Effect of season on scrotal circumference, semen characteristics, seminal plasma composition and spermatozoa motility during liquid storage in INRA180 rams

Intravaginal progesterone device reinsertion during the early luteal phase affects luteal function and embryo yield in superovulated ewes

This study checked the efficacy of progesterone (P4) device reinsertion during the early luteal phase on luteal function and embryo yield in superovulated crossbred ewes. Twenty multiparous ewes received an intravaginal P4 device for nine days (D0 to D9) followed by six decreasing doses (25, 25, 15, 15, 10, 10%) of 133 mg pFSH i.m. at 12 h intervals, starting 60 h before P4 device removal. Ewes were naturally mated at 12 h intervals while in estrus. On D13, ewes with viable corpora lutea (CL; n = 19) were equally allocated for receiving their P4 device reinsertion (G-P4; n = 10) or not (G-Control; n = 9). On D17, the P4 device was removed, and all females received the cervical relaxation protocol 16 h to 20 min before non-surgical embryo recovery. CL count and their functionality classification were performed on D13 and D17 by transrectal B-mode and color Doppler ultrasonography (US). Plasma P4 concentrations (ng/mL) of G-P4 ewes increased (P < 0.05) over the days, being greater on D17 (9.2 ± 2.8) than on D9 (1.9 ± 0.7) and D13 (1.6 ± 0.4). The overall CL count per ewe tended to be greater (P = 0.09) in G-P4 compared with G-Control. The occurrence of premature regression of corpora lutea did not differ (P > 0.05) between G-P4 (30.0%) and G-Control (44.4%). The number of ova/embryos recovered was greater (P < 0.05) in G-P4 (11.6 ± 2.9) compared with G-Control (3.7 ± 2.0), respectively. Altogether, the reinsertion of the P4 device for four days after superovulation in ewes promotes greater P4 concentrations, resulting in greater ova/embryos recovered.

Seasonal Variations in Semen Quality, Testosterone Levels, and Scrotal Size following Dietary Flaxseed Oil and Ascorbic Acid in South African Indigenous Rams

The purpose of this study was to determine the seasonal variations in semen quality, testosterone levels, and scrotal size, following dietary flaxseed oil and ascorbic acid in South African indigenous rams. A total of 22 South African indigenous rams were randomly distributed into five treatment diets from June 2021 to May 2022 (12 months). To allow for the spermatogenesis period, semen was collected after sixty days of dietary supplementation with treatment diets. Blood was collected twice a week using an 18-gauge needle and vacutainer tubes and sent to the laboratory for testosterone analysis. Semen and blood collection were repeated eight times each season. The scrotal size (circumference, length, and width) was measured using a flexible measuring tape. Data was subjected to the General Linear Model (GLM) in Minitab® 2017. Treatment means were separated using Fisher’s t-test and considered significantly different when the p-value was less than 0.05. Seasons and diet had an effect on progression, total motility, and testosterone levels. For instance, NC during the spring season had the lowest progressive motility (42.84 ± 5.32), followed by the summer (49.38 ± 4.49), winter (62.46 ± 4.35), and autumn (63.26 ± 3.58). Notably, when treatment diets were introduced, improvements were realized, and there were significant differences (p < 0.05) among the seasons following supplementation of FLAX, ASCA, and FLAX + ASCA, except for FLAX in the autumn season (53.83 ± 4.16). Total motility did not differ significantly (p > 0.05) between the seasons when the NC and PC diets were supplemented; nevertheless, there was an improvement when FLAX, ASCA, and FLAX + ASCA were supplemented. Testosterone levels were significantly influenced by the seasons when negative and PC diets were supplemented. It is noteworthy that supplementing FLAX + ASCA can reverse the influence of the season on the testosterone levels (spring, 27.52 ± 4.42; summer, 20.23 ± 5.11; autumn, 25.24 ± 3.96; and winter, 25.92 ± 4.42). In conclusion, seasons do affect semen quality and testosterone levels of South African indigenous rams. However, flaxseed oil and ascorbic acid can reverse the seasonal variations in semen quality and testosterone levels.

Ram Semen Cryopreservation for Portuguese Native Breeds: Season and Breed Effects on Semen Quality Variation

The semen quality is one of the determinant factors of ram semen cryopreservation. The present retrospective study aimed to characterize the seasonal ram pattern during the year for ten Portuguese local sheep breeds, hypothesizing that the breed and season had low effects on the main spermatozoa traits. A total of 1471 ejaculates were used and evaluated (fresh semen) from 85 rams between 2004 and 2020 and re-evaluated after thawing (thawed semen). The effect of breed, season, and sperm cryopreservation on nine semen traits were evaluated. The volume per ejaculate, spermatozoa (SPZ) concentration, and total number of SPZ per ejaculate, were affected by breed (p < 0.001) but not by season (p > 0.05). As expected, the semen processing was the most significant (p < 0.001) factor of variation on seminal parameters. Moreover, breed and interactions between breed × semen processing, modulated the response of alive SPZ, abnormal morphology, head, and intermediate piece defects. In fresh semen, season only affected the intermediate piece defects due to the highest percentage observed between February and April period in some breeds. Overall, and despite the mentioned particularities, there were similarities among the ten local breeds. We also concluded that the seasonal effect on ejaculate and SPZ traits is not significant in our region. These local ram breeds have low seasonality and can be employed in natural mating as well as semen donors for cryopreservation and assisted reproductive biotechnologies during the whole year at our latitude.

Seasonal changes in testis size, testosterone levels and sperm production quality in meat rams

The aim of the present study was to evaluate seasonal changes in testes size, serum testosterone (T) levels and sperm production characteristics of 24 adult (2-3 years old) rams of meat breeds: Charollais (n = 6), Ile de France (n = 6), Dorset (Polled) (n = 5) and Dorper (Dorper, n = 7). Semen was collected with artificial vagina using a female in spontaneous oestrus (September-November, breeding season, BS) or a female with induced oestrus (March-July, non-breeding season, NBS). A total of 672 ejaculates were examined. Jugular vein blood was collected to determine testosterone levels during BS and NBS, and serum was extracted. Results of the present study indicate that there was no significant change in parameters such as body weight (kg) and testes length, both right and left, during BS and NBS, irrespective of the breed. The remaining metrics of testes differ in varying degrees between breeds of rams (with the exception of the Dorper breed) between BS and NBS. No significant variation in these parameters was found in Dorper rams. For all breeds, season had a statistically significant effect on important parameters such as total sperm count and progressive sperm motility after thawing. There was also significant seasonal variation in ejaculate volume across the three breeds, excluding il-de-France rams. The most constant was the sperm concentration, which was unchanged in BS and NBS in the three breeds, excluding Dorset rams, which showed a slightly significant decrease in this indicator in the non-breeding season. The serum content of the major male hormone testosterone (T) in rams of all breeds showed significant changes between BS and NBS, decreasing by a highly significant amount in the non-breeding season.

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.

Influence of Season and Liquid Storage at 16 °C on Beni Arouss Bucks' Semen Quality

Simple Summary

Goat production plays an important economic and social role in Northern Moroccan farming. Beni Arouss is an autochthonous North Moroccan goat breed. The use of artificial insemination can largely contribute to optimised preservation and dissemination of valuable traits of this breed and lead to improved productivity. During liquid storage, the stability of semen good quality remains crucial in order to provide greater flexibility between the artificial insemination center and farms where the insemination of does needs to be performed. The study aims to assess the effect of storage and season of the year on fresh semen of Beni Arouss goats. Every month, ejaculates were collected from bucks and were extended and stored at 16 °C for 24 h. Semen motility, viability and normal morphology were assessed at 0, 4, 8 and 24 h after collection. As expected, these parameters showed a significant reduction within 24 h of storage and during all seasons. However, semen collected in summer maintained a better quality after 24 h of storage at 16 °C than semen collected during the other periods. Therefore, the storage ability of Beni Arouss bucks’ semen stored at 16 °C was higher during the summer.

Abstract

The study aimed at determining the effect of storage and season on fresh semen of Beni Arouss goats. Ejaculates were collected at monthly intervals from seven mature bucks and were extended at a final concentration of 800 × 10⁶ spermatozoa. ml^-1 and stored at 16 °C for 24 h. Semen motility, viability and normal morphology were assessed at 0, 4, 8 and 24 h after collection. Motility and normal morphology parameters were recorded using computer-assisted sperm analysis (CASA) and viability was analyzed using eosin–nigrosin staining. As expected, motility, viability and normal morphology parameters showed a significant reduction within 24 h of storage and during all seasons (p < 0.05). However, semen collected in summer maintained a better quality after 24 h of storage at 16 °C than semen collected during the other periods (p < 0.05). In conclusion, the storage ability of Beni Arouss bucks’ semen stored at 16 °C was significantly higher during the summer.

Does advanced age affect reproductive variables, semen composition, and liquid semen storage during different seasons in Boujaâd rams?

The present research was conducted to evaluate the effects of season and age on scrotal circumference (SC), semen characteristics, semen composition, and sperm motility during liquid storage in Boujaâd rams. Semen was collected throughout 1 year from April 2014 to March 2015. Two ram groups, namely older rams including animals aged 5.5 to 6 years of age, and younger rams including animals aged 2.5 to 3 years of age were used. Scrotal circumferences, semen characteristics, and some biochemical variables from semen were measured. After collection and evaluation, the semen was extended in skim milk (SM) at 15 °C to a concentration of 0.8 × 10⁹ spermatozoa/ml. Thereafter, samples were evaluated at different storage times (0, 8, and 24 h). The results indicate that older rams had greater values of SC, lesser semen quality, protein, lipid, and cholesterol concentrations than younger rams. Nevertheless, for both groups there were the least values for semen quality and semen composition in winter. The semen collected from younger rams had greater motility after liquid storage compared with that of the older rams. The least semen quality after liquid storage was recorded in the winter compared with the other seasons of the year for both age groups. In conclusion, results of the present study indicate that older Boujaâd sheep have lesser semen quality, different semen composition than younger rams after liquid storage and during different seasons of the year. Furthermore, there was a strong correlation between semen composition and motility of stored ram semen.

The effects of gelatin supplementation prior to cooling on ram semen quality and fertility

The physical and chemical characteristics of gelatin have been used to justify its inclusion in extenders to preserve the sperm quality and improve results of cervical artificial insemination with cooled semen. The objective of this study was to evaluate the effects of gelatin supplementation in cooling extender on the quality and fertility of ram semen stored at 5°C. Semen samples (n = 24) of Santa Inês rams (n = 6) were diluted in Glycine-Yolk-Milk extender without (control) or with 1.5% of gelatin. The samples were loaded into 0.25 mL straws, cooled to 5°C and stored vertically for 48 and 72 hours. Sample quality was evaluated using straw homogeneity tests based on pH, osmolality and the proportion of spermatozoa (PS) in both upper and lower segments of straws (US and LS), analyses of sperm motility, plasma and acrosomal membrane integrity, and by fertility after artificial insemination. Differences between the US and LS of straws were found for pH and PS (%). They were significant only in the control group at both times: pH - 5.96 vs. 5.71 at 48 h and 6.13 vs. 5.89 at 72 h; PS - 21.66 vs. 78.34 at 48 h and 20.87 vs. 79.13 at 72 h. Storage in gelatin had very little, to no effect on the sperm kinetics or on the sperm membrane integrity evaluations. The addition of gelatin to the extender did not affect the pregnancy rate which ranged from 4.4 to 26.1%. We conclude that gelatin is effective in maintaining the physical and chemical homogeneity of the semen samples. Further research is needed in order to optimize the use of gelatin supplementation and elucidate any potential benefits.

Effect of increasing levels of wasted date palm in concentrate diet on reproductive performance of Ouled Djellal breeding rams during flushing period

Aim

The aim of the study was to assess the effect of two levels of wasted date (WD) by replacing commercial concentrate on the reproductive performance of Ouled Djellal (OD) rams.

Materials and Methods

Eighteen mature (2-year-old) OD rams were equally allocated to three groups and fed during 11 weeks with one of three different experimental diets, that contained 0% (0 WD), 50% (50 WD), or 75% (75 WD) of WDs in concentrate diet. Live body weight (LBW), body condition scoring (BCS), scrotal circumference (SC), testicular weight (TW), sperm production and quality, plasma testosterone concentration (T), and sexual behavior (reaction time and number of mounts with ejaculation) were regularly recorded from every ram.

Results

LBW, SC, and TW changed significantly among diet groups and during the experimental period (p<0.001), the highest averages were recorded in (0 WD) group. LBW, BCS, SC, TW, semen volume, and percentage of the positive hypo-osmotic swelling test were (p<0.001) positively influenced by flushing period. Nevertheless, sperm concentration showed a significant (p<0.001) decrease at day 30, followed by a return to the initial values afterward. There were no differences (p>0.05) between diet groups for plasma testosterone concentration and semen attributes, except that (50 WD) group expressed the lowest overall value of semen concentration. Furthermore, neither time nor diet affected (p>0.05) sperm motility and reproductive behavior parameters.

Conclusions

It is possible to introduce WD as unconventional local feeding resources in flushing diet of breeding rams without disturbing their reproductive performance.