Estrus Synchronization Research Articles

Follicular dynamics in dairy sheep within and out of the breeding season employing high or low progesterone concentration in estrous cycle synchronization

Resumo A dinâmica folicular em ovelhas leiteiras é pouco compreendida. Neste trabalho foi avaliado a dinâmica folicular de ovelhas leiteiras, dentro e fora da estação reprodutiva observando o efeito de duas concentrações de progesterona (60 e 120mg) utilizadas em pessários vaginais na pré-sincronização. O experimento foi realizado nos meses de abril/maio e outubro/novembro, utilizando 40 ovelhas multíparas leiteiras hígidas, predominantemente da raça Lacaune, que foram submetidas a exames ultrassonográficos diários por via transretal. Na estação reprodutiva foram avaliados o número de ovulações (1,35 vs 1,05), o diâmetro(mm) do folículo ovulatório (5,97 vs 5,05), a duração da fase lútea (11 vs 9,14 dias) e a duração do ciclo estral (16,83 vs 16,6 dias) dentro da estação em comparação com fora da estação reprodutiva respectivamente. Fora da estação as ovelhas não apresentaram corpo lúteo no momento da inserção do pessário vaginal, caracterizando anestro. Mesmo com menor duração da fase folicular, o folículo ovulatório apresentou maior diâmetro na estação reprodutiva, sugerindo maior viabilidade e qualidade do oócito ovulado. A aplicação de progesterona exógena amplia a fase lútea na estação reprodutiva (11 vs 9,14 dias). O anestro observado fora de época sugere a necessidade de maior concentração de progesterona nos protocolos reprodutivos. Desta forma, é possível adaptar protocolos reprodutivos para diferentes épocas, sugerindo o uso de pessários vaginais com maior concentração de progesterona (120 mg) fora da estação reprodutiva. Os dados obtidos permitiram caracterizar a dinâmica folicular em ovelhas leiteiras, demonstrando suas diferenças em cada estação a partir do uso de diferentes doses de progesterona na pré-sincronização

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

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. 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. 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. 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.

Assessment of Breeding Practice and Statues of Estrus Synchronization and Mass Insemination of Dairy Cattle in North Shewa Zone, Amhara Region, Ethiopia

Assessment of Breeding Practice and Statues of Estrus Synchronization and Mass Insemination of Dairy Cattle in North Shewa Zone, Amhara Region, Ethiopia

Effect of dietary Chinese herbal preparation on dry matter intake, milk yield and milk composition, serum biochemistry, hematological profile, and reproductive efficiency of Holstein dairy cows in early postpartum period.

The present study investigated the effects of various inclusion levels of dietary Chinese herbal medicine (CHM) preparation on feed consumption, milk yield and milk composition, serum biochemistry, hematological profile, and reproductive efficiency of Holstein dairy cows. A total of 117 lactating Holstein cows were randomly divided into four groups as control (n = 27; without CHM supplementation) and treatment groups CHM-0.5 (n = 31), CHM-0.75 (n = 29), and CHM-1 (n = 30) fed diet supplemented with 0.5, 0.75, and 1 kg/cow/d for 30 days, respectively. The study began at d 20 postpartum (d 0 of the study). At d 50 postpartum, the cows in all groups were subjected to estrus synchronization using a modified Ovsynch protocol (GPGMH) and observed for reproductive variables. Feed intake, milk yield and milk composition, serum biochemistry and hematological profile, and reproductive efficiency were measured. A significantly higher milk yield with improved milk lactose, milk protein and milk fat were found in the CHM-0.75 group compared to the other groups (p < 0.05). Besides, the estrus response, ovulation rate, ovulatory follicle diameter, and pregnancy rate increased in CHM-0.75 compared to CHM-0 or CHM-0.5 group (p < 0.05). The serum metabolites (glucose, AST, arginine, BUN, and NO) showed variations among the treatment groups at different time points (synchronization, AI, or post-AI). In conclusion, CHM supplementation improves the milk yield, milk composition, and serum metabolites in dairy cows. Daily supplementation of 0.75 kg CHM before the GPGMH protocol application enhances the reproductive traits in dairy cows under summer conditions.

Reproductive ability of minipigs as surrogates for somatic cell nuclear transfer.

Pigs are genetically, anatomically, and physiologically similar to humans. Recently, pigs are in the spotlight as a suitable source animal for xenotransplantation. However, to use pigs as source animals, pigs should be raised in designated pathogen-free facilities. There is abundant data from embryo transfer (ET) experiments using farm pigs as surrogates, but data on ET experiments using minipigs are scarce. Eighty minipigs were used for ET experiments and after transplantation, the implantation and delivery rates were investigated. It was also confirmed whether the pregnancy rate could be increased by changing the condition or surgical method of the surrogate. In the case of minipigs that gave birth, the size of the fetal sac on the 28th day of ET was also measured. The factors that can affect the pregnancy rate such as estrus synchronization program, ovulation status at the time of ET, the number of repeated ET surgeries, and the ET sites, were changed, and the differences on the pregnancy rate were observed. However there were no significant differences in pregnancy rate in minipigs. The diameter of the implanted fetal sac on the 28th day after ET in the minipigs whose delivery was confirmed was calculated to be 4.7 ± 0.5 cm. In conclusion, there were no significant differences in pregnancy rate of minipigs in the comparative experiment on various factors affecting the pregnancy rate. However, additional experiments and analyses are needed due to the large individual differences of the minipigs.

Combining two injectable progesterone formulas for estrous synchronization in ewes.

The study aimed to evaluate the effectiveness of combining two injectable progesterone (iP4) formulas for estrous synchronization in ewes and to compare it with traditional intravaginal progesterone devices. Additionally, the study assessed whether the inclusion of GnRH enhances the reproductive outcomes of the iP4 treatment. Two experiments were conducted. In the first experiment, 20 Santa Inês ewes were divided into two groups: one group received intravaginal progesterone devices, and the other received combined long-acting and short-acting iP4. In the second experiment, 30 Corriedale ewes were divided into two groups: one received the combined iP4 with GnRH, and the other without GnRH. Estrous, ovulation, follicular populations, and progesterone concentrations were monitored. The combined iP4 treatment induced an artificial luteal phase and produced reproductive responses similar to those obtained with intravaginal devices. In the first experiment, the iP4 treatment tended to result in more synchronized ovulation compared to the control (P=0.095). In the second experiment, adding GnRH enhanced the quality of the corpus luteum, as indicated by increased diameter and vascularization on Day 23 (P=0.047 and P=0.02, respectively). The combined administration of long-acting and short-acting iP4 effectively synchronized estrous in ewes and showed similar efficacy to traditional intravaginal devices. The inclusion of GnRH improved luteal quality, suggesting potential benefits for reproductive management in ewes. Further studies are needed to evaluate the fertility outcomes of these protocols under field conditions.

The Effect of Conventional Semen, Sexed-Semen, and Embryo Transfer on Pregnancy Rate in Holstein Dairy Cows

In this study, it was aimed to detect the effects of conventional semen, sexed-semen and embryo transfer on pregnancy rates in Holstein dairy cows. In the study, a total of 139 healthy cows with the serum progesterone &amp;gt; 8 ng/ml were used as animal material. Estrus synchronization protocol was applied and cows were divided into three different groups as conventional semen group (G1, n=46), sexed semen group (G2, n=47), and embryo transfer group (G3, n=46) considering age, body condition score, lactation number, and body weight. Cows in G1 and G2 were inseminated with conventional semen and sexed-semen, respectively. Embryo transfer was performed to cows in Group 3 (n=46) 7th day after estrus. The embryos were transferred to recipients as freshly. Pregnancy examinations for the cows were conducted on the 30th and 60th days of gestation. The statistical analysis of the obtained results was performed. Pregnancy rates were detected as %50, %46,8 and %69,56 in G1, G2, and G3 respectively on 30th day. On 60th day, however, pregnancy rates were %45.60, %42.55 and %67.39 in G1, G2, and G3 respectively due to embryonic losses. The pregnancy rate was significantly higher in the embryo transfer group (G3) compared to the conventional semen (G1) and sexed-semen (G2) group (p&amp;lt;0.05) on both 30th and 60th days. There was no significant difference between G1 and G2 (p&amp;gt;0.05). Findings led to the conclusion that higher serum progesterone level may increase pregnancy rate in cattle. In addition, it is evident that embryo transfer has the potential for widespread use in the field of veterinary medicine in terms of genetic progress.

Effect of Self Made Intravaginal Progesterone Sponge on Fertility in Goat

Comparative studies of intravaginal sponges containing three different doses of progesterone on estrous synchronization; fertility, fecundity and prolificacy of synchronized does by natural mating were conducted during the breeding season at Central Sheep Breeding Farm, Hisar. A total of 60 Beetal does selected randomly and divided into group I, II and III with 20 does in each, and subsequently intravaginal sponges containing 50, 100 and 150 mg P4 were inserted respectively for 14 days and an i/m injection of PMSG (@200IU/doe) was injected just after sponge removal in each doe. Effective number of animals remained 55 as 5 does dropped their sponges. Forty eight to sixty hrs after sponge removal, 14, 16 and 15 does from group I, group II and group III respectively were synchronized to estrus and subsequently hand mated individually with bucks of proven fertility. The fertility, fecundity and prolificacy per cent after synchronization of oestrus in group I, group II and group III was 78.57, 87.50 and 86.66; 128.57, 156.25 and 166.66; 163.63, 178.57 and 192.30 respectively. Eighteen animals (6 does from each group) selected randomly out of 60 animals for progesterone estimation. Blood samples were collected immediately before insertion of intravaginal sponges (day 0) and then subsequently on day 7, 14 after sponge insertion and 48 and 72 hrs after sponge removal. Progesterone concentration was above basal level in most of animals on day 0 in all the groups. Increase in plasma progesterone concentration (with in group) was recorded on day 7 and decreased on day 14 &amp; 48 hrs after sponge removal. These changes were significant in group II &amp; III while non-significant in group I. Progesterone concentration decreased non-significantly 72 hours after sponge removal in all the three groups. Significant difference in plasma P4 concentration was reported in between group I and group II &amp; III on day 7 &amp; 14.

Recent Advances in Dairy Animal Breeding and Reproduction: A Review

This review has highlighted the transformative impact of recent technologies on dairy animal breeding and reproduction. Recent advances in the breeding and reproduction of dairy cows involve the integration of molecular genetics, cytogenetics, and reproductive biology into animal breeding practices. This integration of precision technologies has played a critical role in increasing the efficiency and productivity of breeding programs. The development of modern genetic technologies, such as genome mapping, marker-assisted selection, and transgenesis, has revolutionized the identification of superior genetic traits, contributing to accelerated genetic progress in dairy herds. Furthermore, advancements in reproductive technologies, including artificial insemination, embryo transfer, sperm sexing, and synchronization of estrus and ovulation in dairy cows, have supported the optimization of breeding strategies and facilitated improvements in economically important traits in livestock. Efforts have also been directed toward advancing the early detection of estrus stress in dairy cows using sensitive physiological indicators and sensor technologies, aiming to enhance decision-making in estrus management on dairy farms. In conclusion, recent improvements in the breeding and reproduction of dairy animals have demonstrated significant potential for enhancing reproductive efficiency, profitability, and the quality of milk and milk products. However, these technologies face limited applicability in developing countries due to challenges such as poor infrastructure, low costs, or a lack of human resources. Therefore, it is imperative to develop cost-effective technologies tailored to local and regional contexts, subsequently facilitating their broad dissemination within these regions.

Factors Influencing Productivity and Sustainability of Small-Scale Beef Farms in Thailand

Over the past few decades, Thailand has witnessed a decline in production from small-scale beef cattle farming, accompanied by a reduced interest from younger generations in continuing family farming. The present study aimed to determine the state of these farms based on good agricultural practices (GAP) and explored factors influencing beef herd productivity and the willingness of the next generation to sustain the family business. Data from 1,175 questionnaires from 34 provinces was analyzed using SPSS. Beef herds with higher calving rates (CR ≥ 60%) had better herd, reproductive, and health management scores compared with the lower CR (&lt;60%) group. Results from a negative binomial regression showed that factors, i.e., prediction of calving date and routine deworming positively impacted CR, while others like feeding types, mineral supplements, vaccination and hormonal estrus synchronization negatively correlated with CR. Expert opinions (N = 83) highlighted the importance of recording systems, heat detection programs, pregnancy diagnosis, feeding type, sufficient qualified water supply and mineral supplements. The use of Artificial Neural Network (ANN) and GLM analysis also noted that farm potential score, farmer gender, and occupations were pivotal for the sustainability of beef farming. This research aids in strategizing for enhanced sustainable beef production in Thailand.

Синхронизация на еструса при овце от Синтетична популация българска млечна чрез прогестаген и различни последващи третирания

The aim of the present study was to induce estrus synchronization in ewes after administration of progestagen for 12 days and various subsequent treatments (with FFA, GnRH analogue or no treatment) after cessation of its action. The experiment was conducted in August, 2022, with 27 sheep from the Synthetic Bulgarian Dairy Population. All ewes were treated with vaginal sponges, containing 30 mg FGA (duration of stay - 12 days) and the formation of experimental groups was according to follow-up treatment after sponge removal: I group - experimental animals were treated with 400 UI of PMSG at the time of removal of sponges. II group - the sheep were treated with 1 ml of GnRH analogue, containing busorelin acetate 0.004 mg/ml, 24 hours after sponge removal. III group – no treatment after sponge removal. The next parameters were studied: estrus synchronization rate, fertility and fecundity were studied. The estrus synchronization rate was the highest for I group - 100% and the lowest for II group - 66.67%. Fertility was highest in III group - 87.50%, and lowest in II group - 50.0%. Fecundity was highest in I group - 171.43%, while in other groups it was 133.33% and 128.57%, respectively, for II group and III group. Based on the obtained results, it could be concluded that GnRH analogue treatment, given solely 24 hours after sponge removal, didn’t have the synchronization effect as the classical follow- up treatment with PMSG. No follow-up treatment after sponge removal was better alternative that GnRH treatment.

Synchronization of ovulation (FTET) in Turcana sheep as embryo recipients

Due to the fact that the farm wants to crossbreed sheep with meat breeds, it was opted for the fastest solution to bring genetic progress, namely embryo transfer, using sheep from the Turcan breed as embryo recipients and those from the Suffolk breed as embryo donors, so that finally the batch of receivers after parturition will produce a production of Suffolk lambs. Following the selection of recipients considering the standard criteria that include: general health, functional integrity of the genital tract and cyclic activity of the ovaries, two groups were formed for the induction and synchronization of estrus. The first batch consisted of 20 sheep and the second batch of 20. The first batch was subjected to a P4-PG-PMSG protocol and the second batch to the P4-PG-GnRH protocol. The two protocols consisted of the insertion of intravaginal sponges with flugestone acetate in a concentration of 20mg, to induce the progesterone phase, for 13 days, day 0 of the protocols being represented by the day when the progesterone sponges were applied. In continuation of the protocol, Prostaglandinf2α was used on day 12 in a double dose, in the morning and in the evening at a distance of 12 hours in a dose of 0.6 ml/administration/animal. On day 13, the progesterone sponges were removed and PMSG (Folligon) was administered in the case of the first batch at a dose of 600 IU/animal, and in the second batch GnRH (Receptal) was administered at a dose of 12 μg/animal ( 3ml/animal) followed by a dose of 600 IU HCG (Chorulon) 24 hours after GnRH administration. Ovulation was accurately assessed at the time of embryo transfer through laparotomy, due to the highlighting of the ovaries and their macroscopic analysis in the operative field, after identifying the CL on the ovary, their appearance and the number of CL on the ovary. However, the assessment of the rate of entry into heat was assessed 24 hours after the end of the protocol by biostimulating the receptors with the help of detector rams, thus the ewes that entered in estrus at 12 – 24 hours, 24 – 48 of hours or over 48 hours after completing the protocol. The results obtained in the case of the first batch having the highest rate of entering in estrus between 24 - 48 hours being 40%, followed by a rate of 30% between 12 - 24 hours, the lowest rate being 20% that entered in estrus after 48 hours, the second batch with GnRH had the highest rate of entry into estrus of 60% in the first 12-24 hours and the rate at 24-48 hours, respectively those that entered heat after 48 hours was 20%. Compared between the two groups, there were differences in the timing of ovulation assessment, as in the case of the first group with PMSG, a 60% ovulation rate was assessed with well-developed CL, 10% presented CL but these were unsuitable for embryo transfer, 10% presented ovarian cysts, and 10% did not ovulate, in the case of the second batch an ovulation rate of 60% was assessed and the rate of 40% represented the animals that did not ovulate, the difference between the two batches being the fact that it is observed in the case of the first batch rate of 10% with ovarian cysts, which indicates that the PMSG-based pharmaceutical is causing ovarian cysts. In conclusion, the therapeutic protocol used in the off-season for the induction of estrus and ovulation in Turcan sheep, in this study, resulted in the detection of estrus in 90% of the ewes subjected to the protocol, and the ovulation rate was 80% (60% with CL well developed and 20% were with poorly developed CL), regarding the first batch, and regarding the second batch 100% of ewes in oestrus were detected, but 60% of them ovulated with CL well developed. These results can be largely attributed to the reproduction seasonality of the sheep.

Luteal tissue characteristics of Morada Nova ewes with hCG application 7.5 days after the end of estrus synchronization protocol in the breeding season

Results with the use of hCG after synchronization protocol are still inconsistent, which may vary according to breed, season, day of application and dose of the drug used. The aim of the present study was to evaluate the functionality of luteal tissue and ovarian perfusion after hCG treatment during early luteal phase. Estrus-synchronized ewes were randomly assigned to receive i.m. injection of 300 IU of hCG (G-hCG; n = 40) or 1 mL of saline (G-Control; n = 32) on Day 7.5 after progesterone withdrawal. Ultrasonographic evaluations of the ovaries and ovarian and iliac arteries were performed on Days 7.5, 10.5, 13.5, and 21.5. The accessory corpus luteum (aCL) formation rate was 52.5% for G-hCG. There was interaction (p > 0.05) for treatment (G-hCG and G-Control), days (7.5, 10.5, 13.5 and 21.5) and PD (Pregnant and Non-pregnant) for the variables of biometric characteristics of the corpus luteum B-Mode and Color Doppler on days 7.5, 10.5, 13.5 and 21.5. There was no difference (p > 0.05) for pregnancy rates and mean fetuses per ewe between the treatment groups. It is concluded that the application of hCG 7.5 days after the hormonal protocol in Morada Nova ewes in a breeding season is efficient in inducing aCL formation and increasing luteal tissue biometry. However, there was no effect on pregnancy rate.

Development of a new protocol for estrus induction and synchronizationin multiparous weaned sows

Estrus induction and estrus synchronization with P.G. 600 to improve the reproductive performance of multiparous sows is a standard protocol. However, its nonavailability in India and higher cost warrants development of new protocols without compromising the reproductive performance. The present study compared the efficacy of two different protocols for estrus induction and synchronization in multiparous sows. The sows (n=80) were randomly divided into two groups. In group-I, sows (n=40) were injected with P.G. 600 (equine chorionic gonadotropin [eCG] 400 I.U. and human chorionic gonadotropin [hCG] 200 I.U.) and in group-II, P.G. 450 (eCG 300 I.U. and hCG 150 I.U.) intramuscularly. Reproductive performance parameters, including estrus induction, treatment to estrus induction interval, estrus duration, farrowing rate, live born piglets/litter, stillborn piglets, total piglets born/litter, litter size at weaning and pre-weaning mortality were analyzed between two groups. Estrus induction and farrowing rate were numerically higher in group-II but statistically nonsignificant. Treatment to estrus induction interval was 55.59 h and 55.57 h, respectively in group-I and group-II. Similarly, total litter size at birth and litter size at weaning were non-statistically higher in group-II as compared to group-I. In conclusion, the present study demonstrated that estrus induction and synchronization can be successfully achieved in multiparous sows with P.G. 450 and this will reduce the cost of hormonal treatment and optimize the reproductive efficiency in Indian condition.

Reproductive Efficiencies and Productive Potentials of Female Nigerian Indigenous Goat Breeds

Purpose: The overall objective of this study was to examine the reproductive and productive abilities of three Nigerian indigenous goat breeds.&#x0D; Methodology: The study covered 108 primiparous does and nine bucks from Sahel (SH), Red Sokoto (RS), and West African dwarf (WAD) goat breeds. In different pens, the animals were bred in various combinations: RS x RS, WAD x WAD, SH x SH, RS x SH, RS x WAD, SH x RS, and SH x WAD. WAD x SH, WAD x RS. Estrus synchronization was done using prostaglandins. Mating occurred naturally when animals were on heat. Dams were given special care throughout pregnancy. The study measured dams' weights, litter size, and pre-weaning mortality rates in kids. The total kid crop and sexes were also assessed. We measured dam lactation weight loss, birth weight, and weaning weight. SPSS, ANOVA, and the Turkey statistical test were used for data analysis.&#x0D; Findings: The result showed that there was a significant (P&lt;0.05) difference in the weight of does at kidding. The weight of does at weaning varied significantly (P&lt;0.05). Litter size significantly (P&lt;0.05) affected the birth weight and weaning weight of kids. An increase in litter size per birth resulted in a significant (P&lt;0.05) rise in kid mortality rates. Breed type significantly (P&lt;0.05) affected doe production efficiency and weaning weight ratio. Although WAD x WAD goats had lower birth and weaning weights, hybrid vigour (birth and weaning weights) improved significantly (P&lt;0.05) when cross-bred with SH or RS breeds. When crossed with SH or WAD goat breeds, RS breeds had the greatest positive effect on hybrid vigour (heterosis), followed by SH breeds. Both SH x RS and RS x SH progenies recorded higher hybrid vigour than the other nine bred line progenies.&#x0D; Unique contribution to theory, practice and policy: This study found that Nigerian indigenous goat breeds had great reproductive efficiency and breeding potential if properly managed. Genetic variations observed in the study could improve Kids crop, birth weight, litter size, hybrid vigour, and pre-weaning survivorship due to their broad variety. This study recommends a careful selection and crossbreeding of Nigerian indigenous goat breeds with suitable pedigree in order to increase their productivity.

Hormone secretion in serum of bactrian camels during breeding and nonbreeding seasons: Insights into reproductive physiology

To enhance Bactrian camel population through reproductive technologies, 12 female camels (FC) aged 8-12 years underwent reproductive experiments involving synchronized estrus, superovulation, and artificial insemination. Using the enzyme-linked immunosorbent assay (ELISA), we examined the secretion patterns of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estrogen (E2), and progesterone (PROG) in reproductive and non-reproductive seasons of FC. Exogenous hormones GnRH+GnRH, GnRH+PGF2α, and PMSG were given to synchronize estrus in FC. Comparing peak times and secretion levels of reproductive hormones determined the optimal protocol for synchronized estrus. The study found a positive correlation between FSH and LH secretion in FC, with LH higher. Female camels exhibited an increase in E2 secretion during the transition from non-reproductive to reproductive seasons. Conversely, the concentration of PROG in plasma was higher during the Non-reproductive season compared to the reproductive season. A positive correlation was observed between E2 and PROG levels in FC during reproductive and non-reproductive seasons. Exogenous hormones induce LH and E2 peaks in 2-4 hours and 2-8 hours, respectively, for synchronized estrus. The GnRH+PGF2α hormone superior for estrus synchronization. Our study reveals distinct hormone secretion patterns in female camels during reproductive and non-reproductive seasons. Our findings have significant implications for novel breeding technologies.

Üreme Mevsimi Dışında Tuj Koyunlarında Kısa Süreli veya Uzun Süreli Progesteron Temelli Östrus Senkronizasyonunun Fertilite Parametrelerine Etkisi

The objective of this study was to investigate the impact of estrus synchronization on certain fertility parameters in Tuj ewes during the non-breeding season, using short-term (ST) or long-term (LT) progesterone (P4)-impregnated sponge and equine chorionic gonadotropin (eCG). Forty-eight clinically healthy Tuj ewes were selected and divided into three groups: Group I (G1, n=15), Group II (G2, n=18), and Group III (G3, n=15). G1 and G2 received hormonal treatment with a P4-impregnated sponge inserted into the vagina on day 0, and 500 IU eCG was administered intramuscularly five or ten days later, respectively. The sponges were removed from the vagina seven days after insertion for G1 and 12 days after insertion for G2. G3 did not receive any hormone treatment. All groups were exposed to the ram 24 hours after sponge removal. Estrus was monitored every six hours for five days, and pregnancy was confirmed by transrectal ultrasonography. The estrus rate, estrus onset time, and pregnancy rate were significantly different between G1 and G3 and between G2 and G3 (p0.05). In conclusion, ST or LTP4-impregnated vaginal sponge treatment was equally effective on fertility parameters in Tuj ewes during the non-breeding season.

Incorporation of L-Carnitine in the OvSynch protocol enhances the morphometrical and hemodynamic parameters of the ovarian structures and uterus in ewes under summer climatic conditions

Heat stress negatively impacts the reproductive performance of sheep including the efficiency of estrous synchronization regimens. This study aimed to investigate the potential effects of L-Carnitine (LC) administration on the efficacy of the OvSynch protocol in ewes under summer climatic conditions. Ewes were synchronized for estrus using the OvSynch protocol and a dose of LC (20 mg/kg body weight) was intravenously (IV) administered on the same day of PGF2α injection to one group (n = 8; LC group), while other ewes (n = 8; control group) received the same protocol without LC. Ultrasonographic evaluation (including B-mode, color, and pulsed Doppler) was used to assess the morphometrical and hemodynamic parameters of ovarian structures [number, size, and blood flow of follicles (GFs) and corpora lutea (CLs)] and uterus during the estrous phase (Day 0), and on Day 8 post ovulation (luteal phase). Uterine artery blood flow (MUA) was assessed by measuring the resistive index (RI) and pulsatility index (PI) at both stages. The serum samples were collected to measure the concentrations of estradiol (E2), progesterone (P4), and total antioxidant capacity (TAC) using commercial kits. Results revealed a significant (P<0.05) increase in the colored pixel area of GFs and uterus in the LC group (392.84 ± 31.86 and 712.50 ± 46.88, respectively) compared to the control one (226.25 ± 17.74 and 322 ± 18.78, respectively) during Day 0. Circulating E2 and TAC levels were significantly (P<0.05) higher in the LC-treated ewes (31.45 ± 1.53 pg/ml and 1.80 ± 0.13 mM/L, respectively) compared to those in the control ewes (21.20 ± 1.30 pg/ml and 0.98 ± 0.09 mM/L, respectively) during Day 0. Moreover, LC improved the colored pixel area of CLs (2038.14 ± 102.94 versus 1098 ± 82.39) and uterus (256.38 ± 39.28 versus 121.75 ± 11.36) and circulating P4 (2.99 ± 0.26 ng/ml versus1.67 ± 0.15 ng/ml) on Day 8. Values of RI of MUA were significantly lower in the LC group compared to the control one on Day 0 and Day 8 (0.48 ± 0.03 versus 0.72 ± 0.03 and 0.58 ± 0.03 versus 0.78 ± 0.02, respectively). In conclusion, LC incorporation in the OvSynch protocol enhanced the morphometrical and hemodynamic parameters of the ovarian structures and the uterus concomitantly with improvements in the TAC, E2, and P4 concentrations in ewes under hot summer conditions.

A REVIEW ON EFFICIENCY OF ARTIFICIAL INSEMINATION IN CATTLE BREEDING IN ETHIOPIA

Ethiopia has large cattle population in Africa. The output of decades of crossbreeding programme in Ethiopia through AI service was quite insignificant because the exotic breeds and their crossbreds of the country accounted for about 1.44%. The objective of this review is to present the efficiency of Artificial Insemination (AI) service in cattle breeding in Ethiopia. The optimum recommended mean number of services per conception (NSC) for profitable dairy cow is about 1.4. However, conventional cattle AI breeding indicated that the mean NSC of different studies ranged from 1.14 in local cows up to 2.47 in different genotypes of cows kept under different management systems and conception rate at first insemination (CR1) ranged from 7.14% to 75.5% in different genotypes of dairy cows kept under extensive and intensive management systems. Estrus synchronization followed AI breeding indicated that CR1 ranged from 24.69% to 70.6% in Zebu cows kept under semi-intensive management system. Calving rate (CR) is the most appropriate measure of fertility of dairy cows which is defined as the number of calves born per 100 services. The poor efficiency of the country cattle AI service is a huge biological economic loss in cattle production and managerial monetary losses. Strategic interventions on cattle AI service efficiency improvement options should be identified and practiced considering breed type, production system and agro-ecology.

167 Plasma Metabolomics at Weaning and 30 Days Prior to Ai in Beef Heifers with Varying Reproductive Potential

Abstract Cattle are an economically important species, and subfertility is one of the reasons for economical loss for producers. Despite the use of phenotypic measures in selection, such as body condition score, reproductive tract score and age, a subset of heifers will fail to conceive by the end of a defined breeding season. Therefore, diagnostic biomarkers are desired that can successfully discriminate fertile and subfertile beef heifers. Metabolites are small molecules present in biofluids and tissues, relating to metabolic processes of cells and organs. The metabolome, the global population of small molecules, is highly impacted by environmental interactions. Therefore, for this study, metabolomic profiles were generated on beef heifers with varying reproductive potential. Angus-Simmental heifers were subjected to estrus synchronization (Select Synch+CIDR protocol), estrus detection and artificial insemination, and natural breeding service protocols. Blood samples were collected from all the heifers at the time of weaning and from a subset of the same heifers at 30 days before AI. Depending on presence or absence of conceptus after 75 days of AI, the heifers were categorized as fertile (pregnant to AI) or subfertile (not pregnant) groups. Plasma metabolome profiles were generated for 12 heifers (6 in each group) using GC-TOF-MS from the blood plasma collected at weaning and from 7 heifers (3 fertile and 4 subfertile) at 30 days prior to AI. Metabolomic profiles were analyzed using MetaboAnalyst v5.0 utilizing Students t-test, principal component, and partial least squares discriminate analyses. Nine metabolites including arabitol, lyxitol, lactic acid, and nicotinamide were significant (P ≤ 0.05) between subfertile and fertile heifers at weaning. Four metabolites including tryptophan and palmitoleic acid were significant between subfertile and fertile heifers at 30 days before to AI. ROC-AUC curves identified arabitol, tryptophan, and palmitoleic acid with AUC values of 1 (P ≤ 0.05) within their respective timepoints. ROC-AUC curves for lyxitol, lactic acid, and nicotinamide had AUC values of 0.778, 0.917, and 0.806, respectively. These metabolites interact with pathways like pentose and glucuronate interconversions (arabitol and lyxitol), fatty acid degradation (palmitoleic acid), pyruvate metabolism and gluconeogenesis/glycogenesis (lactic acid), aminoacyl-tRNA biosynthesis and tryptophan metabolism (tryptophan), and nicotinate and nicotinamide metabolism (nicotinamide). Additionally, individual activities of these metabolites point to interactions with increased stress at weaning, immune cell efficiency, and energy metabolism. This opens up avenues of testing metabolite levels that could potentially identify heifers in periods of subfertility at multiple time points, reducing the resources and time spent on them for estrus synchronization or AI breeding. However, further targeted study is required to fully elucidate the discriminatory potential of these metabolites.