Effects of Flunixin Meglumine and Prostaglandin F2α Treatments on the Development and Quality of Bovine Embryos In Vitro

Assisted reproduction procedures, such as embryo transfer (ET) and artificial insemination (AI), in cattle could induce the secretion of prostaglandin F₂‐alpha (PGF₂α) from uterine horns which may in turn interrupt embryo development and implantation. This study investigated the effect of flunixin meglumine (FM), prostaglandin F2 alpha (PGF2α) and FM combined with PGF2α supplementation in culture medium (IVC‐II) on the development and quality of in vitro produced bovine embryos. The development rate of embryos was significantly higher in the FM group (33.3%) than in control (24.3%), PGF₂α (23.9%) and FM + PGF₂α groups (24.5%). The percentage of hatched blastocysts was also higher (p < 0.05) in the FM group (41.2%) than in the control (27.8%) and PGF₂α groups (19.8%). While, there was no significant difference in total cell number in all experimental groups, the number of apoptotic cells was significantly higher in the PGF₂α group (8.2 ± 6.6) than in the control (4.7 ± 3.2), FM (4.7 ± 2.5) and FM + PGF₂α (4.9 ± 3.4) groups. Detected by real‐time PCR, secreted vesicle seminal protein 1 (SSLP1) and prostaglandin G/H synthase 2 (PTGS2) gene expression decreased (p < 0.05) in the PGF₂α group. However, SSLP1 and PTGS2 gene expression in the FM + PGF₂α group returned to their baseline levels, similar to the control and FM groups. Caspase 3 (CAPS3) gene expression increased in the PGF₂α group compared with other groups (p < 0.05). In conclusion, addition of FM in vitro culture significantly improved embryo development as well as alleviated the negative impact of PGF₂α.     

Ovarian and Hormonal Responses to Follicular Phase Administration of Investigational Metastin/Kisspeptin Analog,TAK‐683, in Goats

This study evaluated the effects of follicular phase administration of TAK‐683, an investigational metastin/kisspeptin analog, on follicular growth, ovulation, luteal function and reproductive hormones in goats. After confirmation of ovulation by transrectal ultrasonography (Day 0), PGF_2α (2 mg/head of dinoprost) was administered intramuscularly on Day 10 to induce luteal regression. At 12 h after PGF_2α administration, intravenous administration of vehicle or 35 nmol (50 μg)/head of TAK‐683 was performed in control (n = 4) and treatment (n = 4) groups, respectively. Blood samples were collected at 6‐h intervals for 96 h and then daily until the detection of subsequent ovulation (second ovulation). After the second ovulation, ultrasound examinations and blood sampling were performed every other day or daily until the subsequent ovulation (third ovulation). Mean concentrations of LH and FSH in the treatment group were significantly higher 6 h after TAK‐683 treatment than those in the control group (12.0 ± 10.7 vs 1.0 ± 0.7 ng/ml for LH, 47.5 ± 28.2 vs 15.1 ± 3.4 ng/ml for FSH, p < 0.05), whereas mean concentrations of oestradiol in the treatment group decreased immediately after treatment (p < 0.05) as compared with the control group. Ovulation tended to be delayed (n = 2) or occurred early (n = 1) in the treatment group as compared with the control group. For the second ovulation, ovulatory follicles in the treatment group were significantly smaller in maximal diameter than in the control group (3.8 ± 0.5 vs 5.4 ± 0.2 mm, p < 0.05, n = 3). Administration of TAK‐683 in the follicular phase stimulates gonadotropin secretion and may have resulted in ovulation of premature follicles in goats.     

Timing of Ovulation and Fertility of Heifers After Synchronization of Oestrus with GnRH and Prostaglandin F2α

Synchronization of oestrus and/or ovulation can reduce workload in heifer reproductive management. The objective of this study was to compare two protocols to synchronize oestrus and/or ovulation using GnRH and prostaglandin F_2α (PGF_2α) in dairy heifers concerning their effect on follicular dynamics and reproductive performance. Four trials were carried out. In trial 1, 282 heifers were treated with GnRH and PGF_2α 7 days apart (GP protocol). One group was inseminated on detection of oestrus (IDO 1), and the other group received two timed artificial inseminations (AI) 48 and 72 h after PGF_2α administration (TAI 1). In trial 2, 98 heifers were synchronized with the same GP protocol. Heifers in IDO 2 were treated as in IDO 1, heifers in TAI 2 received two TAI 48 and 78 h after PGF_2α administration. In trial 3, heifers in IDO 3 (n = 71) were again treated as in IDO 1. Heifers in TAI 3 (n = 166) received a second dose of GnRH 48 h after PGF_2α (GPG protocol) and TAI together with this treatment and 24 h later. Trial 4 compared the timing of ovulation after the GP and the GPG protocol, using a subgroup of the heifers from trials 1 to 3. The ovaries of the heifers were scanned via ultrasound at 48, 56, 72, 80, 96 and 104 h after PGF_2α administration. Timing of ovulation and size of the ovulatory follicles were compared between the two groups. In trials 1 to 3, conception rates to first service were between 49 and 66%. They did not differ significantly between IDO and TAI groups within or between trials. Pregnancy rates per synchronization were numerically higher in the TAI groups, but the difference was not significant. Conception rates to breeding on spontaneous oestrus in heifers returning to oestrus were higher than that after synchronized oestrus. In trial 4, more heifers ovulated before the end of the observation period in GPG than in GP (96.5% vs 74.7%; p < 0.001). Overall, ovulatory follicles were smaller in GPG (13.1 ± 1.9 mm vs 14.3 ± 1.9 mm; p < 0.001).     

Evaluation of different hormonal treatments on oestral and ovarian responses in Moroccan Beni Arouss goats during anoestrus and breeding season

The efficacy of eight combinations of fluorogestone acetate (FGA, 20 or 40 mg as intravaginal device during 11 days), equine chorionic gonadotropin (eCG, 300 or 500 UI injected 48 hr before FGA removal) and prostaglandin F_2α (cloprostenol, 0 or 50 μg injected 48 hr before FGA removal) aiming at induction and synchronization of oestrus and ovulation was evaluated during the anoestrus season in spring and during the breeding season in autumn in adult Beni Arouss goats. Oestrous behaviour was recorded between 12 and 60 hr after FGA removal. Blood samplings allowing to assess onset of the pre‐ovulatory LH surge and increase of progesterone as sign of an active corpus luteum were performed, respectively, between 20 and 60 hr and 3, 5, 8 and 15 days after FGA removal. No season‐related differences (spring vs. autumn) were observed for oestrous response (95% vs. 93%), pre‐ovulatory LH surge (94% vs. 84%) and luteal response after 3–8 and 11–15 days post‐treatment (respectively 92% vs. 66% and 92% vs. 98%). The onset of oestrus (21 [13–53] vs. 32 [12–54] hr) and LH surge (26 [20–60] vs. 38 [22–60] hr) occurred significantly later in autumn. FGA (40 vs. 20 mg) in autumn significantly delayed the onset of oestrus (36 [16–54] vs. 23 [12–47] hr) and LH surge (44 [26–58] vs. 33 [22–60] hr). Significant treatment‐related differences were recorded for onset of LH surge (earliest for 20 mg FGA, 300 IU eCG, 50 μg PGF_2α) and onset of luteal phase (latest for 40 mg FGA, 300 IU eCG, 50 μg PGF_2α). In conclusion, the hormone combinations tested appeared equally effective in terms of oestrous and ovulation rates. Season has influenced significantly the onset of oestrus and LH surge, and the high dose regimen of FGA delayed the ovarian response in autumn.     

Effect of Oestrus Synchronization with PGF2α/eCG/hCG on Luteal P4 Synthesis in Early Pregnant Gilts

Administration of hormones to synchronize oestrus is a useful tool in animal breeding. However, exogenous ovarian stimulation may be detrimental to reproductive function. This study was aimed to examine whether an oestrus synchronization with PGF2α/eCG/hCG could affect luteal P4 synthesis in early pregnant gilts. Corpora lutea (CLs) were collected on days 9, 12 and 16 of pregnancy from gilts with natural (n = 16) and synchronized (n = 18) oestrus and analysed for (i) the expre‐ssion of steroidogenic acute regulatory protein (StAR), cytochrome P450 family 11 subfamily A polypeptide (CYP11A1), and 3β‐hydroxysteroid dehydrogenase (3βHSD); (ii) the concentration of P4 in the luteal tissue and blood; and (iii) the expression of luteinizing hormone receptors (LHR) and oestrogen receptors (ERα and ERβ). Additionally, the effect of LH on P4 secretion from CL slices collected from synchronized and naturally ovulated animals has been studied in vitro. PGF_2α/eCG/hCG administration increased mRNA expression of StAR, CYP11A1, 3βHSD, and LHR on day 9 and CYP11A1 and LHR on day 12 of pregnancy compared with the control group (p < 0.05). CYP11A1, 3βHSD, LHR, ERα and ERβ proteins were not affected by synchronization; only StAR protein increased in hormonally treated animals (p = 0.017). The concentration of P4 in luteal tissue was greater on day 9 (p < 0.01), but lower on day 16 (p < 0.05) in gilts with hormonally induced oestrus compared with control animals. Blood serum levels of P4 were lower in synchronized than control gilts (p < 0.001). Synchronization did not affect LH‐stimulated P4 secretion from luteal slices; however, greater basal concentration of P4 in incubation medium was detected for CLs collected from synchronized than control gilts (p < 0.05). In conclusion, synchronization of oestrus with PGF2α/eCG/hCG protocol in gilts did not impair the expression of luteal P4 synthesis system, although decreased P4 concentration in the blood.     

Short‐term intake of β‐carotene‐supplemented diets enhances ovarian function and progesterone synthesis in goats

The effect of β‐carotene supplementation upon luteal activity, measured as number (CLT) and volume (VLT) of corpus luteum, and P4 synthesis in goats, was evaluated. Goats (n = 22, 34 months) were randomly assigned to one of two experimental groups: (i) β‐carotene [Beta, n = 10; body weight (BW = 44.8 ± 1.45 kg), body condition score (BCS = 3.25 ± 0.07)], and (ii) Control (Control, n = 12; BW = 45.30 ± 1.32 kg, BCS = 3.33 ± 0.06). Upon oestrus synchronization, the Beta group received 50 mg of β‐carotene per day during 35 days pre‐ and 17 days post‐ovulation. The day 4, 8, 12 and 16 post‐ovulation, blood samples were collected for quantification of serum P4 concentrations by radioimmmunoassay, and transrectal ultrasonographic scanning was performed at day 18 for evaluating CLT and VLT. Overall, CLT and VLT mean were 3.10 and 2211.1 mm³ respectively. The Beta‐goats depicted both the largest values for CLT (p = 0.07) and serum P4 levels (p = 0.05), with no differences (p = 0.53) for VLT between treatments. Results suggest a higher efficiency within the cellular‐enzymatic groups defining the steroidogenic pathways in the β‐carotene‐supplemented goats, generating a larger P4 synthesis. The last is essential for ovulation of healthy oocytes, maintenance of uterine quiescence, nourishment and survival of the embryo around implantation; all of them of paramount significance during the maternal recognition of pregnancy process.     

Dominant follicles development and estradiol‐17β concentrations in non‐ovulating and ovulating post‐partum Bulgarian Murrah buffaloes

This study was designed to evaluate the dominant follicles development and the estradiol‐17β concentrations in non‐ovulating and ovulating post‐partum buffaloes. Sixteen Bulgarian Murrah buffaloes were submitted to transrectal ultrasonographic examination from the 1st post‐partum day until day 50, 3 days apart. The follicular diameter of the different categories of follicles and the ovulations was recorded. The animals were allocated into two groups: I (n = 6) non‐ovulating and II (n = 10) ovulating buffaloes. Serum estradiol‐17β concentrations on the days for dominant follicle registration were measured by enzyme‐linked immunosorbent assay. The results were statistically processed by analysis of variance, non‐parametric and correlation analysis. The mean intervals between calving and first dominant follicle detection differed significantly (p < .05) among the groups (19.5 ± 6.2 vs. 13.8 ± 5.1 days), while the mean intervals between registered dominant follicles from two successive waves were comparable. The mean follicular diameters for the same category follicles in both groups were similar. Different estradiol‐17β concentrations (p < .05) for the first dominant follicle between non‐ovulating (23.5 ± 7.0 pg/ml) and ovulating (33.3 ± 8.4 pg/ml) buffaloes were determined. The cumulative percentages of buffaloes with firstly detected dominant follicle and ovulating animals correlated positively (r ≥ .84; p < .05) to post‐partum days. In conclusion, non‐ovulating and ovulating post‐partum Bulgarian Murrah buffaloes showed differences in the development of the first dominant follicle and estradiol‐17β concentrations during the time of dominant follicles detection.     

Prostaglandin Endoperoxide Synthase 2 (PTGS2) and Prostaglandins F2α and E2 Synthases (PGFS and PGES) Expression and Prostaglandin F2α and E2 Secretion Following Oestrogen and/or Progesterone Stimulation of the Feline Endometrium

Sex steroids in synergy with prostaglandins (PG) are involved in the regulation of cyclic ovarian function. In this study, we investigated the mRNA expression of three genes involved in arachidonic acid (AA) metabolism and hence PG production in domestic cats: PG‐endoperoxide synthase (PTGS2), PGF_2α synthase (PGFS) and PGE₂ synthase (PGES). Feline endometria (n = 16) were collected at oestrus and mid and late phases of pseudopregnancy. In addition, the effects of E₂ and/or P₄ on PG secretion and gene expression on endometrial explants were studied in an in vitro culture system. Expression levels of all examined genes were up‐regulated at the mid phase of pseudopregnancy. The effects of E₂ and/or P₄ treatment on both PG secretion and expression of the genes were observed after 12 h of culture. Expression of PGES was significantly up‐regulated by E₂ plus P₄ at oestrus and the mid phase of pseudopregnancy and was also up‐regulated by a single treatment with P₄ at late pseudopregnancy (p < 0.05). Simultaneous incubation with E₂ and P₄ up‐regulated PTGS2 gene expression at oestrus and mid‐luteal phase (p < 0.05). Progesterone plus E₂ significantly increased PGE₂ secretion at oestrus and the mid phase of pseudopregnancy. However, treatment with E₂ and/or P₄ affected neither PGF_2α secretion nor PGFS expression at any phase after 12 h of culture. The overall findings indicate that genes involved in PG synthesis are up‐regulated at the mid phase of pseudopregnancy. An increase in PGE₂ secretion and up‐regulation of PGES and PTGS2 are the main responses of the endometrium to treatment with E₂ and P₄ at oestrus and the mid phase of pseudopregnancy in the cat. These data support the hypothesis that ovarian sex steroids via endometrial PGE₂ are involved in endocrine homoeostasis, especially at oestrus and the mid, but not the late, phase of pseudopregnancy in cats.     

Subtropical goats ovulate in response to the male effect after a prolonged treatment of artificial long days to stimulate their milk yield

The objectives of this study were to determine (i) if in subtropical goats that gave birth during mid‐December, the exposition to an artificial long‐day photoperiod consisting in only 14 hr of light per day can increase the milk yield and (ii) to test whether these females can respond to the male effect at the end of the prolonged photoperiodic treatment. In experiment 1, 17 lactating goats were maintained under natural short days (control group), while another 22 goats were maintained under artificial long days (treated group) consisting in 14 hr light and 10 hr darkness starting at day 10 of lactation. The continuous exposition to an artificial long‐day photoperiod produced an increase in the milk yield level during the first 110 days of lactation (time × treatment interaction; p = .01), while none of the milk components were modified due to the photoperiodic treatment (p > .05). In experiment 2, all control and treated anovulatory goats were submitted to the male effect using photostimulated males. All females showed oestrous behaviour within the first 10 days that were in contact with males (100% in both groups; p > .05). Thus, the latency to onset of oestrus did not differ between females from control (58.2 ± 3.0 hr) and treated (62 ± 4.6 hr) groups. Male exposition provoked ovulation independently if females were previously under long days or natural photoperiod (96 vs 100%, respectively; p = .79). It was concluded that exposure to 14 hr of light per day in subtropical goats that gave birth in late autumn stimulates milk yield without preventing the ovulation in response to the male effect at the end of the prolonged photoperiodic treatment.     

Effects of GnRH in combination with PGF2α on the dynamics of follicular and luteal cells in post-pubertal Holstein heifers

Holstein heifers were randomly allotted by weight, age and body condition score to one of three treatments to test the hypothesis that GnRH administration concurrent with PGF_2α injection would advance follicle or corpus luteum (CL) development parallel to an induced luteolysis of the pre-existing CL. Heifers in the control group (n = 14) received two treatments of PGF_2α(25 mg, im) given 10 days apart. Groups 2 (n = 14) and 3 (n = 14) received an additional treatment of GnRH (100 μg, im) after the first and second PGF_2α respectively. Estrus detection began immediately after PGF_2α and continued for 80 h. Blood sampling was initiated 7 days prior to the first PGF_2α (day − 7) and continued on days 0, 7, 10 (prior to the second PGF_2α), 17 and 24. Heifers were artificially inseminated after the second PGF_2α and pregnancy diagnosed at 60 days. There was a trend (P < .10) toward a lower estrus response in group 3 when compared to the other groups. Pregnant heifers in group 2 had lower progesterone (0.44 ± 0.09 vs. 1.72 ± 0.56 ng/ml) a week after the second PGF_2α than the non-pregnant animals in that group (P < .05). Similar results were observed in the control group but only within the responding heifers (0.61 ± 0.08 vs. 0.93 ± 0.03 ng/ml; P < .05). Progesterone in heifers in group 2 remained high on day 0, 7, and 10 (1.48 ± 0.37, 1.23 ± 0.39, 1.96 ± 0.36 ng/ml) in spite of the treatment with PGF_2α. This data suggest that administration of GnRH following PGF_2α alters bovine luteal and/or follicular cell function.     

Effect of eCG dose on ovarian haemodynamics,hormonal profiles and prolificacy rate when oestrus was induced during low-breeding season in Beetal goats

The objectives of the experiment were to determine the effect of two doses of equine chorionic gonadotropin (eCG) in a standard synchronization protocol based on a short-term progesterone (P₄) priming on ovarian structures and haemodynamics, concentrations of steroid hormones and prolificacy rate when oestrus was induced during low-breeding season (LBS) in Beetal dairy goats. We hypothesized that inclusion of eCG in a short-term P₄ priming-based synchronization protocol would increase the blood perfusion to ovarian structures leading to enhance oestrous and ovulatory responses and prolificacy rate in goats. Forty-two multiparous acyclic goats were blocked by body condition and, within block, assigned randomly to receive saline as control (CON), low eCG (L-eCG; 300 IU) or high eCG (H-eCG; 600 IU) dose. Initially, a controlled internal drug release (CIDR) device was placed in the anterior vagina on d −8, followed by removal of CIDR on d −3, concurrent with the administration of PGF_2α and eCG according to their respective treatments. Goats were monitored for oestrous response. B-mode and Doppler ultrasonography was performed with 12-h interval, starting from day −3 until natural breeding (day 0), and then on days 5, 10, 15 and 20 post-breeding to monitor follicular and luteal dynamics and blood flow, respectively. Blood was sampled at 0, 12, 24, 36 and 60 h after CIDR removal to quantify plasma concentrations of estradiol-17β (E₂), whereas plasma concentrations of P₄ were assayed at days 5, 10, 15 and 20 after breeding. Pregnancy and prolificacy rates were determined at day 30 and 150 after breeding, respectively. Data were analysed with mixed-effects models, and orthogonal contrasts were used to evaluate the effect of treatment [Con vs. (½ L-eCG + ½ H-eCG)] and dose of eCG (L-eCG vs. H-eCG). Data are presented in sequence as CON, L-eCG, H-eCG (LSM ± SEM). The oestrous intensity score (152.9 vs. 182.7 vs. 186.5 ± 15.1; p = .02) was greater in eCG-treated goats as compared to CON. Administration of eCG reduced the intervals to standing oestrus (66.2 vs. 41.8 vs. 48.9 h ± 5.5; p = .05), breeding (70.2 vs. 44.4 vs. 45.4 h ± 4.5; p = .03) and ovulation (84.5 vs. 61.2 vs. 63.4 h ± 6.2; p = .05) compared with CON goats. The mean growth rate of pre-ovulatory follicle was greater (1.11 vs. 1.49 vs. 1.45 mm ± 0.08; p = .01) in eCG-treated goats resulting in an increased diameter of pre-ovulatory follicle (6.27 vs. 7.20 vs. 7.31 mm ± 0.07; p < .01) and corpora lutea (6.75 vs. 8.26 vs. 8.07 mm ± 0.42; p = .04) than CON. The mean follicular blood flow did not differ among treatments; however, the mean luteal blood flow was greater in L-eCG-treated goats (0.81 vs. 1.61 vs. 1.07 cm² ± 0.12; p = .001). The mean concentrations of E₂ (4.03 vs. 5.21 vs. 4.78 pg/ml ± 0.42; p = .04) and P₄ (4.85 vs. 6.39 vs. 6.22 ng/ml ± 0.34; p = .04) were greater in eCG-treated goats. The twinning rate did not differ between treatments; nevertheless, prolificacy rate was greater (p = .04) in L-eCG-treated goats. Collectively, our data suggest that the administration of eCG improves the induction of oestrous and ovarian dynamics. Administration of L-eCG enhances prolificacy rate, therefore, a low dose of eCG might be practically beneficial to improve reproduction during LBS in acyclic Beetal dairy goats.     

Effect of delaying the time of insemination with sex-sorted semen on pregnancy rate in Holstein heifers

The objective of the study was to evaluate the interval from onset of oestrus to time of artificial insemination (AI) to obtain the optimum pregnancy rate with sex-sorted semen in Holstein heifers. Heifers in oestrus were detected and inseminated only by using heat–rumination neck collar comprised electronic identification tag at the age of 13–14 months. Heifers (n = 283) were randomly assigned to one of three groups according to the timing of insemination at 12–16 hr (G1, n = 97), at 16.1–20 hr (G2, n = 94) and at 20.1–24 hr (G3, n = 92) after reaching the activity threshold. The mean duration of oestrus was 18.6 ± 0.1 hr, and mean peak activity was found at 7.5 ± 0.1 hr after activity threshold. The mean interval from activity threshold to ovulation was 29.4 ± 0.4 hr. The overall pregnancy per AI (P/AI) was 53.0% at 29–35 days and 50.9% at 60–66 days after AI. There was a significant reduction between G1 (13.8 ± 1.4 hr) and G3 (7.9 ± 1.4 hr) related to the intervals from AI to ovulation time. Sex-sorted semen resulted in significantly higher P/AI at 29–35 days when heifers inseminated in G3 (60.9%) after oestrus than those inseminated in G1 (49.5%) and G2 (48.9%). In terms of fertility, when the temperature–humidity index (THI) was below the threshold value (THI ≤65) at the time of AI, there was a tendency (≤65; 57.2% vs. > 65; 47.1%) for high pregnancy rate. There was no effect of sire on P/AI. In addition, the interaction of the technician with the time of AI was found significant, and three-way interaction of technician, sire and time of AI was tended to be significant on pregnancy rate. Thus, in addition to delaying the time of insemination (between 20.1 and 24 hr) after oestrous detection, THI and experienced technician were also found to be critical factors in increasing fertility with the use of sex-sorted semen in Holstein heifers.     

Efficiency of methods applied for goat estrous synchronization in subtropical monsoonal climate zone of Southwest China

Two experiments were undertaken to select the efficient method applied for goat estrous synchronization. In experiment 1, a total of 120 does (Capra hircus) were divided into five groups with a randomized block design, and the does of treatment 1 were synchronized by intravaginal sponges impregnated with 30 mg Levonorgestrel inserted for 10 days. Does of treatments 2, 3, and 4 were treated with further injection of 25 IU follicle-stimulating hormone (FSH), 0.05 mg prostaglandin F2 alpha (PGF_2α), and 25 IU FSH + 0.05 mg PGF_2α at sponge withdrawal, respectively. The does in the control group (n = 40) without estrous synchronization treatment and natural estrous does were observed. In experiment 2, a total of 140 does in five goat farms in breeding and non-breeding seasons were treated with the selective efficient procedure. The results presented that all the employed treatments were capable of inducing and synchronizing estrous goats. According to estrous response and economy, the use of intravaginal sponges impregnated with 30 mg Levonorgestrel and 0.05 mg PGF_2α (treatment 3) is the first choice for estrous synchronization, and 95.0% of synchronized does demonstrated estrus, which was significantly higher than that of treatment 1 (P < 0.05) and control group (P < 0.01). The percentages of ovulating of treatments 3 and 4 were the same (95.0%), which were significantly higher than that of treatment 1 (P < 0.01). The ovulation rates among different groups were not significant (P > 0.05). When the selective procedure was applied to five goat farms, 85.7% (120/140) of does demonstrated estrus, and the kidding percentage, litter size, and prolificacy rate were 53.6%, 0.95, and 177%, respectively.     

Estrus Synchronization in Sheep and Goats Using Combinations of GnRH,Progestagen and Prostaglandin F2α

The objective of this experiment was to evaluate the effect of GnRH, progestagen and prostaglandin F_2α on estrus synchronization in sheep and goats. Sixty Awassi ewes and 53 Damascus does were used in the study. The experiment started at the beginning of the breeding season (June/July). The same treatments were applied to sheep and goats as follows: no treatment (CON), 14‐day progestagen sponges and 600 IU equine chorionic gonadotropin (S), gonadotropin releasing hormone followed 5 days later by prostaglandin F_2α (GP) and gonadotropin releasing hormone, progestagen sponges for 5 days and prostaglandin F_2α on the day of sponge removal (GSP). None of the ewes in the S group lambed from mating during the induced cycle. A greater lambing rate (p < 0.05) was observed in the GSP group compared with the CON and S groups while the GP group was intermediate. The number of lambs born per lambed ewe was similar among the CON, GP and GSP groups. However, the number of lambs per exposed ewe was greater (p < 0.05) in the GSP than the remaining groups. The induced cycle kidding rate was 77% for all treatments combined. Similar kidding rate were observed among treatments. The numbers of kids born per kidded and exposed doe from mating during the induced estrus were also similar among treatments. Greater numbers of multiple births were observed in the GP and GSP than in the S group. In conclusion, a combination of GnRH, progestagen sponges and PGF_2α can be effective in synchronizing estrus and improving fecundity in sheep and goats. Although the use of GnRH–PGF_2α was effective, the addition of progestagen sponges at the time of GnRH administration appeared to improve reproductive parameters.     

Fertility of the West African Dwarf goat in its nagative environment following prostaglandin F2‐alpha induced estrus

Summary

The fertility of ten West African Dwarf goats in which oestrus was induced with PGF₂α was comparable to that of the five West African Dwarf goats in the control group. Performance indices as determined by duration of oestrus and length of gestation were not affected. Similarly the birth weight of kids was not significantly influenced. However, treated goats were superior to controls when the interval from commencement of experiment to oestrus is considered, although there was no difference between the two treated groups of goats (5 mg vs 10 mg PGF₂α).

Results showed that PGF₂α could be an important tool in oestrus synchronization and thus in control of the reproductive performance of the West African Dwarf goats under humid lowland tropical environmental conditions.     

Factors influencing pre-ovulatory follicle diameter and weaning-to-ovulation interval in spontaneously ovulating sows in tropical environment

Follicle development and timing of ovulation are indicators of the reproductive performance of sows. The present study aimed to determine factors influencing pre-ovulatory follicle diameter and weaning-to-ovulation interval (WOI) in spontaneously ovulating sows in tropical climates with special emphasis on breed, parity and backfat thickness at weaning. In total, 80 sows were included in the study. Follicle development was determined by using transrectal real-time B-mode ultrasonography every 6 hr after standing oestrus. Weaning-to-oestrous interval (WEI), oestrous-to-ovulation interval (EOI), WOI and the diameter of graafian follicles were investigated in relation to breed, parity number (1, 2–3 and 4–7) and backfat thickness (low, moderate and high) of sows. Overall, WEI, EOI, WOI and the pre-ovulatory follicle diameter were 92.5 ± 21.6 hr, 64.3 ± 19.3 hr, 156.3 ± 29.1 hr and 10.3 ± 2.0 mm, respectively. Pre-ovulatory follicle size was smaller in primiparous sows compared with sows of greater parity, 4–7 (9.7 ± 0.51 and 11.7 ± 0.52 mm, respectively, p < .05). Weaning-to-ovulation interval was positively correlated with WEI (r = 0.75, p < .001) and EOI (r = 0.66, p < .001), but negatively correlated with size of the graafian follicle (r = –0.34, p < .01). Sows with a shorter WEI had a larger pre-ovulatory follicle diameter (at 64 hr after oestrus) (r = –0.37, p < .01). Sows with low backfat thickness had a WOI 23.4 hr longer than those with moderate backfat thickness (p < .05) and 17.6 hr longer than sows with a high backfat thickness (p = .140). The follicle diameter in primiparous sows with high backfat thickness (11.7 ± 1.1 mm) was higher than in those with low (8.9 ± 0.7 mm, p < .05) or moderate (8.6 ± 0.8, p < .05) backfat thickness. In conclusion, factors influencing follicle diameter and WOI in sows included parity number and backfat thickness at weaning. The impact of backfat thickness on follicle diameter, WEI and WOI was most pronounced in primiparous sows.     

Effect of Progesterone Prior to GnRH-PGF2α Treatment on Induction of Oestrus and Pregnancy in Anoestrous Awassi Ewes

An experiment was conducted to examine the effect of progesterone prior to a GnRH‐PGF_2α treatment on oestrus and pregnancy in seasonally anoestrous Awassi ewes. Twenty‐four ewes were randomly assigned to three groups to be pre‐treated with 60 mg medroxyprogesterone acetate sponges (group A), 600 mg progesterone sponges (group B) or blank sponges (group C) for 4 days. All ewes were injected with 100 μg of GnRH 24 h after sponge removal followed, 5 days later, by 20 mg PGF_2α injection. Ewes were exposed to three fertile rams at the time of PGF_2α injection (day 0, 0 h) and were checked for breeding marks at 6‐h intervals for 5 days. Blood samples were collected from all ewes 1 day (day ?10) prior to sponge insertion, at the time of sponge removal (day ?6), 1 day following sponge removal (day ?5, at the time of GnRH injection) and at the time of PGF_2α injection (day 0) for analysis of progesterone. Progesterone concentrations on days ?10 and ?5 were basal and averaged 0.2 ± 0.04 and 0.2 ± 0.2 ng/ml, respectively. Progesterone concentrations on day ?6 were elevated only in group B ewes and were higher (p < 0.0001) than those of groups A and C. Progesterone concentrations on day 0 were higher (p = 0.002) in groups A and B than group C. Oestrous responses occurred only in ewes of groups A and B (p > 0.05). Induced oestrus conception rate was greater (p < 0.01) in group A than groups B and C. Ewes returned to oestrus 17–20 days following day 0 were two of eight, six of eight and three of eight of groups A, B and C, respectively, all of which eventually lambed. The overall lambing rate was 82% in progesterone‐primed ewes compared with only 38% non‐progesterone‐primed ewes (p < 0.05). Progesterone priming apparently sensitizes GnRH‐PGF_2α‐treated seasonally anoestrous ewes and increases their response in oestrus and pregnancy rates.     

Efficiency of Oestrous Synchronization by GnRH,Prostaglandins and Socio‐Sexual Cues in the North African Maure Goats

This study aims to develop at different seasons, for local North African Maure goats, synchronizing protocols simultaneously to the standard ‘S’ protocol using progestagens in association with prostaglandins and gonadotropin. In late May, 40 goats were assigned to either the ‘S’ protocol or to a protocol where oestrus and ovulation were induced by the buck effect in single‐injection progesterone‐treated goats and provoking early luteolysis using prostaglandin 9 days after exposure to bucks ‘B’. During the 72 h after the treatments ended, 15 and 5 goats expressed oestrus in the ‘S’ and ‘B’ protocols (p < 0.01). Mean time to oestrus was shorter for ‘S’ than for ‘B’ goats. Ovulation rate averaged 2.1 ± 0.22 and 1.60 ± 0.35 for, respectively, ‘S’ and ‘B’ goats (p > 0.05). During mid‐September, 60 goats were assigned to either ‘S’ treatment, ‘PGF’ treatment where oestrus and ovulation were synchronized using two injections of prostaglandin 11 days apart or to ‘GnRH’ treatment where the goats had their oestrus and ovulation synchronized with a GnRH (day 0)–prostaglandin (day 6)–GnRH (day 9) sequence. More ‘S’ goats were detected in oestrus over the 96‐h period after the end of the treatments (88.8, 73.7 and 55% in ‘S’, ‘PGF’ and ‘GnRH’ treatments, respectively; p < 0.05). Mean ovulation rates were 2.3 ± 0.27, 1.33 ± 0.27 and 1.33 ± 0.27 for, respectively, ‘S’, ‘PGF’ and ‘GnRH’ goats (p < 0.001). Despite a similar ovulatory response to ‘S’ protocol, efficiency of prostaglandin and GnRH‐based treatments should be tested in mid‐breeding season.     

GnRH and prostaglandin‐based synchronization protocols as alternatives to progestogen‐based treatments in sheep

The study investigated, for cycling sheep, synchronizing protocols simultaneously to the standard “P” protocol using progestogens priming with intravaginal devices and gonadotropin. In November 2014, 90 adult Menz ewes were assigned to either the “P” protocol, “PGF” treatment where oestrus and ovulation were synchronized using two injections of prostaglandin 11 days apart or a “GnRH” treatment where the ewes had their oestrus and ovulation synchronized with GnRH (day 0)–prostaglandin (day 6)–GnRH (day 9) sequence. The ewes were naturally mated at the induced oestrus and the following 36 days. Plasma progesterone revealed that 92% of the ewes were ovulating before synchronization and all, except one, ovulated in response to the applied treatments. All “P” ewes exhibited oestrus during the 96‐hr period after the end of the treatments in comparison with only 79.3% and 73.3% for “PGF” and “GnRH” ewes, respectively (p < .05). Onset and duration of oestrus were affected by the hormonal treatment (p < .05); “GnRH” ewes showed oestrus earliest and had the shortest oestrous duration. Lambing rate from mating at the induced oestrus was lower for “P” than for “PGF” ewes (55.6% and 79.3%, respectively; p < .05). The same trait was also lower for “P” than for “PGF” and “GnRH” ewes (70.4%, 89.7% and 86.7%, respectively; p < .05) following the 36‐day mating period. Prostaglandin and GnRH analogue‐based protocols are promising alternatives for both controlled natural mating and fixed insemination of Menz sheep after the rainy season when most animals are spontaneously cycling.     

Embryo collection from pigs post‐pseudopregnancy induced by estradiol dipropionate

We aimed to define whether embryo collection carried out after pseudopregnancy was of similar outcome and quality as after artificial abortion. To induce pseudopregnancy, 30 gilts or sows were given 20 mg intramuscular estradiol dipropionate (EDP) 10–11 days after the onset of estrus. Ten additional pigs were inseminated artificially at natural estrus as a control group. Prostaglandin F_2α (PGF_2α) was administered twice with a 24 hr interval beginning 15, 20, or 25 days after EDP‐treatment (n = 10 per group) or between 23 and 39 days after artificial insemination in control pigs. Following this, all pigs were given 1,000 IU equine chorionic gonadotropin and 500 IU human chorionic gonadotropin (hCG) and then inseminated. Embryos were recovered 6 or 7 days after hCG treatment and outcome was recorded. There was no significant difference in the number of normal embryos collected from the pigs with PGF_2α initiated at different time points or from the control group. Embryonic developmental stages 7 days after hCG treatment also did not differ among groups. These results indicate that the use of EDP to induce pseudopregnancy, followed by PGF_2α administration to synchronize estrus for subsequent embryo harvest, is a suitable alternative to the artificial abortion method.