Dose Of PGF2α Research Articles

Effect of protected fatty acid supplementation on ovarian activity, reproductive hormone profiles and reproduction of Barki ewes under semiarid conditions

Abstract. The objective of this experiment was to evaluate the impact of dietary supplementation with rumen-protected fat (calcium soaps of fatty acids, CSFA) and/or hormonal superovulation using equine chorionic gonadotropin (eCG) on ovarian activity, changes in ovarian hormones, and reproductive performance in Barki ewes under semiarid conditions. A total of 39 non-pregnant Barki ewes, with an average body weight of 34.7 ± 0.25 kg and an average age of 3–4 years, were divided into four groups. The first group (9 ewes) served as the control, while the second group (10 ewes) received double doses of PGF2α, administered 9 d apart, and was superovulated with 600 IU (international unit) eCG. The third group (10 ewes) was supplemented with 30 g per head per day of rumen-protected fat. The fourth group (10 ewes) underwent the same superovulation protocol as the second group and was also supplemented with 30 g per head per day of rumen-protected fat. All the ewes were fed a basal diet. Ovarian activity was detected using ultrasonography during the estrus phase in all the groups, after which all the ewes were naturally bred with Barki rams. The results demonstrated significant (P<0.05) increases in estradiol 17-β (E2) and progesterone (P4) levels in the treated groups compared to the control group. Ewes in all the treated groups exhibited large follicles, with an overall mean diameter (≥5 mm) significantly higher than that of ewes in the control group. Although there were no significant differences between the treated and control groups, the ewes treated with CSFA and/or the eCG hormone showed tendencies to improve the reproductive traits of Barki ewes. Overall, the findings of this study demonstrated a positive effect of CSFA alone or in combination with an estrous synchronization protocol on ovarian activity in Barki ewes, as indicated by the number and size of follicles and the presence of large-sized follicles.

(007) Impact of Non-Invasive Oestrus Synchronization on Sexual Behavior in Intact Sprague Dawley Rats

Abstract Introduction Female sexual behavior animal translation data do not translate to acute results and neither current synchronization invasive models (ovariectomy+Estrogen “E2”+Progesterone “P4”) guarantee hormonal physiological values. Objective Therefore, our study investigated the effect of non-invasive oestrus synchronization on sexual behavior. Methods Methods: Twelve week old Sprague Dawley intact rats were synchronized and randomly divided into three groups each of n=8-10. Each group received a dose of prostaglandin F2α “PGF2α” (75, 125 and 250 μg) at days 0 and 3, and 1 mg of progesterone at day four. Vaginal cytology was performed to determine the point of the cycle and the animals underwent an incentive test. To investigate the sexual behavior, the synchronized female rats were paired with trained male rats, and behavior recorded. The videos were quantified by trained operators. Sexual behavior was quantified as paracopulatory (hops, darts, ear wiggling, sniffing from male and from female) or copulatory (male mounting female, thrusting from male, intromission, ejaculation, female for sniffing position, lordosis, orgasm, female mounting on male, female rotation in her axis and female licking itself), E2 and Follicle Stimulating hormone (FSH) in plasma and E2 in vaginal fluid were quantified by immune assay. Results Based on the vaginal cytology, the proportion of animals in proestrus (p), estrus (e) or metestrus (m) was calculated with values of 0.5 (p), 0.25 (e) and 0.25 (m) for the group which received 0.75 μg PGF2α; 0.4 (p), and 0.6 (e) for the group which received 0.125 μg PGF2α; 0.2 (p), 0.5 (e), and 0.3 (m) for the group which received 250 μg PGF2α. The numbers of hops was higher in the proestrus compared to the metestrus, and of mounts higher in the estrus compared to the metestrus phase. The sexual encounter profile and E2 levels were unchanged with the different PGF2α doses, but in the high-dose group no hops were observed. The levels of sexual behavior was comparable to previous studies of hormone substituted ovariectomized rats, but E2 and FSH plasma levels were in a physiological range. Conclusions In summary, the non-invasive synchronization protocol could substitute the state-of-the-art used ovariectomized+hormone (E2) model. Our findings suggest the largest part of rats were synchronized in the oestrus phase with 125 μg PGF2α. but the 250 μg had also a positive profile. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Initiator Pharma A/S.

Reproductive Performance of Buffalo-heifers under Stressful condition

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.

PSIII-12 The Effects of PGF2 and PGF2 Plus Gnrh on Estrous Behavior and Pregnancy Outcomes in Dairy Goats

Abstract Artificial insemination protocols depend on efficient behavioral estrus detection and insemination time in dairy goats. Here we examined the effects of two synchronization protocols, prostaglandin F2α (PGF2α; protocol 1) and PGF2 plus gonadotropin-releasing hormone (GnRH; protocol 2) on estrus behavior, body temperature, pulse frequency, pregnancy protein B (PPB) concentrations, and pregnancy rates in Alpine and Saanen goats. Forty does (3.9 ± 0.28 year) were divided into two groups (20 each) with 10 Alpine and 10 Saanen females in each group. In protocol 1 goats were injected with 10 mg/goat PGF2α on day 0 and 11. In protocol 2, each goat was injected with 10 mg PGF2α on day 0, and 43 µg GnRH on day 9 and then 10 mg PGF2 α on day 11. Estrus signs were detected 24 to 36 hours after the second dose of PGF2α. Body temperature and pulse frequency were recorded on days 11, 12, 13, and 14 after the second dose of PGF2α. Goats that showed estrus signs were naturally bred with the same breed mature buck. Blood samples were collected on days 28, 35, and 42 post-breeding (PB) to assess PPB concentrations, and ultrasonography was performed on day 50 (PB) to confirm pregnancy. The percentage of female showed estrous was higher in protocol 1 than in 2 (70% vs. 60%). Irrespective of the breed, rectal and vulval temperature was higher in the protocol 2 than 1 at day 11 after PGF2 α injection; however, it was the opposite at days 12, 13, and 14. However, the pulse frequency was greater (P < 0.05) in protocol 2 at all the time point. Pregnancy rates were 71.4% and 75.0% for protocols 1 and 2, respectively. Irrespective to the synchronization protocols, the pregnancy rates were greater (P < 0.05) in Alpine than Saanen goats. In conclusion, both PGF2 and PGF2-GnRH protocols were effective in synchronizing estrus in Alpine and Saanen goats, with minor differences in estrus response rates and pregnancy outcomes. Breed-specific variations were observed within the protocols, indicating a potential influence of breed on the efficacy of estrous synchronization. This study contributes valuable insights to goat breeding programs and promotes more efficient and sustainable livestock management practices.

PSIV-15 Economic Impact of a 14-D Cidr Pre-Synchronization on Cost Per Pregnancy in Holstein Heifers

Abstract Feed cost is the largest expense in developing dairy heifers with improved reproductive performance there is opportunity to reduce costs through decreasing days on feed to first calving. The objective of this study was to compare the economic impact of a 14-d CIDR pre-synchronization protocol to no pre-synchronization in Holstein heifers during an 84-d breeding period. Heifers were divided in two treatment groups 1) 14-d CIDR pre-synchronization (pre-synch; n = 20) and 2) control (n = 16). Heifers in the pre-synch treatment received a CIDR on d -30 which were removed on d -16. On d 0 (day of breeding eligibility) heifers in both groups were administered PGF2α and an Estrotect patch for estrus detection. On d 0, body weight of the heifers was estimated using a heart girth tape for large breeds. Estrotect patches were assessed once daily in the morning and heifers with ≥ 50% of the patch scratched received AI the same morning with Holstein sexed semen. After AI, heifers received a new Estrotect patch to facilitate return to estrus. Heifers that failed to express behavioral estrus within 14 d after PGF2α administration received another dose of PGF2α every 14 d until the first behavioral estrus was observed. Approximately thirty days after AI, heifers were subjected to ultrasonography of uterine contents for pregnancy diagnosis, and re-confirmed pregnant at ~60 d. Heifers diagnosed open received an injection of PGF2α and a new Estrotect patch. Partial budget analyses utilize these prices: feed cost ($1.75/heifer/day), PGF2α ($3.29/dose), needle and syringes ($0.12/per injection), Estrotect patch ($1.20/unit), AI procedure ($10.00/AI), semen ($35.00/straw), CIDR ($16.60/unit), pregnancy diagnosis ($5.00/heifer), overall labor ($0.41/heifer/day), and extra labor for CIDR group ($1.25/heifer). The partial budget was calculated per heifer and per pregnant heifer by charging pregnant heifers the cost of the remaining open heifers at the end of the 84-d period. There was no difference (P ≥ 0.26) in weight at d 0 (399.9 ± 15.2 vs 398.4 ± 15.8 kg), age at d 0 (371.6 ± 8.7 vs 371.5 ± 8.9 d), days to first AI (6.85 ± 2.28 vs 6.27 ± 2.50 d), days to pregnancy (20.55 ± 7.52 vs 14.09 ± 8.22 d), average number of services (2.10 ± 0.30 vs 2.06 ± 0.34 AI/heifer), average number of services to pregnancy (1.56 ± 0.24 vs 1.50 ± 0.27 AI/heifer), proportion of heifers receiving AI in the first 7 d (85.0 ± 8.0 vs 68.8 ± 11.6 %), proportion of heifers pregnant at first service (50.5 ± 12.5 vs 56.4 ± 13.5 %) and final pregnancy rates (80.0 ± 8.9 vs 75.0 ± 10.8 %) for pre-synch and control, respectively. Average cost per animal ($ 194.50 ± 30.27 vs 170.44 ± 33.85) and average cost per pregnancy ($ 243.12 ± 37.16 vs 206.95 ± 42.91) were not statistically different (P ≥ 0.53) between pre-synch and control, respectively. In summary, the use of a 14-d CIDR pre-synchronization did not have a significant economic impact on the performance of Holstein heifers during an 84-d breeding period.

Effect of Using Low Doses of PGF2α and GnRH Hormones on Reproduction of Dairy Cows

Effect of Using Low Doses of PGF2α and GnRH Hormones on Reproduction of Dairy Cows

Control of the Estrus Cycle Using Different Doses of the PGF2α Hormone in Kacang Goats

Control of the Estrus Cycle Using Different Doses of the PGF2α Hormone in Kacang Goats

Influence of GnRH and its timing of application on the fertility of artificially inseminated dairy cows synchronized with double doses of PGF2α”

Influence of GnRH and its timing of application on the fertility of artificially inseminated dairy cows synchronized with double doses of PGF2α”

Luteolytic failure as the cause of low efficiency in synchronization with prostaglandins in cows under tropical grazing

Objective: To determine the reason for the low response to the exclusive use of prostaglandin in synchronization programs in cows under tropical grazing compared with the use of progesterone (CIDR). Design/Methodology: Thirty-five cows with CL were randomly distributed in two groups. The first group (GPG; n=23) was synchronized using two doses of PGF2α (25 mg of Dinoprost®) with a 12-day interval. The second group (GCIDR; n=12) was synchronized with an intravaginal device (1.9 g of progesterone, 2 mg of estradiol benzoate, and 50 mg of progesterone); a PGF2α (pm) dose was applied on day 7, before removing the CIDR (am) on day 8. CL regression, luteolytic failure, progesterone concentration, and CL size were determined. Data was subjected to a normality test, followed by the Mann-Whitney U test or independent Student's t-test and chi-square test. Results: Only 82.6 % (19 out of 23) of the GPG cows that received the second dose of prostaglandins have a functional CL (<1 ng mL-1 of progesterone). The CL recorded a regression only in 43.5% of the cows in GPG vs. 91.7% in GCIDR (P=0.0001). In addition, GPG cows showed a luteolytic failure of 39.1% and an asynchrony of 17.4%. Conclusions: The low effectiveness of prostaglandin on the synchrony and regression of the CL (luteolytic failure) in cows fed under tropical grazing can be attributed to the low efficiency of the synchronization programs.

Efficiency of conventional and nanoparticle oxytetracycline in treatment of clinical endometritis in postpartum dairy cows

The incidence of clinical endometritis in dairy cows postpartum is one of the important reasons for financial losses in the dairy industry. The costs of treatment, milk losses, infertility, repeated breeding, and high annual culling rate of dairy cows present immediate losses in case of treatment failure. The commonly used therapeutic methods for clinical endometritis have not been successful nor have given definitive solutions to overcome the complications of the disease in dairy cows. Therefore, it was necessary to propose an innovative treatment program to overcome the reasons for the failure and lack of effectiveness of the treatment of clinical endometritis. This was tackled in the current study; oxytetracycline with different concentrations, oxytetracycline 5% (OTCC5%), oxytetracycline 20% (OTCC20%), and oxytetracycline 20% nanoparticles (OTC-NPs) were used for the treatment of clinical endometritis. Diagnosis of clinical endometritis was based on the assessment of high serum concentration of pro-inflammatory cytokines, acute phase protein, increased endometrium thickness, and intrauterine discharges with different degrees of echogenicity monitored by ultrasonography. Application of OTC-NPs revealed a decrease in serum concentration of pro-inflammatory cytokines (IL-1, IL-6, and TNF-α) and acute phase proteins compared to OTCC20% and OTCC5% groups. The improvement achieved by OTC-NPs may be attributed to the reduction of OTC particles into nano size which facilitates its tissue bioavailability, dispersion, penetration power to deeper tissues, and its more broad-spectrum activities. These activities were clearly apparent after the evacuation of uterine contents using a single dose of PGF2α. The OTC-NPs revealed a reduction in serum concentration of cytokines compared to OTCC20% and OTCC5% groups arranged as follows: 10.11, 25.45, 35.56 for IL-1; 99, 300, 319 for IL-6; 1.01, 4.40, 8.06 for CRP; and 46, 183, 266 for TNF-α. Furthermore, an increase in serum concentration of albumin (3.34) was obtained by OTC-NPs compared to OTCC5% (1.70). This improvement can be taken as evidence of liver resumption functions and inflammatory reactions. On the other side, globulin concentration recorded an increase like albumin and total proteins in OTC-NPs compared to others. A reduction in the endometrium thickness in OTC-NPs with the disappearance of intrauterine discharges was monitored by ultrasonography. This confirmed the subsiding of clinical endometritis in OTC-NPs group. Moreover, a significant improvement in conception and pregnancy rate in OTC-NPs compared to other groups were observed.

The use of prostaglandin applied in Bai Hui Acupoint on mare reproductive efficiency

SummaryProstaglandin F2α (PGF2α) is one of the most frequently used drugs for pharmacologic manipulation of the oestrous cycle in mares. Among its roles, PGF2α induces luteolysis, leading to an early oestrus return, which reduces the dioestrous phase and the inter‐ovulatory intervals. Interestingly, mares are more sensitive to PGF2α than other domestic species, hence lower doses are used; even so, the side effects are still adverse and inconvenient for animals and breeders. Recent studies of acupuncture, a traditional Chinese medicine technique, have been performed as an alternative to decrease the PGF2α dose for mares. The efficacy described of applying lower doses of PGF2α at specific acupoints is similar to that obtained with the regular dose. Therefore, the objective of this study was to analyse the reproductive performance and characteristics of oestrus in embryo recipient and donor mares using different doses at the Bai Hui—an acupoint located on the dorsal midline, also known as ‘the point of one hundred meetings’, as its region of effect encompasses many nerve trunks, nerve endings and vascular networks—a useful veterinary acupuncture treatment for ovarian disorders. For this study, 76 Quarter Horse mares were randomly assigned to three experimental groups: Control (CTR)—Intramuscular (IM) administration of 5 mg PGF2α; Bai Hui 5 mg (BH5)—application of 5 mg at the Bai Hui acupoint; and Bai Hui 2.5 mg (BH2.5)—application of 2.5 mg at the Bai Hui acupoint. In the results, there were no differences regarding uterine oedema, pregnancy rate or body condition score among the groups. However, oestrous expression was lower (p < 0.001) in both BH groups compared with CTR. Lastly, the interval between application and ovulation was shorter in BH5 compared with CTR (p = 0.042). The results indicate BH5 and BH2.5 as viable alternatives to the IM administration.

The effect of reduced dose of PGF2α on certain reproductive parameters in awassi yearlings in anestrus synchronisation protocol following the end of the of the breeding season

The aim of this study was to investigate the effect of the administration of half or full dose of prostaglandinF2α (PGF2α; Gestavet Prost, d-cloprostenol, HIPRA®) injection in a routine synchronization protocol following theend of the breeding period including intravaginal sponge (medroxyprogesterone acetate; Espanjovet, HIPRA®) andeCG (Oviser 500, HIPRA®) on certain fertility parameters in ewes.Two hundred thirty-eight Awassi yearlings (agedone year old) divided into two groups:116 ewes received a half dose (HSDP; 37.5 μg) of PGF2α and 122 ewes receivedfull dose (FSDP;75 μg).The pregnancy rates were 67.2% and 72.1% for HSDP and FSDP, respectively (P>0.05).The lambing rates were 64.7% and 63.9% for HSDP and FSDP, respectively (P>0.05).The single lambing rate inHSDP(94.7%) was higher (P<0.05) compared to that in FSDP (73.1%). The twin and multiple birth rates of FSDPwas higher (P<0.05) than HSDP. As a result, it was inferred that aHSDP could be used in Awassi yearlings withoutexperience of lamb care and in a herd in which single lambing was preferable. Moreover, due to the fact that it is moreaffordable and not detrimentalto fertility, it was concluded that HSDPcan offer an advantage in large flocks and can beused for manipulating fecundity ratesin yearlings.

Effects of additional gonadotropin-releasing hormone and prostaglandin F2α treatment to an estradiol/progesterone-based embryo transfer protocol for recipient lactating dairy cows

This study was designed to evaluate whether the utilization of a second PGF2α treatment at the end of an estradiol/progesterone (E2/P4)-based protocol with or without GnRH at the beginning of the protocol would improve pregnancy rates of lactating Holstein cows assigned to timed embryo transfer. A total of 501 lactating Holstein cows in 5 farms were enrolled in the experiment. Within farm, cows were blocked by parity and, within block, were assigned randomly to (1) insertion of an intravaginal P4 device (controlled internal drug-releasing device; CIDR) and estradiol benzoate on d -11, PGF2α on d -4, CIDR withdrawal and an injection of estradiol cypionate on d -2, and timed embryo transfer on d 7 (1-PGF; n = 164); (2) the same treatments as 1-PGF, but with PGF2α administered on d -4 and -2 (2-PGF; n = 171); and (3) 2-PGF with the addition of a GnRH treatment on d -11 (GnRH+2-PGF; n = 166). Ovaries were scanned by transrectal ultrasonography on d -11, -4, and 7, and blood samples were collected on d -11, -4, 0, and 7 for P4 determination. Treatment comparisons were performed using contrasts. The proportion of cows with a new corpus luteum on d -4 was greater in GnRH+2-PGF cows. Cows in 1-PGF had a greater P4 concentration on d 0 but lesser P4 on d 7 compared with cows in the other groups. Cows assigned to receive 2-PGF (2-PGF and GnRH+2-PGF) had greater estrus expression, and a greater proportion of cows ovulated to estradiol cypionate. No further contrast effects were observed for follicle diameter, double ovulation rate, pregnancy per embryo transfer (P/ET) on d 32 and 60, or pregnancy loss. As P4 concentration on d -4 increased, P/ET on d 60 tended to increase. Cows with P4 ≥3.66 ng/mL on d -4 had greater P/ET on d 32 and 60 than those with P4 below that threshold. Regardless of treatment, cows with P4 concentration ≥3.66 ng/mL also had a greater pregnancy per synchronized protocol (P/SP) on d 60. Also, a P4 concentration on d -4 (low or high) × follicle diameter (continuous) interaction tendency was observed when evaluating P/ET. Although P/ET did not differ among cows with different follicles sizes with reduced P4 concentration on d -4 (<3.66 ng/mL), it increased in cows with larger follicles exposed to increased P4 concentration (≥3.66 ng/mL). When P4 on d 0 was evaluated, P/ET on d 32 and 60 was greater for cows with low (≤0.09 ng/mL) versus high (>0.21 ng/mL) P4; as P4 concentration on d 0 increased, P/ET linearly decreased. In summary, cows with increased P4 concentrations during growth of the ovulatory follicular wave had improved P/ET. Administering a second PGF2α dose reduced P4 concentration on d 0 and increased ovulatory response to the protocol, but no benefits were observed on P/ET or P/SP.

Comparing the effect of estradiol benzoate and 17β-estradiol plus progesterone on follicular turnover and development, and pregnancy outcomes in a timed artificial insemination protocol

The objective of this study was to compare the efficiency of estradiol benzoate (EB) and 17β-estradiol (E2) associated with progesterone (P4) in a fixed-time artificial insemination (FTAI) protocol. We hypothesized that E2+P4 induces an earlier emergence of a new follicular wave (NFW), improving pre-ovulatory follicle diameter and pregnancy rates to FTAI (P/FTAI). In Exp.1, on Day 0 (D0), all Bos indicus cows (n = 12/group) received an intravaginal P4 device and a dose of PGF2α analogue. On D0, females were randomly assigned to receive EB or E2+P4. On D8.5, P4 intravaginal devices were removed and a dose of PGF2α and EB were administered in all females followed by fixed-timed AI on D10. Between D0 and D10, the dominant follicular growth was determined by ovary ultrasonography exams. On D8.5 and D10 the percentage of color power-Doppler signals in the dominant follicular wall was evaluated. In Exp. 2, 467 females (2-year-old nulliparous [n = 76], primiparous [n = 92] and pluriparous [n = 299]) were subjected to the similar FTAI and assigned to be treated with EB (n = 243) or E2+P4 (n = 224). Pregnancy diagnosis was performed 30 days after FTAI by ultrasonography. The day to emergence of NFW was similar between treatments (EB: 3.7 ± 0.37 vs. E2+P4: 3.3 ± 0.3, P = 0.76). Females treated with E2+P4 presented greater (P = 0.06) follicular growth between the emergence and D9 (1.18 ± 0.07) than those treated with EB (0.97 ± 0.08). There was also a positive effect (P < 0.05) of E2+P4 on diameter of the dominant follicle on D9 (13.0 ± 0.6 vs. 10.9 ± 0.55) and blood perfusion of the follicle wall on D8.5 (49 vs. 40%). There was a treatment by parity category interaction effect on P/FTAI (P < 0.05). Treatment with E2+P4 was advantageous to P/FTAI of primiparous cows (E2+P4: 58% and EB: 30%). However, for nulliparous and pluriparous cows, P/FTAI was similar between treatments (∼50%). In conclusion, in a E2/P4-based protocol for FTAI, E2+P4 is as efficient as EB in inducing new follicular emergence within a similar day range, but it results similar or greater P/FTAI.

Effect of the addition of GnRH and a second prostaglandin F2α treatment on pregnancy per artificial insemination in lactating dairy cows submitted to an estradiol/progesterone-based timed-AI protocol

Two experiments determined whether the addition of GnRH at the beginning of an estradiol (E2)/progesterone (P4)- based synchronization protocol and/or a second dose of prostaglandin F2α (PGF2α) the day before P4 device removal improves pregnancy rate in lactating dairy cows. On Day 0, all cows received a CIDR-B device and 2 mg i.m. estradiol benzoate, and half received 200 μg i.m. gonadorelin acetate (GnRH). On Day 7, cows were further subdivided to receive PGF2α (500 μg i.m. cloprostenol) or no PGF2α treatment. On Day 8, CIDR-B were removed, and all cows received PGF2α, 1 mg estradiol cypionate and 400 IU eCG i.m., and an estrus detection aid. Experiment 1 was designed to evaluate the effect of treatments on follicular development from P4 device removal to ovulation, expression of estrus, time of ovulation and serum P4 concentrations. Cows (n = 76) were examined by ultrasonography and bled for serum P4 determinations every 12 h from the time of P4 device removal but were not inseminated. In Experiment 2, all cows (n = 1036) were inseminated based on estrus detection using tail-paint. Cows with >50% of the paint rubbed-off by 48 h after P4 device removal were inseminated at that time, whereas those not in estrus received 100 μg i.m. of GnRH and were inseminated 12 h later. In Experiment 1, the interval from P4 device removal to ovulation was 71.7 ± 1.5 h and did not differ among groups. However, cows that received 2 injections of PGF2α had a greater (P < 0.01) estrus rate and lower (P < 0.01) P4 concentrations at 48 h after P4 device removal than those that received 1 PGF2α (estrus rate: 86.8% vs 68.4% and P4 concentration: 0.12 ± 0.01 vs 0.36 ± 0.07, for 2 and 1 PGF2α, respectively). In Experiment 2, estrus rate was also influenced by the number of PGF2α treatments, regardless of whether cows received or did not receive GnRH on Day 0 (2 PGF2α: 84.7%, 438/517 vs 1 PGF2α: 65.7%, 341/519; P < 0.01). Furthermore, there was a GnRH treatment by number of PGF2α treatments interaction (P < 0.05) on P/AI that was attributed to greater (P < 0.05) P/AI in cows that received GnRH on Day 0 and 2 PGF2α than in the other three treatment groups (EB+1 PGF2α: 45.2%, 119/263; EB+2 PGF2α: 45.8%, 119/260; EB + GnRH + 1 PGF2α: 45.7%, 117/256 and EB + GnRH + 2 PGF2α: 57.2%, 147/257). It was concluded that the addition of GnRH on Day 0 and a second dose of PGF2α the day before P4 device removal improves P/AI in lactating dairy cows synchronized with an estradiol/P4-based protocol.

Effect of PGF2α and GnRH administration on reproductive performance in Ghezel ewes

The main aim of the current study was to evaluate the effect of GnRH administration on day five after mating as well as PGF2α injection at the time of CIDR removal on the reproductive performance of Ghezel ewes. Estrus synchronization was performed using an intravaginal application of CIDR for 14 days and injection of 500 IU of PMSG at the time of CIDR removal. A total of 114 healthy fat-tailed ewes were randomly allotted into three groups as follow: control group (n = 35), did not receive any additional treatment; PG group (n = 44), each ewe received a dose of PGF2α at the time of CIDR removal; and PG+GnRH group (n = 35), the ewes received a dose of PGF2α at the time of CIDR removal and a single dose of GnRH, five days post-mating (post-conceptional day (PCD)− 5). Body condition score (BCS) of total ewes was determined at the time of CIDR insert. Blood samples were collected on PCD-19 for determining the serum progesterone levels. All the ewes were examined by transrectal ultrasonography 30–35 days after mating for pregnancy diagnosis. The serum values for P4 concentration were in control, PG and PG+GnRH groups 6.34 ± 1.17, 9.19 ± 2.55 and 10.57 ± 2.0 ng/mL respectively. The PG+GnRH treatment significantly increased the litter size compared to the control group (P = 0.04), but there were no significant differences in another reproductive indices between experimental groups. The multiple birth, twin, fecundity rates and litter size (P = 0.05, p = 0.03 and p = 0.003 respectively) were significantly higher in ewes with BCS > 2 compared to ewes with BCS ≤ 2. It is concluded that GnRH on PCD-5 treatment in addition to PGF2α injection at the time of CIDR removal could improve reproductive performance of Qezel ewes during non-breeding season.

Ovulatory response to GnRH agonist during early and late fall in mares

This study aimed to assess the ovulatory response of deslorelin acetate during the fall and the response to PGF2α 8 d post-ovulation. One hundred estrous cycles from 22 mares kept in 40° latitude were evaluated. Mares were checked by transrectal ultrasonography until a preovulatory follicle was detected and ovulation induced with deslorelin acetate. Ovulation was confirmed by ultrasonography performed at 24, 36 h post-induction and then repeated at 2-h intervals post-induction. Serum progesterone concentrations and luteal tissue area were determined daily to assess CL function. A dose of PGF2α was administered 8 d post-ovulation and interval to the subsequent ovulation was observed; each mare completed up to five cycles. The effects of local climate on endpoints were analyzed. Cycles were grouped as early (Sept 13, 2020–Oct 31, 2020; n = 55; 22 mares) and late fall (Nov 1, 2020–Dec 31, 2020; n = 45; 20 mares) based on the date of induction. The overall number of cycles with ovulations between 24 and 48 h was 90%. The number of multiple ovulations were similar between early (n = 5) and late (n = 4) fall (P = 0.87). There were no differences in deemed spontaneous ovulations occurring before 24 h between early (n = 6) and late (n = 2) fall (P = 0.29). Two failures to respond to deslorelin by 48 h were recorded in early fall and none in the late fall. The interval from induction to ovulation was similar in early (40.6 ± 0.4 h) and late (41.2 ± 0.5 h) fall (P = 0.55). The percentage of mares ovulating between 36 and 48 h post-deslorelin did not vary between early and late fall (91 vs. 95%, P = 0.21), as did not for ovulation occurring between 38 h and 44 h (62 vs. 60%, P = 0.69). Edema scores varied with time relative to ovulation (P < 0.001) and were lower in late fall (P = 0.01). Progesterone concentrations varied with time (P < 0.001) but did not differ between early and late fall (P = 0.73) and correlated weakly with the luteal area (r = 0.13; P = 0.031). Follicles <35 mm at the PGF2α had a shorter interval to the next ovulation than follicles ≥ 35 mm (9.2 ± 0.5 d vs. 10.6 ± 1.2 d) (P = 0.03). Lower temperature was associated with a smaller follicle size at induction (P = 0.0021) and ovulation (P = 0.009) and lower relative humidity was associated with a larger follicle size at ovulation (P = 0.032). In conclusion, cycling mares displayed a highly efficacious response to deslorelin acetate and apparently normal luteal function during the fall, despite lower edema scores in late fall.

PGF&lt;sub&gt;2α&lt;/sub&gt; induced estrus synchronization of native buffaloes in Bangladesh

Buffaloes have low fertility due to silent estrus, seasonal anestrous, delayed puberty and long calving interval. This study was aimed to investigate the effect of single and double doses of prostaglandin F2alpha (PGF2a) on synchronization of estrus in buffaloes. A total of 66 buffaloes were selected and subjected to estrus synchronization experiments: single dose PGF2a, and double dose PGF2a. In single dose PGF2a experiment, buffaloes were injected with either 500 or 875 µg of cloprostenol (PGF2a) and all buffaloes were examined to identify corpus luteum through rectal palpation before administration of PGF2a. In double dose experiment, buffaloes were injected with either 500 or 875 µg of cloprostenol (PGF2a) on Day 0 and Day 12 without identifying corpus luteum. The buffaloes were examined for estrus by collecting cervical mucus using universal artificial insemination gun from the mid cervix and timed artificial inseminations (TAI) were done after 72 hrs of last dose of PGF2α injection. The results showed that there were no significant differences in estrus rate (75±3.96% and 85±0.79%) single dose of PGF2α with 500 and 875 µg of cloprostenol, respectively. However, 875 µg of cloprostenol significantly (P&lt;0.05) increased estrus rate in buffaloes than double doses with 500 and 875 µg of cloprostenol (60 ± 12.72% and 63 ± 2.22%). The conception rate in buffaloes were 45±6.91% and 55±6.91% in 500 µg and 875 µg of cloprostenol in single dose of PGF2a and 30±14.69% and 37±8.81% in 500 µg and 875 µg of cloprostenol in double dose of PGF2a. The calving rate in buffaloes were 10±5.20% and 15±0.79% in 500 µg and 875 µg of cloprostenol in single dose of PGF2a and 10±8.33 and 12±6.18% in 500 µg and 875 µg of cloprostenol in double dose of PGF2a. However, there were no significant differences in conception and calving rates in buffaloes neither between single and double doses PGF2a nor different concentrations of PGF2a. In conclusion, single dose of PGF2a with 875 µg of cloprostenol injection efficiently increased estrus synchronization rate in buffaloes.&#x0D; Bang. J. Anim. Sci. 2021. 50 (2): 80-85

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons.

This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.

Ovarian response to prostaglandin F2α in lactating dairy cows: A clinical update.

Prostaglandin F2α (PGF2α) and its analogs are used to induce luteolysis in estrus synchronization programs to terminate unwanted pregnancies or to promote ovulation in certain cow subpopulations. In the past few decades, the luteolytic dose of PGF2α has remained unchanged. This review explores the clinical implications of increasing the standard dose for these applications in high-producing dairy cows. Ultrasonography may assist in selecting the most appropriate PGF2α dose and improve the results. A reference has been used for PGF2α for promoting ovulation in herds showing poor reproductive performance.