PGF2α Administration Research Articles

Prostaglandin F<sub>2α</sub> induced luteolysis is delayed but not prevented by acute administration of luteotropic drugs in lactating nonpregnant Holstein cows

Inadvertent use of prostaglandin F2α (PGF2α) in pregnant cattle could result in luteolysis and pregnancy loss. Using a nonpregnant cow model, we determined if luteotropic agents could counteract luteolytic effects of PGF2α. Ovarian status of 20 lactating nonpregnant Holstein cows was synchronized using an Ovsynch protocol and ovulation confirmed by transrectal ultrasonography 48 hours after the second gonadotropin releasing hormone (GnRH). Eight days after ovulation, 25 mg of dinoprost (native PGF2α) was administered IM to induce luteolysis. Five minutes after PGF2α, cows were treated IM with gonadorelin (GnRH, 100 μg; n = 5), human chorionic gonadotropin (hCG, 1,000 IU; n = 6), porcine pituitary luteinizing hormone (pLH, 25 mg; n = 5), or saline (control, 2 ml; n = 4). Blood samples were collected before PGF2α (0 hour) and at 1, 6, 12, 18, 24, 30, 36, 42, 48, 60, 72, and 84 hours after PGF2α to monitor subsequent luteal activity by measuring plasma progesterone concentrations. Although none of the treatments counteracted the luteolytic action of PGF2α, the rate of decline in plasma progesterone within 1 hour after PGF2α was greater (p = 0.04) in control than in GnRH, hCG, and pLH (2.2 versus 0.2, 0.3, and 0.1 ng/ml/hour, respectively). In addition, pLH-treated cows tended (p = 0.07) to have greater overall mean plasma progesterone for up to 84 hours (1.6 ± 0.2 ng/ml) than other treatments combined (1.1 ± 0.1 ng/ml). In the present study, giving GnRH, hCG or pLH 5 minutes after PGF2α administration was not effective in countering luteolytic effects of PGF2α. Nevertheless, pLH treatment tended to delay PGF2α induced luteolysis, which warrants further investigation.

Administration of PGF2α during the periovulatory period increased fertilization rate in superovulated buffaloes

The aim of the present study was to determine the recovery of embryonic structures (ova/embryos) and fertilization rate in superovulated buffaloes treated with PGF2α during the periovulatory period. On day 0 (D0), buffaloes at random stages of the estrous cycle were treated with an intravaginal progesterone device (P4; 1.0 g) and estradiol benzoate (EB, 2.0 mg i.m.). From D4 to D7, all buffaloes received i.m. FSH (200 mg total) twice-daily over 4 days in decreasing doses. On D6 and D7, the animals were given PGF2α analogue (0.53 mg i.m. sodium cloprostenol) and the P4 device was removed on D7. On D8, all buffaloes received GnRH (20 μg i.m. buserelin acetate). Buffaloes were then randomly allocated to one of three groups: control (Group C, n = 18), no further treatment; PGF2α analogue injection (Group IM-PGF; n = 18), four injections (0.53 mg i.m. sodium cloprostenol) 12 h apart, from D8 to D10; PGF2α analogue osmotic pump (Group OP-PGF; n = 18), s.c. osmotic mini-pump (2.12 mg sodium cloprostenol) from D8 to D10. The study had a crossover design (three treatments x three replicates). All animals underwent timed AI, 12 and 24 h after treatment with GnRH. Embryonic structures were recovered on D14. Ovarian ultrasonography was used on D8 and D14 to record follicular superstimulation and superovulatory responses. Blood samples were obtained on Days 7, 8, 9 and 10 to measure circulating concentrations of P4, E2 and PGFM. Data were analyzed by GLIMMIX procedure of SAS®. There was no effect (P = 0.58) of treatment on the total number of embryonic structures (Group C, 2.1 ± 0.8; Group IM-PGF, 2.1 ± 0.6; Group OP-PGF, 1.4 ± 0.4). There was also no effect (P = 0.93) of treatment on the recovery rate of embryonic structures (oocytes and embryos D14/CL D14). The fertilization rate was higher (P = 0.04) in Groups IM-PGF (84.6%) and OP-PGF (88.0%), which did not differ, than Group C (63.2%). The viable embryos rate was greater (P < 0.01) for Groups IM-PGF (82.0%) and OP-PGF (88.0%) than Group C (52.6%). There was no interaction between treatment and time and treatment effects for P4, E2 and PGFM concentrations. The findings showed that treatment with PGF2α during the periovulatory period has potential to increase fertilization rate and embryo production in superovulated buffaloes.

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 20mg intramuscular estradiol dipropionate (EDP) 10-11days after the onset of estrus. Ten additional pigs were inseminated artificially at natural estrus as a control group. Prostaglandin F2α (PGF2α ) was administered twice with a 24hr interval beginning 15, 20, or 25days after EDP-treatment (n=10 per group) or between 23 and 39days after artificial insemination in control pigs. Following this, all pigs were given 1,000IU equine chorionic gonadotropin and 500IU human chorionic gonadotropin (hCG) and then inseminated. Embryos were recovered 6 or 7days after hCG treatment and outcome was recorded. There was no significant difference in the number of normal embryos collected from the pigs with PGF2α initiated at different time points or from the control group. Embryonic developmental stages 7days after hCG treatment also did not differ among groups. These results indicate that the use of EDP to induce pseudopregnancy, followed by PGF2α administration to synchronize estrus for subsequent embryo harvest, is a suitable alternative to the artificial abortion method.

150 Administration of prostaglandin F2α 24 h prior to CIDR removal impacts reproductive performance of suckled beef cows assigned to the 7-d CO-Synch + CIDR protocol

Abstract Angus-influenced cows received 100 µg of GnRH and a CIDR device containing 1.38 g of progesterone (P4) on d 0, and were randomly assigned to 25-mg injection of PGF2α on d 6 (PG6; n = 147) or d 7 (PG7; n = 162). The CIDR device was removed on d 7, and cows received 100 µg of GnRH and artificial insemination (AI) on d 10. An estrus detection patch was attached to the tailhed of each cow on d 7, and estrus expression assessed at AI (&gt; 50% coating removal). Blood samples were collected on d 0 to determine the presence of a functional corpus luteum via plasma P4 (CL, P4 ≥ 1.0 ng/mL; NOCL P4&lt; 1.0 ng/ mL). A subset of cows (70 cows/treatment) were assigned to ultrasonography at AI to verify dominant follicle diameter (DFD). Blood samples for plasma P4 analysis were collected (42 cows/treatment) on d 6, and on d 7 at CIDR removal and 1 h later. A similar proportion of PG6 and PG7 cows were classified as CL (P = 0.38). Plasma P4 at CIDR removal and 1 h later were less in PG6 vs. PG7 cows classified as CL (1.81 vs. 3.99 and 1.06 vs. 2.89 ng/mL), and did not differ (P ≥ 0.43) within NOCL. Estrus expression was greater in PG6 vs. PG7 cows classified as CL (72.8 vs. 48.3%), but similar (P = 0.96) within NOCL. Pregnancy rates did not differ between treatments (P = 0.53), despite a numerical difference (P = 0.15) between PG6 vs. PG7 cows classified as CL (65.5 vs. 55.0%). No other treatment effects were detected (P ≥ 0.20). Hence, PGF2α administration 24 h prior to CIDR removal appears to benefit reproductive performance of beef cows with a functional CL at the beginning of the 7-d CO-Synch + CIDR protocol

Effect of Utilization of Single or Double Prostaglandin Administration Within an Ovsynch Fixed-Time Artificial Insemination Protocol During Summer Season in Dairy Cows

Abstract This study investigated the fertility of dairy cows during summer season after treatment with a single or double PGF2α in a progesterone (P4)-based Ovsynch protocol for fixed-time artificial insemination (FTAI). The data were compared to a treatment effectuated during winter season. Two groups of 60 dairy cows each were randomly assigned on day 60 post-partum to single PGF2α or double PGF2α group. At removal of the P4 treatment the single PGF2α group received a single dose and the double PGF2α group received two doses of PGF2α at 24 hours apart. In each group, 30 cows were treated during the summer (June, July and August) and 30 cows during the winter (December, January and February) season. During summer season a double PGF2α dose did not influence pregnancy rate at FTAI but improved cumulative pregnancy rate 60 days after FTAI (43% vs 69% for single PGF2α and double PGF2α administration, respectively; P&lt;0.05). During winter season the single or double PGF2α administration did not modify PR or cumulative PR. In conclusion, during summer the utilization of a double instead of single PGF2α treatment into a P4-based Ovsynch-FTAI protocol did not increase pregnancy rate at FTAI but improved cumulative pregnancy rate.

Superovulation of Boer goats with different synchronization regimens at different times of the year in the northern temperate zone

The present study addresses a comparison of various estrous cycle control protocols and the effect of season in the northern temperate zone on the superovulatory response in Boer goats. Four groups of 12 does each were treated in February, May, August and November, respectively. Does were provided with progestogen containing intravaginal pessaries to synchronize estrus. Half the does of each group received sponges impregnated with 20 mg fluorogestone acetate (“Cronolone”), the other half “Eazy-Breed” CIDRs containing 0.3 mg progesterone. Pessaries remained in place for 7 days. Within each subgroup half the does were treated with PGF2α (“Dinoprost”) at pessary insertion, the other half at pessary withdrawal. Beginning 48 h before pessaries were removed does received i.m. injections of 4, 4, 2, 2, 2 and 2 Armour Units (AU) FSH, supplemented with 40% LH, at 12 h intervals. Estrus detection was conducted at 8 h intervals and ovarian activity was monitored by daily transrectal ultrasonography. Does were mated and 7 days later non-surgical embryo collection was conducted. It transpired that the type of intravaginal pessary had no effect on the time passing between pessary withdrawal and onset of estrus (sponge: 40.7 h vs. CIDR: 35.2 h), number of ovulations/doe assessed by echographic counting of collapsed large follicles (7.2 vs. 7.6) or corpora lutea (7.1 vs. 9.8), embryo recovery rate (39% vs. 41%) and proportion of transferable embryos (66% vs. 65%). The number of collapsed large follicles was significantly higher than that of corpora lutea on the day before embryo collection (7.4 vs. 8.5; P < 0.05), the correlation between the two being r = 0.55 (P < 0.05). The effect of PGF2α administration at the onset or at the end of progestogen treatment and the effect of season were not significant, except for a shorter interval between pessary removal and onset of estrus in August in comparison to the other months (29.3 vs. 39.4, 40.6 and 42.1 h; P < 0.05). In conclusion, Boer goats, although being seasonal breeders in the northern temperate zone, will respond to superovulatory treatment and produce embryos of high quality year round regardless of type of pessary and time of PGF2α administration.

Hormonal regulation and function of an RNA helicase, Ddx5 in corpus luteum of adult Wistar rats

Corpus luteum (CL) is an endocrine tissue involved in regulation of reproductive cycle and early pregnancy establishment. In the present study DEAD-box helicase-5 (Ddx5), a member of the DEAD box family of RNA helicases was investigated for its expression, regulation and function in CL of Wistar rats. Ddx5 was expressed in adult rat CL. Primary cell culture from supra-ovulated ovaries were established for in vitro studies. Addition of luteinizing hormone (LH; 100 ng/ml), a luteotrophic factor in primary cell culture, decreased Ddx5 RNA expression (foldchange:0.6 ± 0.075) while prostaglandin alpha (PGF2α; 1μM), a luteolytic factor caused an increase (foldchange:2.4 ± 0.4) compared to control group. Under in vivo conditions, the administration of PGF2α or gonadotropin-releasing hormone antagonist; cetrorelix (CET) caused luteolysis as well as an increase in the protein level of Ddx5 (foldchange:1.9 ± 0.27 and 1.4 ± 0.09 viz.; p < 0.05) in CL of adult rats. LH was administered post CET treatment which suppressed Ddx5 protein expression (foldchange:0.8 ± 0.16; p < 0.05) compared to CET treated group. Further, it was observed that the expression of Ddx5 was upregulated (foldchange:1.5 ± 0.23; p < 0.05) in CL during late pregnancy compared to mid pregnancy concomitant to luteolysis in adult rats. Overall, the results suggest for the first time that Ddx5 is expressed in rat CL and regulated by luteolytic and luteotrophic factors in an inverse fashion. Further, the data significantly correlates ddx5 expression to CL regression suggesting involvement of ddx5 in luteolysis. These results suggest a significant role of Ddx5 in female reproduction biology and warrant in depth examination of the function of Ddx5 in CL.

Effect of presynchronization with prostaglandin F2α before the 5-d timed AI protocol on ovarian responses and pregnancy in dairy heifers

The objectives were the determine the effects of presynchronization with PGF2α 2 days before the 5-d timed artificial insemination (AI) protocol on ovarian responses and pregnancy per AI (P/AI) in dairy heifers. The hypothesis was that PGF2α would induce responsive heifers to be in proestrus at the initiation of the timed AI protocol, which was expected to improve ovulatory responses and P/AI. Weekly cohorts of Holstein heifers were blocked by age and, within block, randomly assigned to remain as control (CON; n = 255) or receive PGF2α on experiment Day −10 (PG; n = 255). All heifers were subjected to the 5-d timed AI protocol (Day −8, GnRH + intravaginal progesterone controlled internal drug release insert; Day −3, PGF2α and insert removal; Day −2, PGF2α; and Day 0, GnRH and AI). A subset of 22 blocks of heifers (n = 43) had their ovaries scanned by ultrasonography on experiment Days −8, −3, 0, and 2 and blood was sampled and analyzed for concentrations of progesterone on experiment Days −8, −7, −5, and −3. Pregnancy was diagnosed on experiment Days 32 and 60. On the day of the first GnRH of the timed AI protocol, PG heifers had smaller concentration of progesterone in plasma (CON = 4.5 ± 0.5 vs. PG = 0.5 ± 0.5 ng/mL), but larger follicular diameter (CON = 9.1 ± 0.5 vs. PG = 11.0 ± 0.5 mm), and a greater proportion of them had a follicle with at least 8.0 mm in diameter (CON = 61.9 vs. PG = 90.9%) than CON heifers, which resulted in increased ovulation to GnRH (CON = 19.0 vs. PG = 86.3%). Ovulation to the initial GnRH of the protocol increased as the concentration of progesterone in plasma decreased, from less than 20% when progesterone was greater than 5.0 ng/mL to more than 65% when progesterone was less than 1.0 ng/mL. More CON than PG heifers spontaenously ovulated before the day of timed AI. Detection of estrus on the day of timed AI did not differ between treatments (CON = 50.9 vs. PG = 46.6%), but P/AI on Days 32 (CON = 52.9 vs. PG = 61.1%) and 60 (CON = 49.0 vs. PG = 57.1%) after insemination tended to be greater for PG than CON; however, the benefit to presynchronization was observed in heifers inseminated with conventional (CON = 54.7 vs. PG = 67.4%), but not in heifers inseminated with sex-sorted semen (CON = 50.9 vs. PG = 52.8%). Administration of PGF2α 2 days before initiating the timed AI protocol induced heifers to be in proestrus, which enhanced ovulation to the initial GnRH and favored pregnancy per AI, particularly in heifers inseminated with conventional semen.

Follicular dynamics and changes in oestradiol-17β, progesterone and LH profiles following PGF2α induced oestrus in early and late ovulating Beetal goats.

This study compares the factors associated with variable interval to oestrus and ovulation between early versus late ovulating goats following PGF2α administration. The time of ovulation in Beetal goats (n=38) was monitored through transrectal ultrasound at every 6hr following a single dose of PGF2α (experiment 1). Variations in oestrus and ovulation times were further explored throughthe changes in follicular dynamics, endocrine profiles and behaviour in another set of goats (n=13) following single PGF2α given randomly during the lutealphase (experiment 2). The ovulation time varied between 60 and 96hr, and 57% of ovulations occurred by 72hr following PGF2α (experiment 1). Accordingly, the goats (n=13) in the second experiment were retrospectively dividedeither into early and/or late ovulating, that is, ≤72 and/or ≥84hr following PGF2α . The onset of oestrus, peak estradiol-17β concentration and LH surge after PGF2α was first observed in early than late ovulating goats (p<0.05). The goats ovulating early had larger follicleand smaller CL in diameter at the time of PGF2α administration than those ovulating late (5.4±0.2 vs. 4.3±0.2mm and 10±0.6 vs. 11.8±0.3mm, respectively; p<0.05). Likewise, plasma progesteroneconcentration tended to be lower (p=0.087) in earlythan late ovulating goats. In conclusion, the size of dominant follicle and CL at the time of PGF2a determines the interval toovulation following a single dose of PGF2a during the luteal phase.

Induction of parturition by double administration of prostaglandin F2α in sows reduces the variation of gestation length without affecting the colostrum yield and piglet performance.

The objective of the present study was to investigate whether double intra-vulvo submucosal administration of prostaglandin F2α (PGF2α) could improve farrowing synchronization compared to single administration, and the effects of the induction of farrowing on colostrum yield and piglet performances. In total, 91 sows were randomly assigned to one of three groups: i) treatment with a single or ii) double administration of PGF2α or iii) control group without any treatment. A synthetic analogue of PGF2α was administrated via the intra-vulvo submucosal route on day 114 of gestation, at 0800 hr (single administration) or at 0800 and 1400 hr (double administration). The animals were monitored during the farrowing process. The time interval from the first administration of PGF2α to the onset of parturition was compared between groups. The proportion of sows that farrowed within 32 hr of induced parturition was higher in the double administration group than in the single administration group (100 vs. 84.4%, P=0.046). The duration of farrowing was higher in single administration sows than in control (241.1 vs. 169.5 min, P=0.004) and tended to be higher than in double administration sows (241.1 vs. 190.3 min, P=0.088). Birth interval of piglets born after double administration of PGF2α was shorter than those born after a single administration (14.6 and 20.1 min, P=0.024). In sows, the induction of parturition using a double administration of PGF2α reduces variation in gestation length and significantly increases the proportion of sows with an early response to PGF2α.

Treatment Approach of Different Hormonal Therapy for Repeat Breeding Dairy Animals in Nepal

Repeat breeders are the animals with more than 3 to 4 inseminations after calving having regular cyclicity yet failed to conceive. Therefore, it is considered as one of the most emerging and frustrated reproductive disorders among dairy herds in Nepal that hinders favorable productivity and causes heavy economic losses to the livelihood of the farmers. We performed a systemic review to be acquainted with hormonal therapy as a treatment of repeat breeding. The aim of the present review is to summarize the current information about the ongoing methods in the treatment of repeat breeders. Based on the review of articles, it was found that gonadotropin-releasing hormone (GnRH) administration improved the conception rate in repeat breeder buffaloes and cows bearing dominant follicle in the ovary. In repeat breeder buffaloes and heifers with predominant corpus luteum and adequate body condition score (BCS), administration of PGF2α increased the pregnancy rates. Conception rate with Ovsynch protocol (GnRH-PGF2α -GnRH-TAI) usually was improved when initiation of program done during mid-diestrus i.e. days 5-12 of estrus cycle. Exogenous progesterone administration resulted in increased serum progesterone level during PGF2α injection that usually improves fertility of lactating dairy cows. In conclusion, hormonal treatment is considered to be most effective treatment to mitigate the problems of repeat breeding syndrome in Nepal. However, the first step of treatment involves good care, nutrition, better oestrus detection, timely insemination, periodic deworming to control parasite load and management of mating with bulls.

Study on the hormonal profile in crossbred dairy cows in relation to repeat breeding at Baghabari milk shed areas, Bangladesh

Repeat breeding (RP) is a one of the most significant problem in dairy cattle because it increased production cost of insemination, treatment, feed, labor and management and also increased calving interval with decreased milk production. This study was conducted at the different Bathan areas of Shahjadpur Upazila under Sirajgonj district. The total of 30 repeat breeder cows was selected randomly to determine their reproductive hormonal profile before and after synchronization at the selected areas and repeat breeder cows were marked by ear tag and collected breeding history of each individual cow. All experimental RP were synchronized by the administration of GnRH (day- 0), PGF2α (day-7) and Artificial Insemination (AI) with GnRH (day-9). Blood samples were collected before and after synchronization during standing heat period of estrous cycle of each cow. The total experiment was done and analyzed in the laboratory by using endocrine detection kits (Mono LelacR USA). This present study revealed that the level of luteinizing hormone (LH), follicle stimulating hormone (FSH), progesterone (P4) were significantly differed between repeat breeder cows and synchronized repeat breeder cows. These findings clearly indicated that reproductive hormonal aberrations might be one of the major causes of repeat breeding in Baghabari milk shed areas.&#x0D; Asian Australas. J. Biosci. Biotechnol. 2018, 3 (3), 237-240

Intra-ovarian dynamic blood flow in pseudopregnant rabbits during prostaglandin F2α-induced luteolysis.

In the present study, we evaluated the dynamic changes of intra-ovarian blood flow, by real-time colour-coded and pulsed Doppler ultrasonography, as well as the immunopresence of prostaglandin F2α (PGF2α) receptor (FP) and peripheral plasma progesterone concentrations in pseudopregnant rabbit after PGF2α treatments at either early- (4days) and mid-luteal (9days) stages. During the pre-treatment observation interval of one hour, the ovarian blood flows showed a fluctuating pattern. Independently of luteal stage, PGF2α administration caused a fourfold decline in the blood flow within 40min that was followed 50min later by a reactive hyperaemia that lasted several hours, while the resistive index showed an opposite trend. Twenty-four hour later, the blood flow was one half that measured before PGF2α injection. At day 4 of pseudopregnancy, PGF2α did not affect peripheral plasma progesterone concentrations, but at day 9, it caused functional luteolysis as progesterone levels declined 6hr later to reach basal values after 24hr. The changes in the ovarian blood flows of pseudopregnant rabbits receiving PGF2α were accompanied by simultaneous changes in the resistance index. This biphasic response in the blood flow and vascular resistances likely reflects reactive hyperaemia following vasoconstriction. By immunohistochemistry, strong positive immune reaction for FP was detected in the cytoplasm of endothelial cells of ovarian arteries, veins and capillaries. In conclusion, these results suggest that PGF2α could acutely regulate the ovarian blood flow of pseudopregnant rabbits, even if there is no evidence of a blood flow reduction anticipating luteolysis.

The stimulatory effect of subluteal progesterone environment on the superovulatory response of passive immunization against inhibin in goats

The objective of the current study was to investigate the effect of subluteal progesterone environment on the efficacy of the ovarian responses in goats passively immunized against endogenous inhibin. Twelve cycling female Shiba goats were synchronized using two doses of prostaglandin F2α 11 days apart. After detection of ovulation (D0, by ultrasonography), goats were randomly assigned into 2 groups: (1) Subluteal P4 group (SLP; n = 6), treated with a previously once-used controlled intravaginal progesterone-releasing device (ou-CIDR) intravaginal from D 6 to D 12 concurrently with a luteolytic dose of PGF2α at D6 (2) Normal Luteal P4 group (NLP; n = 6), had neither ou-CIDR nor PGF2α. In both groups, goats were treated with an intravenous injection of 10 ml of inhibin antiserum at D10. After that, another luteolytic dose of PGF2α was administrated to goats in both groups at D12, and withdrawal of ou-CIDR in the SLP group. Detection of estrous behavior was checked again 24 h following PGF2α administration and or ou-CIDR withdrawal at 8 h intervals with a teaser buck. The follicle populations ≥4 mm in each goat were monitored through transrectal ultrasonography daily from 1 day after inhibin antiserum administration (0 h) and continued until ovulation had been detected (disappearance of large dominant follicles by ultrasonography). In addition, a repeated ultrasonographic scanning was performed 7 days after ovulation, and the ovulation rate had been estimated by counting the number of observed corpora lutea by ultrasonography. Blood samples were collected for measurement of plasma circulating inhibin binding activity, FSH, LH, estradiol (E2), and progesterone (P4) in both groups. Results revealed significant increases in maximum diameter of the preovulatory follicles (5.92 ± 0.17 mm vs 5.31 ± 0.26 mm; P < 0.05), and the mean maximum number of follicles ≥ 4 mm in diameter (18.45 ± 3.40 vs 12.15 ± 6.21; P < 0.05) in the SLP group compared with that of the NPL group. No significant differences were observed between both groups in term of inhibin binding activity %, and FSH. Following immunization, significant increases in the concentrations of circulating LH (at 72 h) and E2 (from 48 to 84 h) were noted in the SLP group as compared with the values obtained from the goats in the NLP group. Moreover, significant increases in ovulation rate (13.85 ± 1.40 vs 5.67 ± 2.10; P < 0.01) and subsequent P4 concentrations (from 192 to 288 h) were found in the SLP group as against those of the NLP group. In conclusion, maintaining a subluteal P4 environment concurrently with passive immunization against endogenous inhibin may improve the superovulatory response in female Shiba goats.

Comparison of luteolysis and timed artificial insemination pregnancy rates after administration of PGF2α in the muscle or the ischiorectal fossa in cattle

Prostaglandin F2α (PGF2α) is commonly injected intramuscularly (IM) in female cattle in synchronization protocols. A novel site for administration of PGF2α that improves beef quality assurance is the ischiorectal fossa (IRF). The objective of this study was to determine whether administration of PGF2α in the IRF results in a similar physiological response to an intramuscular injection.Yearling angus-cross heifers (n = 112) were blocked by weight and randomly assigned within blocks to be injected with 5 mL PGF2α either IM in the neck or in the IRF. Blood samples taken at 0, 8, 16, 24, 36, and 48 h post-injection were analyzed for serum progesterone concentration using a radioimmunoassay. Progesterone concentration curves for each heifer were plotted to determine luteolysis. The median times to luteolysis for neck and IRF injections were 18.1 h and 20.0 h, respectively (p = 0.06).Angus cross commercial beef cows (n = 1471) at least 30 days post-partum were blocked by age and randomly assigned within blocks to be injected with 5 mL PGF2α either IM in the neck muscle or in IRF as part of a 7-Day CO-Synch + CIDR synchronization protocol. Pregnancy diagnosis was performed via ultrasound at 60 days post insemination. Results were analyzed with Proc Glimmix (SAS). Pregnancy rates for neck and IRF injections were 52.6% and 57.2%, respectively (p = 0.06).In summary, injection of PGF2α in the IRF for synchronization of estrus and luteolysis did not differ from IM injection. Utilizing the ischiorectal fossa as an injection site for PGF2α may serve as an alternative that more closely aligns with beef quality assurance.

Role of progesterone concentrations during early follicular development in beef cattle: II. Ovulatory follicle growth and pregnancy rates

Two experiments were conducted to investigate the role of relatively lesser and greater progesterone (P4) concentrations during early follicular development on ovulatory follicle growth and pregnancy rate in beef cattle. In Experiment 1, time of ovulation was synchronized with the 5 d CO-Synch + CIDR (Controlled Internal Drug Release) program in multiparous cows (n = 241). Six days after the 2nd GnRH injection of the pre-synchronization program (d 0), ablation of follicles ≥ 5 mm in the ovaries was performed and cows were assigned to receive either a previously used CIDR and 2x-25 mg PGF2α doses 8 h apart (LoP4), or a new CIDR (HiP4). On d 5, CIDR were removed from all cows, 2x-25 mg PGF2α were administered, and estrous detection tail paint was applied. Timed artificial insemination (TAI) was performed on d 8. On d 5, P4 concentrations were greater (P < 0.01) in the HiP4 (4.9 ± 0.13 ng/mL) than LoP4 (1.0 ± 0.06 ng/mL) treatment group. Conversely, d 5 estradiol (E2) concentrations and follicular diameter were greater (P < 0.01) in the LoP4 (5.0 ± 0.23 pg/mL and 8.9 ± 0.20 mm) than HiP4 (1.5 ± 0.12 pg/mL and 7.4 ± 0.15 mm) treatment group. Follicular diameter at TAI (12.0 ± 0.12 mm, Table 1) and TAI pregnancy rate did not differ (P > 0.10) between treatment groups. In Experiment 2, a new follicular wave was induced with estradiol benzoate on d -7, and cows (n = 275) were assigned on d 0 to receive 25 mg PGF2α and either have the CIDR replaced with a new CIDR (HiP4) or the used CIDR was left in place (LoP4).Furthermore, all cows received GnRH on d 0. The CIDRs were removed from all cows on d 5 and two doses of -25 mg PGF2α were administered. Estrous detection combined with AI 12 h later (Estrus-AI) was performed for 60 h after CIDR removal with TAI coupled with GnRH administration at 72 h if estrus was not detected. The concentrations of P4 on d 5 were greater (P < 0.01) in the HiP4 (2.8 ± 0.10 ng/ml) than LoP4 (1.7 ± 0.05 ng/mL) treatment group. For cows that were detected in estrus after PGF2α administration, estrous response (83.5%) and interval to estrus (55.0 ± 0.5 h) did not differ between treatment groups. Pregnancy rate (combined Estrus-AI and TAI) that resulted from breeding at the time of the synchronized time of estrus was similar between treatment groups (HiP4: 77.1%; LoP4: 82.3%). In conclusion, differences in P4 concentrations during early follicular development do not effect pregnancy rate in beef cows when the cows are inseminated at the time of a synchronized estrus if the cows have similar intervals of proestrus.

Karayaka Koyunlarında Gonadotropin Salgılatıcı Hormon Uygulamasının (GnRH) Ovaryum Aktivitesi Üzerine Etkisi

Bu çalışmanın amacı, Karayaka koyunlarında dönem içi gonadotropin salgılatıcı hormon (GnRH) uygulamasının kızgınlık gösterme oranı ve ovaryum aktivitesi üzerine etkisini belirlemektir. Çalışmada en az iki doğum yapmış ve benzer vücut ağırlığına sahip 20 baş Karayaka ırkı koyun hayvan materyali olarak kullanılmıştır. Deneme başında tüm koyunlara ovaryum üzerinde mevcut olabilecek olan korpus luteum (CL)‘un yıkımı için 1 ml PGF2α kas içi enjekte edilmiştir. PGF2α uygulamasından 9 gün sonra ise koyunlar rastgele iki eşit gruba ayrılmıştır. Birinci gruptaki koyunlara (n=10) 40 mg flugestone asetat içeren sünger vajina içine yerleştirilmiştir ve bu uygulamadan 14 gün sonra süngerler çıkartılarak, 1 ml PGF2α kas içi enjekte edilmiştir. PGF2α enjeksiyonunu takiben 36 saat sonra 1 ml GnRH kas içi enjekte edilmiştir. İkinci gruptaki koyunlara (n=10) ise mevcut olabilecek olan korpus luteum (CL)‘un yıkımı için 1 ml PGF2α kas içi enjeksiyonun dışında herhangi bir uygulama yapılmamış olup, bu grup çalışmamızın kontrol grubunu oluşturmuştur. Bu işlemleri takiben her iki gruptaki bütün koyunlar Karayaka koçuna verilmiş ve 72 saat boyunca kızgınlık gösteren koyunlar belirlenmiştir. Kızgınlık taramasının sonunda bütün koyunlar kesime sevk edilmiş ve her iki ovaryum üzerindeki küçük (1-3 mm), büyük (&gt;3 mm) ve toplam folikül sayısı ve CL sayısı belirlenmiştir. GnRH uygulaması yapılan koyunlar (%100) kontrol grubundaki koyunlara (%70) göre daha yüksek oranda kızgınlık göstermişlerdir. GnRH uygulaması yapılan koyunların her iki ovaryumundaki küçük ve toplam folikül sayısının ve CL sayısının, kontrol grubundaki koyunlarınkinden daha yüksek olduğu tespit edilmiştir. Ancak büyük folikül sayısı bakımından deneme grupları arasında bir farklılık tespit edilmemiştir. Sonuç olarak bu çalışmada mevsim içi dönemde Karayaka koyunlarında sünger uygulaması sonrasındaki GnRH uygulamasının kızgınlık gösterme oranını yükselttiği ve ovaryum aktivitesini arttırdığı tespit edilmiştir.

Comparison of two alternate PGF2α products in two estrus synchronization protocols in beef heifers.

Two experiments were conducted to evaluate the effects of a high concentrate, s.c. PGF2α compared with a conventionally concentrated, i.m. PGF2α in estrus synchronization protocols for heifers. In Exp. 1, 869 Angus-based beef heifers were enrolled at 8 locations. All heifers were exposed to the 7-d CO-Synch + controlled internal drug release (CIDR) estrus synchronization protocol. On day 7 of the protocol heifers received 100 µg of GnRH i.m., and a CIDR insert for 7 d. On day 0, at CIDR removal, estrous detection patches were applied to heifers and, within location, heifers randomly received 1 of 2 PGF2α treatments: 5 mL of Lutalyse i.m. (CONTROL; n = 434) or a 2 mL of Lutalyse HighCon s.c. (HiCON; n = 435). A second GnRH injection was administered at 54 ± 2 h and heifers were fixed-time AI (TAI). Heifers were evaluated for estrous activity at TAI by determining the activation of estrous detection patches. Pregnancy rates to AI (PR/AI) were diagnosed by transrectal ultrasonography between 35 and 55 d after TAI. The percentage of heifers exhibiting estrus between day 0 and TAI did not differ (P = 0.68) between CONTROL and HiCON treatments (47 vs. 46 ± 4%, respectively). Additionally, PR/AI were similar (P = 0.65) between CONTROL and HiCON treatments (46 vs. 45 ± 3%). In Exp. 2, 190 Angus-based beef heifers were enrolled at 2 locations. Heifers were exposed to the melengestrol acetate (MGA)-PGF2α protocol where they were offered 0.5 mg MGA per day from days 1 to 14. On day 33, heifers were randomly assigned to receive CONTROL (n = 95) or HiCON (n = 95) treatment, and estrous detection aids were applied. Heifers were exposed to AI 12 h after detection of estrus. Heifers not detected in estrus at location 1 received a second PGF2α injection 6 d after the initial PGF2α injection and were placed with fertile bulls. Heifers at location 2 that did not express estrus were administered 100 µg of GnRH i.m. and exposed to TAI 96 h after the initial PGF2α injection. Transrectal ultrasonography was used to diagnose PR/AI between 51 and 57 d after the initial PGF2α injection. The percentage of heifers exhibiting estrus during the estrus detection period was similar (P = 0.40) between CONTROL and HiCON treatments (82 vs. 87 ± 4%). Furthermore, PR/AI were similar (P = 0.62) between CONTROL and HiCON treatments (60 vs. 65 ± 5%). In summary, the 2 concentrations and corresponding routes of administration of PGF2α were similar in efficacy at synchronizing estrus in beef heifers.

THE EFFECTIVENESS OF PROGESTERONE HORMONE OR PGF2α AND hCG APPLICATION TO INCREASE REPRODUCTIVE EFFICIENCY OF POSTPARTUM OF ANESTRUS PE GOATS

This study aimed to improve reproductive condition of postpartum anestrus of Etawa crossbreed (PE) goats using PGF2α hormone or progesterone (controlled internal drug release/CIDR-G) and improve pregnancy success from artificial insemination (AI) with human chorionic gonadotrophin (hCG) hormone administration. Administration of progesterone increased estrus by 100%, which was higher than the 70% produced from prostaglandin F2 alfa (PGF2α) administration. Estrus onset in CIDR group (35.80±13.33 hours) was faster than PGF2α group (45.6±9.2 hours). Clinical signs of vulva (redness and swollen) were more intense in CIDR-G group (80% and 70%, respectively) compared to PGF2α group (70% and 57%, respectively). Estrus duration in PGF2α group (52.17±3.34 hours) was longer than CIDR-G group (49.61±3.56 hours). Pregnancy success in group given hCG was 66.7% while in non-hCG group was 50%. In conclusion, CIDR-G and PGF2α administration is effective to induce estrus of postpartum anestrus PE goats. Administration of hCG at the onset of estrus is effective to improve pregnancy success.

Response of lactating dairy cows with or without purulent vaginal discharge to gonadotropin-releasing hormone and prostaglandin F2α.

Purulent vaginal discharge (PVD) is a common uterine disease in dairy cattle that has negative effects on reproductive performance. Reproductive management programs that synchronize ovulation use gonadotropin-releasing hormone (GnRH) to induce ovulation and prostaglandin F2α (PGF2α) to induce luteolysis. The objectives of this study were to evaluate ovarian response to treatment with GnRH and the odds of bearing a corpus luteum or being inseminated in dairy cows with or without PVD. Another objective was to determine the hazard of insemination after administration of PGF2α in dairy cows with or without PVD. Primiparous (n = 291) and multiparous (n = 402) cows were evaluated for PVD using a Metricheck device at 46 ± 3 and 35 ± 3 days in milk (DIM) (study day 0), respectively. On study day 14, primiparous (n = 107) and multiparous (n = 197) cows were treated with GnRH and subsequent ovulation was recorded. Primiparous (n = 178) and multiparous (n = 368) cows not inseminated by study day 21 were administered PGF2α and response to PGF2α treatment was determined by detection of estrus. Furthermore, cows were categorized by the presence of a CL or being inseminated by study days 14, 21, and 35. Overall prevalence of PVD was 28.5% and 13.4% for primiparous and multiparous cows, respectively. Projected 305-d milk yield was less (P < 0.01) in PVD+ multiparous cows compared with PVD- multiparous cows, however, no (P = 0.26) difference was detected between primiparous PVD+ and PVD- cows. Ovulatory response to GnRH treatment was 51.8% and 47.8% for primiparous and multiparous cows, respectively. Primiparous PVD- cows tended (P = 0.06) to be less likely to ovulate to GnRH than primiparous PVD+ cows, whereas multiparous PVD+ cows were less (P = 0.04) likely to ovulate to GnRH than PVD- multiparous cows. The odds of bearing a corpus luteum or being inseminated by study days 14, 21, or 35 was not associated with PVD in primiparous cows. In contrast, the odds of bearing a corpus luteum or being inseminated by study days 14 and 21 was (P ≤ 0.03) associated with PVD in multiparous cows, but not (P = 0.11) on study day 35. Hazard of insemination after PGF2α was not (P ≥ 0.38) associated with PVD in primiparous or multiparous cows. Purulent vaginal discharge is associated with response to treatment with GnRH in dairy cattle. Purulent vaginal discharge might negatively affect reproductive management programs that use GnRH to induce ovulation.