Melatonin administration enhances the reproductive capacity of young rams under a southern Mediterranean environment

This study tested the effect of melatonin treatment, initiated in late February on reproductive traits of young rams. A total of 14 young Barbarine rams were used. Seven animals were treated with three melatonin subcutaneous implants (Melatonin) on 28 February while the remaining rams remained untreated (Control). After 60 days of melatonin administration, scrotal circumference reached average values of 32.1 ± 1.54 and 29.5 ± 1.0 cm for Melatonin and Control animals, respectively (P < 0.05). Semen characteristics did not differ between groups; melatonin treatment tended (P = 0.091) to increase sperm concentration 60 days after implantation when means reached 5.87 ± 0.703 and 4.61 ± 0.654 × 10⁹ spermatozoa/mL for Melatonin and Control rams, respectively. Melatonin treatment significantly affected total activity time, number of lateral approaches and mount attempts in comparison to controls. During a 6‐h sampling period, mean plasma testosterone concentrations increased as a result of melatonin treatment (P < 0.001) and testosterone pulse frequency averaged 3.45 ± 2.24 and 1.25 ± 1.0 (P = 0.086) for Melatonin and Control rams. Data clearly suggest that abrupt treatment of young rams with melatonin implants in winter is sufficient to improve reproductive traits.     

Assessment of the accuracy of testicular dysfunction detection in male donkey (Equus asinus) with the aid of colour-spectral Doppler in relation to plasma testosterone and serum nitric oxide levels

This study aimed to determine the usefulness of colour and pulsed Doppler modes for the accurate diagnosis of donkeys suffering from subfertility to determine whether testicular vascularity assessment could be an indicator for sperm functionality. The study sample was composed of 10 male donkeys with normospermia (control group) and 10 donkeys with hypospermia. Animals underwent scrotal circumference measurement, testicular Doppler examination, seminal evaluation, blood sampling and hormonal assay. Semen volume and concentration were significantly (p ≤ .05) lower in the subfertile group (30.25 ± 1.22 ml and 89.44 ± 2.55 × 10⁶/ml) as compared with the control group (82.76 ± 1.65 ml and 452.78 ± 1.25 × 10⁶/ml), and total sperm/ejaculation was significantly (p ≤ .05) higher in the normal donkeys (28.30 ± 2.32 × 10⁹/total ejaculated) as compared with the subfertile group. Intratesticular coloured area showed a marked decline in the hypospermic males. There was no significant difference between the two groups in testosterone level, although the normal group showed an increase in nitric oxide metabolites. Both Doppler indices of the three branches of the testicular artery were elevated significantly (p ≤ .05) in abnormal donkeys, whereas Doppler peak systolic and end-diastolic velocities were increased in the normal group. Male donkeys with subfertility demonstrated lower arterial vascularity parameters in the form of intratesticular coloured area and blood flow rate; therefore, the most optimal parameters for differentiating subfertile hypospermic from normospermic donkeys were found to be the two Doppler indices, velocities parameters, testicular blood flow rate and nitric oxide levels.     

Kisspeptin injection improved the semen characteristics and sperm rheotaxis in Ossimi ram

The aim of the present study was to investigate the effect of kisspeptin-10 (Kp10) injection on semen characteristics, testosterone (T) production and sperm rheotaxis using microfluidic devices in immature ram. Computer-assisted sperm analysis (CASA) with controlled flow velocity was used to explore the kinetic parameters of sperm and positive rheotaxis (PR %). PR % was defined as the number of PR sperms over the number of motile sperms. Healthy Ossimi rams were randomly divided into two groups; a saline-treated control group and Kp10-treated one (5 µg/kg body weight). Treatments were given by intramuscular injection once a week for 1 month. After 1 month, the semen was collected and evaluated weekly for 6 weeks, while the blood samples were collected every 2 weeks for the next 8 weeks. Semen properties were significantly affected by Kp10 injection (p < .01). The Kp10 increased the volume, sperm concentration and percentages of live sperm compared with those of control. Additionally, sperm trajectories and rheotaxis get improved by the injection of Kp10 with time. Furthermore, kisspeptin improved the secretion of testosterone levels throughout the period of study. In conclusion, injections of the Kp10 had a positive impact on semen characteristics as well as improved sperm rheotaxis of Ossimi rams in subtropics.     

Seasonal changes in breeding activity, testicular size, testosterone concentration and seminal characteristics in rams with long or short breeding season

Breeding activity (libido), testicular size, testosterone levels and seminal characteristics of 10 DLS adult rams (a population of 1/2 Dorset, 1/4 Leicester and 1/4 Suffolk selected for extended breeding season) were compared with those of 10 adult Suffolk rams. The study lasted 18 mo during which the data were recorded over 30 collection periods. All characteristics varied significantly with the season of the year, being lowest during the summer and highest during the fall. Suffolk rams had higher libido but lower testosterone levels than the DLS rams throughout the study. Testosterone increased earlier and decreased later in the breeding season in DLS compared with Suffolk rams, the interaction breed X period being significant. Testosterone concentration was highly associated with testicular size and libido, accounting for 65 and 28% of the variation in the Suffolk and 37 and 18% in the DLS rams, respectively. Seminal output and quality (motility and percentage of live spermatozoa) were highest in October and November and lowest in April and May. Rams within breeds differed significantly in the seminal characteristics studied. Results of the study showed that selecting the DLS ewes for extended breeding season may have altered the reproductive performance of the rams of that breed.     

Melatonin and CIDR improved the follicular and luteal haemodynamics,uterine and ovarian arteries vascular perfusion,ovarian hormones and nitric oxide in cyclic cows

This study hypothesizes that melatonin with exogenous progesterone (CIDR) can improve follicular, luteal, ovarian and uterine haemodynamic of heat-stressed cows. Holstein cows (N = 12) studied for two spontaneous oestrous cycles during winter then divided equally during summer into the CIDR group received CIDR for 7 days and the melatonin group (Mel) received three injections of melatonin (75 mg/head) at the CIDR insertion, removal and ovulation days. Blood samples were collected to assay oestradiol (E2), progesterone (P4) and nitric oxide (NO). On day 0 (Ovulation), Mel had more small follicles (p < .05), higher ipsilateral and contralateral ovarian arteries (Ov.A.) peak systolic velocity (PSV), higher ipsilateral uterine artery (Ut.A.) PSV (p = .031) and blood flow volume (BFV), also Mel elevated contralateral Ut.A. PSV and BFV (p < .0001) but lowered contra Ut.A. pulsatility index (PI, p < .0001), E2 (p < .01) and NO (p < .0001). Mel increased the corpus luteum diameter (CL, p < .001), coloured area (p < .007) and P4 (p < .0001) on day 5 and reduced them (p < .05; p < .01) on Day 14. On day 10, Mel obtained CL diameter (p < .03) and coloured area (p < .002) of spontaneous that was higher than CIDR and decreased P4 (p < .003). Mel increased CL diameter, area and coloured area and decreased them thereafter. Mel increased the ipsilateral ovarian and uterine arteries PSV and BFV before ovulation and until day 8. Mel increased P4 and decreased NO until days 6 and 14. In conclusion, the improvement in follicular, luteal, ovarian and uterine haemodynamic and the decrease of NO production proved our hypothesis Melatonin doses higher than 75 mg/head is recommended to improve the heat-stressed cow's fertility.     

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

There is a paucity of information on the relationships of testicular morphology, echotextural attributes, and blood flow dynamics with pubertal development of rams raised in a subtropical climate. Forty‐five Dorper rams (24 rams aged 8–11 months and 21 rams aged 12–24 months) were examined using a portable ultrasound scanner connected to a 7.5‐MHz transducer. Computer‐assisted analyses of testicular ultrasonograms utilized commercially available Image ProPlus^® analytical software. Spectral Doppler scans of testicular arteries were performed immediately after scrotal (B‐mode) ultrasonography to determine peak systolic velocity (PSV), end‐diastolic velocity (EDV), resistive index (RI = [PSV?EDV]/PSV), and pulsatility index (PI = [SPV–EDV]/mean velocity) of the blood vessels. The length of the testes (9.7 ± 0.3 compared with 9.0 ± 0.2 cm) and scrotal circumference (33.3 ± 0.5 compared with 31.8 ± 0.4 cm) were greater (p < 0.05) but testicular depth (4.5 ± 0.1  compared with 4.9 ± 0.08 cm) was less (p < 0.05) in sexually mature compared with peripubertal rams. [Corrections added on 9 Jan 2019 after initial online publication: The testicular size values in the sentence were corrected.] There were no differences (p > 0.05) between the two age groups of Dorper rams in blood flow indices of testicular arteries. Mean numerical pixel values (100.5 ± 4.1 compared with 89.2 ± 4.8) and pixel heterogeneity (25.6 ± 0.6 compared with 23.6 ± 0.5) of testicular parenchyma were greater (p < 0.05) in peripubertal than in postpubertal rams. Semen volume was negatively correlated with PI of testicular arteries (r = ?0.57, p = 0.04). In summary, the attainment of sexual maturity in the rams of the present study was associated with significant changes in testicular length and depth, scrotal circumference, and parenchymal echogenicity/hetrogeneity but not in testicular volume and blood perfusion rates. Testicular artery PI can be used to predict the volume of ejaculate in rams.     

Testicular shape,scrotal skin thickness and testicular artery blood flow changes in bulls of different ages

The aim of this study was to compare the biometric testicular characteristics, skin thickness and haemodynamics of the testicular artery of 12- and 24-month-old bulls using Doppler ultrasonography, the study was conducted using 48 indicus-taurus animals. The scrotal circumference (SC) and biometry characteristics of the bulls were measured to calculate the testicular volume. Doppler ultrasonography was used to obtain the haemodynamic values of the testicular artery. The skin thickness and volume were lower (p<.01) in the younger bulls (12 months:4.68 ± 0.68 mm; 168.76 ± 47.96 cm³) versus 24 months (5.05 ± 0.89; 499.73 ± 129.24 cm³) animals (p<.01). During diastole, mean velocity was lower in the 12 months (7.98 ± 3.83) than in the 24 months (11.37 ± 4.15) animals (p <.05). The 12-month-old animals had higher pulsatility and resistivity indices (0.49 ± 0.02; 0.51 ± 0.20) compared to the 24-month-old animals (0.32 ± 0.16; 0.40 ± 0.15) (p < .05). The final testicular end velocity was lower in animals with long/moderate-shaped (L/M) (7.31 ± 2.91) than in those moderate/oval-shaped (M/O) (11.48 ± 3.88) testicles (p < .05). Animals with L/M testes presented higher pulsatility values and resistivity indices (0.51 ± 0.05; 0.55 ± 0.04) compared to animals with M/O shape (0.29 ± 0.20; 0.36 ± 0.15). We showed that the blood flow of the supra testicular artery between the two evaluated ages differed, and that 24-month-old bulls presented better thermoregulation capacity. Animals with a long/moderate testicular format presented a greater vascular resistance, which was imposed on the blood flow due to the anatomical differences in the testicular artery, resulting in lower velocity, and indicating better heat dissipation in this format.     

Seasonal variations in sexual behavior, testosterone, testicular size and semen characteristics, as affected by social dominance, of tropical hair rams (Ovis aries)

The purpose of this study was to examine the effect of day length on seminal characteristics, testicular size, sexual behavior and testosterone concentration (T4) in dominant and subordinate Pelibuey rams. Six groups of three animals were evaluated every 2 weeks over a 12 month period. Dominant (D), medium (M) and subordinate (S) animals in each group were identified through a food competition test every 15 days. All rams ejaculated and produced semen throughout the year. A linear hierarchy was clearly established and maintained during the year. S rams had lower levels (P < 0.05) of semen volume, sperm concentration and testicular volume than D rams, regardless of season. Scrotal circumference was not influenced (P > 0.05) by their social position. D rams were more affected by the photoperiod, decreasing (P < 0.05) reaction times, increasing (P < 0.05) T₄ and producing more (P < 0.05) sperm per ejaculation than S rams during short days (14.65 ± 1.22 vs 26.92 ± 1.65 s; 8.68 ± 0.44 vs 7.37 ± 0.40 ng/mL and 3.37 ± 0.17 vs 2.04 ± 0.16 sperm/10⁹, respectively). Semen volume and sperm concentration were significantly (P < 0.05) greater during short days in all rams, regardless of their social status, with the exception of sperm concentration in D rams where no variation was found. M rams displayed variable values in the range between the D and S rams. It was concluded that the magnitude of the seasonal effects was not sufficient to prevent the rams being used for breeding throughout the year and that seasonal variation within the variables affected the social ranks differently.     

Effect of weaning method on body weight,testicular growth,sexual behavior,age of puberty,and testosterone concentration of Beetal bucks

The current study evaluates the effects of early (8th week) and late (16th week of age) weaning of male goat kids on their body growth, testicular growth, sexual behavior, plasma testosterone concentration, and pubertal age. Early (n = 6) and late (n = 7) weaned Beetal bucks were weekly monitored from 18th to 38th week for their body weight, scrotal circumference, testicular volume, testicular echogenicity (via ultrasonography), sexual activities, and plasma testosterone concentration. In comparison to early-weaned, late-weaned bucks showed a marked increase (p < .05) in body weight (11.4 ± 0.8 vs. 13.7 ± 0.6kg), testicular volume (44.1 ± 7.2 vs. 79.8 ± 18.7cm³), scrotal circumference (10.7 ± 0.6 vs. 12.8 ± 0.7cm), and testicular echogenicity (28.3 ± 2.7 vs. 38.3 ± 2.1) from 18th, 28th, 21st, and 24th week onward, respectively. Sexual activities started earlier in late- than early-weaned bucks (22nd vs. 25th week, respectively). Moreover, the sexual behavior index was better (p < .05) after the 34th week in late than early-weaned bucks. The plasma concentration of testosterone (at 39 weeks of age) was relatively more and the onset of puberty was 2–3 weeks earlier (p < .05) in late than early-weaned bucks. In conclusion, age-based early weaning of male kids impairs their testicular growth, sexual behavior, and age at puberty compared to conventional weaning.     

Melatonin alters bovine uterine artery hemodynamics,vaginal temperatures,and fetal morphometrics during late gestational nutrient restriction in a season-dependent manner

The objectives were to examine melatonin-mediated changes in temporal uterine blood flow (UBF), vaginal temperatures (VTs), and fetal morphometrics in 54 commercial Brangus heifers (Fall, n = 29; Summer, n = 25) during compromised pregnancy. At day 160 of gestation, heifers were assigned to one of the four treatments consisting of adequately fed (ADQ-CON; 100% National Research Council [NRC]; n = 13), global nutrient restricted (RES-CON; 60% NRC; n =13), and ADQ or RES supplemented with 20 mg/d of melatonin (ADQ-MEL, n = 13; RES-MEL, n = 15). In the morning (0500 hours; AM) and afternoon (1300 hours; PM) of day 220 of gestation, UBF was determined via Doppler ultrasonography, while temperature data loggers attached to progesterone-free controlled internal drug releases were used to record VTs. At day 240 of gestation, heifers underwent cesarean sections for fetal removal and morphometrics determination. The UBF and VT data were analyzed using repeated measures of analysis of variance (ANOVA), while the morphometrics was analyzed using the MIXED procedure of SAS. Seasons were analyzed separately. In Fall, a nutrition by treatment interaction was observed, where the RES-CON heifers exhibited reduced total UBF compared with ADQ-CON (5.67 ± 0.68 vs. 7.97 ± 0.54 L/min; P = 0.039). In Summer, MEL heifers exhibited increased total UBF compared with the CON counterparts (8.16 ± 0.73 vs. 6.00 ± 0.70 L/min; P = 0.048). Moreover, there was a nutrition by treatment by time interaction in VT for Fall and Summer heifers (P ≤ 0.005). In Fall, all groups had decreased VT in the morning compared with the afternoon (P < 0.05). Whereas, in Summer, VT increased for ADQ-CON and RES-CON (P < 0.0001) from morning to afternoon, the ADQ-MEL and RES-MEL remained constant throughout the day (P = 0.648). Furthermore, the RES-MEL-PM exhibited decreased VT compared with ADQ-CON-PM (38.91 ± 0.09 vs. 39.26 ± 0.09 °C; P = 0.018). Lastly, in Fall, a main effect of nutrition was observed on fetal weights, where the RES dams had fetuses with decreased body weight when compared with ADQ (24.08 ± 0.62 vs. 26.57 ± 0.64 kg; P = 0.0087). In Summer, a nutrition by treatment interaction was observed on fetal weights where the RES-CON dams had fetuses with reduced weight when compared with ADQ-CON and RES-MEL (P < 0.05). In summary, nutrient restriction decreased UBF and melatonin supplementation increased UBF depending on the season. Additionally, melatonin appeared to decrease VT and rescue fetal weights when supplemented in the Summer.     

Ultrasonographic and morphological sequelae to repeated testicular biopsies in stallions in relation to the lateral branching of the testicular artery

The objectives of this study were to investigate the sequelae to repeated testicular biopsies in stallions and to determine if arterial injuries can be prevented. This study was part of a larger project focused on the antispermatogenic effects of an oral contraceptive compound, RTI‐4587‐073(l), which was given to 3 mature Miniature horse stallions, while another 3 received a placebo treatment. Testicular biopsies were taken once before treatment and 3 times after treatment. They were obtained from alternating testes, 2 procedures per testis, 2 samples each time, using a 18 gauge split‐needle core biopsy instrument (penetration depth: 22 mm). Colour Doppler ultrasonography was performed prior to the procedure to detect and thus avoid lateral branches of the testicular artery. Testicular parenchyma was evaluated ultrasonographically just before, and 2–6 h, 3 days and weekly after the biopsies were obtained. Changes in testicular volumes and semen parameters were monitored. All stallions were then castrated and the testes were evaluated for any gross pathology. There was no major scrotal swelling or gross haemorrhage after the procedures. Only mild, focal lesions were found in the testicular parenchyma 3 and 7 days after taking the biopsies. Three lateral branches of the testicular arteries were punctured, but there was no evidence of significant bleeding or other complications associated with these injuries. We conclude that repeated testicular biopsies may be taken from stallions without causing major complications, regardless of a presence or absence of the lateral branches of the testicular artery. Furthermore, we conclude that using colour Doppler ultrasonography to detect the lateral branches of the testicular arteries is unreliable; however, puncturing these vessels during a biopsy procedure does not necessarily result in significant haemorrhage.     

Effect of eCG dose on ovarian haemodynamics,hormonal profiles and prolificacy rate when oestrus was induced during low-breeding season in Beetal goats

The objectives of the experiment were to determine the effect of two doses of equine chorionic gonadotropin (eCG) in a standard synchronization protocol based on a short-term progesterone (P₄) priming on ovarian structures and haemodynamics, concentrations of steroid hormones and prolificacy rate when oestrus was induced during low-breeding season (LBS) in Beetal dairy goats. We hypothesized that inclusion of eCG in a short-term P₄ priming-based synchronization protocol would increase the blood perfusion to ovarian structures leading to enhance oestrous and ovulatory responses and prolificacy rate in goats. Forty-two multiparous acyclic goats were blocked by body condition and, within block, assigned randomly to receive saline as control (CON), low eCG (L-eCG; 300 IU) or high eCG (H-eCG; 600 IU) dose. Initially, a controlled internal drug release (CIDR) device was placed in the anterior vagina on d −8, followed by removal of CIDR on d −3, concurrent with the administration of PGF_2α and eCG according to their respective treatments. Goats were monitored for oestrous response. B-mode and Doppler ultrasonography was performed with 12-h interval, starting from day −3 until natural breeding (day 0), and then on days 5, 10, 15 and 20 post-breeding to monitor follicular and luteal dynamics and blood flow, respectively. Blood was sampled at 0, 12, 24, 36 and 60 h after CIDR removal to quantify plasma concentrations of estradiol-17β (E₂), whereas plasma concentrations of P₄ were assayed at days 5, 10, 15 and 20 after breeding. Pregnancy and prolificacy rates were determined at day 30 and 150 after breeding, respectively. Data were analysed with mixed-effects models, and orthogonal contrasts were used to evaluate the effect of treatment [Con vs. (½ L-eCG + ½ H-eCG)] and dose of eCG (L-eCG vs. H-eCG). Data are presented in sequence as CON, L-eCG, H-eCG (LSM ± SEM). The oestrous intensity score (152.9 vs. 182.7 vs. 186.5 ± 15.1; p = .02) was greater in eCG-treated goats as compared to CON. Administration of eCG reduced the intervals to standing oestrus (66.2 vs. 41.8 vs. 48.9 h ± 5.5; p = .05), breeding (70.2 vs. 44.4 vs. 45.4 h ± 4.5; p = .03) and ovulation (84.5 vs. 61.2 vs. 63.4 h ± 6.2; p = .05) compared with CON goats. The mean growth rate of pre-ovulatory follicle was greater (1.11 vs. 1.49 vs. 1.45 mm ± 0.08; p = .01) in eCG-treated goats resulting in an increased diameter of pre-ovulatory follicle (6.27 vs. 7.20 vs. 7.31 mm ± 0.07; p < .01) and corpora lutea (6.75 vs. 8.26 vs. 8.07 mm ± 0.42; p = .04) than CON. The mean follicular blood flow did not differ among treatments; however, the mean luteal blood flow was greater in L-eCG-treated goats (0.81 vs. 1.61 vs. 1.07 cm² ± 0.12; p = .001). The mean concentrations of E₂ (4.03 vs. 5.21 vs. 4.78 pg/ml ± 0.42; p = .04) and P₄ (4.85 vs. 6.39 vs. 6.22 ng/ml ± 0.34; p = .04) were greater in eCG-treated goats. The twinning rate did not differ between treatments; nevertheless, prolificacy rate was greater (p = .04) in L-eCG-treated goats. Collectively, our data suggest that the administration of eCG improves the induction of oestrous and ovarian dynamics. Administration of L-eCG enhances prolificacy rate, therefore, a low dose of eCG might be practically beneficial to improve reproduction during LBS in acyclic Beetal dairy goats.     

Melatonin reduces apoptotic cells,SOD2 and HSPB1 and improves the in vitro production and quality of bovine blastocysts

Effects of adding different concentrations of melatonin (10^?7, 10^?9 and 10^?11 M) to maturation (Experiment 1; Control, IVM  + 10^?7, IVM  + 10^?9, IVM  + 10^?11) and culture media (Experiment 2; Control, IVC  + 10^?7, IVC  + 10^?9, IVC  + 10^?11) were evaluated on in vitro bovine embryonic development. The optimal concentration of melatonin (10^?9 M) from Experiments 1–2 was tested in both maturation and/or culture media of Experiment 3 (Control, IVM  + 10^?9, IVC  + 10^?9, IVM /IVC  + 10^?9). In Experiment 1, maturated oocytes from Control and IVM  + 10^?9 treatments showed increased glutathione content, mitochondrial membrane potential and percentage of Grade I blastocysts (40.6% and 43%, respectively). In Experiment 2, an increase in the percentage of Grade I blastocysts was detected in IVC  + 10^?7 (43.5%; 56.7%) and IVC  + 10^?9 (47.4%; 57.4%). Moreover, a lower number and percentage of apoptotic cells in blastocysts were observed in the IVC  + 10^?9 group compared to Control (3.8 ± 0.6; 3.6% versus 6.1 ± 0.6; 5.3%). In Experiment 3, the IVC  + 10^?9 treatment increased percentage of Grade I blastocysts with a lower number of apoptotic cells compared to IVM /IVC  + 10^?9 group (52.6%; 3.0 ± 0.5 versus 46.0%; 5.4 ± 1.0). The IVC  + 10^?9 treatment also had a higher mRNA expression of antioxidant gene (SOD 2) compared to the Control, as well as the heat shock protein (HSPB 1) compared to the IVM  + 10^?9. Reactive oxygen species production was greater in the IVM /IVC  + 10^?9 treatment group. In conclusion, the 10^?9 M concentration of melatonin and the in vitro production phase in which it is used directly affected embryonic development and quality.     

Male-to-female aggression in cage-housed common pheasants (Phasianus colchicus) during the breeding season was not related to male plasma testosterone level

1. The aim of this study was to investigate if male-to-female aggression of common pheasants in the course of the breeding season was related to the concentration of plasma testosterone and/or other biochemical plasma indicators in male pheasants housed in breeding cages. The influence of season on the concentration of testosterone and biochemical indicators was also investigated.

2. Males were divided into non-aggressive and aggressive groups during the breeding season based on ethological evaluation. At the beginning, in the middle and at the end of the breeding season, a blood sample was taken from all males on the same day and the concentration of selected biochemical indicators and the total circulating testosterone in the plasma were determined.

3. Male-to-female aggression during the breeding season of pheasants was not influenced by the total plasma testosterone of males.

4. The concentration of total plasma testosterone in males decreased gradually during the breeding season.

5. Male-to-female aggression of pheasants did not have a significant effect on any of the assessed biochemical indicators.

6. The influence of the breeding season affected the activities of alanine aminotransferase and aspartate aminotransferase as well as the concentrations of glucose, magnesium, potassium and chloride in the blood plasma of cage-housed male pheasants.     

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.     

Relationship between angioarchitecture of the testicular artery and spermiogram parameters in Egyptian buffalo bulls (bubalus bubalis)

The current study aimed to investigate the effect of testicular artery angioarchitecture on the spermiogram parameters in Egyptian Buffalo bulls. Eight adult buffalo bulls aged between 2 and 8 years were used for semen evaluation. For anatomical studies, the masculine gonads were collected after slaughtering 30 adult bulls and prepared for injection by different masses (Urographine^®, Latex and Epoxy) through the testicular artery. The mass activity of the ejaculate was assessed immediately after collection. The sperm motility in fresh bull ejaculate was more than 80%. The overall mean percentage of sperm abnormalities was <18%. The recorded sperm abnormalities were mostly secondary one including distal protoplasmic droplet, fragmented tail, detached head, detached galea capitis and bent tail. The highest percentage of sperm viability was recorded just after sperm collection (alive > 85%). The results revealed that testicular artery can be divided into three parts (abdominal, funicular and marginal parts) along its course. The coils of the funicular part forming a cone-like structure with its base fixed to the head of the testis. Two epididymal branches to the head and tail of epididymis emanate from the funicular part which continues as pars marginalis on the lateral surface of testis before its division into the lateral and medial testicular arteries on approaching the tail extremity of the testis. The increase in the length of the testicular artery with increase in the size of the testes played a great role in the degree of complexity of the architectural vascular patterns. The degree of complexity is affected by the number of coils formed by the vessel. The increase in the convolutions of the vessel will reduce the speed of blood flow to the gonads. Thus in turn will enabling the thermoregulatory mechanism to work more efficiently and will affect the semen value.     

Monitoring of libido and semen quality parameters in melatonin‐treated French alpine bucks during the non‐breeding season

The aim of this study was to investigate the effects of exogenous melatonin on libido and semen quality parameters in bucks during the non‐breeding season. Twelve bucks of the French alpine breed from 1.5 to 4 years of age were assigned into melatonin (MG) and control (CG) groups, with 6 bucks in each group. The experimental period was 3 months (March–May), divided into six periods of 15 days each. The bucks in the MG group received four melatonin implants at the end of March. Two semen samples were taken from the bucks by artificial vagina once per week and their libido estimated. Volume and spermatozoa concentration, their mass motility and motility, proportion of live and total abnormal and forms with abnormal head and tail were determined in the obtained ejaculate samples. The total number of spermatozoa and functional spermatozoa fraction in the ejaculate was also calculated. The MG bucks had significantly higher mass motility and motility of spermatozoa in the first half of April, and a higher proportion of live spermatozoa in the first and second half of April (p < .05). Differences in libido intensity were not significant. The results indicated that the application of melatonin significantly improved the qualitative parameters of semen in bucks, as seen in increased mass motility, motility of spermatozoa and proportion of live spermatozoa shortly following melatonin insertion. Therefore, the results of the current study are novel regarding the use of melatonin treatment during the non‐breeding season to improve the qualitative parameters of ejaculates in bucks.     

Ovarian and testicular function in the blue fox (Alopex lagopus) after oral administration of fenchlorphos during the breeding season

The possible effect of fenchlorphos, 0-0-dimethy1-0-(2.4.5-trichlorophenyl) phosphorothioate, upon the reproductive endocrinology in blue foxes (Alopex lagopus) was investigated. Five females were administered fenchlorphos orally at a dose of 100 mg/kg daily from 10 days before oestrus and up to the 21st day of gestation. This dose represents the therapeutic dose for the treatment of sarcoptic mange. Blood samples were collected for the analyses of progesterone, oestradiol-17β and luteinizing hormone (LH) in plasma. The vixens were ovario-hysterectomized on day 23, except 1 animal in the control group which was operated on day 17. Additionally, sperm quality and mating performance in 3 male blue foxes, which were administered 100 mg/kg fenchlorphos daily during the first 3 weeks of the mating season, were examined.Pregnancy was recorded in 2 medicated and 4 control animals. No pathological changes were observed in the uterus and the ovaries. The plasma concentrations of the hormones were similar to those obtained from the control group. No evidence of any disturbances concerning spermatogenesis in the males was observed. However, their libido appeared to be reduced. None of the males achieved a mating during and after the period of medication.     

Reproductive response in suckling Corriedale ewes to the ram effect during the non-breeding season: Effect of postpartum condition and the use of medroxyprogesterone priming

The response to the ram effect and the use of progestagen priming was studied in postpartum suckling Corriedale ewes. Two experiments were carried out during the non-breeding season. In experiment 1, the effectiveness of the ram effect to induce fertile oestrus in postpartum ewes was determined. While no significant differences in the frequency of ewes in oestrus were found, the overall conception rate was significantly higher in ewes that were weaned at least 6 months before the study started (63.3%) than in 60–90 days postpartum ewes (45.3%, p < 0.01). In experiment 2, the influence of medroxyprogesterone acetate priming on the response to the ram effect in suckling Corriedale ewes was determined. The frequency of ewes in oestrus and conception rate between ewes that remained unprimed and 6-days-primed ewes were similar. We conclude that it is possible to induce oestrus in postpartum suckling Corriedale ewes using the ram effect during the non-breeding season and that the use of progestagen priming seems to be ineffective in improving the response of postpartum ewes to the ram effect.     

Energy and protein allowances and requirements in stallions during the breeding season, comparing different nutritional systems

This study was conducted to estimate the nutritional value of diets given to stallions of different breeds during the reproductive season, and comparing allowances with requirements. The systems compared were the French INRA, the 1989 NRC, and the 2007 NRC. Data on reproductive activity, daily exercise, BW, BCS, feed intake, and feed composition during 4 mo (from March to June) were recorded on 12 stallions used for commercial AI programs. Stallions belonged to 3 different breeds: Italian Haflinger (IH, n=4), Holstein (HOL, n=4), and Italian Heavy Draft horse (IHDH, n=4). Data recorded were used to estimate the actual energy and protein intakes and theoretical requirements of the stallions using the aforementioned systems. A deviation index [DI = (intake - requirement)/intake × -1] was calculated to allow a comparison among methods as a proportion of under- or overestimates of theoretical requirements. All data were statistically analyzed with a mixed model for repeated measurements. The reproductive activity of the stallions was affected by month (less in March and greater in subsequent months; P<0.05). Daily exercise was generally low during the middle breeding season, and the intensity and kinds of exercise differed according to the breeds. Changes of BW and BCS of the stallions were not statistically significant (P=0.69 and P=0.17, respectively) during the experimental period, and therefore diets could be considered balanced to support all animal needs. However, the energy and protein allowances were not always consistent with the theoretical requirements considering all 3 nutritional systems. Energy and protein INRA recommendations showed, on average, +0.90 and +0.27 greater DI than actual intakes, respectively, for IH and HOL stallions, whereas the theoretical requirements were much closer to allowances for the IHDH stallions (DI close to 0). The 1989 NRC energy and protein recommendations, respectively, were +0.67 and +0.87 greater than intake for IH, +0.28 and +0.43 greater for HOL, and only +0.06 and +0.17 greater for IHDH stallions. The 2007 NRC energy and protein recommendations, respectively, were +0.70 and +0.52 greater for IH, +0.33 and +0.17 greater for HOL, and +0.52 and +0.49 greater for IHDH than actual intakes. Therefore, all systems overestimated the requirements of the stallion, particularly in lighter breeds. Further studies to validate requirements for breeding stallions of different sizes are recommended.