Induction Of Estrus Research Articles

Evaluating single and double doses of prostaglandin (PGF 2α ) injection on estrus induction and conception rate in Boran cattle breed in Southwestern Ethiopia

Evaluating single and double doses of prostaglandin (PGF _2α ) injection on estrus induction and conception rate in Boran cattle breed in Southwestern Ethiopia

Success of Artificial Insemination in Rural Area Cows

Biotechnologies of reproduction like artificial insemination were identified as a mean to intensify the local production. Therefore, some factors are still responsible to the failure of their applications in rural area. This survey was conducted from April to June 2023, to evaluate the effects of age, body weight, body condition score (BCS), calving rank, postpartum to artificial insemination interval and feed complementation on the success rate of artificial insemination in females Goudali. Thus, activities took place at two peri-urban livestock farms in the town of Ngaoundéré, in the Adamaoua region of Cameroon where 34 cows were concerned. The selected cows have an average of 8.21±2.41 years old, a body weight of 343±52.28 kg, a body condition score of 3.23±0.55, a calving rank of 2.21±1.22 and a postpartum to insemination interval of 4.39±1.40 months. The induction and synchronization of estrus were carried out based on the PRID-PGF2α-PMSG protocol which allowed to obtain a synchronization rate of 97.06% and the insemination were done 56-57 hours after the previous operation, with an imported semen of Brahman bull. During rectal palpation and early pregnancy diagnosis based on progesterone level measurement, the result shown that, 20 cows out of 33 inseminated were pregnant. The success rate of artificial insemination recorded was 60.6%. Amongst all the studied factors, analysis shown no significant (P> 0.05) effect on the success rate after artificial insemination. Thus, recommendations were made to popularize the use of artificial insemination and early pregnancy diagnosis test as a mean to improve reproductive performances of local farms. However, studies must be done to evaluate the cost of their applications in rural areas.

Management of postpartum anoestrus in Vechur cows by hormonal methods

The study aimed to evaluate suitable hormonal treatment regimen for inducing oestrus in postpartum anoestrus Vechur cows and its reproductive outcome. The efficiency of Ovsynch and Ovsynch + progesterone protocols in 12 anoestrus cows was studied. Six anoestrus cows were kept as untreated control and they were observed for a period of 180 days postpartum. Both treatment protocols resulted in a complete oestrus induction response of 100 per cent. The interval from treatment to induced oestrus was significantly lower in the Ovsynch group (50.10 ± 1.44 h) than in the Ovsynch + progesterone (54.40 ± 0.48 h) group. In comparison to the control group, treatment group animals displayed a high intensity score for oestrus. The duration of oestrus in the Ovsynch group (26.41 ± 0.53 h) was significantly longer than the control (24.45 ± 0.46 h) group and the Ovsynch + progesterone group (24.13 ± 0.42 h). The overall conception rate for three consecutive AI in Ovsynch, Ovsynch + progesterone and control group were 66.67, 83.33 and 33.33 per cent, respectively. The calving to conception intervals were significantly (p<0.001) shorter in Ovsynch (118.33 ± 9.71 d) and Ovsynch + progesterone (106.67 ± 8.12 d) groups than the control (191.5 ± 5.36 d). It is concluded that hormonal treatment is effective in inducing postpartum oestrus and reducing the calving to conception interval in Vechur cows. Keywords: Ovsynch, postpartum anoestrus, progesterone, Vechur

Comparative assessment on the effect of long vis-à-vis short-term progesterone priming on reproductive attributes in silent estrus goats

Silent estrus results in spread-out kidding and extended inter-kidding interval in goats. Progesterone (P4) priming for 12-14 days could be one of the approaches for estrus induction with optimum fertility. The present work was carried to comparatively assess the duration of P4 priming on estrus and fertility in silent estrus goats. Sirohi does (n=18) with a history of anestrus and high basal P4 in paired samples were equally divided into three groups. Does in P-0 d group received 200 IU of equine chorionic gonadotropin by intramuscular route. Does in group second and third were subjected to per-vaginal P4 sponges for 7 (P-7 d) and 14 (P-14 d) days, respectively and were given 200 IU equine chorionic gonadotropin following sponge withdrawal. Estrus was monitored for 72 h at 12 h intervals using teaser buck to record estrus per cent, induction time and duration. Estrus induction was highest in P-14 d (6/6) than P-0 d and P-7 d (4/6 and 5/6), respectively. Estrus induction time was shorter in P-7 d and P-14 d than P-0 d. The estrus duration was shortest in P-14 d group. The conception and pregnancy rate did not differ significantly among the groups, though all the does in P-14 d conceived. The fertility was non-significantly higher in P-14 d (6/6) and P-7 d group (5/5) than P-0 d (3/4). It could be concluded that P4 priming for 7-14 days in silent estrus does results in improved reproductive performances.

Mounting exhibited between cows is not associated with sexual motivation

Females of various species exhibit mounting behavior toward other mature females, i.e., female–female (f–f) mounting. Cows exhibit f–f mounting, which is commonly considered a sexual behavior based on a few similarities with male sexual mounting. Here, we hypothesized that the degree of f–f mounting exhibited by cows in estrus would increase when they are sexually motivated by sexually relevant stimuli. To test this hypothesis, two groups of four cows each were prepared. First, estrus was induced in one of the cows in each group by injecting estradiol in the presence of a non-sexually active male steer as a stimulus animal (steer-stimulus condition), and all f–f mounts were recorded. Estrus induction was repeated until induced in all cows. We then changed the stimulus animal from the steer to a sexually active bull (bull-stimulus condition), and the estrus induction procedures were repeated as before. We confirmed that estrus was induced successfully in cows injected with estradiol and that they were sexually motivated by switching the stimulus animal from steer to bull, as they spent relatively more time with the stimulus animal in the bull-stimulus than in the steer-stimulus condition and when not in estrus. However, f–f mounting frequency in the bull-stimulus condition showed no significant difference to that in the steer-stimulus condition. We observed that six of the eight subjects exhibited f–f mounting when not in estrus, which accounted for 44.6 % of f–f mounting we observed (n = 668). These findings suggest that f–f mounting in cows is not associated with sexual motivation.

Relationship of external genitalia measurement with antral follicular count and estrus induction response in pre-pubertal Murrah buffalo heifers

Relationship of external genitalia measurement with antral follicular count and estrus induction response in pre-pubertal Murrah buffalo heifers

Diagnosis of Pregnancy in Iraqi Awassi Ewes Through Progesterone Hormone Measurement and Ultrasonography Following Induction of Fertile Estrus with Sulpiride

Diagnosis of Pregnancy in Iraqi Awassi Ewes Through Progesterone Hormone Measurement and Ultrasonography Following Induction of Fertile Estrus with Sulpiride

Effects of dietary supplementation with omega-3 fatty acid-rich linseed on the reproductive performance of ewes in subtropical climates.

The present study evaluated the effects of omega-3 (ω-3) fatty acid-rich linseed supplementation on the reproductive performance, endocrine profile, and biochemical profile of ewes reared in subtropical climates. Forty-eight acyclic and clinically healthy Marwari sheep, aged 1.5-2.5 years with no parity, were divided into four groups (n = n = 12 in each). Ewes in the control group (group I) were fed only a basal feed, whereas ewes in the treatment groups II, III, and IV were fed the basal diet along with 10%, 15%, and 20% linseed, respectively, daily on a dry matter basis. The experiment was conducted during the typical breeding season (October-November) of the sheep. The estrus induction rate was significantly higher (p < 0.05) in all treatment groups than in the control group. The estrus induction interval was significantly lower (p < 0.05) in group III. The conception rate in group I was significantly lower (p < 0.05). In addition, ewes in the control group had a significantly lower (p < 0.05) lambing rate than all treatment groups. Serum progesterone concentrations differed significantly (p < 0.05) between the control and the treatment groups on days 15, 30, 45, and 60 of supplementation. On treatment days 15 and 30, the serum estrogen concentrations were significantly higher (p < 0.05) in all treatment groups compared to that in group I. In all treatment groups, monounsaturated fatty acid (MUFA) decreased significantly (p < 0.05), whereas polyunsaturated fatty acid (PUFA) increased significantly (p < 0.05) from day 15 onward. In conclusion, by providing 15% dietary linseed supplementation to ewes, their reproductive performance can be improved in subtropical climates. Future studies are recommended to further elucidate the role of linseed supplementation in sheep reproduction in subtropical climates.

Effect of prostaglandin treatment on the estrus behaviour, follicular and luteal morphometry and serum hormone profile in sub-estrus buffaloes during non-breeding season.

Sub-estrus buffaloes do not exhibit estrus signs despite being cyclic contributing to extended service periods and inter-calving intervals causing significant economic loss. The present study described the effect of synthetic prostaglandin (PGF2α) on estrus behaviour, follicular and luteal morphometry, and serum estradiol (E2) and progesterone (P4) profile in sub-estrus buffaloes during the non-breeding season. The incidence of sub-estrus was 38.4% during the non-breeding season. The sub-estrus buffaloes (n = 33) were divided into two groups, viz., Control (n = 16) and PGF2α treatment (Inj. Cloprostenol 500 μg, i.m., n = 17). Estrus induction response was significantly greater in the treatment (100 vs. 18.75%, p < .001), and a relatively greater proportion of animals conceived in the treatment group (29.41 vs. 6.25%, p = .08). The time elapsed to induction of estrus and insemination following treatment was significantly lower in the treatment group than control. A significant increment in the follicle diameter (9.72 ± 0.45 vs. 13.00 ± 0.45 mm, P < .0001) and serum estradiol (E2) concentration (66.01 ± 11.92 vs. 104.9 ± 13.21 pg/mL, p = .003) observed at the post-treatment period in the PGF2α treatment group. At the same time, CL diameter was reduced significantly at a higher regression rate in the PGF2α treated buffaloes than those of control. Of the responded buffaloes, only 30% showed high-intensity estrus attributed to the expulsion of cervico-vaginal mucus (CVM), uterine tonicity, micturition, and mounting response by a teaser bull. From this study, it can be concluded that the administration of PGF2α could induce estrus in the sub-estrus buffaloes during the non-breeding season. Behavioural changes, along with sonographic observation of POF, regressing CL, and serum E2 and P4 concentration would be useful to determine the right time of insemination in sub-estrus buffaloes during non-breeding season.

The male effect associated with prostaglandins and reproductive outcomes in photo‐stimulated Saanen goats during the non‐breeding season

AbstractThe efficiency of combining oestrous induction via a light program (16 h of light and 8 h of darkness for 60 days, ending on Day 0 – D0) with cloprostenol administration, followed by the male effect or not, was tested in acyclic Saanen goats during the non‐breeding season (June/2019 to January/2020). Initially, all animals (males and females) were submitted to the described light program; 60 days after its ending (D60), the females were divided into two groups, with (G1; n = 67) or without (G2; n = 61) a male effect from D60 to D75 after the light program. At D75, both groups received two cloprostenol doses (120 μg; intramuscular) 7.5 days apart (D75 and D82.5). Artificial insemination was performed at a specific time according to the oestrous onset (approximately 68.4 ± 1.2 h between the second cloprostenol dose and IA). Ultrasound scans were performed at different intervals to evaluate follicular dynamics and confirm pregnancy. At the first cloprostenol dose (D75), the proportion of does with at least a corpus luteum (CL), which indicates resumed cyclicity, was greater in G1 than in G2 (85.2% vs. 48.8%; p &lt; .05), although no difference was found at the second dose (p &gt; .05). The adjusted pregnancy rates (number of pregnant goats/oestrous goats) differed between G1 and G2 (21.7% vs. 42.0%; p &lt; .05). G1 also showed a higher frequency of functional CL (based on blood flow and morphology) compared to G2 (96.9% vs. 66.7%; p &lt; .05) at D116. A male effect using photo‐stimulated bucks after the first cloprostenol dose increased the number of does presenting CL after buck removal, and no impairment in the pregnancy rates of multiparous does was found.

Serum Metabolomic Analysis of Synchronous Estrus in Yaks Based on UPLC-Q-TOF MS Technology.

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.

Cloprostenol effect with and without male stimulation on oestrus synchronization in Peru guinea pigs.

Cloprostenol, a synthetic derivative of prostaglandin F2α, effectively triggers functional and morphological regression of the corpus luteum (luteolysis). In rural Peru, the guinea pig (Cavia porcellus) holds significance within the local economy and serves as a valuable protein source. Enhancing reproductive efficiency is crucial to achieve uniformity in weight, age, and litter size across commercial systems. Thus, our study aimed to evaluate the effect of cloprostenol with and without male stimulation on the onset, duration, and intensity of oestrus in Peru guinea pigs. A total of 128 guinea pigs (120 females and eight males) between 8 and 12 months of age, weighing between 800 and 1200 g, were distributed in cages of 15 females per treatment. Cloprostenol sodium (0 [control], 0.20, 0.25, and 0.30 mg/animal) was IM administered to the groups with and without male stimulation. Four isolated males in individual cages, different from the one used for the treatment, were considered to detect oestrus. The oestrus intensity was assessed by observing sexual behaviour signs such as restlessness, moaning, attempts to mount, pelvic elevation, loin stretching, and vulvar inflammation. The oestrus was manifested 2 days after the administration of cloprostenol sodium. At a dose of 0.30 mg/animal and with male stimulation, the earliest oestrus was observed at 46.9 h. There was a reduction in the oestrus duration (p < .05) in guinea pigs that received the three doses of cloprostenol sodium compared to the control group. The highest percentages of frank oestrus intensity (66.7%) were strongly associated with the administered doses of cloprostenol sodium (p < .01). In conclusion, the cloprostenol sodium administration was proper for rapid oestrus induction in Peru guinea pigs.

Efficacy of Intravaginal Lactic Acid Bacteria, Cell-Free Supernatant, or Enrofloxacin on Vaginitis and Fertility in Ewes Synchronized with Progesterone-Based Protocol

An intravaginal sponge impregnated with progesterone is commonly used for estrus induction and synchronization in ewes. Although using an intravaginal sponge containing progesterone positively affects the synchronization rate, varying degrees of vaginitis occur during its application. This study aimed to investigate the impacts of various intravaginal treatment options on the vaginitis severity and pregnancy rate in Merino ewes synchronized with intravaginal sponges impregnated with progesterone. During the breeding period, 589 ewes, aged 2–6, received intravaginal sponges for 14 days. The control group (CON) received no treatment, whereas vaginal sponges absorbed with enrofloxacin (ENR), Lactobacillus plantarum (LAC), or Lactobacillus plantarum supernatant (CFS) were applied in the treatment groups. All groups received 500 IU of equine chorionic gonadotropin intramuscularly. The ENR group showed lower scores in vaginal discharge and sponge odor compared with the CON, LAC, and CFS groups. Although estrus responses did not differ between groups, the pregnancy rate tended to be higher in the ENR group. In conclusion, intravaginal ENR application, but not LAC or CFS, reduced vaginitis severity and tended to increase pregnancy rates in ewes synchronized with intravaginal sponges impregnated with progesterone.

Evaluation and Comparison of Therapeutic Efficacy of Various Hormonal Protocols in Anoestrus Buffalo Heifers of Semi-Arid Region

To assess and compare different hormonal protocols' treatment efficacy in anoestrus buffalo heifers in a semi-arid region. Forty buffalo heifers with a history of anoestrus were chosen randomly from the semi-arid region of Banaskanth and divided into four equal groups.Group-I: Heatsynch protocol (n = 10), Group-II Ovsynch protocol (n = 10), Group-III Doublesynch protocol (n = 10) and Group-IV Control (n = 10) are followed by artificial insemination at a predetermined period in treated buffalo heifers and insemination during spontaneous estrus in group-IV buffalo heifers. In Groups I, II, and III, the corresponding percentages of estrus induction were 90, 80, and 80 percent. Major symptoms such as edoema, erythema, dampness of vulva and estrus mucus secretion were present during the expression of estrus. Fifty percent of the buffalo heifers in Group IV displayed estrus at varying intervals. After three consecution services, Group II had the highest overall fertility rate (50%) followed by Group III (40%), Group I (30%), and Group IV (30%). In true anoestrus buffalo heifers, the Heatsynch, Ovsynch, and Doublesynch procedure can be applied with success to induce estrus. Buffalo heifers that follow the Ovsynch protocol may have a higher conception rate.

Blood Plasma Biochemical Changes and Conception Rate in Anoestrus Buffaloes Treated with Various Hormone Protocols

To study certain blood biochemical parameters (total cholesterol, total protein, calcium and inorganic phosphorus) at various periods of treatment. Total 40 anestrous buffalo heifers with history of anoestrus were selected from the semi-arid area of Banaskanth and randomly divided into four equal groups. (1)Group-I:Heatsynch protocol (n=10), (2)Group-II:Ovsynch protocol(n=10), (3)Group-III: Doublesynch protocol (n=10) and (4)Group-IV: Control(n=10) followed by fixed time artificial insemination in treated buffalo heifers and insemination at spontaneous estrus in buffalo heifers of group-IV. The overall conception rate following 3 consecution services was maximum in Group II (50%) followed by Group III (40%), Group I (30%) and Group IV (30%). The blood plasma was collected at the time of initiation of treatment (P1), at the time of inj. PGF2α (P2), at the time of 1st FTAI (P3) and day 21st post insemination (P4) for the estimation of biochemical parameters. The blood biochemical profiles include total protein (range: 4.54± 0.19 to 6.11± 0.52 g/dl) which in all group did not show any significant difference during the different period but significant (P&lt;0.05) difference between the groups was noticed. Similarly calcium and phosphorus found ranging between 5.73± 0.20 to 9.53± 0.95 mg/dl and 5.46± 0.22 to 6.95± 0.30 mg/dl, respectively in all four groups. The cholesterol estimated values (range: 34.12 ± 1.75 to 41.97± 2.43 mg/dl) were found not-significantly varying between the groups as well as among the different periods. Heatsynch, Ovsynch and Doublesynch protocol can be successfully used for the induction of estrus in true anoestrus buffalo heifers with Better conception rate would be achieved following Ovsynch protocol in buffalo heifers.

Biostimulatory effects of boar seminal gel, saliva and semen on sexual behavior of young boars, gilts and sows

The present study aimed to identify novel biostimulatory compounds in boar seminal gel (SG), saliva and semen using Gas chromatography-mass spectrometry (GC-MS). The bio-stimulatory effect of SG, SG + saliva and SG + semen on young boar for semen collection as well were employed to study bio-stimulatory effects on gilts and sows. Distilled water (DW) exposure was kept as control. SG, saliva and semen were screened for total 105, 96 and 89 compounds. The highest concentration was of alkanes followed by sugar alcohols, then hydrocarbons, amino acids and fatty acids. Elaidic acid was the novel compound identified in pigs. Significantly higher (p < 0.05) number of males got trained in exposure to SG (80%), SG + saliva (75%) and SG + semen (75%) than control (0%). The time (hrs) taken by young boars to get trained on exposure to combination of SG + saliva (244 ± 22.19) and SG + semen (216 ± 13.14) was lesser (p < 0.05) than SG (356 ± 61.85) alone. Interval (hrs) from initiation of exposure for exhibition of different sexual behaviour by males on exposure to SG, saliva and semen was lesser (p < 0.05) than control. Significantly (p < 0.05) higher number of females showed estrus response to exposure of SG (72.72%), SG + saliva (69.23%) and SG + semen (76.92%) than control (0). Interval (hrs) taken to exhibit estrus was shorter (p < 0.05) in females exposed to SG + saliva (201.88 ± 12.66), SG + semen (198.20 ± 9.42) than SG (262.14 ± 20.06) alone. Interval (hrs) for exhibition of different sexual behaviour by females on exposure to SG + saliva and SG + semen was lesser (p < 0.05) than control. In conclusion, novel compounds were identified in boar seminal gel, saliva and semen with biostimulatory properties have been identified in boar SG, saliva and semen. The combined exposure of SG with saliva and semen has more intense biostimulation effect than SG alone for training of young boars and estrus induction in gilts and sows. Such compounds biostimulatory effects can be exploited for augmenting reproductive efficiency in pigs.

Gonadotropic Activity of Pituitary Extract of African Catfish, Clarias gariepinus, in Mammals using Immature Wistar Rats as Models.

The pituitary glands normally produce and stores gonadotropic hormones (GnH) that are responsible for ovulation and spermiation in animals. However, whether fish pituitary extracts can elicit same effects in treated animals need elucidation as a prelude to their practical usage in animals. The aim of this study was to investigate the oestrus-inducing potential of the pituitary gland extract of the Africa Catfish (Clarias gariepinus) in immature Wistar rats. The experiment involved the use of 18 immature female Wistar rats and 10 male catfish brood stocks with the use of six Wistar rats per groups as follows: Group A had human chorionic gonadotropin (hCG) treatment. Group B had only normal saline treatment as the control whereas Group C had the C. gariepinus pituitary extract administration to induce oestrus with treatments occurring twice six hours apart in each group. There was an obvious expression of visible signs of heat and the presence of uterine horn oedema with significant (p < 0.05) increase in reproductive tract weight and uterine width and length. However, only progesterone levels increased significantly (p < 0.05) in the hCG and the C. gariepinus pituitary extract treated groups compared to other assayed hormones. These results showed that C. gariepinus pituitary extract has the capacity to induce oestrus in Wistar rats because of its gonadotropic effects, which needs further investigations at higher doses and for longer exposure periods for possible oestrus induction and synchronization in higher mammals. Further favourable results could herald the possible patent of the catfish pituitary extract for either experimental or commercial use in mammals.

Oestrus induction and fertility response in post-partum anoestrus dairy cows treated with homeopathic medicine

The study was carried out to evaluate the effect of two homeopathic medicines to induce oestrus in 36 postpartum anoestrus crossbred Jersey dairy cows. Group 1 cows were fed a mineral mixture, and group 2 and 3 were medicated with Pulsatilla and Sepia drenched at the dose rate of 20 mL twice daily for 8 days, respectively. The mean plasma progesterone level (ng/mL) estimated using a radio immunoassay kit was significantly higher in group 2, followed by group 3 before and after medication on day 28 and 60, post artificial insemination (AI). Out of 12 induced for oestrus, 10 cows (83.33 %) and 9 cows (75.0 %) in group 2 and 3 were confirmed pregnant by rectal palpation on day 60 post AI, respectively. Both the homeopathic medicines showed 100% oestrus induction with a mean interval of 25.17 to 25.50 days, and Pulsatilla medicated cows showed improved fertility response than Sepia. The significantly higher level of progesterone after the withdrawal of homeopathic medication might be due to the release of circulating hormone, which blocks estradiol negative feedback. The subsequent increase reduces uterine PGF2 alpha secretion for a better conception rate.

Factors affecting the efficiency of equine embryo transfer (EET) in polo mares under subtropical conditions of Pakistan.

Equine embryo transfer (EET) is a prominent technology in the equine breeding industry, and its efficacy is affected by a number of factors. The current study aimed to determine the effects of the breed of donor/recipient mares, estrus/ovulation induction treatment, cooled transportation of embryos, and synchrony between donor and recipient mares on the efficiency of the EET under subtropical conditions of Pakistan. A total of eighty-four (n = 84) Polo-playing donor mares (Argentino-polo = 41 and Anglo-Arab = 43) and seventy (n = 70) recipient mares (light breed = 26 and heavy breed = 44) were used for EET. The donor mares exhibiting natural estrus (n = 28) were detected by teaser a stallion, and corpus luteum (CL) having mares (n = 56) were treated with prostaglandin (150 μg of Cloprostenol) for estrus induction. The mares' follicular growth was monitored through ultrasonography until the dominant follicle's size reached 35 mm or more with a moderate to obvious uterine edema score. Afterward, the mares were treated either with GnRH, i.e., 50 μg of Lecirelin acetate (n = 41) or Ovusyn, i.e., 1500 IU hCG (n = 43). Insemination with chilled semen was performed 24 hours later. The embryos were collected non-surgically, 7 or 8 days after ovulation, from the donor mares. The collected embryos were transferred into the well-synchronized recipient mares as fresh (n = 44) or chilled (n = 26) embryos. The pregnancy after ET was checked through ultrasonography. Statistical analysis revealed that the embryo recovery rate (ERR) remained significantly higher (P<0.05) for the Prostaglandin (PG) treated group of donors as compared to the natural heat group of donors. The breed of donor mares, type of ovulatory treatment given, and day of embryo collection did not significantly (P>0.05) affect the ERR. There was no significant effect of the type (fresh vs chilled), classification, and stage of development of embryo on pregnancy outcomes (P>0.05). ET pregnancy rate was significantly affected by the breed of recipient mares and ovulation synchrony between donor and recipient mares (P<0.05). In conclusion, under the subtropical conditions of Pakistan, PG-based estrus induction of donor mares, breed of recipient mares, and ovulation synchrony between the donor and recipient mares had a substantial effect on the efficiency of EET.

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

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