause changes in several reproductive parameters of domestic animals. The ingestion of polyunsaturated fatty acids (PUFAs) of the omega-3 family, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), has been described and correlated with changes in the semen quality, testosterone levels and male fertility. Nevertheless, few studies monitored and registered effects after ceasing supplementation. In the present study, we monitored the Doppler velocimetric and ultrasonographic parameters of nine dogs' testis for 90 days (D90) checking the effect of salmon oil supplementation, and monitoring continued for 60 days more, after ceasing supplementation (D150). Ultrasonographic evaluations comprised determining the Doppler velocimetric parameters, testicular and epididymal volume, and testicular echotexture. Peak systolic velocity (PSV) as well as final diastolic velocity (EDV) in the supratesticular arteries (STA), and marginal artery (MA) increased during the period of treatment and kept that level up to D150. There was no difference between the fish-oil supplementation period and the unsupplemented one regarding the testicular and epididymal volume and echogenicity and heterogeneity characteristics. A negative correlation was found between heterogeneity of testis and sperm production (r = -.41, p = .008). Doppler velocimetry indices were affected by the supplementation, leading to an increase in testicular blood flow.

New Approaches to Assess Fertility in Domestic Animals: Relationship between Arterial Blood Flow to the Testicles and Seminal Quality

The early identification of infertile males improves reproduction efficiency at a production level and is essential to secure high production rates. Before entering a breeding program, males must pass an initial breeding soundness examination (BSE) which consist of several diagnostic exams whose end point is to estimate their future fertility. There is ongoing research to find new markers that allow better identification of fertile males. Doppler mode allows the quantitative and qualitative evaluation of the irrigation of organs. When evaluating the reproductive system, Doppler mode has been successfully used for the evaluation of the uterine and ovarian irrigation. In males, it is gaining relevance for the evaluation of testicular irrigation. Researchers have found a relationship between pulsed-wave Doppler velocimetric parameters and seminal quality in various domestic animal species. This suggests Doppler ultrasound parameters should be considered as objective parameters to evaluate testicular function. In this review, we analyze the results in the main domestic animal species and discuss the differences and similarities among the results. We also discuss the effect of the location of the measurements, breed, season and laterality in the measurement of Doppler velocimetric parameters as well as the impact and limitations of this method of assessing breeding soundness.

Advances in applications of color Doppler ultrasonography in the andrological assessment of domestic animals: A review

Compared to human cases, potential applications of Doppler imaging technology in farm animals' practice are still limited and are mostly concerned with females. Testicular blood perfusion (TBP) is the pathway through which all nutrients, oxygen, and regulatory agents pass through to the testis. TBP is crucial to the testis function because of the high metabolic rate and very low concentration of oxygen in the seminiferous tubules, which constitute about 70%-80% of the testicular mass. Color Doppler ultrasonography is one of the recent non-invasive technologies, which plays a vital role in the assessment of blood flow to the testis in various animal species. In the past 20 years, a significant number of studies have highlighted the importance of assessments of TBP using color Doppler ultrasonography to illustrate its potential uses for breeding soundness examination, diagnosis, and monitoring of infertility problems in farm animals. This review was aimed at providing, for the first time, updated knowledge on the potential clinical uses of color Doppler ultrasonography for the assessment of TBP in domestic animals. Additionally, a few essential details on the relationship between TBP and male fertility are discussed in this review. Furthermore, a number of caveats relating to the use of color Doppler ultrasonography are discussed, which collectively appear to constrain its routine, on-farm application for breeding soundness assessments, at least at the present. The new perspectives related to animal reproduction that researchers claim to do in further investigations are also discussed.

Passive immunization against inhibin increases testicular blood flow in male goats

The present study investigated whether or not passive immunization against inhibin modulates testicular blood flow in goats. Male Shiba goats were injected with either 10 ml of inhibin antiserum (INH group; n = 5) or 10 ml of normal castrated goat serum (NGS group; n = 4). Concentrations of FSH, LH, testosterone (T), and estradiol (E2) in the plasma were measured by radioimmunoassay. Blood flow within the supratesticular (STA) and marginal testicular arteries (MTA) were measured by color pulsed-Doppler ultrasonography, and Doppler indices (resistive index; RI and pulsatility index; PI) were recorded. Results revealed significant increases in concentrations of FSH and E2 in the INH group compared to those in the NGS group (P < 0.05). Animals in the INH group had greater (P < 0.05) FSH concentrations than those in the NGS group in the period between 60 h and 144 h after treatment than at any other time. Estradiol concentrations were greater (P < 0.05) in the INH group than in the NGS group at 6 h (12.15 ± 2.09 pg/ml vs 5.49 ± 1.17 pg/mL), 12 h (8.27 ± 1.29 pg/mL vs 3.05 ± 0.38 pg/mL), and 36 h (9.35 ± 1.31 pg/mL vs 5.09 ± 0.46 pg/mL) after treatment than at any other time. Concentrations of LH and T did not significantly change between the two groups. Goats in the INH group had lesser (P < 0.05) RI of the STA than those in the NGS group and RI values were lesser at 24 h (0.37 ± 0.031 vs 0.49 ± 0.004) and 120 h (0.38 ± 0.028 vs 0.55 ± 0.048) after treatment than at any other time. Furthermore, values of RI and PI of the MTA were significantly lesser (P < 0.05) in the INH group compared to those in the control group at 48 h (RI of MTA: 0.21 ± 0.014 vs 0.37 ± 0.039; PI of MTA: 0.24 ± 0.016 vs 0.46 ± 0.058) after treatment than at any other time. In conclusion, passive immunization against inhibin has a stimulatory effect on testicular blood flow in goats by inducing decreases in the RI values of the STA and MTA.

Ultrasonographic characteristics of the testes, epididymis and accessory sex glands and arterial spectral indices in peri- and post-pubertal Nelore and Caracu bulls

Ultrasonography can provide information about the integrity of organs; however, rarely is applied to the reproductive organ evaluation of bulls. The objective of the present study was to characterize and compare values for variables and ultrasonographic characteristics of the testes, epididymis and accessory sex glands, as well as spectral Doppler indices of the testicular and internal iliac arteries, between peri- and post-pubertal Nelore and Caracu bulls. Nelore (n = 203) and Caracu (n = 79) bulls were assigned by age class: peri-pubertal (12-15 months) and post-pubertal (> 22 months). Data were analyzed using SAS's PROC MIXED procedure (P < 0.05). The biometric variables of the testes and cauda epididymis differed between peri- and post-pubertal Nelore and Caracu bulls. There was a difference between breeds for the vesicular glands, ampulla of vas deferens, disseminate portion of the prostate, and craniocaudal dimension of the bulbourethral glands. Echogenicity of the testicular parenchyma differed between breeds and age classes. The pulsatility and resistive indices of the testicular arteries differed between Nelore and Caracu bulls. The biometric and ultrasonographic characteristics of the testes, epididymis and accessory sex glands, as well as of the arterial indices in bulls are affected by genetic group and age class, and when assessed there is useful information regarding the progression of sexual maturation.