Estrus Synchronization In Ewes Research Articles

Effect of Different Protocols of Estrus Synchronization on Vaginal Microflora with Antibiotic Susceptibility to Bacteria

To investigate the effect of different protocols for estrus synchronization in ewes on the vaginal tract bacteria and evaluate the sensitivity of bacteria to different antibiotics. Sixteen local breed ewes were allocated to four groups, each containing four. Group A: ewes treated with sponges for 10 days; Group B ewes treated with CIDR for 10 days; Group C ewes treated with sponges for 14 days and finally Group D ewes treated with CIDR for 14 days. Sterile swaps were taken from the vaginaʼs mucous before insertion of sponge or CIDR and after removing it for each group. Vaginal swabs from synchronized ewes were obtained from the vaginaʼs mucous before insertion of sponge or CIDR and after removing it for each group to use in different bacteriological tests. The results showed that the most dominant bacteria were E-Coli 7/7 (100%), and Staphylococcus aureus (71%) before insertion, while in group A, the percentage was 75% and 100% for E-Coli only in group B and group C respectively. According to E-coli, the results showed that it was more sensitive to Doxycycline (3.36±0.3), Enrofloxacin (3.23±0.2), and Ciprofloxacin (3.18±0.3) figure (2). Also, Staphylococcus aureus was sensitive to Doxycycline (3.32±0.4), Enrofloxacin (3.17±0.3), and Ciprofloxacin (3.12±0.3). It was concluded that the E-coli was the most prominent microflora in the vagina in ewes before and after insertion of sponges. Doxycycline, Enrofloxacin, and Ciprofloxacin are the most effective antibiotics against E-coli and Staphylococcus aureus.

SYNCHRONIZATION OF ESTRUS IN EWES

A group of 15 Awasi ewes were inserted with intravaginal sponges of Veramix plus which were removed thirteen days later. Immediately after removal of the sponges, they were injected with 500 IU of FSH intramuscularly. All ewes were came to estrus within 2-3 days after injection. They were serviced, then, after completing a successful pregnancy, all ewes had twin lambs. : This trial indicates the success of estrus synchronization in ewes.

Comparing CIDR with progesterone injections and eCG with human recombinant FSH for synchronizing estrous cycle in ewes.

It is desirable in estrus synchronization in sheep to avoid intravaginal devices and to shorten the program from 14 to 6 days. Moreover, replacement of eCG with safe, cheap, and efficient gonadotropin is in worldwide demand. This study investigates the possibility of replacing eCG with human recombinant FSH (hrFSH) and CIDR with progesterone injections for estrous synchronization in ewes. Assaf and Lacaune ewes (n=170) were divided into two groups and synchronized with either progesterone injections for 6 days or CIDR for 14 days. Ewes assigned in the injection group, received progesterone (37.5 mg; SC) and GnRH analogue (7.5 µg Alarelin acetate; IM) on day 0 of the experiment. On days 3 and 6, ewes received 25 and 12.5 mg progesterone (SC), respectively. On day 6, ewes in both groups received prostaglandin F2α (250 µg Cloprostenol; IM), and were divided into two subgroups to receive either hrFSH (75 IU Follitropin alfa; SC) or eCG (400 IU; IM). On day 7, fertile rams were introduced to ewes for 21 days. Data were analyzed using GLM and Glimmix. There was no difference in the respective lambing rates, prolificacy, and fecundity between CIDR (71.1, 1.63, and 1.16%) and injections (66.7, 1.55, and 1.03%); between eCG (71.4, 1.60, and 1.14%), and hrFSH (66.3, 1.58, and 1.05%, P>0.05). In conclusion, 6-day progesterone injection-based protocol produced similar results to 14-day CIDR program and hrFSH could be an effective alternative for eCG during estrus synchronization in ewes.

Синхронизация на еструса при овце от Синтетична популация българска млечна чрез прогестаген и различни последващи третирания

The aim of the present study was to induce estrus synchronization in ewes after administration of progestagen for 12 days and various subsequent treatments (with FFA, GnRH analogue or no treatment) after cessation of its action. The experiment was conducted in August, 2022, with 27 sheep from the Synthetic Bulgarian Dairy Population. All ewes were treated with vaginal sponges, containing 30 mg FGA (duration of stay - 12 days) and the formation of experimental groups was according to follow-up treatment after sponge removal: I group - experimental animals were treated with 400 UI of PMSG at the time of removal of sponges. II group - the sheep were treated with 1 ml of GnRH analogue, containing busorelin acetate 0.004 mg/ml, 24 hours after sponge removal. III group – no treatment after sponge removal. The next parameters were studied: estrus synchronization rate, fertility and fecundity were studied. The estrus synchronization rate was the highest for I group - 100% and the lowest for II group - 66.67%. Fertility was highest in III group - 87.50%, and lowest in II group - 50.0%. Fecundity was highest in I group - 171.43%, while in other groups it was 133.33% and 128.57%, respectively, for II group and III group. Based on the obtained results, it could be concluded that GnRH analogue treatment, given solely 24 hours after sponge removal, didn’t have the synchronization effect as the classical follow- up treatment with PMSG. No follow-up treatment after sponge removal was better alternative that GnRH treatment.

Comparative evaluation of estrus synchronization protocols on reproductive performance and estrus behavior in Barbados Black Belly sheep.

Estrus synchronization of ewes has been accomplished using several protocols with various degrees of success in improving reproductive efficiency and obtaining the most effective protocol used in sheep farming. This study aimed to compare the effectiveness of three treatment protocols and to record the intensity and duration of estrus signs and pregnancy rate in Barbados Black Belly (BBB) sheep. Thirty-two primipara BBB ewes aged 18-24 months were equally divided into three treatment groups. T1: the ewes were injected intramuscularly with 2 mL Lutalyse (PGF2α) (10 mg) on days 0 and 10. T2: 1 mL Fertiline (50 μg; Gonadorelin acetate) on day 0 and 2 mL lutalyse (10 mg) on day 7. T3: 1 mL fertiline (50 μg) on day 0, 2 mL lutalyse (10 mg) on day 7, and 1 mL Fertiline (50 μg) on day 9. Estrus response was assessed using naturally mating rams and ewes. Pregnancy was determined using ultrasonography between 55 and 80 days after the last hormonal injection. The following estrus signs were noted: Swollen vulva, mucus discharge, sniffing, excitement, loss of appetite, mounting, and rapid tail movement. Of the expressed signs, swollen vulva was most frequent, whereas loss of appetite and mucus discharge were the least overt signs recorded. The estrus response (%), onset (%), and duration (h) in ewe synchronization of the three treatment protocols were 100%, 58.3 ± 23.4%, and 48.0 ± 18.2 h (T1), 100%, 61.7 ± 41.2%, and 45.0 ± 27.0 h (T2), and 37.5%, 32.1 ± 1.7%, and 29.2 ± 1.25 h (T3), respectively. The pregnancy rates were 87.5%, 87.5%, 37.5%, and 50.0% in T1, T2, T3, and T4, respectively. Prostaglandin F2α+PGF2α and GnRH+PGF2α synchronization protocols were more effective in the fertilization of BBB ewes with better expression of estrus signs compared with the GnRH+PGF2α+GnRH (OVS) protocol.

Development and evaluation of an injectable slow-release progesterone formulation for estrus synchronization in ewes out of the breeding season.

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

Comparative study of short term and long term protocols for progesterone based estrus synchronization in ewes during breeding season

The study was designed to compare the effect of length of progesterone treatment (6 d vs 10 d vs 14 d) on synchronization efficiency and fertility response in multiparous ewes. The crossbred ewes (30) were equally allotted to three groups designated as short (6 days), medium (10 days) and long-term (14 days) treatment. All the ewes were injected PGF2α 250 μg, intramuscularly 24 h before sponge removal. After the sponge removal ewes were kept with breeding rams for tupping upto 72 h. Although the onset of estrus was more precise in short and long term groups, however overall estrus response rate was highest in short treatment group (90%) followed by long treatment group (70%) and medium treatment group (60%). The pregnancy rates were non-significantly higher for short and medium treatment groups than long treatment group. The progesterone values in pregnant ewes, decreased significantly from day pre-treatment to day 0 followed by significant increase from day 0 to day 10, 17 and 35. In conclusion, short term (6 d) intravaginal progesterone treatment may replace the traditional long term treatment (14 d) for induction of estrous during breeding season. However, the results should be validated in larger number of animals before recommending the protocol.

The Effect of the Different Artificial Insemination Time Periods on the Pregnancy Rate of Sapudi Ewes

Brucellosis Artificial insemination is required to increase the reproduction rate in ruminant breeding. The artificial insemination success rate in sheep only reaches 47.6%, whereas the proposed ideal rate is 70%. One of the factors influencing the artificial insemination success rates in sheep is improper estrus detection, resulting in no fertilization. The present study aimed to determine the effect of different artificial insemination time periods on the pregnancy rates of Sapudi ewes. The research design was based on a completely randomized design. A total of 20 female Sapudi sheep were divided into four treatment groups with five repetitions (for each group). In addition, the observed variables were artificial insemination time in Sapudi ewes. Estrus synchronization in ewes was conducted by injecting PGF2α. The results of the research indicated that ewes subjected to artificial insemination 6, 12, 18, and 24 hours after estrus had a pregnancy rate of 20%, 100%, 60%, and, 60%, respectively. It can be concluded that the time differences in artificial insemination significantly influence the pregnancy rate in Sapudi ewes’.

Non Hormonal Induction of Oestrus in Nellore Ewes

A non hormonal induction of synchronization of estrus in ewes of Nellore breed, in two seasons June-July and September – October, covering 39980 and 42370 ewes respectively, spread over 2015 to 2019, with micro minerals (Bioplex High Seven), after onset of monsoon and deworming the sheep, appropriate to the season and type of prevailing parasitic infection, were studied. All the supplemented ewes came to estrus within a week, and were bred with stud rams. After the completion of gestation period all the ewes were lambed within a week uniformly. This may be due to elimination of stress due to environment, nutrition, parasites, replenishment of minerals and stimulation of folliculogenesis with Bioplex. The current extension method induction of estrus is safe, economical, easy to adopt and eco-friendly.

Hormonal Protocols for the Synchronization and Induction of Synchronized Estrus in Dairy Ewes Kept under Tropical Conditions

Background: Lacaune is an important sheep breed and shows reproductive seasonality which affects dairy product supply. The most common hormonal protocols are based on progesterone-releasing devices in order to reach reproductive activity. Due to international consumer demand for natural, green, and clean methods, such issues encourage the minimal or absent use of synthetic hormones in livestock. In this sense, the present study tested the efficiency of induction and estrus synchronization protocols in lacaune ewes, considering: application interval of synthetic prostaglandin at the breeding season; length of synthetic progesterone exposure; and eCG dose at the outbreeding season.Materials, Methods & Results: In study 1, 52 ewes were submitted to estrus synchronization protocol using two doses of d-cloprostenol 7 or 9 days apart. In study 2, 47 ewes were submitted to estrus induction protocol using an intravaginal device containing 60 mg of medroxyprogesterone acetate maintained for 6, 9, or 12 days. In study 3, 46 ewes were submitted to synchronized estrus induction protocol using intravaginal progesterone device for six days. On the fifth day, d-cloprostenol and 300 IU or 400 IU of eCG were administered. For all studies, signs of estrus beginning/ending were recorded and natural mating was performed. After 30 days, transrectal ultrasound was performed for pregnancy diagnosis. In study 1, groups presented similar rate of estrus behavior (78.8%) and pregnancy (average 75.6%). Meanwhile, compared to G9days (37.8 ± 7.2 h), interval between the second dose of prostaglandin and beginning of estrus was smaller in G7days (31.5 ± 7.8 h). No difference was found among variables studied in study 2 (P > 0.05), nevertheless the SD for the estrus duration was shorter (P < 0.05) in G6days and G12 days when compared with the G9days. Equally, the SD for the interval between sponge withdrawal and beginning and end of estrus was shorter (P < 0.05) in G12days when compared with the G9days. The pregnancy rate, at 30 days, was 71.1%. With regards to study 3, there was no effect of parturition order on sexual behavior between experimental groups (P > 0.05). Equally, no differences were found between variables studied (P > 0.05). The pregnancy rate was 52.2% and number of concepts was 1.5 ± 0.6.Discussion: This paper provides important data on estrus synchronization protocols in dairy sheep kept under tropical conditions. In study 1, both d-cloprostenol protocols were efficient in synchronizing estrus of dairy ewes and reached a fair pregnancy rate. Therefore, it was demonstrated that a d-cloprostenol treatment was a viable alternative to a progestogen treatment, commonly used for estrus synchronization in ewes even during the breeding season. In study 2, all protocols (6, 9 and 12 days of exposure to synthetic progesterone) were efficient in inducing and synchronizing estrus in dairy ewes during the outbreeding season. Therefore, considering not only its efficiency but also the reduction of damage to the vaginal microbiota, the authors strongly encourage the use of the 6-day synthetic progesterone exposure protocol. The third study showed that it is possible to reduce the eCG dose (400 to 300 IU) in dairy ewes while maintaining protocol efficiency, saving 25% of the farmer spending, and avoiding high doses that are related to immune resistance and lower progressive fertility response to IA. In conclusion, the present study verified the efficiency of different hormonal protocols applied for dairy Lacaune ewes kept under tropical conditions, demonstrating that it is possible to decrease: (i) the interval between prostaglandin applications for 7 days apart during the breeding season; (ii) the length of exposure to synthetic progesterone for 6 days; and (iii) the eCG dose to 300 IU during the outbreeding season.

Efficacy of controlled internal drug release (CIDR) treatment durations on the reproductive performance, hormone profiles, and economic profit of Awassi ewes

This study was conducted using 80 multiparous Awassi ewes during the breeding season to compare the effects of controlled internal drug release (CIDR) treatment durations on ewe reproductive performance, hormone profiles, and economic production measures. Ewes were evenly allotted to one of various CIDR treatment durations (3, 6, 9, or 12 d) in four groups (CIDR3, CIDR6, CIDR9, and CIDR12 (control), respectively). The ewes in all groups were injected with 300 IU of equine Chorionic Gonadotropin (eCG) at the time of withdrawal. Blood samples were collected at the time of CIDR insertion and withdrawal, as well as at the time of insemination to measure serum estradiol (E2) and progesterone (P4) concentrations. Timed insemination was performed at 48 h post CIDR withdrawal. The heat detection rate was significantly (P < 0.05) highest in CIDR12 and CIDR9 (100% and 84.21%, respectively). The total pregnancy rate was significantly (P < 0.05) higher in CIDR9 and CIDR6 (68.4% and 60%, respectively) than in CIDR3. Additionally, fecundity was significantly (P < 0.05) lowest in CIDR3. At insemination, the P4 level was significantly (P < 0.05) lower in CIDR9 and CIDR12 than in the other groups. At insemination, the E2 level was higher (P < 0.05) in CIDR6 followed by that in CIDR3 and CIDR9, and then in CIDR12. The total variable cost, total cost, the return and net profit were higher in CIDR6 than in other groups. In conclusion, although use of CIDR for 6, 9, and 12 d is efficient to synchronize estrus in ewes with similar reproductive performance, CIDR use for 6 d provided higher return and net profit than that for 9 or 12 d. CIDR use for 3 d is inefficient for estrus synchronization in ewes.

Efficacy of anti-microbial agents on vaginal microorganisms and reproductive performance of synchronized estrus ewes

Objective: To isolate and identify microflora and fungal species at different phases during estrus synchronization of ewes and estimate their prevalence; compare the effectiveness of antimicrobial administration to intravaginal sponge on the changes in the vaginal microorganisms and reproductive performance. Methods: Sixty Egyptian ewes were allocated into three equal groups (G: 1, 2 and 3). G1 was inserted with vaginal sponge containing medroxy- progesterone acetate and served as control; without antimicrobial additive. The other two groups were treated as G1, but sponges were previously injected with ciprofloxacin (G2), while sponges of G3 were injected with ciprofloxacin and clotrimazole. Vaginal swabs were collected from each treated ewe, prior sponge insertion, at sponge withdrawal and 48 h later for microbiological investigation and bacterial count. On the day of sponge removal, 300 IU/eCG was administered for each treated ewe. The identified bacterial strains before sponge insertion were tested for sensitivity with antimicrobial disks. Results: Bacterial isolates before sponge insertion were more sensitive to ciprofloxacin. Frequencies of ewes in estrus; the interval from sponge withdrawal to onset estrus and the duration of estrus were statistically similar among treated groups. The pregnancy rate in G2 (100.0%) was higher than G1 (66.7%) and G3 (82.4%). The total bacterial count before sponge insertion was similar between all treatments and increased significantly in all groups on the day of sponge withdraw. The prevailing bacteria on D0, D14 and 48 h after sponge removal for all treated groups were Staphylococcus spp. followed by Escherichia coli. Regarding to fungus species, percentages of isolation increased from 5.00% (before sponge insertion) to 100.00% and 88.89% at sponge withdraw for G1 and G2, respectively. In G3, the fungus was declined from 10% (before sponge insertion) to 5% (at sponge removal). Conclusions: The concomitant treatments by antimicrobial to the vaginal sponge which used for estrus synchronization in ewes can improve reproductive performance.

REPRODUCTIVE PERFORMANCE OF MORADA NOVA EWE SUBJECTED TO ESTRUS INDUCTION BY MALE EFFECT

This study aimed to evaluate the reproductive performance of crossbred sheep (New Address) nulliparous, primiparous and pluriparous, subjected or not to the male effect. There were used 79 ewes and two rams (one vasectomised ram – teaser ram) and a breeder). In the first year, the females were subjected to the male effect (ME: male effect), in the following year, there has been no application of this method (AME: absence of male effect). Ewes subjected to ME showed a higher synchronization (P &lt;0.05) compared to AME females. Nulliparous and primiparous ewes subjected to ME exhibited a higher synchronization, in relation to ewes in the absence of male effect. When specified by birth order, there were superior results (P &lt;0.05) within the same method (AME) for prolificacy index and twinning rate for pluriparous females relative to nulliparous and primiparous. There were also significant differences (P &lt;0.05) for the use of the male effect, but with superiority of pluriparous and primiparous females when compared to nulliparous. Between the methods, ME primiparous females (72.22%) were superior (P &lt;0.05) to AME ewes (33.33%) for twinning rate. Thus, it can be concluded that the male effect is feasible for estrus synchronization in ewes up to the first lambing birth, besides possibly causing better ovulation rate, due to better results of twinning rate and prolificacy index.

Estrus synchronization schemes and application efficacies in anestrus lanzhou fat-tailed ewes

ABSTRACTThis study aims to investigate the estrus efficacy of FIS (fluorogestone intravaginal sponges)/eCG (equine chorionic gonadotropin) and cloprostenol treatments to establish the optimum protocols for estrus synchronization in ewes. Forty-two ewes were assigned into groups A (FIS/eCG group) and B (CLO (cloprostenol) group). Each group was randomly divided into three subgroups (n = 7) according to the dose of eCG (ECG1, ECG2 and ECG3) or cloprostenol (CLO1, CLO2 and CLO3). The estrus rates, lambing rates and average litter sizes were accounted. Serum concentrations of progesterone (P4), follicle-stimulating hormone (FSH) and luteinizing hormone were determined. Selected optimum schemes were employed in 636 ewes in four sheep farms. Estrus rates of groups A and B were 85.72% and 57.14%. Estrus onset times (EOTs) were 53.91 ± 12.26 and 46.41 ± 4.65 h for groups A and B. EOT of ECG1 was longer than that of CLO3 (P < .05). Lamb numbers, lambing rate and litter size of group B were lower than those of group A. The maximum and minimum lambing rates were calculated in ECG3 and CLO1 (157 vs. 57). On day 11, higher P4 values (P < .05) were determined of ECG3 and CLO1 compared to CLO2 and CLO3 subgroups. FSH concentration of ECG1 was significantly higher than that in group B (P < .05). Application results showed that estrus rate, pregnancy rate and lambing rates of ECG3 and CLO3 protocols were 95.97% vs. 70.91%, 91.37% vs. 88.89% and 149.87% vs 132.69% (P < .05), respectively. FIS/eCG and cloprostenol improved estrus synchronization. Injection of 400 IU eCG after FIS withdrawal was an optimum protocol for estrus synchronization of ewes.

Use of fluorogestone acetate sponges or controlled internal drug release for estrus synchronization in ewes: Effects of hormonal profiles and reproductive performance

This study was carried out using 300 multiparous Najdi ewes during breeding season to compare the effects of fluorogestone acetate (FGA) sponges and controlled internal drug release (CIDR) dispensers to synchronize estrus on reproductive performance and hormonal profiles. Ewes were equally and randomly allotted into group A (FGA) and group B (CIDR); intravaginal progestagen was administered for 14-day period with intramuscular administration of 600-IU eCG at withdrawal time. Estrus was detected using a vasectomized ram starting 12 hours after progestagen withdrawal and repeated every 12 hours up to 84 hours. Blood samples were collected at the time of progestagen withdrawal (0 hour), 24 hours, and 48 hours. Follicle-stimulating hormone, LH, estradiol, and progesterone serum concentrations were measured using commercial ELISA kits and microtitrimetric plates. Timed laparoscopic insemination was performed 48 hours after progestagen withdrawal. Pregnancy and the number of fetuses were diagnosed by ultrasonography on Day 23 after insemination and confirmed on Days 35 and 60. The results revealed that the retention, vaginal discharge, and drawstring breakage rates after progestagen removal were significantly (P ≤ 0.05) higher in the FGA group (94.00, 98.58, and 9.22, respectively) than those in the CIDR group. On the other hand, pregnancy, fertility, twinning rates, and fecundity were significantly (P ≤ 0.05) higher in the CIDR group (77.86, 75.57, 34.34, and 1.02, respectively) than in the FGA group. Estrus responses in FGA and CIDR groups increased gradually to attain their significantly (P ≤ 0.05) higher percentages after 48 hours of progestagen withdrawal (91.49 and 92.37, respectively); thereafter, they decreased. The overall estrus responses and prolificacy did not differ between the FGA and CIDR groups. Follicle-stimulating hormone was significantly higher in the FGA group at 24 and 48 hours after progestagen withdrawal, whereas LH was significantly higher in the CIDR group at 48 hours after progestagen withdrawal. Estradiol and progesterone were significantly higher in the CIDR group at 0, 24, and 48 hours after progestagen withdrawal. These results indicated that although FGA and CIDR devices are efficient in synchronizing estrus in ewes, CIDR provided higher pregnancy, fertility, twinning rates, and fecundity than FGA.

Effect of progestin-impregnated sponges and progesterone injection on estrous appearance and pregnancy rate in Awassi ewes : comparative study

The objective of this study was to compare between two methods of estrus synchronization (progestin-impregnated vaginal sponges and intra-muscular (i.m) progesterone analogue injection ) and its influence on estrus occurance and pregnancy rate in Awassi ewes . Twenty eight ewes were equally divided into two groups ( A and B ) . Vaginal sponges impregnated with 20 mg of fluorogestone acetate ( FGA ) were used to synchronize the estrus in group A-ewes . The animals in group B were i.m. injected with 7 mg/day of progesterone analogue for 12 days . Post – withdrwal of sponges and at the end of progesterone injection , 500 IU of equine chorionic gonadotropin ( eCG ) were injected to both groups of ewes . The ewes were naturally mated with fertile rams ( 1 ram/group ) . the rams were left for 48 hrs. to ensure a good conception rate . The differences between two groups in estrus signs appearance lacked significance . On the other hand , group A – ewes exhibited higher ( P < 0.05 ) pregnancy rate than group B ( 78 VS 50% ) . In conclusion , estrus synchronization of ewes using vaginal sponges impregnated with FGA in conjuction with eCG treatment is effective and low-cost regime that achieved agood reproductive performance .

The effects of three methods of synchronization on estrus induction and hormonal profile in Kalkuhi ewes: A comparison study

Due to the importances of estrus synchronization in sheep reproduction and fertility, the present trial had been carried out to compare the three methods of estrus synchronization in ewes during breeding season. 60 cycling, fat-tailed Iranian Kalkuhi ewes were randomly allocated in equal numbers (n = 20) to 3 treatment groups. In two treatment groups, sponges (medroxyprogesterone) and controlled intravaginal drug-releasing devices (CIDR) were inserted for a period of 14 and 12 days respectively; also, another group received two injections of prostaglandin F2alpha (PGF2α) (with 11 days interval). At the time of CIDR/sponge removal and second PGF2α administration, all the animals received 400 IU of pregnant mare serum gonadotropin (PMSG). Blood samples were collected from all of the treated ewes, and progesterone (P4) and estradiol (E2) concentrations were measured by double-antibody enzyme immune-assay (ELA). Estrus synchronization by CIDR was as effective as Sponge and PGF2α treatments; also CIDR treated ewes exhibited overt signs of estrus earlier than those in other treatment groups. Following hormonal assays, P4 concentrations at first and second sampling and estradiol concentrations at second and third sampling were significantly different (P < 0.05). Key words: Ewe, reproduction, synchronization, estradiol, progesterone.

33 TIMING OF OVULATION AND ESTRUS IN LONG PROTOCOLS WITH OR WITHOUT CIDR REPLACEMENT IN Santa Inês SHEEP DURING BREEDING SEASON

Low levels of progesterone (P4) during synchronization of estrus in ewes can promote excessive growth of the follicles, resulting in large persistent and old ovulatory follicles. Timing of ovulation or the LH surge in relation to onset of estrus is also more variable with lower P4. These findings have been related to reduction in fertility in ewes (Viñoles et al. 2001 Theriogenology 55, 993-1004). To avoid prolonged periods of subluteal P4 concentrations, the aim of this study was to compare long protocols with or without CIDR replacement in Santa Inês sheep during the breeding season. Twenty-three adult ewes were divided into 2 groups (G-1CIDR, n = 11 and G-2CIDR, n = 12). Estrus was synchronized with a P4 device (CIDR™; Pfizer-New Zealand, Auckland, New Zealand) for 14 d. However, in G-2CIDR, the CIDR was replaced by a new one on Day 7. Doses of 2.5 mg of dinoprost, i.m. (Lutalyse™, Pfizer-New Zealand) were administered on Days 0 and 14. All ewes received 300 IU of eCG (Novormon™, Syntex, Buenos Aires, Argentina) on Day 14. Estrus detection was accomplished using a teaser ram starting 12 h after CIDR removal and was repeated 3 times a day for 4 d. Ultrasonographic exam was used every 8 h for 5 d after the end of the treatment to determine the moment of ovulation and the diameter of the ovulatory follicle. Data were analyzed by ANOVA using SAS software (chi-square and Tukey tests). The proportions of treated ewes that were detected in estrus did not differ statistically between groups (G-1CIDR: 90.9% and G-2CIDR: 100%). The interval from onset estrus to CIDR removal differed (P &lt; 0.05), between G-1CIDR (37.80 ± 8.02 h) and G-2CIDR (49.00 ± 9.16 h) groups. The frequency distributions of estrus in G-1CIDR ewes were 10, 70, 10, and 10% at 24, 36, 48, and 54 h, respectively, compared with 8.33, 8.33, 50, 8.33, and 25% at 30, 36, 48, 54, and 60 h after CIDR removal in the G-2CIDR ewes. All ewes ovulated at the end of the synchronization protocols. Ovulation occurred at 69.45 ± 10.00 h and 76.66 ± 15.04 h after the end of the protocols in G-1CIDR and G-2CIDR, respectively (P &gt; 0.05). The ovulation frequency distribution for ovulation time in G-1CIDR was 27.27, 54.54, 9.09, and 9.09% at 60, 68, 84, and 92 h, whereas in G-2CIDR, 8.33, 50, 16.66, 8.33, 8.33, and 8.33% ovulated at 60, 68, 76, 92, 100, and 108 h after the end of treatment. The interval between estrus and ovulation was 29.40 ± 9.97 h in G-1CIDR compared with 27.66 ± 11.71 h in G-2CIDR (P &gt; 0.05). The number of ovulations per animal and diameters of ovulatory follicles were 1.54 ± 0.82 and 6.95 ± 0.75 mm in G-1CIDR and 1.33 ± 0.77 and 7.00 ± 1.22 mm in G-2CIDR, respectively (P &gt; 0.05). These results showed a later onset of estrus in G-2CIDR. However, the treatment with CIDR replacement did not promote an effect on ovulation rate and number of ovulatory follicles. Both protocols showed efficiency. Funding support: FAPESP.

15 FERTILITY LEVELS IN EWES TREATED WITH MEDROXIPROGESTERONE ACETATE OR FLUOROGESTONE ACETATE SPONGES PLUS EQUINE CHORIONIC GONADOTROPIN IN DIFFERENT PHASES OF THE OESTRUS CYCLE

Commercial programs of estrus synchronization in ewes are performed with intravaginal sponges impregnated with synthetic progestagens such as medroxiprogesterone acetate (MAP) or fluorogestone acetate (FGA). Normally, sponges are placed deep into the vagina in cyclic females at different points in the estrus cycle. The aim of the present study was to compare fertility levels in ewes with estrus synchronized by using commercial sponges impregnated with either 60 mg of MAP (eMAP) or 30 mg of FGA (eFGA), placed during the follicular or luteal phase of the estrus cycle, plus eCG. A total of 273 sexually mature Merino ewes belonging to the same herd, aged between 2.5 and 5.5 years and clinically healthy, were scanned by transrectal ultrasonography with an 8-MHz probe (Aquila, Esaote-Pie Medical, Maastricht, The Netherlands) to visualize the ovarian status in the reproductive season. Ovaries without CL and follicles ≥4 mm were considered in the follicular phase, whereas ovaries with CL and follicles ≤4 mm were considered in the luteal phase. Thus, estrus synchronization was performed in 134 ewes treated with eMAP (Sincrogest, Ovejero Lab, Spain), of which 40 were in the follicular phase and 94 were in the luteal phase. In contrast, 139 ewes were treated with eFGA (Sincropart, CEVA Lab, Barcelona, Spain), of which 42 were in the follicular phase and 97 were in the luteal phase. Sponges were removed in all females after 12 days and 500 IU of eCG (Serigan, Ovejero Lab, Leon, Spain) was given. Ewes were then placed jointly with rams, at a ratio of 5 to 1, until no signs of mount were detected. Twenty-five days after the withdrawal of males, pregnancy rates were determined by transrectal ultrasonography with an 8-MHz probe. Fertility levels of synchronized estrus with the eMAP or eFGA sponges during the follicular or luteal phase are expressed as a proportion of ewes and were analyzed by a chi-square Pearson analysis. Significance was set at a level of P &lt; 0.05. After ultrasound scanning of the initial 273 ewes, 30.04% were considered to be in the follicular phase, whereas 69.96% were in the luteal phase of the estrus cycle. Pregnancy rate for eMAP-treated ewes during the follicular phase was 67.50% and was 69.14% for treatments during the luteal phase. In addition, for ewes treated with eFGA, pregnancy rate was 73.80% during the follicular phase and 73.19% during the luteal phase. No significant differences were found in pregnancy rates for either eMAP- or eFGA-treated ewes during the follicular or luteal phase of the estrus cycle. In conclusion, these results suggest that during the breeding season, fertility levels were not affected in ewes whose estrus was synchronized with intravaginal sponges impregnated with MAP or FGA. In addition, pregnancy rates were not affected when the synchronization treatments began during the follicular or luteal phase of the estrus cycle.

Economic Assessments of Hormonal and Nutritional Treatments for Improvement of Awassi Sheep Production in Jordan

The animal production sector in Jordan is characterized by shortages of locally produced feedstuffs derived from rangeland, forage plants or from human food crops as by products. This is exacerbated by insufficient rainfall, overgrazing, early grazing and high stocking rate. Thus, subject to these constraints, other technological improvements are highly desirable to meet the needs of crop growth and animal production. Alternative adapted technologies are also desirable in order to meet the increased demand for red meat in relation to population growth along with the changes in the price subsidy for feedstuff. The technologies are those, which have been introduced to the animal production sector, obtained in agricultural research stations besides on-farm demonstrations. They include technologies suited for increasing birth and twining rates, synchronizing the mating period, introducing the early weaning method, and animal feed and sheep production. Economic assessments conducted in this study demonstrate promising results of hormonal and nutritional practices in improving production efficiency of Awassi sheep in Jordan. Jordanian published data between 1991 and 1998 were used. The examined practices were: 1) use of PMSG in estrus synchronization in ewes, 2) introduction of early lamb weaning program, 3) supplementation with AD 3 E for ewes and 4) the use of agro-industrial feed block as a feed supplement for grazing lambs. Production data were then subjected to partial budgeting for economical evaluation. The use of PMSG outperformed the control groups in fertility and net returns per ewe by US$ 8.36/ewe. The early weaning of lambs increased the net returns by US$ 3.90/lamb. The injection with vitamin AD 3 E showed an average additional net return of US$ 5.66/ewe. Feeding agriculture by-product blocks improved weight gain in the feed block groups and resulted in additional net returns of US$ 3.5/lamb. The economic viability and reproductive performance indicators demonstrate that efforts should be undertaken to disseminate these new practices in the development program.