Technical recommendations for artificial insemination in sheep

Comparison various level ascorbic acid and lycopene additions in semen diluent enhanced sperm quality of Sapudi ram

The primary cause of sperm quality decline during the freeze-thaw pathway is the peroxidation hazard caused by reactive oxygen species produced by the biological molecules of sperm. Ascorbic acid (Vitamin C) and lycopene are two potent antioxidants that operate to prevent oxidation processes. This study aimed to analyse the effects of ascorbic acid and lycopene on the motility, viability, abnormality and plasma membrane integrity of post-thawed Sapudi rams. Sperm samples were obtained and pooled from six sexually mature Sapudi rams, separated into ten equal proportions and diluted with Tris-egg yolk-glycerol (TEY) extender. Semen was supplemented with 0 (C0; L0), 1 (C1; L1), 2 (C2; L2), 3 (C3; L3) and 4 (C4; L4) mg/100 mL (1%-4%) diluent each of ascorbic acid and lycopene, respectively. Total sperm motility, viability, abnormalities and semen membrane plasma (%) were analysed after thawing. C3 and L3 extenders resulted in higher total motility (p < 0.05) compared to the other extenders, with all treatments higher than that of the control. The extender C3 (p < 0.05) exhibited the highest semen quality. Finally, the current findings show that C3 and L3 can increase the quality of post-thawed Sapudi ram spermatozoa.

Metabolomics analysis of the effect of GnRH on the pregnancy rate of ewes with estrus synchronization scheme based on progesterone

Introduction

Gonadotropin-releasing hormone (GnRH) is widely used in the timed artificial insemination protocol for sheep. However, there remains a debate regarding its impact on pregnancy rates during artificial insemination. This study aims to evaluate the effect of GnRH on the pregnancy rates in Huyang ewes, analyze the pre-implantation metabolite changes caused by GnRH using metabolomics, and elucidate the mechanism effect on pregnancy rates.

Methods

All ewes were administered a vaginal progesterone sponge containing 45 mg of flurogestone acetate for 12 days and received 330 units of equine chorionic gonadotropin (eCG) intramuscularly after sponge removal. The experimental group (n = 69) received an intramuscular treatment of 17 μg GnRH agonist triptorelin 48 h after sponge removal on Day 0, while the control group (n = 41) received 1 mL of sterile saline solution. All ewes underwent a single vaginal insemination 58 h after the withdrawal of the progesterone sponge. The difference in pregnancy rates between the two groups was calculated. Metabolomic analysis was performed on plasma samples collected on Day 7 after the treatment of GnRH agonist.

Results

Gonadotropin-releasing hormone (GnRH) treatment significantly reduced the pregnancy rate in the experimental group compared with the control group (72.2 vs. 82.9%, p < 0.05). Metabolomic analysis indicated that GnRH treatment affected metabolites involved in collagen synthesis and prostaglandin synthesis in the endometrial tissue, which includes a marked decrease in hydroxyproline amino acid content and a significant increase in corticosterone and prostaglandin D2 lipids and unsaturated fatty acids.

Conclusion

In summary, the injection of GnRH agonist Triptorelin 48 h after progesterone sponges removal reduces the pregnancy rate of Huyang ewe following artificial insemination. It also affects the metabolite levels related to endometrial collagen and prostaglandin synthesis, harming embryo implantation.

Uterine tone influences fertility of Merino ewes following laparoscopic artificial insemination

Artificial insemination (AI) plays a critical role in facilitating rapid genetic and production gains within the sheep industry. However, variable rates of AI success remain a concern for the industry and a barrier to adoption. Furthermore, the degree to which female factors influence the success of intrauterine laparoscopic AI rather than natural mating remains unknown. As such, this study investigates the effect of several factors collected during the time of AI, on the success of intrauterine laparoscopic AI. Data was generously donated by artificial breeding companies and stud breeders during routine commercial AI operations. AI data was collected over 3 breeding seasons during commercial AI programs (N = 24 programs) using Merino ewes (N = 24,700). Sire ID (N = 253), time of AI following progesterone removal (approx. 43-59 h post removal), uterine tone and intra-abdominal fat (both scored 1-5) as well as age of the ewe were all recorded at the time of AI. Transcutaneous ultrasound subsequently determined pregnancy rate approximately 55 days post-AI. A multivariate regression analysis was performed and revealed pregnancy success to increase when semen was inseminated into a ewe with a uterine tone score of 4 or 5 (P < 0.001). The remaining factors fell short of significance within the multivariate model. An interclass coefficient variation matrix was also used to determine the proportion of variation contributed to AI success by random factors allocated in the model; site, sire, AI date and breeding season (45.99 %, 29.94 %, 15.15 % and 8.92 %, respectively). These results highlight the influence of uterine tone on ewe fertility following laparoscopic AI, but also that program location and the sire used can further modify this influence on pregnancy rate. These factors must now be considered in combination with semen factors per individual sire used during AI to ascertain the contribution of several factors to the success of laparoscopic AI in Australia.

Use of coenzyme Q-10 to improve the pregnancy rate in sheep

One of the factors responsible for less pregnancy rates is the use of frozen semen in sheep due to the oxidative stress created by the process. The aim of this experiment was to test the effects of adding coenzyme Q-10 (CoQ10) to the seminal extender on sperm quality and the pregnancy rate of sheep. In this study, ejaculates from eight Dorper rams of reproductive age were used and tested in four treatments: Control (pure BotuBov®), C1 (175 µM of CoQ10), C3 (350 µM of CoQ10), and C7 (700 µM of CoQ10). Samples were collected in triplicate from each animal, and sperm analysis was performed by CASA after thawing at 0 h and 2 h. The samples were also analyzed by flow cytometry for plasma and acrosomal membrane integrity, stability, lipid peroxidation, mitochondrial potential, and superoxide anion production. In total, 198 ewes were inseminated by laparoscopy and divided into two groups: control (n=98) and C7 (n=100). Pregnancy diagnosis was performed at 30 days. Coenzyme Q10 proved to be safe for semen cryopreservation, not altering sperm kinetic values between the groups post-thawing. In flow cytometry, the C1 and C7 groups achieved a better index of plasma membrane integrity and membrane stability (P<0.05). A increased pregnancy rate was observed in C7 (52 %) compared to the control (38 %). In conclusion, coenzyme Q10 assists in the cryopreservation process, protecting the sperm cell and improving pregnancy rates in ewes.

Evaluating estrus synchronization and early pregnancy detection in Ossimi sheep: The influence of fluorogestone acetate treatment duration and dosage

Estrus synchronization is important for improving sheep reproduction. To enhance sheep reproduction efficiency, this study investigated the impact of different durations (7 vs. 14 days) and fluorogestone acetate (FGA) doses in intravaginal sponges on estrus synchronization and early pregnancy detection in Ossimi sheep. Two hundred ewes were evenly divided into two groups, each receiving a full 40 mg or a halved 20 mg FGA sponge for their respective durations. The study aimed to optimize breeding efficiency by examining the effectiveness of these treatments in synchronizing estrous cycles and by evaluating the use of serum levels of pregnancy-associated glycoprotein 1 (PAG1) and progesterone (P4) as markers for early pregnancy identification. Prostaglandin F2α and equine chorionic gonadotropin were administered to enhance the synchronization process. Results highlighted that the 7-day treatment protocol significantly improved estrus, pregnancy, and lambing rates compared to the 14-day protocol. Furthermore, pregnant ewes demonstrated elevated levels of PAG1 and P4, with PAG1 levels particularly higher in ewes with multiple pregnancies. The findings underscore that the shorter duration of FGA treatment is more effective for reproductive management in Ossimi sheep without significantly affecting PAG1 levels based on the dose or duration of FGA. PAG1 also proved to be a reliable marker for early pregnancy detection, offering a promising approach to identifying fetal numbers early in pregnancy. This research suggests optimizing FGA sponge use could be cost-efficient for improving reproductive efficiency and early pregnancy management in sheep.

β-Nicotinamide mononucleotide improves chilled ram sperm quality in vitro by reducing oxidative stress damage

OBJECTIVE

The present study aimed to investigate the effect of β-nicotinamide mononucleotide (NMN) supplementation on ram sperm quality during storage at 4°C in vitro.

METHODS

Tris-citric acid-glucose solution containing different doses of NMN (0, 30, 60, 90, and 120 μM) was used to dilute semen collected from rams and it was stored at 4°C. Sperm motility, plasma membrane integrity as well as acrosome integrity were evaluated at 0, 24, and 48 h time points after storage at 4°C. In addition, sperm mitochondrial activity, lipid peroxidation (LPO), malondialdehyde (MDA) content, reactive oxygen species (ROS) content, glutathione (GSH) content, superoxide dismutase (SOD) activity, and apoptosis were measured at 48 h time point after storage at 4°C.

RESULTS

Results demonstrate that the values obtained for sperm motility, acrosome integrity, and plasma membrane integrity in the NMN treatments were significantly higher than control (p<0.05). The addition of 60 μM NMN significantly improved ram sperm mitochondrial activity and reduced LPO, MDA content, and ROS content compared to control (p<0.05). Interestingly, sperm GSH content and SOD activity for the 60 μM NMN treatment were much higher than those observed for control. NMN treatment also decreased the level of Cleaved-Caspase 3, Cleaved-Caspase 9, and Bax while increasing Bcl-2 level in sperm at 48 h time point after storage at 4°C.

CONCLUSION

Ram sperm quality can be maintained during storage at 4°C with the addition of NMN at 60 μM to the semen extender. NMN also reduces oxidative stress and apoptosis. Overall, these findings suggest that NMN is efficient in improving the viability of ram sperm during storage at 4°C in vitro.

Factors affecting the success of laparoscopic artificial insemination in sheep

Successful artificial breeding underpins rapid genetic and production gains in animal agriculture. In sheep, artificial insemination with frozen semen is performed via intrauterine laparoscopy as frozen-thawed spermatozoa do not traverse the cervix in sufficient numbers for high fertility and transcervical insemination is anatomically impossible in most ewes. Historically, laparoscopic artificial insemination has always been considered reasonably successful, but recent anecdotal reports of poor fertility place it at risk of warning adoption. Understanding the male, female and environmental factors that influence the fertility of sheep is warranted if the success of artificial insemination is to be improved and genetic progress maximised for the sheep industry. This review details the current practice of laparoscopic AI in sheep. It explores the effects of semen quantity and quality, the ewe, her preparation, and environmental conditions, on the fertility obtained following laparoscopic artificial insemination.

DNase I rescues goat sperm entrapped by neutrophil extracellular traps

Artificial insemination has been a predominant technique employed in goat husbandry for breeding purposes. Subsequent to artificial insemination, sperm can elicit inflammation in the reproductive tract, resulting in substantial the accumulation of neutrophils. Recognized as foreign entities, sperm may become entrapped within neutrophil extracellular traps (NETs) released by neutrophils, thereby exploiting their properties of pathogen elimination. Deoxyribonuclease I (DNase I), which is known for disintegrating NETs and causing loss of function, has been utilized to ameliorate liver and brain damage resulting from NETs, as well as to enhance sperm quality. This study investigated the mechanism of sperm-induced NETs and further explored the impact of DNase I on NETs. Sperm quality was evaluated using optical microscopy, while the structure of NETs was observed through immunofluorescence staining. The formation mechanism of NETs was examined using inhibitors and PicoGreen. The findings revealed that sperm induced the formation of NETs, a process regulated by glycolysis, NADPH oxidase, ERK1/2, and p38 signaling pathways. The composition of NETs encompassed DNA, citrullinated histone H3 (citH3), and elastase (NE). DNase I protects sperm by degrading NETs, thereby concurrently preserving the integrity of plasma membrane and motility of sperm. In summary, the release of sperm-induced NETs leads to its damage, but this detrimental effect is counteracted by DNase I through degradation of NETs. These observations provide novel insights into reproductive immunity in goats.

Exploring Endogenous and Exogenous Factors for Successful Artificial Insemination in Sheep: A Global Overview

Artificial insemination (AI) plays a vital role in animal breeding programs. AI is applied to enhance animal genetics and facilitate the widespread integration of desirable characteristics with a high potential for productivity. However, in sheep, this biotechnology is not commonly practicable due to multi-factorial challenges, resulting in inconsistent outcomes and unpredictable results. Thoughtful selection of semen donors and recipients based on genetic merit deeply impacts ovine AI outcomes. Additionally, endogenous factors such as breed, age, fertility traits, genetic disorders, and cervical anatomy in ewes contribute to ovine AI success. Extensive research has studied exogenous influences on sexual behavior, reproductive health, and hormonal regulation, all impacting ovine AI success. These exogenous factors include techniques like estrus induction, synchronization, semen handling methods (fresh/chilled/frozen), and insemination methods (cervical/laparoscopic), as well as nutritional factors and climatic conditions. This overview of the literature highlights the endogenous and exogenous challenges facing successful ovine AI and proposes strategies and best practices for improvement. This paper will serve as a guide for understanding and optimizing the success of ovine AI.

Failure of isoxsuprine HCl to increase sheep fertility after cervical versus laparoscopic AI using chilled semen at different durations

To improve the fertility of cervical artificial insemination (AI) in sheep, we investigated isoxsuprine HCl usage on the cervical passage during cervical AI. We also compared cervical and laparoscopic AI fertility results of using chilled semen at different durations. Semen was collected from rams and diluted as 20 × 106 or 400 × 106 spermatozoa/straw for laparoscopic and cervical AI, respectively, and chilled to 4°C within 2 h. Sheep were inseminated with chilled semen for 8 or 24 h via the laparoscopic or cervical AI method. Moreover, some of the cervical inseminated sheep were injected intramuscularly with 0.5 mg/kg of isoxsuprine HCl 15 min before AI. As a result, the use of isoxsuprine HCl did not affect cervical transit and fertility. In addition, fertility was affected by the storage duration of the semen; laparoscopic AI was more successful than cervical AI in terms of fertility; if cervical AI is performed, the duration between semen collection and AI should be less than 8 h after chilling the semen at 4°C, and if laparoscopic AI is performed, the time between semen collection and insemination can be up to 24 h after chilling the semen at 4°C. Longer storage periods should be studied.

Comparative evaluation of estrus synchronization protocols on reproductive performance and estrus behavior in Barbados Black Belly sheep

Background and Aim

Estrus synchronization of ewes has been accomplished using several protocols with various degrees of success in improving reproductive efficiency and obtaining the most effective protocol used in sheep farming. This study aimed to compare the effectiveness of three treatment protocols and to record the intensity and duration of estrus signs and pregnancy rate in Barbados Black Belly (BBB) sheep.

Materials and Methods

Thirty-two primipara BBB ewes aged 18-24 months were equally divided into three treatment groups. T1: the ewes were injected intramuscularly with 2 mL Lutalyse (PGF2α) (10 mg) on days 0 and 10. T2: 1 mL Fertiline (50 μg; Gonadorelin acetate) on day 0 and 2 mL lutalyse (10 mg) on day 7. T3: 1 mL fertiline (50 μg) on day 0, 2 mL lutalyse (10 mg) on day 7, and 1 mL Fertiline (50 μg) on day 9. Estrus response was assessed using naturally mating rams and ewes. Pregnancy was determined using ultrasonography between 55 and 80 days after the last hormonal injection. The following estrus signs were noted: Swollen vulva, mucus discharge, sniffing, excitement, loss of appetite, mounting, and rapid tail movement.

Results

Of the expressed signs, swollen vulva was most frequent, whereas loss of appetite and mucus discharge were the least overt signs recorded. The estrus response (%), onset (%), and duration (h) in ewe synchronization of the three treatment protocols were 100%, 58.3 ± 23.4%, and 48.0 ± 18.2 h (T1), 100%, 61.7 ± 41.2%, and 45.0 ± 27.0 h (T2), and 37.5%, 32.1 ± 1.7%, and 29.2 ± 1.25 h (T3), respectively. The pregnancy rates were 87.5%, 87.5%, 37.5%, and 50.0% in T1, T2, T3, and T4, respectively.

Conclusion

Prostaglandin F2α+PGF2α and GnRH+PGF2α synchronization protocols were more effective in the fertilization of BBB ewes with better expression of estrus signs compared with the GnRH+PGF2α+GnRH (OVS) protocol.

Cryopreservation and Transfer of Sheep Embryos Recovered at Different Stages of Development and Cryopreserved Using Different Techniques

This article presents data from experiments to determine the cryoresistance of Charollais sheep embryos, depending on the stage of embryo development and the method of freezing, as well as the results of embryo transfer. The study design consisted of a study on the cryopreservation of ewe embryos at different developmental stages (early, 2-8 blastomeric and late, at the morula/blastocyst stage), two cryopreservation protocols (slow freezing and ultra-fast vitrification), and embryo transfer of cryo- and fresh embryos. Embryos from Charollais sheep donors (n = 12) were recovered after induction of superovulation. The embryos were recovered surgically (laparotomy) on days 2 and 6 after insemination. Before there was transfer to recipients, part of embryos was cryopreserved using standard slow freezing and ultra-fast vitrification methods. The average ovarian response was 7.54 ovulations per donor, and 5.83 embryos per donor were collected. No effect of the cryopreservation method and embryo development stage on the preservation of the morphological structure of embryos was found. There were no significant differences in the survival rate of cryoembryos at different development stages, frozen using different techniques, and after transfer to recipients. Differences in cryoresistance between embryonic developmental stages in favor of the morula/blastocyst stage were found (survival after thawing 86.4% vs. 75.0% in early embryos). At different stages of development, the survival rate of fresh embryos (45.8%) compared to cryopreserved ones (30.2%) was significantly higher (p < 0.05), while among fresh ones, the best survival rate (50.0%) was observed after the transfer of morules and blastocysts.

Review: Non-surgical artificial insemination and embryo recovery as safe tools for genetic preservation in small ruminants

Artificial insemination (AI) and in vivo embryo production (or multiple ovulation and embryo transfer, MOET) programs are both instrumental in accelerating the propagation of genetically and economically superior goats and sheep. The aim of this review was to present the current gestalt of non-surgical AI and embryo recovery (NSER) procedures in small ruminants. Small body size, precluding rectal palpation, and highly limited penetrability of the uterine cervix in ewes are the major reasons for the scarce use of non-surgical assisted reproduction techniques in this species. As a result, AI and embryo recovery techniques in sheep mainly involve laparoscopy or laparotomy (LAP). In does, however, the Embrapa method of AI allows for successful intrauterine deposition of semen, resulting in pregnancy rates from 50 to 80% under field conditions (>3 000 goats inseminated) when frozen-thawed semen is used. After the administration of prostaglandin F2α (PGF2α), non-surgical (transcervical) embryo recovery is also feasible in goats, with the cervical penetration rate approaching 100%. There is a paucity of information on the efficacy of non-surgical AI using frozen semen in sheep, but the results are satisfactory with fresh, cooled, or chilled ram semen. An application of the NSER technique in ewes has greatly improved over the last decade, and cervical penetration rates of ∼90% can be achieved when a hormonal cervical dilation protocol using PGF2α, oxytocin, and/or estradiol ester (e.g., estradiol benzoate) is applied. In some genotypes of sheep, sufficient cervical dilation can be induced without estradiol ester included in the protocol. Several studies indicated that recovery of transferable quality ovine embryos using NSER is comparable to that employing a ventral midline laparotomy, and NSER is evidently a method of choice when animal welfare is concerned. Considering both the number of retrievable embryos and animal well-being, the NSER is a viable alternative for surgical procedures. With further developments, it has the makings of a primary, if not exclusive, embryo recovery technique in small ruminants worldwide.

Assessment of Constraints of Artificial Insemination Service in Smallholder Dairy Cattle Keepers in Kacha Bira District of Southern Ethiopia

Artificial insemination (AI) is among the most effective reproductive biotechnologies that afford widespread propagation of genes carried by superior males. A cross-sectional study followed by a simple random sampling technique was conducted from December 2021 to May 2022 to assess the constraints of artificial insemination (AI) provision in and around Kacha Bira district, Southern Ethiopia, using a structured questionnaire. A total of 200 respondents were surveyed accordingly. In this study, the education level of farmers revealed no statistically significant difference $\left(P>0.05\right)$ with the identification of time of insemination. Conception failure (62.5%), unavailability of artificial insemination technicians (7.5%), dystocia (3.5%), and both conception failure and unavailability of artificial insemination technicians (4.5%) were found to be the major constraints of AI service in the study area according to dairy cattle owners’ response and revealed a statistically significant difference $\left(P<0.05\right)$ with AI service. Although statistically significant $\left(P<0.05\right)$ , differences in AI service interruptions during both regular working hours and weekends and holidays were also observed. Among total respondents, 20.5% of dairy cattle owners got AI service at right time, but 79.5% of them used it at the wrong time. Regarding inbreeding problems, 77.5% of dairy cattle owners responded that there was no inbreeding problem and the remaining 22.5% of farmers indicated presence of inbreeding problem of which 10.5% and 10% had a perception that local breeds had low milk production and low genetic improvement than exotic breeds, respectively. On the other hand, 11.5% of dairy cattle owners responded that local breeds have a similar level of disease resistance to that of exotic breeds (11%). 48.5% of dairy farmers reported that bellowing is the most frequent sign that they used to detect heat followed by vulval discharge (23%) and mounting on other cows (10%). Majority (78.5%) of the dairy cattle owners interviewed were found to be not satisfied with the artificial insemination services. In general, different AI technicians and cattle and dairy cattle keeper-related factors constrain the AI service and its result in survey site. Therefore, smallholder dairy cattle owners should be trained sufficiently about the AI service strategies, usage, and proper management of dairy farms and the technical constraints should be avoided in order to provide AI service sufficiently.

Moringa oleifera leaf ethanolic extract benefits cashmere goat semen quality via improving rumen microbiota and metabolome

Background

Artificial insemination (AI) is an effective reproductive technique to improve the performance of cashmere goats and prevent the spread of diseases, and the quality of the semen determines the success of AI. The potential of Moringa oleifera leaf powder (MOLP) and Moringa oleifera leaf ethanolic extract (MOLE) to improve semen quality has been reported, but the underlying mechanisms remain unclear. For the purpose, 18 mature male cashmere goats were randomly assigned into three groups: the control (CON), MOLP, and MOLE groups. The CON group received distilled water orally; the MOLP group was orally treated with 200 mg/kg body weight (BW) MOLP; and the MOLE group was orally treated with 40 mg/kg BW MOLE.

Results

Results showed that MOLE contained long-chain fatty acids and flavonoids. Treatment with MOLP and MOLE increased the activities of the serum catalase, superoxide dismutase, and glutathione peroxidase (P < 0.05), enhanced the total antioxidant capacity (P < 0.05), and reduced the serum malondialdehyde level (P < 0.05). At the same time, MOLE increased the contents of serum gonadotropin releasing hormone and testosterone (P < 0.05). Moreover, MOLE significantly increased sperm concentration, motility, and viability (P < 0.05). Meanwhile, MOLE raised the Chao1 index (P < 0.05) and altered the composition of the rumen microbiota; it also raised the relative abundance of Treponema (P < 0.05) and Fibrobacter (P < 0.05) and reduced the relative abundance of Prevotella (P < 0.1). Correlation analysis revealed the genus Prevotella was significantly negatively correlated with sperm concentration, as well as sperm motility and viability. Furthermore, MOLE significantly increased the rumen levels of the steroid hormones testosterone and dehydroepiandrosterone (P < 0.05), as well as the polyunsaturated fatty acids (PUFAs) alpha-Linolenic acid, gamma-Linolenic acid, docosapentaenoic acid, and 9-S-Hydroperoxylinoleicacid (P < 0.05).

Conclusions

Oral MOLE supplementation can improve semen quality by increasing the antioxidant capacity and altering the rumen microbiota and metabolites of cashmere goats. Moreover, the MOLP supplementation could enhance the antioxidant capacity of cashmere goats.

Effects of Cell Concentration During Cryopreservation On the Post-thaw Quality of Santa Inês Ram Sperm

BACKGROUND: Non-surgical artificial insemination techniques for sheep may benefit from larger numbers of sperm in the insemination dose because the ewe's cervix is convoluted and often cannot be traversed with an insemination gun resulting in deposition of the sperm at the os cervix. OBJECTIVE: To compare a range of sperm concentrations when cryopreserving semen from Santa Inês rams and determine the effects of this on post-thaw quality. MATERIALS AND METHODS: One ejaculate from each ram (n = 10) was diluted to four sperm concentrations to obtain the following groups: G – 400, G – 800, G – 1200, and G – 1600 x 10 6 sperm/mL. The semen samples were packaged in 0.25 mL straws, cooled to 5 ºC, cryopreserved in liquid nitrogen vapor, thawed in a water bath (40 ºC/20 s), and were analyzed for computerized kinetics, capacitation and acrosome integrity, and plasma membrane integrity of sperm. RESULTS: The G – 400 treatment resulted in samples with the highest linearity and progressive motion (P < 0.05) and had significantly greater plasma membrane integrity, and lower capacitation and acrosome reaction rates compared to G-1600 (P < 0.05). Overall, use of the G – 400 treatment resulted in better kinetics, less plasma membrane damage and less early capacitation. However, despite reducing the ejaculate yield and increasing the costs of the semen freezing process, the G – 800 and G – 1200 treatments make a greater absolute number of sperm with good kinetics, plasma membrane integrity and capacitation status available. CONCLUSION: Ram sperm concentration impacts cryopreservation, and higher concentrations may be advantageous if a single rtificial insemination protocol is desirable.

Can Honey Improve the Quality of Cryopreserved Cross Bred Ram Semen Added to Tris Egg Yolk Extender?

BACKGROUND: Honey can improve the quality of cryopreserved ram semen because of its multinutrient and cryoprotective nature added to standard tris egg yolk extender. OBJECTIVE: Different concentrations of honey were added to the standard tris egg yolk extender to improve the post-thaw quality of crossbred ram semen. METHOD: Thirty six (36) ejaculates from eight healthy cross bred rams were pooled and divided into four aliquots. Standard tris egg yolk extender without any alteration acted as Control (C) and was supplemented with different concentrations of honey, viz. T1 (honey 1.5%), T2 (2.5%), and T3 (3.5%). RESULTS: The percent (mean ± S. E. M) sperm motility at pre-freeze was significantly (P<;0.05) higher in Group T2 and at post-thaw in Group T3 in comparison to T1 and C treatment groups. The percent (mean ± S. E. M) HOST reacted spermatozoa at post-thaw was significantly (P< 0.05) higher in Group C and at pre-freeze the value was significantly (P< 0.05) higher in the same treatment group than Group T1. The mean MDA level (mean ± S. E. M) at post thaw was significantly (P<0.05) low er in Group T3 than the treatment groups C and Group T1. CONCLUSION: From this study it is concluded that the addition of 3.5% honey to the standard tris egg yolk extender provides better protection to ram semen than the addition of 1.5% honey (i. e., Control).

The Role of Housing Conditions on the Success of Artificial Insemination in Intensively Reared Dairy Ewes in Greece

The objective was to assess the effect of housing conditions during the summer months on the success rates of cervical artificial insemination (AI) with cooled semen, in intensively reared dairy ewes in Greece. The study involved 2083 Lacaune ewes from 23 flocks that were serviced during May to September. An estrous synchronization protocol with the insertion of progestogen sponges for 14 days and eCG administration at sponge removal, was used. All ewes were inseminated 54−57 h after sponge removal with cooled semen (15 °C) from 10 Lacaune rams. Pregnancy diagnosis was performed via trans-dermal ultrasonography at 35−40 days after AI. Data recording started the day after sponge placement (15 days prior to AI), and lasted up to 14 days after AI. Daily records included temperature, relative humidity, and Temperature-Humidity Index (THI) inside the shed. Available space and volume per animal, frequency of bedding renewal, access to a yard, and indoor light were also recorded in each farm. Binary logistic regression of data records showed that temperature and THI increases at days −15 to +4 around AI (day 0) had a negative effect on pregnancy rates (reducing the likelihood of pregnancy by 3−6% and 7%, respectively). The latter also decreased significantly (p < 0.05) in farms with high stocking density, non-frequent bedding renewal, and outdoor access by ewes (by 30%, 34%, and 44%, respectively). Overall, the results indicate that appropriate housing conditions are warranted to increase the success of AI in dairy ewes during the summer months.

Efficiency of Artificial Insemination at Natural Estrus in Organic Churra Ewes

Simple Summary

Hormonal treatments used to synchronize estrus in sheep artificial insemination procedures can cause several physiological problems that can affect negatively fertility and animal health; however, alternative protocols based on the detection of natural estrus offer a more sustainable option while reaching successful fertility results. Therefore, in this study, an artificial insemination protocol at natural estrus in organic Churra sheep was performed. In the protocol design phase, 125 ewes were exocervically inseminated, and their fertility was assessed based on the number of inseminations, physiological state, body condition, estrus detection–insemination interval and vaginal fluids in cervix. That protocol was repeated in six consecutive years. In all ewes, fertilities based on the timing of insemination after estrus detection were very high. Lactating ewes produced better results than did dry ewes, which was probably because of the better feeding of the former. In addition, double insemination increased the fertility of ewes, whose estrus was detected within 16 h of onset. Body condition and amount of vaginal fluid were correlated with fertility. In conclusion, exocervical inseminations at natural estrus can produce acceptable fertility and prolificity in Churra ewes, avoiding physiological problems derived from the use of hormonal treatments.

Abstract

Hormonal treatments used in the artificial insemination (AI) of sheep can cause several physiological problems that can affect negatively fertility and animal health; however, AI protocols based on the detection of natural estrus offer a more sustainable option and can achieve high fertility. In this study, an AI protocol at natural estrus in organic Churra sheep was performed. In the first phase (AI protocol development), 125 ewes were exocervically inseminated, and their fertility was assessed based on the following factors: number of AI, physiological state, body condition, estrus detection–AI interval, and vaginal fluids in cervix. That protocol was repeated for six consecutive years. In all individuals, fertilities based on the timing of insemination after estrus detection were very high. Lactating ewes produced better results than did dry ewes, which was probably because of the better feeding of the former. In addition, double insemination increased the fertility of ewes whose estrus was detected within 16 h of onset. Body condition and amount of vaginal fluid were correlated with fertility. Exocervical inseminations at natural estrus can produce acceptable fertility and prolificity in Churra ewes.

Effect of pre-synchronisation with progestogen and eCG on reproductive activity in synchronised ewes during anoestrous season

The objective of the study was to investigate the effect of pre-synchronisation on the occurrence of the oestrus and pregnancy rate after fixed time artificial insemination (FTAI) in synchronised ewes during the anoestrous season. Kivircik ewes (n = 84) were randomly assigned to one of the two treatment groups with (PRE; n = 42) or without (SYN; n = 42) pre-synchronisation. In the SYN group, the ewes were subjected to a 7-d short-term protocol (P4 insertion-6d-PGF2α-1d-P4 removal + eCG). In the PRE group, the same short-term protocol as in the SYN group was applied with 7 days apart for a pre-synchronised synchronisation protocol. A cervical FTAI was performed with fresh semen at 54 h after sponge removal. At the beginning of the synchronisation protocol, the oestrous response (66.7% vs. 0.0%) and cyclicity rates (64.3% vs. 14.3%) based on progesterone (P4) were higher in the PRE group compared to those in the SYN group, respectively (P < 0.01). However, the oestrous response after synchronisation was lower within 96 h (57.1% vs. 95.2%; P < 0.01) in the PRE group compared to that in the SYN group. Although the pregnancy rate after the FTAI was significantly (P < 0.05) lower in the PRE group (14.3%) than the SYN group (35.7%), the overall pregnancy rate after natural mating was not different (95.2%) between the groups. In conclusion, the pre-synchronisation decreased the oestrous response leading to a lower pregnancy rate after the FTAI in the synchronised ewes during the anoestrous season. Thus, attention should be paid to two consecutive administrations of eCG in a pre-synchronisation and synchronisation protocol in ewes.

Comparison of Five Protocols of Estrous Synchronization on Reproductive Performance of Hu Sheep

The purpose of this study is to compare five protocols of estrous synchronization for Hu ewes to obtain the most effective and economical protocol, to apply the advantageous scheme in large-scale sheep farming. Healthy multiparous Hu ewes (n = 150) were randomly divided into five groups, and all ewes were administered fluorogestone acetate (FGA, 45 mg) vaginal sponge. The sponges of the first three groups (Groups I, II, and III) were removed on the 11th day, and 0.1 mg of PGF_2α was injected intramuscularly on the ninth day. Group I received 6 μg of gonadotropin-releasing hormone (GnRH) by intramuscular injection at 36th h after withdrawal of the sponge. Group II was injected 330 IU of pregnant mare serum gonadotropin (PMSG) on the ninth day. The combination of 6 μg of GnRH and 330 IU of PMSG was treated in Group III at the same time as Group I and Group II. The sponges of the latter two groups (Groups IV and V) were removed on the 13th day, and 330 IU of PMSG was injected intramuscularly simultaneously. PGF_2α (0.1 mg) was administered on the 12th day in Group IV. All ewes were detected for estrus at 24, 36, 48, 60, and 72 h after the sponge removal. The loss of sponge and vaginitis was recorded when the sponge was withdrawn. Cervical artificial insemination (AI) was performed with fresh semen of Dorper rams diluted with skimmed milk. After 30 days of insemination, the conception was detected with a veterinary B-ultrasound scanner. The lambing status of all ewes and the cost of drugs for estrous synchronization in each group were recorded. The results showed the following: (1) on the whole, the average percentage of estrous ewes in the period of 24–36 h and 36–48 h after removal was significantly higher than other three periods and that of the period of 60–72 h was significantly lower than the first three periods after removal; (2) there was no significant difference in percentages of estrous ewes in any of the five time periods, sponge loss rate, vaginitis rate, total percentage of estrous ewes, conception rate, single lambing rate, twinning rate, and multiple lambing rate of ewes among five protocols; (3) total percentage of estrous ewes and conception rate were more than or equal to 80% in the Groups II and III, and the twinning lamb rate of the Group II protocol was 70%; (4) there was no difference in lambing rate of ewes among Groups II, III, IV, and V; (5) the Group III had the highest drug cost of 22.5 CNY. In conclusion, considering the lambing rate, twinning lamb rate, and drug cost for estrous synchronization, Group II was the most advisable for application and promotion in large-scale sheep farms among these five protocols of estrus synchronization.

The use of oxytocin to cause cervical dilation for transcervical insemination in nulliparous goats: Improving pregnancy and kidding rates

To evaluate the effect of oxytocin as a cervical dilator, a study was carried out on nulliparous goats inseminated transcervically at the beginning of the breeding season. One hundred sixteen nulliparous goats with a mean live weight of 33.4 ± 0.68 kg and an age of 13.7 ± 0.37 months were used. The goats were exposed to active bucks of proven fertility for a period of 14 d in order to induce oestrus. One week later, the Ovsynch protocol was applied, which consisted of the application of 20 mg of gonadorelin (Day Zero), 0.075 mg of cloprostenol (Day 7) and of a second dose of 20 mg of gonadorelin applied on Day 9. Artificial insemination (AI) was performed 16 hr later. Three treatments were evaluated: T1 = 50 IU saline, T2 = 25 IU oxytocin; T3 = 50 IU of oxytocin, intravenously applied 10-15 min before AI. The time required to inseminate each treated goat from groups T2 and T3 was 49.56 and 56.25 s, respectively, versus 85.78 s needed for the goats from group T1 (p < .0001). In the T1 group of goats, the insemination catheter was inserted 2.1 cm into the cervical canal and in goats from groups T2 and T3 it reached 3.41 and 3.77 cm into the cervical canal, respectively (p = .02). Pregnancy rates and prolificacy (kids/doe) were higher (p = .02) for groups T2 (82.93%; 1.16) and T3 (76.92%; 1.21) respectively than for control goats (61.11%; 0.69). In conclusion, the intravenous administration of oxytocin led to greater dilation and depth of cervical penetration, obtaining higher pregnancy rates and prolificacy.

The Impact of Bacteriocenoses on Sperm Vitality, Immunological and Oxidative Characteristics of Ram Ejaculates: Does the Breed Play a Role?

Bacterial contamination of semen is an often overlooked, yet important, factor contributing to decreased sperm vitality. Understanding the impact of bacterial presence on sperm structural integrity and functional activity may assist the development of effective strategies to prevent, or manage, bacteriospermia in the breeding practice. The aim of this study was to describe the bacterial profiles of ram semen (n = 35), and we also focused on the associations between bacteriospermia, sperm structure, and function, as well as oxidative and inflammatory characteristics of semen. For a better insight, the samples were divided into three groups, according to the breeds used in the study: native Wallachian (NW), improved Wallachian (IW), and Slovak dairy (SD) breeds. The results showed a significantly lower motility and membrane integrity in the NW group in comparison to the IW and SD groups, which was accompanied by a significantly higher concentration of leukocytes, increased reactive oxygen species (ROS) generation, and subsequent oxidative insults to the sperm lipids and proteins. Accordingly, the NW group presented with the highest bacterial load, in which Staphylococcus and Escherichia were the predominant representatives. The Pearson correlation analysis uncovered positive relationships amongst the bacterial load and leukocytospermia (r = 0.613), the extent of lipid peroxidation (r = 0.598), protein oxidation (r = 0.514), and DNA fragmentation (r = 0.638). Furthermore, positive correlations were found between the bacterial load and pro-inflammatory molecules, such as the C-reactive protein (r = 0.592), interleukin 1 (r = 0.709), and interleukin 6 (r = 0.474), indicating a possible involvement of the immune response in the process of bacteriospermia. Overall, our data indicate that ram semen quality may be equally affected by the bacterial load and diversity. Furthermore, we can assume that the presence of bacteria in ejaculates triggers inflammatory processes, causes ROS overproduction, and, thereby, contributes to alterations in the sperm structure, while at the same time compromising the fertilization ability of male gametes.

Toxic and Microbiological Effects of Iron Oxide and Silver Nanoparticles as Additives on Extended Ram Semen

The aim of the study was to investigate the effect of iron oxide (Fe) and silver (Ag) nanoparticles (NPs) on ram semen. A skim milk extender without antibiotics was used as a diluent of 21 ejaculates (8 rams; 2-3 ejaculates/ram). The groups of control (C; semen without NPs), Fe NPs (3.072 mg Fe₃O₄/mL semen), and Ag NPs (2.048 mg Ag-Fe/mL semen) were incubated (15 °C; 30 min), and then a magnetic field was used for NPs' removal. Standard microbiological procedures were performed for all groups. Post-treated samples were stored (15 °C) for 24 h, and sperm variables (kinetics by computer assisted sperm analysis (CASA); viability; morphology; HOST; DNA integrity) were evaluated at 6 and 24 h. Semen data were analyzed by a mixed model for repeated measures and microbiological data with Student's t-test for paired samples. At 6 h of storage, VCL and rapid movement-spermatozoa, and at 24 h, total/progressive motility and amplitude of lateral head displacement (ALH) were significantly decreased in group Ag compared to control. In group Fe, progressive/rapid movement-spermatozoa were significantly lower compared to control after 24 h of storage. Only in group Ag was a significant reduction of total bacterial count revealed. In conclusion, the examined Fe NPs demonstrated slight antibacterial effect, while the examined Ag NPs provided higher antibacterial properties accompanied by cytotoxicity.

Multiparametric Study of Antioxidant Effect on Ram Sperm Cryopreservation-From Field Trials to Research Bench

Simple Summary

The use of antioxidant compounds could be a successful tool to improve sperm cryopreservation protocols in ovine species. These molecules have been widely employed in different mammalian species with this purpose. It is important to consider the existence of a species-specific antioxidant effect discarding the extrapolations from other animal species. To corroborate the real effectiveness of these compounds is important to combine two approaches: in vitro sperm quality analyses and in vivo field trials based on fertility. In the first scenario, a multiparametric analyses and novel tests based on spermatozoa redox balance, as the main target of antioxidants, could improve the accuracy on antioxidant effectiveness on sperm quality. Moreover, an extensive field insemination study provides the definitive tool to select the best antioxidant treatment. All these aspects have been applied and extensively discussed throughout this manuscript. Novel approaches have been incorporated, such as RedoxSYS, to provide more accuracy in the integrative studies of Redox status in spermatozoa. The effectiveness of an antioxidant treatment, as trolox in our study, should be demonstrated in an integrative way, from in vivo (fertility trials) to in vitro analyses (sperm quality assays), especially when the final aim is to reach AI implementation.

Abstract

The optimization of sperm cryopreservation protocols in ram is a feasible tool to reinforce artificial insemination technologies considering the desirable application of sperm by vaginal/cervical or transcervical deposition. Cryopreservation provokes different types of damage on spermatozoa and many of these detrimental effects are triggered by redox deregulation. For this reason, the antioxidant supplementation in sperm cryopreservation protocols to decrease reactive oxygen species (ROS) levels and to equilibrate redox status has been widely employed in different species. Despite this, more fertility trials are necessary to provide the definitive tool to ensure the antioxidant effectiveness on sperm quality. For this reason, in this work, we performed a multiparametric analysis of some previously tested antioxidants (crocin, GSH and Trolox) on ram sperm cryopreservation from field trials to sperm quality analyses focused on new strategies to measure redox balance. Attending to fertility trial, Trolox supplementation registered an improvement concerning to fertility (when we considered high fertility males) and multiple lambing frequency and other complementary and descriptive data related to lambing performance such as prolificacy and fecundity. This positive effect was more evident in multiple lambing frequency when we considered low fertility males than in global male analysis. In vitro analyses of sperm quality confirmed in vivo trials registering a positive effect on sperm viability and redox balance. In this study, we provided the definitive evidence that the role of trolox on redox balance maintenance has a direct effect on fertility parameters, such as prolificacy. The effectiveness of antioxidant treatments was tested, for the first time in ovine species, using an integrative and multiparametric approach combining in vivo and in vitro analyses and novel approaches, such as RedoxSYS. These types of strategies should be applied to improve sperm conservation methods and optimize AI technologies upgrading the correlation between in vitro and in vivo analyses.

Addition of eCG to a 14 d prostaglandin treatment regimen in sheep FTAI programs

In the present study, there was evaluation of the alternative of adding eCG as part of a long-interval prostaglandin-F_2α (PG) treatment on the reproductive efficiency of Merino sheep during the breeding season. A total of 210 ewes and 182 ewe lambs were randomly assigned to three experimental groups to induce the timing of estrus among ewes in a: Long-interval PG, group being synchronized using two doses of PG 14 days apart; Long-interval PG + eCG group being synchronized using the same treatment regimen as Group PG with the addition of 200 IU eCG to the regimen, administered concomitantly with the second PG administration; and MAP + eCG group being synchronized with intravaginal progestin sponges for 14 days plus 200 IU eCG, administered at the time of sponge removal. The percentage pregnancy rate in ewes of the MAP + eCG group was greater than the ewes of the Long-interval PG and Long-interval PG + eCG groups (76.4 % compared with 52.0 % and 62.5 %, respectively; P < 0.05). The prolificacy rate was greater in the ewes of the Long-interval PG+eCG group compared with the other groups (114 % compared with 100 % and 103 %, respectively; P < 0.05). When considering the fecundity rate, ewes of the Long-interval PG+eCG and MAP+eCG groups had greater values than ewes of the Long-interval PG group (71.2 % and 78.8 % compared with 52.0 %, respectively; P < 0.05). The Long-interval PG+eCG is an alternative to the conventional progestin sponge plus eCG treatment regimen with there being a greater fecundity rate when this regimen is used compared with the Long-term PG and similar to MAP-eCG treatment regimens.

ProAKAP4 as Novel Molecular Marker of Sperm Quality in Ram: An Integrative Study in Fresh, Cooled and Cryopreserved Sperm

To improve artificial insemination protocols in ovine species it is crucial to optimize sperm quality evaluation after preservation technologies. Emerging technologies based on novel biomolecules and related to redox balance and proteins involved in sperm motility such as ProAKAP4 could be successfully applied in ram sperm evaluation. In this work, a multiparametric analysis of fresh, cooled, and cryopreserved ram sperm was performed at different complexity levels. Samples were evaluated in terms of motility (total motility, progressive motility, and curvilinear velocity), viability, apoptosis, content of reactive oxygen species, oxidation‒reduction potential, and ProAKAP4 expression and concentration. As expected, cryopreserved samples showed a significant decrease of sperm quality (p < 0.05), evidencing different freezability classes among samples that were detected by ProAKAP4 analyses. However, in cooled sperm no differences were found concerning motility, viability, apoptosis, ROS content, and redox balance compared to fresh sperm that could explain the reported decrease in fertility rates. However, although the proportion of sperm ProAKAP4 positive-cells remained unaltered in cooled sperm compared to fresh control, the concentration of this protein significantly decreased (p < 0.05) in cooled samples. This altered protein level could contribute to the decrease in fertility rates of cooled samples detected by some authors. More importantly, ProAKAP4 can be established as a promising diagnostic parameter of sperm quality allowing us to optimize sperm conservation protocols and finally improve artificial insemination in ovine species.