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Simple Summary: The timing of ovulation varies widely among gilts, leading farms to often perform multiple inseminations to ensure that sperm and eggs meet in the reproductive tract, thus enhancing fertility. Administering a gonadotropin-releasing hormone (GnRH) agonist, such as buserelin, at the onset of estrus can induce ovulation and reduce the variation in ovulation timing among sows. This study examined the effect of adding buserelin to boar semen on the litter size of gilts. Gilts were inseminated with semen enriched with either 5 or 10 µg of buserelin acetate during the initial insemination. Although there were no significant differences in the farrowing rate between the groups, the group receiving 10 µg of buserelin acetate had a higher total number of piglets and live-born piglets. Additionally, this group exhibited greater litter birth weight compared to the control group. These findings indicate that supplementing boar semen with a GnRH agonist enhances litter size in gilts. The use of exogenous hormones has long been of interest for improving reproductive performance in swine production. Enhancing litter size directly impacts the economic efficiency of pig production. Various strategies, including nutritional, genetic, and hormonal approaches, have been explored with varying degrees of success. Administering a gonadotropin-releasing hormone (GnRH) agonist, such as buserelin, at the onset of estrus can induce ovulation and reduce the variation in ovulation timing among sows. This study assessed the impact of GnRH agonist supplementation in boar semen doses on the litter size of inseminated gilts. The research was conducted on a commercial swine herd in northern Thailand. A total of 231 Landrace × Yorkshire crossbred gilts, aged 224.5 ± 16.2 days at the onset of estrus synchronization, participated in the experiment. The gilts' estrus was synchronized with oral altrenogest supplementation at a dosage of 20 mg/day for 18 days. After exhibiting standing estrus, the gilts were randomly divided into three groups. Control group: gilts were inseminated at 0 and 12 h post standing estrus onset with a conventional semen dose (n = 94). Treatment 1: similar to the control group, but with an added 5 µg (1.25 mL) of buserelin acetate to the boar semen dose during the first insemination (n = 71). Treatment 2: similar to the control group, but with 10 µg (2.5 mL) of buserelin acetate added to the boar semen dose during the first insemination (n = 66). All gilts were inseminated twice during their standing estrus using the intrauterine artificial insemination method. Each semen dose contained 3.0 × 109 motile sperm in 80 mL. The farrowing rate averaged 78.8% and did not significantly differ between the groups (p = 0.141). The total number of piglets born per litter in the treatment 2 group was greater than in the control group (14.0 ± 0.3 vs. 13.2 ± 0.3, respectively, p = 0.049), but was not significantly different from the treatment 1 group (13.3 ± 0.3, p = 0.154). Similarly, the number of live-born piglets in the treatment 2 group was greater than in the control and treatment 1 groups (13.2 ± 0.4 vs. 12.3 ± 0.3 and 12.0 ± 0.4, respectively, p < 0.05). Moreover, the live-born piglets' litter birth weight in the treatment 2 group was greater than in the control group (17.0 ± 0.4 vs. 15.6 ± 0.3 kg, respectively, p = 0.008) and the treatment 1 group (15.7 ± 0.4 kg, p = 0.025). In conclusion, adding a GnRH agonist to boar semen appears to enhance the litter size of gilts. Further research should focus on understanding the underlying mechanisms and determining the optimal dose and timing for GnRH agonist supplementation. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the impact of feeding selenium (Se) and vitamin E on the physiological and reproductive performance of 18 multiparous Awassi ewes through the breeding season. The ewes received three levels of oral selenium-vitamin E for 60 days until the study was completed. The experimental ewes were assigned into three groups; the control group (SE0) received 2 mL of sterile saline per head, the second group (SE1) received 1.5 mL/head Se and vitamin E (150 mg a-Tocopherol acetate + 0.15 mg Sodium selenite), while the third group (SE2) received 3 mL/head (150 mg a-Tocopherol acetate + 0.15 mg Sodium selenite). The SE1 and SE2 groups demonstrated significant highest (p<0.05) rate of conception and overall pregnancy. The study results showed the lambing rate in the SE2 group increased significantly (p<0.05) compared to the other groups. All groups had low plasma progesterone levels on day 14, even though concentrations increased in SE0 and SE1, which had higher progesterone levels than SE2. SE1 had the highest estrogen concentration on day 16 compared to SE0 and SE2. On day 14, the SE0 group had a significantly lower ALT enzyme compared to the SE1 and SE2 groups. SE1 had significantly lower mean corpuscular volume (MCV), white blood cells (WBC), and platelets (PLT) concentrations than the other two groups. Overall, the estrus synchronization program and the administration of Se and vitamin E resulted in a significant improvement in pregnancy and lambing rates among Awassi ewes. Physiological and reproductive potential of sheep can be increased by improving their diet throughout the period of reproduction by including Se and vitamin E. [ABSTRACT FROM AUTHOR]

The current study was conducted to assess the ovsynch estrus synchronization in imported pure Holstein Friesian and Holstein Friesian-Jersey crossbred cows at district Thatta Sindh. A total 30 Holstein Friesian and Holstein Friesian-Jersey crossbred cattle were selected and divided into three groups i.e., A (10 pure Holstein Friesian cows), B (10 Holstein Friesian-Jersey crossbred cows), and C (5 pure Holstein Friesian and 5 Holstein Friesian–Jersey crossbred cows) as control group. All selected animals were scanned through ultrasound to ensure the normality of reproductive tract. Animals of group A and group B were treated with Ovsynch protocol {GnRH; (Dalmarelin, FATRO) intramuscular at day 0 followed by PGF2α (Dalmazin; FATRO) intramuscular at day 7 and 2nd GnRH intramuscular at day 9} for estrus synchronization while animals of group C was kept as untreated control (intramuscular injection of normal saline as placebo on day 0, 7 and 9). Animals of all group underwent fixed time insemination at 16 h of last treatment. Results showed that estrus response vary significantly among the groups (P<0.05). Overall estrus response was observed significantly higher in group B (80%), followed by A (60%) and C (10%). Intensity of estrus was determined by observing the estrus signs. Results showed significantly higher intensity of estrus signs in Group B than A and C for mucus discharge 90%, 65%,10%, flehmen 90%, 60%,10%, standing heat80%, 60%, 10% and sniffing vagina 80%, 70%, 10%, respectively. Estrus duration differs significantly among the treatment groups (P<0.05). Significantly maximum estrus duration was noted in group B (15.02 ± 0.21 h), then A (13.58 ± 2.22 h) and C (10 ± 0.00 h). In all groups blood samples were collected from the milk vein on day 0 (the first treatment), day 7, day 11 (one day after artificial insemination), day 18 and day 30 from all groups for determining progesterone level. Statistical analysis showed non-significant differences in progesterone level among groups at day 0. Furthermore, on Day 7, Group C differed significantly in progesterone level than A and B; however non-significant difference were observed in group A and B, while in group C difference was significant. On day 11 significantly highest values of blood progesterone were seen in group C (2.63 ± 0.22) followed by A (1.65 ± 0.35) and then B (1.48 ± 0.22). Statistical analysis showed that group C was significantly different from A and B, but there was non-significant difference between A and B. At day 18 highest P4 values were seen in B (4.20 ± 0.44) followed by A (3.33 ± 0.39) and then C (1.88 ± 0.59). Statistical analysis showed that group B and A had non-significant difference among each other, while both groups had significant differences with group C. Blood progesterone level for all the three groups on day 30 showed highest values in group B (10.90 ± 2.44) followed by A (8.28 ± 3.33) and C (4.53 ± 0.44). Statistical analysis showed significant difference among all three groups on day 30. It was concluded that in term of estrus response, cyclic activities and fertility rate, Ovsynch protocol was more effective in Holstein Friesian- Jersey cross breed cows than in Holstein Friesian pure cows. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Estrus synchronization is widely used in ovulation induction in dairy ewes in the non-breeding season. Objectives: This study aimed to investigate the differences in reproductive performance between cyclic and Anestrus Lacaune dairy ewes in synchronization protocol using a vaginal implant of progesterone and equine chorionic gonadotropin (eCG) in non-breeding season programming. Methods: Eighty-four 15 to 20 months old Lacaune ewes were chosen, with one delivery, and 90 days had at least passed. Two blood samples were taken for progesterone (P4) evaluation 10 days apart. Plasma P4 concentrations were determined using an ELISA. Ewes with P4<1 ng/mL in two blood samples were considered acyclic and compared with cyclic ewes in estrus expression, pregnancy rate, lambing rate, litter size, fecundity, birth weight, and sex of lambs. The ewes were kept in a separate place about 5 km away from the rams for >2 months. Results: Out of 84 ewes, 31 were cyclic (36.90%), and 53 were anestrous (63.10%). In anestrous ewes, mean P4 concentrations were 0.43±0.4 and 0.45±0.04 ng/mL in the first and second blood sampling, respectively. In cyclic ewes, mean P4 concentrations were 2.46±0.39 and 2.77±0.34 ng/mL in the first and second blood sampling, respectively. Expression of behavioral estrus did not differ between anestrous and cyclic ewes (P>0.10). The pregnancy and lambing rates tended to be greater in cyclic ewes than in anestrous ewes (odds ratio (OR)=3.35; 95% CI, 0.88%, 12.77%; P=0.08). Litter size, fecundity, birth weight of lambs, and offspring sex ratio were not different between anestrous and cyclic ewes (P>0.10). Conclusion: The cyclic ewe using synchronization protocols outside the breeding season could cause high pregnancy and lambing rates compared to Anestrus ewe. [ABSTRACT FROM AUTHOR]

Background: Copper and selenium were proven modulaters of reproductive function in ruminants under dietary supplementation. Their effects under pareneral administraton during estrus synchronization are not clearly defined. On this background the present was aimed to evaluate the effect of copper and selenium on estrus associated responses in goats. Methods: Thirty adult female Salem black goats were selected. On day ten of the estrus cycle, 250 µg of cloprostenol injection was given intramuscularly to all the animals and assigned to five groups. GI: control, GII: 4 µg of Buserelin, GIII: 20 mg cupric chloride, GIV: 10 mg sodium selenite and GV: copper plus selenium injections were administrated. Whole blood was collected for seven days for hormone assay. Estrus was detected using aproned bucks. Result: There was no significant (p>0.05) difference in estrus response, onset and duration of estrus between groups. The progesterone concentration decreased significantly (p<0.05) from day 0 (before PGF2a) to day 1 (after PGF2a) in all groups. There was a significant (p<0.05) increase in estradiol and progesterone concentration in the GnRH group compared to other groups. Parenteral administration of copper and selenium did not significantly improve estrus behavior, estradiol and progesterone concentration in Salem black goats. GnRH was once again proved to be effective in the improvement of estrus associated responses in goats. [ABSTRACT FROM AUTHOR]

Two female goats with infertility were reported in December during the breeding season. Both patients showed normal physiology on the day of presentation. Patient A, a 2.5-year-old primiparous lactating alpine with a history of blurred signs of estrous behavior, refused to mate with a buck since the breeding season in August. Patient B, a 2-year-old nulliparous alpine, failed to conceive after three times of natural mating and did not return to estrus. Two protocols of estrus synchronization were prescirbed for each patient and the changes of progesterone (P4) profile were monitored. Hormones integrating eCG (400 IU) plus hCG (200 IU) on Day 1, GnRH (0.1 mg gonadorelin) on Day 6, PGF2 α (0.125 mg clopostenol sodium) on Day 13, and eCG (400 IU) plus hCG (200 IU) on Day 14 were used in patient A. The increasing P4 concentrations from 0.16 ng/mL to 24.14 ng/mL during the treatment course were detected, then an estrous induction was performed, followed by natural mating with a buck for 2 days. Pregnancy was confirmed by abdominal ultrasonography 50 days after mating. Patient B failed to respond to the treatment of 5 consecutive injections of GnRH (a total of 0.5 mg gonadorelin) as all the P4 values were less than 1 ng/mL. Furthermore, vaginal speculum revealed a stenosis of vagina, possibly elucidating a case of infertility in this young goat. Our results demonstrated that an eCG-based protocol without pretreatment of progesterone was beneficial to help restore cyclicity for breeding in an alpine goat with seasonal anestrus. [ABSTRACT FROM AUTHOR]

Simple Summary: Gonadotropin-releasing hormone (GnRH), a critical regulator of pituitary gonadotropin secretion, plays a fundamental role in controlling physiological aspects of mammalian reproduction. GnRH is produced in the hypothalamus and regulates the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary. GnRH analogs, including agonists and antagonists, have been developed for the reproductive management of animals. This review focuses on the functions of hypothalamic GnRH in reproductive processes and the enhancement of reproductive efficiency in farm animals. Various GnRH analogs have been synthesized to improve their potency and reproductive function. This review specifically highlights the application of GnRH in estrus synchronization to increase the reproductive efficiency of dairy cows. GnRH is essential for the regulation of mammalian reproductive processes. It regulates the production and release of pituitary gonadotropins, thereby influencing steroidogenesis and gametogenesis. While primarily produced in the hypothalamus, GnRH is also produced in peripheral organs, such as the gonads and placenta. GnRH analogs, including agonists and antagonists, have been synthesized for the reproductive management of animals and humans. This review focuses on the functions of hypothalamic GnRH in the reproductive processes of cattle. In addition to inducing the surge release of LH, the pulsatile secretion of GnRH stimulates the pituitary gland to release FSH and LH, thereby regulating gonadal function. Various GnRH-based products have been synthesized to increase their potency and efficacy in regulating reproductive functions. This review article describes the chemical structures of GnRH and its agonists. This discussion extends to the gene expression of GnRH in the hypothalamus, highlighting its pivotal role in regulating the reproductive process. Furthermore, GnRH is involved in regulating ovarian follicular development and luteal phase support, and estrus synchronization is involved. A comprehensive understanding of the role of GnRH and its analogs in the modulation of reproductive processes is essential for optimizing animal reproduction. [ABSTRACT FROM AUTHOR]

Simple Summary: The synchronization process of yak estrus plays a crucial role in enhancing the reproductive success rate of yaks and safeguarding the continuation of the species. Metabolomics, a branch of bio-chemistry, primarily focuses on the quantitative analysis of all metabolites within an organism, aiming to identify the relative relationships between metabolites and physiological changes. It serves as a valuable tool for delving into the molecular mechanisms and responses of metabolic pathways under various perturbations. In this study, metabolomics methods were utilized to analyze blood samples collected from non-estrus yaks as well as those that underwent hormonally induced synchronized estrus to identify differential metabolites. The research results provide a theoretical basis for the optimization and application of synchronized estrus technology in yaks, promoting the healthy development of the yak industry. The yak is a unique species of livestock found in the Qinghai-Tibet Plateau and its surrounding areas. Due to factors such as late sexual maturity and a low rate of estrus, its reproductive efficiency is relatively low. The process of estrus synchronization in yaks plays a crucial role in enhancing their reproductive success and ensuring the continuation of their species. In order to clarify the characteristics of the serum metabolites of yak estrus synchronization, the yaks with inactive ovaries were compared with the estrus synchronization yaks. In this study, yaks were divided into the inactive ovaries group (IO), gonarelin-induced yak estrus group (GnRH), and chloprostenol sodium-induced yak estrus group (PGF). After the completion of the estrus synchronization treatment, blood samples were collected from the jugular veins of the non-estrus yaks in the control group and the yaks with obvious estrus characteristics in the GnRH and PGF groups. Metabolites were detected by ultra-high performance liquid chromatography-mass spectrometry, and differential metabolites were screened by multivariate statistical analysis. The results showed that a total of 70 significant differential metabolites were screened and identified in the GnRH vs. IO group, and 77 significant differential metabolites were screened and identified in the PGF vs. IO group. Compared with non-estrus yaks, 36 common significant differential metabolites were screened out after the induction of yak estrus by gonarelin (GnRH) and cloprostenol sodium (PGF), which were significantly enriched in signaling pathways such as the beta oxidation of very long chain fatty acids, bile acid biosynthesis, oxidation of branched chain fatty acids, steroidogenesis, steroid biosynthesis, and arginine and proline metabolism. This study analyzed the effects of gonadotropin releasing hormone (GnRH) and prostaglandin F (PGF) on the reproductive performance of yaks treated with estrus synchronization, which provides a theoretical basis for the optimization and application of yak estrus synchronization technology and promotes the healthy development of the yak industry. [ABSTRACT FROM AUTHOR]

Estrogens have proven to be effective in bovine estrus induction protocols. Considering the extensive use of these products in large-scale estrus synchronization, the primary objective of the present study was to assess their effects on pregnancy rate (PR) using a meta-analysis approach. A total of 797 papers were screened from three major databases (PubMed, Web of Science, Scopus). Sixty-one studies were eligible for inclusion in the meta-analysis. The pregnancy status (success or failure) at 30 days post-insemination was considered as the effect size data. The odds ratios (OR) of PR were evaluated by considering the effects of estrogens in groups with or without estrogen intervention. The impact of estrogen (including factors such as type, dose, and time of administration) and animal characteristics (such as breed, type, and parity) was taken into account when assessing the effectiveness of estrogen response as PR. The results showed an OR of 1.25 (95% CI: 1.15–1.36; P = 0.000) for PR in animals that received estrogen compared to cattle that did not receive estrogen. Estradiol benzoate (OR = 1.3) and estradiol cypionate (OR = 1.2), with doses ranging from 1 to 3 mg (OR = 1.13–1.7), significantly increased the OR of PR. In terms of PR, beef cattle exhibited a higher odds ratio (OR = 1.4; P = 0.000) compared to dairy cattle (OR = 1.1; P = 0.09). The administration of estrogens in the estrus synchronization protocol significantly improved PR in both artificial insemination (OR = 1.2; P = 0.000) and embryo transfer (OR = 1.3; P = 0.033) programs. In summary, incorporating estrogens into estrus induction protocols led to an enhancement of the OR of PR among cattle. • A moderate heterogeneity was observed among the screened studies on estrus synchronization in cattle. • The inclusion of estrogens in an estrus synchronization program raised the odds ratio of pregnancy rate in healthy cattle. • The odds ratio for pregnancy rate is higher in beef cattle than dairy cattle following treatment with estrogen. • The highest odds ratio for pregnancy was calculated within the estrogen dosage range of 1–3 mg. • Estrogens did not yield a notable impact on the odds ratio for pregnancy in animals with reproductive abnormalities. [ABSTRACT FROM AUTHOR]

Twin pregnancies compromise the health and well‐being of dairy cattle. A recent genomic prediction model for twin pregnancies has been developed based on twin calving or abortion. However, the incidence of double ovulation is significantly higher than that of twin births. This study aimed to evaluate whether genomic prediction values for twin pregnancies are associated with the incidence of double ovulation in primiparous dairy cows. Factors influencing the double ovulation rate were analysed using binary logistic regression on 676 cows: 475 (70.3%) inseminated at spontaneous estrus and 201 following one of two different estrus synchronization protocols for fixed‐time artificial insemination (FTAI). The odds ratio for double ovulations was 0.92 (p =.002) per unit increase in prediction value and 2 (p =.01) for cows subjected to an FTAI protocol. Our findings suggest that genomic prediction values for twin pregnancies can effectively identify the risk of double ovulation at the herd level. [ABSTRACT FROM AUTHOR]

This study aimed to compare three protocols used for induction and estrus synchronization followed by fixed-time artificial insemination (FTAI) during the non-breeding season in anestrous Cluj Merino ewes. Estrus was synchronized in 80 healthy multiparous ewes using intravaginal sponges containing 20mg of fluorogestone acetate (FGA) for 14 days. Ewes were previously divided into three groups. At the time of sponge removal, ewes in groups II and III received a dose of 500 IU eCG, while those in Group I received a half dose, respectively 250 IU eCG, followed by the administration of 50 μg of GnRH 30 hours later. Ewes from Group III were previously implanted with subcutaneous mini-implants of melatonin, 20 days before progesterone (P4) treatment. We could not find significant differences in terms of reproductive performances between Group I and Group II, with results showing that Group I had a conception rate of 47.05%, which is lower than that of Group II (56.52%). However, there were significant differences (P < 0.05) between melatonin-supplemented Group III and Group I (63.33% vs. 47.05%). Thus, the potential substitution of eCG with GnRH still needs to be optimized, while supplementation with melatonin can increase the conception rate during the non-breeding season in anestrous ewes.

Introduction: Estrus synchronization is a valuable management tool that has been employed in enhancing reproductive efficiency in ewes. Synchronization of estrus and ovulation for fixed-time artificial insemination in sheep is mostly based on the insertion of intravaginal devices containing either progesterone CIDR (Controlled Internal Drug Release) inserts or progestagens (sponges impregnated with fluorogestone acetate (FGA) or medroxyprogesterone acetate (MAP)). Intravaginal sponges are usually inserted over periods of 12 to 14 day and used together with eCG, particularly out of season, administered at the time of sponge withdrawal or 48 hours prior to sponge removal. It has now been indicated that shortening the duration of progesterone treatment with intravaginal instruments, while being effective in inducing estrus and ovulation, reduces the incidence of vaginal infections and consequently improves fertility. On the other hands, it has been reported that pregnancy rates of progestagen-synchronized ewes were lower during anestrus than during the breeding season. Therefore, this study was conducted to investigate the reproductive performance of indigenous ewes in Khanmirza city with short-term and long-term estrous synchronization programs accompanied by eCG during breeding and anestrous season. Moreover, efficacy of estradiol injection instead of gonadotropin during short-term progesterone treatment was evaluated in both seasons.Materials and Methods: The experiment was performed at two periods, during the breeding and the anestrus seasons on 2 different groups of 400 ewes. During each season, ewes (2 to 5 years of age and average body weight of 45±2.5 kg) were allocated to 4 groups of 100, in the way that each experimental group contained an equal number of ewes of a particular age. Experimental groups were: Control (without any synchronization program), Short term-estradiol group (ewes received 12 days progesterone treatment and intramuscular injection of 1mg estradiol benzoate at the time of sponge removal), Short term-eCG group (ewes received 12 days progesterone treatment and intramuscular injection of 400 IU eCG at the time of sponge removal) and Long term-eCG group (ewes received 14 days progesterone treatment and intramuscular injection of 400 IU eCG at the time of sponge removal). The progesterone treatment consisted on a vaginal sponge which contained 60 mg Medroxyprogesterone Acetate. Then, the ewes were placed in pens and one healthy ram was introduced for every 5 ewes, in order to detect heat and mating. Estrus signs were detected and recorded every hour for 5 days. The percentages of ewes that showed overt signs of estrus during a period of five days (estrus rate), estrus onset (the time elapsed between sponge removal and the first accepted mating) and pregnancy rate (The number of ewes without showing signs of estrous after 42 days of mating/total number of ewes×100) were recorded. Fecundity and prolificacy rate was calculated based on the number of lambs born. Lambs were monitored for 30 days after birth and deaths among them during this period were recorded against the ewes which were their mothers, and the survival rate was determined. The multiple birth rate was calculated by combining the twin and triplet birth rates.Results and Discussion: The results showed that reducing the duration of treatment with progesterone sponge in both trial period (autumn and spring) led to a significant reduction in estrus rate (P ≤ 0.05), but had no significant effect on other reproductive parameters (P > 0.05). Regardless of the season, injection of estradiol instead of eCG on sponge removal day, while increasing the estrus rate of ewes, led to a sharp increase in the rate of return to estrus (P ≤ 0.05) and caused decreases in the percentage of pregnant ewes, percentage of parturition ewes and lambing rate (P ≥ 0.05). In the breeding season, the mortality rate of lambs born from progesterone-synchronized ewes decreased and fecundity increased numerically compared to the corresponding group in breeding season group. Lack of possible effect of the anestrus season during synchronization programs on estrous rate and fertility of ewes can be attributed to optimal nutritional conditions of ewes in this season.Conclusion: Short term progesterone treatment (12 day) as well as injection of estradiol benzoate instead of eCG is not recommended to synchronize the estrous of ewes during both reproductive and anestrus seasons. In other words, short-term progesterone treatment (12 days) was not effective to synchronize estrus in breeding and anestrous sheep which can be attributed to follicular dynamics.

The review aimed to explore and document the underestimated; but pertinent challenges of cattle breeding in order to get due attention from the scientific communities, policy makers, and farmers. Ethiopian cattle genetic improvement is significantly confronted with many under-considered constraints. The under-considered constraints are lack of record keeping, inbreeding, lack of breeding animals, lack of awareness on efficient cattle reproductive management, lack of awareness on causes of unsuccessful artificial insemination, and lack of breeding cooperatives. Inbreeding can be reduced by keeping good pedigree records and bull rotation. Cows in mixed farming systems cannot reproduce timely due to a lack of breeding bulls. Unskilled AI Technicians, inability to heat detection and time of insemination, internal problems of the cows and bulls, and lack of pregnancy tests are the potential causes of unsuccessful artificial insemination. The practices, experiences, and knowledge of cattle producers for keeping records, disadvantages of inbreeding, efficient cattle reproduction, determinants of successful insemination, and use of breeding cooperatives have been observed to be low. The cattle producers, therefore, should be well-trained with sustainable, efficient, and profitable cattle production and management. The concerned professionals and policymakers ought to give more due attention to addressing the underestimated problems of cattle breeding.

AbstractThis study was conducted in Adiyo and Telo districts of Kaffa Zone, South Western Peoples Regional State (SWEPRS) of Ethiopia with the aim of evaluating the performance of Bonga sheep under farmer’s management conditions. To this end, the farmers who have ewes were registered and 200 respondents were randomly selected. The study revealed that both participant and non-participant farmers have been rearing sheep for the purpose of income generation, followed by saving, social value, meat and wealth in decreasing order. The current study also revealed that disease and parasites are the major constraints for both groups, followed by predator and shortage of fodder. Lambing interval (LI) was 9.4 ± 0.18 months, days open (DO) were 20.2 ± 0.13 days and liter size (LS) was 1.4 ± 0.04, and lambing interval (LI) was shorter (8.5 ± 0.22 months) in Community based breeding program (CBBP) participants than in non-participants (10.5 ± 0.28 months). The birth, weaning and six month weight were 3.8 ± 0.06, 16.0 ± 0.10 and 27.8 ± 0.33 kg. The preweaning average daily weight gain and postweaning average daily weight gain were 136.0 and 133.0 ± 0.02 g/day respectively. Both participants and non-participants’ reproductive and growth performances have shown a remarkable progression. In conclusion, engagement of farmer in CBBP improved lambing interval, birth weight, weaning weight, six month weight, pre-weaning weight average daily gain, and post weaning average daily gain of bonga sheep. Hence, CBBP strategy is likely to be important to attain the designed benefit from sheep production in the area.

Background: It is desirable in estrus synchronization in sheep to avoid intravaginal devices and to shorten the program from 14 to 6 days. Moreover, replacement of eCG with safe, cheap, and efficient gonadotropin is in worldwide demand. Aims: This study investigates the possibility of replacing eCG with human recombinant FSH (hrFSH) and CIDR with progesterone injections for estrous synchronization in ewes. Methods: Assaf and Lacaune ewes (n=170) were divided into two groups and synchronized with either progesterone injections for 6 days or CIDR for 14 days. Ewes assigned in the injection group, received progesterone (37.5 mg; SC) and GnRH analogue (7.5 µg Alarelin acetate; IM) on day 0 of the experiment. On days 3 and 6, ewes received 25 and 12.5 mg progesterone (SC), respectively. On day 6, ewes in both groups received prostaglandin F2a (250 µg Cloprostenol; IM), and were divided into two subgroups to receive either hrFSH (75 IU Follitropin alfa; SC) or eCG (400 IU; IM). On day 7, fertile rams were introduced to ewes for 21 days. Data were analyzed using GLM and Glimmix. Results: There was no difference in the respective lambing rates, prolificacy, and fecundity between CIDR (71.1, 1.63, and 1.16%) and injections (66.7, 1.55, and 1.03%); between eCG (71.4, 1.60, and 1.14%), and hrFSH (66.3, 1.58, and 1.05%, P>0.05). Conclusion: In conclusion, 6-day progesterone injectionbased protocol produced similar results to 14-day CIDR program and hrFSH could be an effective alternative for eCG during estrus synchronization in ewes. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to determine the effects of biologically active substances and electrical stimulation of the uterus in cows on the effectiveness of estrus synchronization. Materials and Methods: Ninety (n = 90) Kazakh white-headed cows were synchronized with two injections of gonadotropin-releasing hormone on days 0 and 9 and prostaglandin F2a on day 7. The cows were divided into six groups and, during the protocol, treated with biologically active substances (Tetramag, Selevetum, antiseptic-stimulator Dorogov 2 fraction, groups 2, 3, and 4). Cows in groups 5 and 6 were treated with the same substances but additionally had electrical stimulation of the uterus, while cows in group 1 were left untreated and served as a control. Results: The results have shown that on Day 0, no differences were observed in E2 concentrations between the groups. However, on the 10th day, a significant disparity was noted in the E2 level among cows in group 6 compared to groups 2, 3, 4, and the control group. Conversely, no significant differences were observed between groups 5 and 6. Likewise, the fertility rate in cows from group 6 was significantly higher compared to groups 2, 3, 4, and the control group, with no significant differences between groups 5 and 6. Conclusion: It can be concluded that the utilization of electrical stimulation of the uterus and the inclusion of certain biological substances during the estrus synchronization protocol demonstrate a positive effect on the reproductive performance of beef cattle in Kazakhstan. [ABSTRACT FROM AUTHOR]

The vaginal microbiota plays a key role in animals' health. Understanding its diversity and composition and associated changes occurring through the reproductive cycle represents valuable knowledge to disclose the mechanisms leading to dysbiosis and eventually to infection. Even if the human vaginal microbiota has been thoroughly studied, scarce research has been conducted on the vaginal microbiota of livestock. In this study, 16S rRNA gene-based sequencing was performed on vaginal samples of ten nulliparous ewes at three different sampling points: before the estrus synchronization protocol (T0), at the time of estrus before mating (Testrus), and the day of the pregnancy diagnosis (Tpreg). Preputial samples from the three males collected pre and post-mating were also analyzed. Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria were the most abundant phyla in vaginal samples. The most abundant genera were Porphyromonas, Anaerococcus, and Peptinophilius. Vaginal microbiota biodiversity decreased during pregnancy. Tenericutes (Ureaplasma spp.) increased significantly at Tpreg in both pregnant and nonpregnant ewes. Differences were observed between pregnant and non-pregnant ewes at Tpreg where pregnant ewes had a significantly higher abundance of Actinobacillus spp. and Ureaplasma spp. Ewes that were diagnosed with pregnancy at Tpreg showed a decreased abundance of gram-negative bacteria such as Bacteroidales, Campylobacterales, and Enterobacteriales. In addition, a significant decrease in the relative abundances of genera within Firmicutes, such as Alloicoccus (Lactobacillales), Atopostipes (Lactobacillales), and an uncultured bacteria W5053 from Family XI (Firmicutes, Clostridiales) was observed in non-pregnant ewes at Tpreg. The four most abundant phyla in the rams' prepuce were the same as in the ewes' vagina. The most abundant genus was Corynebacterium. No major differences were observed in the ram's preputial microbiota between pre and post-mating samples. Nevertheless, the differences in the taxonomic composition of ewes' vaginal microbiota between Testrus and Tpreg could be explained by the exposure to the preputial microbiota. This study offers new insights into the effects of several key steps of the ewe's reproductive cycle such as estrus-synchronization protocol, mating, and pregnancy on ovine vaginal microbiota. The knowledge of the microbiota dynamics during the reproductive cycle can help improve the reproductive outcomes of dams by identifying biomarkers and putative probiotics. [ABSTRACT FROM AUTHOR]

In large-scale intensive farms, dairy goats often undergo frequent estrus synchronization (ES) treatment, which may result in a decline in reproductive performance; however, the underlying mechanism remains unclear. The present study aimed to investigate the effect of pregnant mare serum gonadotropin (PMSG) and progesterone (P4)-mediated ES treatment on fertility in dairy goats, while also identifying key metabolic and endocrine mechanisms that influence reproductive performance in does subjected to repeated ES treatment. Forty-eight Saanen does were randomly assigned to two groups (24 goats each) that received ES treatments either thrice fortnightly (3-PMSG) or once (1-PMSG) simultaneously with the third ES treatment of the 3-PMSG group during the breeding season. ES treatment was performed via the intravaginal insertion of a controlled internal drug release (CIDR) device impregnated with 300mg P4, followed by 300IU PMSG injections 48h before CIDR withdrawal. Blood was collected to detect the level of hormones and blood biochemical indices. Additionally, estrus rate, fecundity rate, body weight, size, and lactation performance were measured. The results showed that repeated ES treatment markedly decreased the estrus rate and fecundity rate of goats. Among the does in all groups, there was no substantial difference in follicle stimulating hormone, luteinising hormone, gonadotropin-releasing hormone, melatonin, growth hormone, PMSG, total cholesterol, total protein, and glucose levels, as well as the body weight, body size, and lactation performance. Repeated ES treatment elevated estrogen (E2) levels 36, 48, and 72h post-CIDR removal; increased P4 upon CIDR insertion; and raised PMSG antibody levels 24, 48, and 72h post-CIDR removal. The results suggest that elevated anti-PMSG levels are the primary reason for the decline in ES efficiency, and that high E2 and P4 levels at some time points also impair reproductive performance. These findings provide novel insights into the metabolic effects of repeated PMSG stimulation in goats, guiding future reproductive hormone use in breeding practices. [ABSTRACT FROM AUTHOR]

Two experiments were designed to evaluate later timepoints for fixed-time artificial insemination (FTAI) of beef heifers and cows, with the hypothesis that use of a later timepoint would allow a greater proportion of animals to express estrus prior to FTAI and result in greater conception rates among estrous females inseminated with sex-sorted semen. In Experiment 1, estrus was synchronized for 1640 heifers using the 14 d CIDR-PG protocol: insertion of an intravaginal progesterone-releasing insert (CIDR; 1.38 g progesterone) on Day −33 and removal on Day −19, and administration of prostaglandin F 2α (PG; 500 μg cloprostenol sodium) on Day −3. Heifers were inseminated at one of three FTAI timepoints: 66 h, 70 h, or 74 h after PG administration. In Experiment 2, estrus was synchronized for 414 beef cows using the 7 & 7 Synch protocol: administration of PG coincident with CIDR insertion on Day −17, gonadotropin-releasing hormone (GnRH; 100 μg gonadorelin) on Day −10, and PG coincident with CIDR removal on Day −3. Cows were inseminated at one of two FTAI timepoints: 66 h or 72 h after PG administration. In both experiments, only animals that expressed estrus prior to FTAI were inseminated with sex-sorted semen. In Experiment 1, the proportion of heifers that expressed estrus prior to FTAI (66 h: 62 %; 70 h: 67 %; 74 h: 71 %) was greater when FTAI was performed at 74 h versus 66 h (P = 0.0097); however, conception rate of heifers that expressed estrus and were serviced with sex-sorted semen did not differ among treatments (P = 0.67; 66 h: 56 %; 70 h: 53 %; 74 h: 53 %). In Experiment 2, the proportion of cows expressing estrus prior to FTAI did not differ between treatments (P = 0.30; 66 h: 71 %; 72 h: 76 %). Additionally, conception rate of estrous cows inseminated with sex-sorted semen did not differ between treatments (P = 0.24; 66 h: 45 %; 72 h: 40 %). These results indicate that performing FTAI later following the 14 d CIDR-PG protocol increases the proportion of heifers that express estrus and are serviced with sex-sorted semen but does not improve conception rates. Later timing of FTAI following the 7 & 7 Synch protocol was not observed to increase the proportion of cows expressing estrus prior to FTAI or improve conception rates among estrous cows inseminated with sex-sorted semen. Together, these results provide further insight into optimal timing of FTAI when using sex-sorted semen. • Delayed timing of FTAI when using sex-sorted semen was evaluated. • A greater proportion of heifers expressed estrus prior to FTAI at later timepoints. • Conception rates were not improved among animals inseminated at later timepoints. [ABSTRACT FROM AUTHOR]

The aim was to characterize and assess the reproductive performance of a long interval prostaglandin (PG)–based protocol for timed AI (TAI) at different times. During breeding season three experiments were done involving 622 Merino ewes, 11 rams, and five androgenized wethers per 100 ewes. All ewes were estrus synchronized with two PG injections 15–day apart (PG15): Day −15 and 0 (Hour 0). Estrous distribution respect to Hour 0, estrous response and synchrony after Hour 0, and interval from Hour 0 to estrus detection (PG–estrus) was evaluated (Experiment I; n = 105 ewes). Interval from estrus detection to ovulation (estrus–ovulation) and from Hour 0 to ovulation (PG–ovulation) was determined (Experiment II; n = 12 ewes). Visual–physical score of cervical mucus at TAI, non–return to service to Day 23 (NRR23), fertility, prolificacy, and fecundity to Day 60 in four cervical fresh semen TAI groups was evaluated (Experiment III; n = 505 ewes; 107 nulliparous-398 multiparous). Three groups with single service at 56 (Control), 44 or 68, and one with double service at 44 and 68 ± 1.5 h after Hour 0 (PG15–56, PG15–44, PG15–68, and PG15–44/68 groups, respectively) were tested. Ninety-eight-point one percent of the ewes showed estrus from Hour −48 up to 84 respects to Hour 0. Twenty percent of them showed estrus from Hour −48 up to 0, and 78.1 % from Hour 12 up to 84 (Experiment I). The largest proportion of ewes in estrus was observed between Hour 36 and 60 (80.5 %). PG–estrus interval was 54.1 ± 10 h (means ± SD). Estrus–ovulation interval was 32.4 ± 5.8 h, and PG–ovulation interval was 77.0 ± 16.6 h (Experiment II). Ewe parity did not affect any of the reproductive variables (P > 0.05; Experiment III). There were no significant differences (P > 0.05) between Control and different groups in mucus score (2.18 ± 0.08, 2.02 ± 0.07, 2.14 ± 0.09, 2.25 ± 0.10), NRR23 (76.0, 71.9, 78.6, 79.4 %) or fertility (66.4, 64.1, 66.7, 73.8 %; PG15–56, PG15–44, PG15–68 or PG15–44/68 groups, respectively). Prolificacy in PG15-44 group was lower (1.07 ± 0.03; P < 0.05) than other groups (1.27 ± 0.05, 1.23 ± 0.05, 1.20 ± 0.04), and fecundity than PG15–44/68 group (0.84, 0.69, 0.82, 0.89), without differences among other groups (PG15–56, PG15–44, PG15–68 or PG15–44/68 groups, respectively). We concluded that any time between 56 and 68 h after PG15 protocol could be used to perform cervical TAI using fresh semen, without benefits of a double TAI service at 44 and 68 h. • Estrous response after second PG dose (Hour 0) in PG15 protocol was 78.1 % of ewes. • The largest proportion of ewes was observed between Hour 36 and 60 (80.5 %). • PG–estrus interval was 54.1 ± 10 h, PG–ovulation interval was 77.0 ± 16.6 h. • Any time between 56 and 68 h after PG15 protocol could be used to perform TAI. • No benefits of using double insemination service were observed at times evaluated. [ABSTRACT FROM AUTHOR]

The objectives were to determine the reproductive response of Holstein heifers in small-scale dairy herds to estrus synchronization protocols based on prostaglandins (PG), estradiol benzoate (EB), and progesterone (P4). Heifers at least 13 mo old (n= 138) were randomly included in one of two synchronization protocols: PG) administration of 500 μg cloprostenol i.m. at d 0 and d 14; and PGPE) similar to PG but with an additional application of 100 mg P4 + 2 mg EB on d 7. The estrus rate of the PG group was similar to that of the PGPE group (84.3 vs 79.4 %; P>0.1). Heifers in PGPE had a higher percentage of estrus between 37-84 h post-treatment vs the PG group (94.2 vs 82.5 %; P=0.05). The conception rate of the PGPE group was higher than that of the PG group (94.4 vs 83.1 %; P=0.05). In the PG group, body development at weaning was lower in heifers that did not show estrus vs those that did (P<0.05). Nonetheless, in the PGPE group, birth weight was lower in heifers that showed estrus than those that did not (P<0.05). In conclusion, heifers in the small-scale dairy system have a good reproductive response to prostaglandin-based estrus synchronization (cloprostenol). The inclusion of EB + P4 into the hormonal synchronization protocol with PG improves conception rate but has a minimal effect on the distribution of the beginning of estrus expression after treatment. [ABSTRACT FROM AUTHOR]

The purpose of the study was to determine the effect of thermal stress on the reproductive efficiency of buffalo heifers. This study was carried out on 100 buffalo heifers, during two different environmental seasons (winter and summer). Heifers were mature, free from pathological and congenital affections, and fed on balanced rations. Animals were divided into two groups (25 per each) and each group was divided into two subgroups. In addition, 10 buffalo heifers were kept indoors as a control group in a closed building and 15 heifers kept outdoors exposed to direct environmental stress (ambient temperature and humidity). Temperature humidity index (THI) was calculated. Estrus synchronization using two doses of PGF2α 11 days' interval was carried out. Heifers were examined by ultrasonography per rectum and blood samples were collected on the 1st and 15th day of the synchronized estrous cycle to accurate detection of progesterone, estrogen, cortisol, and glucose. Mating was done naturally using fertile buffalo bulls introduced to heifers after the 2nd PGF2α injection. Pregnancy diagnosis was carried out through ultrasonography and conception rates were determined. The results indicated that THI outdoors was significantly higher than indoors in the summer season and not significantly different during winter. Blood levels of estradiol, progesterone and glucose were lower during summer when compared to winter season, while cortisol levels were higher. Also, conception rates were significantly higher indoors than outdoors during winter and summer seasons. respectively. In conclusion, environmental stress resulted in lowering reproductive performance in buffalo heifers, especially in the summer season, and indoor housing significantly improved reproduction. [ABSTRACT FROM AUTHOR]

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The “Dairy Village” concept was designed to overcome the constraints of estrus synchronization and AI particularly associated with seletion of the breeding animals and subsequent management of estrous cows in Ethiopia. All necessary inputs, including sexed semen, were acquired before the fieldwork. The knowledge and skill gaps were identified and addressed with the active involvement of veterinarians and AI technicians who underwent specialized training to ensure proper physical and gynecological examinations during the selection of cows and heifers. Accordingly, a refresher training was delivered on topics of reproductive anatomy and physiology, assessment of ovarian status, semen handling, and insemination at the optimal time to establish pregnancy. Besides, awareness creation seminars were held every year on topics of benefits of reproductive technologies and management of breeding cows to 99 smallholder dairy farmers. Only 578 cows/heifers were found fit for breeding out of the 1262 cows/heifers that were brought for evaluation; including 81 animals that spontaneously showed estrus. A total of 497 cows/heifers were synchronized using a single IM injection of Lutalyse. Animals responding to the treatment (404 cow/heifers) and those spontaneously in estrus (81cows/ heifers) were inseminated using sex-sorted HF semen 18-24hrs into the standing estrus. Pregnancy rate was 80% (388/485) and 287 calves were born (96% female). Results of this project indicate that rigorous gynecological examination during the selection of cows prior to estrus synchronization and judicious application of hormonal treatments can yield improve the success of ES/AI projects under field conditions. Furthermore, the dairy village approach to enhanced milk production through efficient use of sex-sorted semen has generated replacement heifers from superior breed that will substantially improve the livelihoods of village farmers. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of a low dose of hCG or FSH on follicle growth and pregnancy per artificial insemination (AI) in crossbreed beef heifers subjected to a split-time AI program. All heifers (n = 386) were subjected to a 7-d Co-synch protocol and an intravaginal controlled internal drug release (CIDR) device (GnRH and CIDR insertion; 7 days later PGF2α, CIDR removal, and application of a tail head estrus detection patch; 36 hours later AI of heifers detected in estrus, 24 hours later timed AI of remaining heifers). At CIDR removal, heifers were randomly assigned to receive either 150 IU of hCG, 20 mg of FSH, or remained as untreated controls. The diameter of the preovulatory follicle and the pregnancy per AI did not differ among treatments. A smaller (P = 0.035) proportion of heifers in the hCG group were detected in estrus compared with control. Additionally, the incidence of premature ovulation was greater (P

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.

Improving reproductive efficiency, estrus synchronization and controlled breeding protocols are efficient management techniques in dairy cows. Therefore, the present study was designed to compare the efficacy of Cosynch protocol in the cows carrying corpora lutea (CL), without CL or with unexamined ovarian structure. Fifty-six cows were divided into 4 groups; control group1 (n=12) and Co-synch treated groups; group2: cows with unexamined ovarian structure group (n=9), group3: cows having only follicles without mature Cl (n=16) and group4: cows having mature Cl (n=19). Ultrasonography was performed before and after gonadotropin (GnRH) injection. Blood was collected for analysis of progesterone (P4) and estradiol 17-ß. Reproductive data was obtained regarding 1st service conception rate (1st SCR), number of services/conception (s/c) and days open. Ultrasonography revealed luteinization in cows without mature CL. While those having mature CL showed increase in the size of the CL or formation of accessory CL. Results revealed significant decrease in serum P4 before GnRH treatment in cows having no mature CL. Significant increase in serum P4 levels in all groups was recorded after GnRH treatment. Besides, the highest P4 level was assessed in cows having mature CL. Estradiol 17-ß was significantly decreased in cows having mature CL before and after treatment. Cows having mature CL revealed significant upgrade in the percentage of 1st SCR, decrease in s/c and shortening in days open as compared with other groups. In conclusion, applying Co-synch to the cows carrying CL is beneficial and promises protocol to improve reproductive performance in dairy cows. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effect of replacing equine chorionic gonadotropin (eCG) with human chorionic gonadotropin (hCG) and also improving the efficiency of hCG using a slow-release compound (alhydrogel) on the reproductive performance of Afshari ewes after laparoscopic artificial insemination. For this purpose, 48 Afshari ewes (2.5-4 years old with the mean weight of 68±2.5kg and an body condition score of 3.04±0.3 were treated with intravaginal controlled internal drug release (CIDR) for 14 days. The ewes were then divided into 4 groups: the first group: injection of eCG (400IU), 48 hours before CIDR removal (eCGS), the second group: injection of eCG (400IU) combined with alhydrogel, 48 hours before CIDR removal (eCGSR), the third group: injection of hCG (400IU), 48 hours before CIDR removal (hCGS) and the fourth group: injection of hCG (400IU) combined with alhydrogel, 48 hours before CIDR removal (hCGSR). The results showed that there was no significant difference between eCGSR and eCGS treatments in Measured parameters (P>0.05). The lowest pregnancy rate (25%) and fecundity (33%) were recorded in related to the hCGS treatment. However, in the hCGSR treatment, these parameters were increased to the values recorded in eCGSR and eCGS treatments. The results of this study showed that hCG in the presence of slow release compound can be a suitable substitute for eCG in the estrus synchronization protocol based on progesterone and eCG. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of a low dose of hCG or FSH on follicle growth and pregnancy per artificial insemination (AI) in crossbreed beef heifers subjected to a split-time AI program. All heifers (n = 386) were subjected to a 7-d Co-synch protocol and an intravaginal controlled internal drug release (CIDR) device (GnRH and CIDR insertion; 7 days later PGF2α, CIDR removal, and application of a tail head estrus detection patch; 36 hours later AI of heifers detected in estrus, 24 hours later timed AI of remaining heifers). At CIDR removal, heifers were randomly assigned to receive either 150 IU of hCG, 20 mg of FSH, or remained as untreated controls. The diameter of the preovulatory follicle and the pregnancy per AI did not differ among treatments. A smaller (P = 0.035) proportion of heifers in the hCG group were detected in estrus compared with control. Additionally, the incidence of premature ovulation was greater (P < 0.01) among heifers treated with hCG compared with control. In conclusion, using a low dosage of hCG or FSH at the time of device removal did not affect pre-ovulatory follicle growth or the proportion of pregnant heifers. [ABSTRACT FROM AUTHOR]

Copyright of Anbar Journal of Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Stimulation of ovulation using different methods can improves reproduction performance by increasing the proportion of ewes having twin ovulations and thereby increase lambing percentage. Estrus synchronization or the induction of estrus is a valuable management tool for increasing the pregnancy rate in ewes. It has been proposed that estrus synchronization can impose oxidative stress in animals and hence, supplying antioxidants at the time estrus synchronization could improve their fertility by decreasing the oxidative damage. Vitamin E and Se are important antioxidants and can prevent the cellular damage caused by free radicals and influence the reproductive performance of ewes and their lambs. The important roles of supplemental vitamin E and Se in sheep and goat reproduction and lamb survival have been intensively reviewed. The aim of this study was to investigate the effects of injecting estrus-synchronized Moghani ewes with vitamin E-Se on their reproductive performance, birth weight of lambs and some blood metabolites. Material and Methods: The experiment was carried out on 200 mature (2–5 years of age), non-lactating ewes with an average body weight 70 kg. The current study was performed in the non-breeding season under natural photoperiod environment. In the control group, only estrus synchronization was performed, but the second group was received two intramuscular (5 ml) injections of E-se (0.5 mg/mL of selenium as sodium selenite and 50 IU vitamin E as DL-α- tocopheryl) on the days of sponging and sponge removal. Synchronization of estrus was done by inserting intravaginal sponges for 14 days followed by 400 IU eCG at sponge withdrawal. Two days after sponge withdrawal, ewes were joined with fertile rams. At the beginning of the experiment, 20 ewes from each group were selected randomly and their blood was sampled. The first and second blood samplings were done before inserting intravaginal sponges and three weeks after ram exposure, respectively. Then, some blood plasma metabolites were determined. After parturition, reproductive traits were calculated in each group. The birth weight of lambs was recorded after parturition as well. The reproductive parameters were analyzed by ProcGenmod using SAS 9.2 in completely randomized design. The means of all reproductive traits were compared by using Chi-Square test. Born weight of lambs and blood metabolites concentration data were analyzed using the GLM procedure of SAS and P < 0.05 was considered as the significant level. Results and Discussion: The results showed that there was no significant effect of E-se on the estrus response and pregnancy rate in non-breeding season. Lambing rate in E-se treatment (88%) was higher (P < 0.05) than the control group (73%). Control group had lower fecundity rate (84%) than the treatment group (111%). In Ese-treated group, percentage of prolificacy was significantly different (P < 0.05) compared with control (126.1% vs 112.3%, respectively). Twinning rate in E-se groups was greater (P < 0.05) than the control (21.6% vs 12.3%, respectively). The birth weight of lambs was not significantly affected by E-Se administration compared with control. Glucose and cholesterol concentration of blood were significantly higher in group receiving E-se three weeks after mating (P < 0.05). Likely, the main reason of these contradictory results with the other researcher results develops from duration and time of E-Se use, dosage, source, and route of E-Se administration in pre-breeding ewes. Conclusion: In conclusion, using of vitamin E-Se caused improvement of reproductive efficiency of Moghani ewe in non-breeding season. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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. [ABSTRACT FROM AUTHOR]

This document provides a comprehensive overview of research on reproductive management in farm animals, specifically focusing on sheep and goats. The studies discussed in the document explore the effects of different hormonal treatments, such as GnRH and eCG, on ovulation induction, estrus synchronization, and fertility outcomes. The use of nanotechnology, specifically aluminum hydroxide nanoparticles, as a carrier for hormone delivery is also explored. The results of these studies provide valuable insights for researchers and practitioners in the field of animal production. [Extracted from the article]

This study aimed to compare the effects of a single dose of GnRH or hCG administered at the beginning of the short-term oestrus synchronization protocol on ≥4 mm diameter follicles in Saanen goats during the breeding season. The goats es-trus cycles were synchronized with intravaginal sponges containing 60 mg of medroxy-progesterone acetate for five days. Additionally, 1 ml of physiological saline solution (control-group; n=30), 0.004 mg of buserelin acetate (GnRH-group; n=31) or 150 IU of hCG (hCG-group; n=31) were injected intramuscularly to the goats during the sponges insertion. Transrectal ultrasonographic examination was performed immediately be-fore and 24 h after intravaginal sponge application into all goats and follicles with a diameter of ≥4 mm in the ovaries were counted. Blood samples were collected on the same days to determine serum progesterone (P4) and estradiol (E2) concentrations. At the first ultrasonographic examination, the percentages of ≥4 mm diameter follicles were 56.66% (17/30), 54.83% (17/31) and 70.96% (22/31) in the control, GnRH and hCG groups, respectively. The percentage of goats with reduced follicle diameters 24 h later was 29.41% (5/17), 52.94 (9/17) and 59.09% (13/22) in the same groups, respectively. The mean regression rates of follicle diameters between days 0 and 1 in each group were significantly different (P

Background and Aim: The adhesive progestin patch was investigated for estrus synchronization in mares because this method is convenient and safe in other species. This study aimed to compare the efficacy of a transdermal progestin patch versus oral altrenogest on estrus synchronization, preovulatory follicle development, and ovulation. Materials and Methods: Twenty-four broodmares were randomly divided into two groups. In Group 1, mares (n = 12) were fed 0.044 mg/kg altrenogest daily for 14 days. Group 2 (n = 12) mares were treated with adhesive transdermal progestin patches for 14 days. Mares were observed for estrus daily, from day 3 until day 7, after hormone withdrawal. Follicular development was determined by ultrasonography. The preovulatory follicle size and ovulation time after hormone treatments and ovulation rate were determined for both groups. Plasma progesterone levels were measured during the experimental periods and 2 days after hormone termination in both groups. Results: The results revealed that the transdermal progestin patch efficiently controlled follicular growth and estrus synchronization in mares. The percentage of mares exhibiting estrus was similar in the altrenogest (100.00%) and transdermal patch (91.67%) groups. Ovulation rates were equivalent with either altrenogest or progestin patch protocols (91.67% [11/12] vs. 83.33% [10/12]). In addition, the preovulatory follicle size was similar in mares treated with altrenogest and progestin patches. Conclusion: This study revealed that the transdermal progestin patch provides effective estrus synchronization and ovulation, similar to altrenogest treatment. However, the transdermal patch was more convenient with a shorter predictable ovulation time after estrus synchronization and should be considered as an alternative method for mares.

Simple Summary: The use of estrogens in food animals is banned in several countries, but fixed-timed artificial insemination protocols (without the necessity of estrus detection) for beef cattle in South America are primarily based on estrogen. This study determined the optimal non-estrogen-based protocol in grazing Bos taurus suckling beef cows maintained under typical pasture conditions in Argentina. A total of 697 cows were enrolled in two experiments and the gonadotrophin-releasing hormone-based fixed-timed artificial insemination protocols resulted in similar or greater fertility compared to estrogen-based protocols in Bos taurus suckled beef cows. The greatest fertility was attained with the 7 & 7 protocol, which includes gonadotrophin-releasing hormone, prostaglandin and an intravaginal progesterone device. This study shows that non-estrogen-based fixed-timed artificial insemination protocols can successfully synchronize Bos taurus suckled beef cows under grazing conditions. Hence, beef cattle producers in South America could use the 7 & 7 fixed-timed artificial insemination protocol in order to meet those requirements imposed by countries that do not allow the use of estrogen in food animals. Fixed-timed artificial insemination (FTAI) protocols for beef cattle in South America are primarily based on estradiol esters and intravaginal progesterone-releasing devices (IVPD). The objective of this study was to determine the optimal gonadotropin-releasing hormone (GnRH)-based protocol as an alternative to the use of estrogen-based protocols in grazing Bos taurus suckling beef cows. All cows received an IVPD on the day of protocol initiation and prostaglandin F2α (PG) plus equine chorionic gonadotropin (eCG) treatments at the time of IVPD removal. In Experiment 1, cows (n = 235) were randomly assigned to one of four treatments: (i) 7-day estradiol = 2 mg of estradiol benzoate (EB) at IVPD insertion on Day 9 and 1 mg of estradiol cypionate (ECP) at IVPD removal on Day 2; (ii) 7-day GnRH = 10 µg of GnRH at IVPD insertion on Day 10, IVPD removal on Day 3 and GnRH at FTAI; (iii) 7 & 7 estradiol = PG at IVPD insertion on Day 16, EB on Day 9 and ECP at IVPD removal on Day 2; (iv) 7 & 7 GnRH = PG at IVPD insertion on Day 17, GnRH on Day 10, IVPD removal on Day 3 and GnRH at FTAI. In Experiment 2, cows (n = 462) were randomly assigned to one of four treatments: (i) 6-day estradiol = EB at IVPD insertion on Day 9, IVPD removal on Day 3 and GnRH at FTAI; (ii) 7-day estradiol; (iii) 7-day GnRH; (iv) 7 & 7 GnRH. In Experiment 1, plasma progesterone concentrations and percentage of cows with a corpus luteum (CL) at IVPD removal, and pregnancy per AI (P/AI) were greater for cows subjected to GnRH-based protocols compared with cows subjected to estrogen-based protocols (p < 0.01). In Experiment 2, cows subjected to the 7 & 7 GnRH protocol had the greatest P/AI (p < 0.01). In summary, GnRH-based FTAI protocols resulted in similar or greater P/AI compared to estrogen-based FTAI protocols in grazing postpartum Bos taurus suckled beef cows. The greatest P/AI was attained with the 7 & 7 GnRH protocol. [ABSTRACT FROM AUTHOR]

The present work was conducted to study the influence of different synchronization protocols on estrus expression and its intensity in Surti goats. Thirty goats were selected and divided into five equal groups (n=6 each). The goats of groups G1, G2 and G3 were implanted with intra-vaginal progestagen sponges (IVPS) for 11 days, without and with exposure to buck in G1 and G2, and with injection of 125 μg cloprostenol at the time of sponge removal in G3 group. Animals of group G4 were exposed to buck only for 11 days, while group G5 acted as control without any treatment or buck exposure. Estrus detection was performed by apronized bucks. Estrus intensity was determined based on behavioural and physiological signs associated with estrus. The mean scores, scales and ranks for estrus intensity did not differ significantly (p>0.05) between the groups. However, group G3 had highest mean score, scale and rank for estrus intensity, while overall the maximum frequency of behavioral signs was wagging of tail (100.00%), standing to be mounted (96.67%) and clustering around buck (93.33%). It was thus concluded that expression of induced estrus was similar to natural estrus and none of the synchronization protocols significantly influenced the pattern of estrus expression and its intensity in Surti goats. [ABSTRACT FROM AUTHOR]

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 (p<0.05). However, there was no difference between the treatment groups (G1 and G2) in terms of fertility parameters (p>0.05). In conclusion, ST or LTP4-impregnated vaginal sponge treatment was equally effective on fertility parameters in Tuj ewes during the non-breeding season. [ABSTRACT FROM AUTHOR]

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The objectives of the study were to investigate changes in the mRNA expression levels of five genes during antral follicle development and to assess the efficacy of four timed-artificial insemination (TAI) protocols in female yaks (Bos grunniens). RT-qPCR analysis revealed that expression levels were greater for follicle-stimulating hormone receptor and bone morphogenic protein 15 in the small follicle, luteinizing hormone receptor, and kit ligand in the large follicle, and growth differentiation factor 9 in the medium follicle (p < 0.05). Non-suckling yaks were treated as a 7-d CIDR, and PGF2α + eCG at CIDR withdrawal and TAI with frozen yak semen at 56–58 h after PGF2α (PPe-7d); either a 7-d CIDR (PPG-7d) or a 5-d CIDR (PPG-5d), and PGF2α at CIDR withdrawal and TAI + GnRH at 70–72 h after PGF2α; and GnRH treatment on Day 0, followed by PGF2α on Day 7 and TAI + GnRH on Day 9 (GPG-7d). The results showed that the pregnancy rate (P/AI) was greater in PPG-5d than in GPG-7d (p < 0.05), but the P/AI was not different among the other TAI protocols. In conclusion, the expression levels of these genes in follicles are dynamically changed during antral follicle development in yaks. The PPG-5d protocol achieved a greater P/AI. [ABSTRACT FROM AUTHOR]

Background and Aim: The adhesive progestin patch was investigated for estrus synchronization in mares because this method is convenient and safe in other species. This study aimed to compare the efficacy of a transdermal progestin patch versus oral altrenogest on estrus synchronization, preovulatory follicle development, and ovulation. Materials and Methods: Twenty-four broodmares were randomly divided into two groups. In Group 1, mares (n = 12) were fed 0.044 mg/kg altrenogest daily for 14 days. Group 2 (n = 12) mares were treated with adhesive transdermal progestin patches for 14 days. Mares were observed for estrus daily, from day 3 until day 7, after hormone withdrawal. Follicular development was determined by ultrasonography. The preovulatory follicle size and ovulation time after hormone treatments and ovulation rate were determined for both groups. Plasma progesterone levels were measured during the experimental periods and 2 days after hormone termination in both groups. Results: The results revealed that the transdermal progestin patch efficiently controlled follicular growth and estrus synchronization in mares. The percentage of mares exhibiting estrus was similar in the altrenogest (100.00%) and transdermal patch (91.67%) groups. Ovulation rates were equivalent with either altrenogest or progestin patch protocols (91.67% [11/12] vs. 83.33% [10/12]). In addition, the preovulatory follicle size was similar in mares treated with altrenogest and progestin patches. Conclusion: This study revealed that the transdermal progestin patch provides effective estrus synchronization and ovulation, similar to altrenogest treatment. However, the transdermal patch was more convenient with a shorter predictable ovulation time after estrus synchronization and should be considered as an alternative method for mares. [ABSTRACT FROM AUTHOR]

Estrus synchronization(is a vital strategy in sheep production and is accomplished most often via controlled internal drug release (CIDR) devices. Reuse of CIDR devices can reduce operating costs and ewe exposure to progesterone (P4), but remains controversial. A comparison was made of the effects of new and reused natural progesterone-releasing intravaginal (CIDR) devices in six-day protocols on reproductive performance variables and blood serum progesterone concentrations in multiparous ewes. A total of 172 sheep (average body weight = 59 kg) were randomly distributed into four treatments: CIDR1 (control group, new devices), CIDR2 (second-use), CIDR3 (third-use) and CIDR4 (fourth-use). The variables ewes in estrus, pregnancy rate, fertility rate and parturition type did not differ (P>0.05) between treatments. Estrus onset was later (P=0.05) in CIDR1 (40 ± 10 h) than in CIDR2 (31 ± 9 h). Ewes in estrus ranged from 93 to 100 %, average pregnancy rate was 80.8 %, average fertility rate was 80.2 % and the prolificacy index was 1.26. The single delivery rate was higher (P=0.05) than the double delivery rate in all four treatments. Intravaginal CIDR devices can be used in ewes up to four times in six-day estrus synchronization protocols without affecting reproductive variables. [ABSTRACT FROM AUTHOR]

The aim of the presented study was to establish the conception rate in Bulgarian Murrah buffaloes submitted to estrus synchronization via Presynch/Ovsynch protocol applied in non-breeding and breeding season. The experiment was conducted in 24 buffaloes with at least 40 days postpartum, allotted into two groups according to the treatment season: Group I (n=8) - non-breeding season, Group II (n=16) - breeding season. On day 0 and day 35 after artificial insemination, the buffaloes were examined by transrectal ultrasound to identify ovarian structures and prove pregnancy, respectively. The initial ultrasound examination revealed the presence of a corpus luteum and a follicle with a diameter =10 mm in 33.33% (8/24) of all cases, solely a follicle =10 mm in 45.84% (11/24) and follicles with a diameter <10 mm in 20.83 % (5/24). The total conception rates between Group I (37.50%, 3/8) and Group II (43.75%, 7/16) did not differ significantly (P = 0.39), and the overall conception rate after estrus synchronization (41.67%, 10/24) was within the normal range for the species. The applied protocol leads to successful conceptions of buffaloes in both seasons. The high percentage of conception is registered in the hormonal treatment of buffaloes with follicle > 10 mm. [ABSTRACT FROM AUTHOR]

Synchronization of estrus involves handling the estrus cycle so that a large number of cows can be bred at approximately the same time. Proper cow/heifer selection as well as efficient coordination are all key elements for the success of synchronization programs which were lacking in the study area. The study was conducted with the objective to evaluate the effect of Alfaglandin C and fixed factors on estrus synchronization and efficiency of Artificial Insemination (AI) in North Shoa zone of the Oromia region. The study population encompassed indigenous and crossbred cows and heifers found in six purposively selected kebeles (smallest administrative unit within a district) from the three selected districts (Wucale, Dagam and Kuyuu). Multistage sampling procedure was used to select target districts, kebeles and experimental cows/heifers. A total of 180 cows and heifers fulfilling estrus synchronization criteria were selected purposively and injected with synchronizing hormone (Alfaglandin C). The level of significance among categorical variables was determined using the chi-square (ω²) test. About 70.6% of the cows and heifers injected with Alfaglandin C exhibited estrus. Exhibition of estrus following hormone injection was significantly (p<0.05) lower in Wuchale district compared with that of the other two districts. Likewise, the agroecology, farming system, herd group, and breed had a significant (p<0.05) effect on estrus exhibition. Among cows and heifers inseminated following estrus exhibition, 62.2% conceived as confirmed by pregnancy diagnosis (PD) test conducted at 45-day post AI, which dropped to 58.3% as observed by the PD test conducted three months' post AI. Agroecology, farming system, herd group, and genotype of cows and heifers showed significant (p<0.05) influence on the conception rate (CR). The highest CR was observed among cows of Kuyuu district, which was significantly (p<0.05) different from that of the other two districts. The overall calving rate was 91.1%. The semi-intensive part of the study also showed better estrus synchronization response and better reproductive performances which directly associated with the management practices. Treating industrial byproducts, better management, and promoting AI can achieve better estrus synchronization and efficiency of artificial insemination. [ABSTRACT FROM AUTHOR]

This study was aimed at developing a type of slow‐release progesterone micro‐particles useable in a single intramuscular injection for estrus synchronization in non‐breeding season ewes. A total of 66 ewes were randomly assigned into four groups: CIDR (n = 16): exposed to intravaginal CIDR for 12 days, and three experimental groups, i.e., T100 (n = 16), T150 (n = 17) and T200 (n = 17), receiving a single intramuscular injection of 100, 150 and 200 mg slow‐release progesterone, respectively. Blood sampling was performed on all ewes at five different times, and the ELISA method measured progesterone levels. No significant differences were observed in progesterone levels among the groups in each sampling time. More than 90% of ewes in the CIDR, T100 and T150 groups and all those in T200 showed estrus behaviour, and the rate was not significantly different between groups. The difference in the mean interval from progesterone treatment to estrus was also insignificant. The parturition rate declined by increasing the dose of injected progesterone; although it was similar in CIDR and T100 groups, it decreased significantly in T150 and T200. Since our injectable progesterone formulation was successful in the induction and synchronization of estrus in ewes out of the breeding season, it can be applied as an alternative to the conventional progesterone containing intravaginal devices. [ABSTRACT FROM AUTHOR]