Intravaginal Sponges Research Articles

Surveillance and management of estrous cycle in Awassi and Lacaune ewes during out of season

The purpose of this study was to increase fertility in sheep by applying modern biotechnology: induction and synchronization of estrous in non- breeding season. The ewes were divided into 3 equal batches. In all batches intravaginal sponge (Veramix/Intervet) containing 60 mg of MPA was left in the vagina for 14 days. Immediately after removal of the sponge an injections of prostaglandin (Dinolytic/Pfizer) at the dose of 12.5 mg (2,5ml)/animal was administered in batch II. Batch III received two injections: PMSG hormone (Folligon/Intervet) at the dose of 500 IU/animal and prostaglandin (Dinolytic/Pfizer) at the dose of 12.5 mg (2,5 ml)/animal. The research focused on several directions: assessment of estrous manifestation; occurrence of estrous interval after completion of hormonal therapy; duration of estrous; appreciation of gestation after the first and second estrous clinically manifested; percentage of fecundity. From the results obtained it follows that induction and synchronization of estrous in non-breeding season showed economic advantages by shortening the time needed for the installation of gestation, the possibility of lambing distribution, preparation and organization of mating.

Effect of breeding season on fertility of sheep following estrus synchronization and fixed-time artificial insemination under field conditions in semi-arid tropical region

Accelerated lambing system is heavily reliant on reproductive technologies meant to enable off the season breeding in sheep. Therefore, the present study was programmed to assess the effect of breeding season (BS) on fertility of sheep following estrus synchronization (ES) and fixed time artificial insemination (FTAI). A total of 248 and 365 ewes were synchronized and inseminated during the BS (Febuary–March and July–September) and non-breeding season (NBS) respectively, during 2012–14. Synchronization of estrus was done by AVIKESIL-S, intra-vaginal progesterone sponges kept in situ in vagina for 12 days. 200 IU eCG was administered intramuscularly on 12th day after sponge withdrawal. FTAI was performed twice in ewes exhibiting signs of estrus at 48 and 56h after sponge removal, using liquid chilled semen of Patanwadi/Malpura rams containing 100 million sperm. Breeding season had no significant (p<0.05) effect on estrus synchronization. The estrous responses during the BS and NBS were 84.68% and 83.29% respectively. The lambing percentage during BS was 66.67%, which is significantly (p<0.05) higher than the lambing percentage of NBS (57.57%). Although, the lambing percentage in NBS maneuvered ewes were lower than the BS ewes but still the technology can be used to offset the effect of anestrus and to augment production in sheep.

Reproductive response of mature and nulliparous yearling ewes to the ram effect during the non-breeding season

Sudden introduction of rams to ewes that remained isolated from males during the non-breeding season induces ovulation and thus out-of-season breeding. The aim of this study was to compare the reproductive response of mature and nulliparous yearling ewes to the ram effect during the non-breeding season. The experiment was performed during October–November (mid non-breeding season) with 122 Merilin ewes 56 were mature multiparous (group ME) and 66 nulliparous, 1year old ewe lambs (group HE) that previously remained isolated from males. All ewes were pretreated with intravaginal sponges for 6days before the introduction of the rams. More ME than HE ewes ovulated (87.5 vs 66.7%, P<0.01), and come into oestrus (66.1 vs 30.3%, P<0.0001), and the ovulation rate was also greater in ME than HE (1.27±0.05 vs 1.10±0.04, P<0.05). The pregnancy rate in the first oestrus period was also greater in ME than in HE ewes (39.3 vs 16.7%, P<0.01). Overall, yearling ewes can respond to the ram effect ovulating and becoming pregnant during the non-breeding season. However, the reproductive response was lower compared with that of mature ewes.

Thermophysiological, haematological, biochemical and behavioural stress responses of sheep transported on road.

The study was conducted to evaluate the thermophysiological, haematological, biochemical and behavioural stress responses of sheep transported on road. A total of 44 Chamarita breed adult ewes were randomly allotted to one of two groups, one control group (untransported) and transported group (journey of 4h), and blood stress indicators were measured 1day before transport and at four time points post-transport (0, 4 and 24h). Thermophysiological profiles of ewes were measured by temperature buttons (iButton Thermochron® ) and placed in intravaginal sponges. Direct observations, with a combination of scan and behaviour sampling, were carried out to collect information on individual behaviour and the time it took the ewes to drink water, eat and rest after returning to their pen respectively. Transported ewes lost approximately 1kg live weight compared to controls and had higher body temperatures until 12h post-transport. Cortisol, glucose, non-esterified fatty acid (NEFA) concentrations as well as the neutrophil-lymphocyte ratio (N/L) and other physiological indicators were higher immediately after unloading in transported ewes but mostly returned to normal after 4h, with complete recovery after 24h. Behavioural analysis post-transport demonstrated that transported ewes chose to eat before drinking and spent less time resting than controls in the first 3h after unloading. The study demonstrates that transportation even under short-journey conditions induced behavioural, physiological and thermophysiological responses indicative of the induction of significant stress, leading to live weight shrinkage that may jeopardize farmer's incomes. Finally, results of this study validated the use of iButton Thermochron® data loggers for monitoring the stress response during transport.

Ovulation rate, prolificacy and pregnancy rate in goats treated with oral glycerol

This study tested whether the oral administration of glycerol at the time of progestin removal and in the first 6 days of the estrous cycle increased the ovulation rate, prolificacy, and pregnancy rate in goats. Intravaginal sponges impregnated with fluorogestone acetate were inserted into 129 goats for 12 days; upon sponge removal, goats were randomly assigned to one of the two following treatment groups: the glycerol group (n = 65), which received an oral drench of 100 mL of glycerol upon sponge removal and was repeated on days 0, 2, 4, and 6 following estrus (estrus = day 0), and the control group (n = 64), which did not receive glycerol. The goats in estrus were mated, and their ovulation rate was determined by ultrasonography between days 8 and 12 of the estrous cycle. Pregnancy was diagnosed by ultrasonography on day 40, and the prolificacy was determined at birth. In 6 goats treated with glycerol and 5 controls, their insulin concentrations at 0, 2, 4, 8, and 12 h after the glycerol drench were determined by radioimmunoassay. The proportion of goats with multiple ovulations (glycerol = 71 vs control = 64) and the proportion of goats with multiple births (glycerol = 52 vs control = 56) were similar (P &gt; 0.05) between treatments. Likewise, the pregnancy rate was similar (P &gt; 0.05) between treatments (glycerol = 88 vs control = 85%). The insulin concentrations tended to be higher in goats treated with glycerol (P = 0.08). In conclusion, an oral drench of 100 mL of glycerol at the time of progestin withdrawal and in the first 6 days of the estrous cycle did not increase the ovulation rate, prolificacy, or pregnancy rate in goats.

Lambing rate and prolificacy in inseminated hair sheep treated with bovine somatotropin.

This study evaluated whether the administration of 50 and 100 mg bovine somatotropin (bST) at the start of estrous synchronization and at the time of artificial insemination improves lambing rate and prolificacy in hair sheep. Four hundred eighty adult hair ewes (Pelibuey, Blackbelly, Dorper, Katahdin, and their crosses) were synchronized with intravaginal sponge containing 40 mg of fluorogestone acetate. On the day of sponge insertion, ewes were assigned to three treatments: the bST-100 treatment (n = 156) received 100 mg bST at the start of synchronization (d 0) and at the time of insemination (d 14), the bST-50 treatment (n = 159) received 50 mg bST in the same schedule as the previous group, and the control (n = 165) did not receive any bST. Lambing rate and percentage of multiple births were analyzed using the GENMOD procedure of SAS. Prolificacy data were analyzed using the MIXED procedure of SAS. The IGF-1 and insulin concentrations were analyzed with ANOVA for repeated measures. The bST application did not affect the lambing rate (P = 0.06). The proportion of ewes with multiple births (P = 0.01) and prolificacy (P = 0.04) were higher in the bST-50 (54.3% and 1.57 ± 0.1) than the bST-100 (18.2% and 1.25 ± 0.1) and control (33.3% and 1.28 ± 0.1) groups. The IGF-1 and insulin concentrations were higher (P < 0.05) in the bST-treated groups, but the insulin concentration was higher (P = 0.001) in the bST-100 group than in the bST-50 group. The administration of 50 or 100 mg bST at the start of synchronization and at the time of artificial insemination does not increase lambing rate. However, the dose of 50 mg increased the proportion of multiple births and prolificacy.

Expression of cumulus-oocyte complex genes and embryonic development in goats subjected to progestogen-based estrus synchronization

The objective was to investigate the effect of short-term (7 days) and long-term (14 days) progesterone-based estrus synchronization on number of follicles, progesterone concentrations, cumulus-oocyte complex (COC) gene expression, and embryonic development in goats. Nulliparous Thai-native goats (n = 45) were randomly assigned to one of two estrus synchronization treatments. Goats were treated with intravaginal sponges containing 60-mg medroxyprogesterone acetate (MAP; Synchrogest esponjas, Spain) during 7 or 14 days (short-term or long-term protocol, respectively). Multiple follicular development was induced by intramuscularly injections of 300-IU eCG in both groups (1 day before sponge withdrawal). An ovariectomy was performed at 24 hours after sponge removal to evaluate number of follicle and collect oocyte for IVF. Oocyte quality (healthy or nonhealthy) was determined by morphology of COCs before IVM. Recovery of COCs and total cellular RNA isolation were applied to determine apoptosis-related gene expression. After IVF, embryos were evaluated during the eight-day culture as numbers of cleaved oocyte, morula, and blastocyst embryo. Total numbers of follicles and oocytes were similar for both treatments. Plasma progesterone concentrations were not different during MAP insertion period (P > 0.05). However, goats that received the short-term protocol had a greater number of 4 to 6-mm follicle, healthy oocytes, cleaved oocytes, and morula embryos than goats that received the long-term protocol (P < 0.01). In addition, the expression of B-cell lymphoma 2 messenger RNA was greater (P < 0.05) in COCs derived from the 7 days MAP-treated when compared to the 14 days MAP-treated goats. These data highlight that the 7-day progestin–based treatment may contribute to quality of oocytes and embryonic development in goats.

Pregnancy rate in Bulgarian White milk goats with natural and synchronized estrus after artificial insemination by frozen semen during breeding season

Abstract Objective To determine the pregnancy rate (PR) in goats with natural and synchronized estrus after artificial insemination (AI) by frozen semen during breeding season. Methods The experiment was carried out with 89 Bulgarian White milk goats divided as follows: group I ( n = 54) animals with natural estrus (NE), allocated in two subgroups treated with or not with GnRH after the last insemination and group II ( n = 35) goats with synchronized estrus by intravaginal sponges and injection of PMSG after the sponges withdrawal. Both groups were also divided according to number AI – single or double. All animals in group I were inseminated by frozen semen after proved standing estrus as a part of goats received second insemination 8 h later. Single insemination in synchronized goats was done 48 and double at 48 and 56 h after the sponge removal. Ultrasound pregnancy diagnosis was performed on day 30 post insemination. Results The pregnant animals in both subgroups with natural estrus and single AI (33.3% and 45.2%) were less than those (58.3%) after estrus synchronization (ES). The pregnancy rate in synchronized goats with double insemination was 63.6%, whereas in animals with natural estrus varied from 40 to 50%. Overall pregnancy rate in group I (60%) was significantly ( P Conclusion The goats with natural estrus and GnRH treatment tend to enhance pregnancy rate after double artificial insemination 8 h apart. The insemination number has no significant impact on pregnancy rate in synchronized goats as the overall pregnancy rate is better than in animals with natural estrus without GnRH administration.

Different progestagen treatment duration on estrous synchronization during the natural breeding season in non-lactating Anatolian black goats

The objective of this study was to evaluate the duration of four progestagen treatments on estrous synchronization and pregnancy rate in non-lactating Anatolian black goats during the natural breeding season. All does were divided into four groups according to progestagen treatment duration using intravaginal sponges (60 mg MAP): group 1, 13 days (n = 23), group 2, 11 days (n = 25), group 3, 9 days (n = 25) and group 4, 6 days (n = 25). In addition, 24 h before sponges removal, each doe was injected with 0.075 mg of cloprostenol (PGF2α) and 500 IU eCG. The goats within the same group were naturally mated at fixed time 40 h following progestagen removal, using the same breed fertile bucks (1:5 mating ratio). The total estrous response for the first 12 h, total estrous response within 60 h, time to onset of the induced estrus, duration of the induced estrus and pregnancy rate were 3.0, 96.9%, 26.5 ± 0.7 h, 22.6 ± 0.8 h and 92.0%, respectively. In terms of the onset of induced estrus there were significant differences between group 1 and groups 3 and 4 and between group 2 and group 3 (P < 0.05). The protocols used were equally efficient in synchronizing and inducing estrus in non-lactating Anatolian black does during the natural breeding season. Conclude on pregnancy rate. In addition, pregnancy rates were similar results.

Pregnancy rate in dry and lactating goats after estrus synchronisation with artificial insemination and natural breeding (a field study)

The objective of this study was to determine the pregnancy rate in dry and lactating goats after estrus synchronisation with artificial insemination and natural breeding of unconceived animals. The investigation was conducted with 75 dry (group I) and 32 lactating (group II) local goats in breeding season. All animals were submitted to estrus synchronisation by intravaginal sponges for 12 days, PMSG injection on day of sponge removal and two artificial inseminations (AI) with fresh semen – 48 and 56 hours after sponge withdrawal. Two weeks after the AI, daily test for goats which had not conceived after the AI was performed by teaser and the detected animals in estrus were naturally mated with a fertile buck. Ultrasonographic pregnancy examination was carried out at 20-day intervals until day 100 after the AI. The pregnancy rate in artificially inseminated and naturally bred animals and the interestrus intervals were calculated. The pregnancy rate between both synchronised groups differed significantly (P<0.05), while the values in the groups with natural breeding were comparable. Different pregnancy rates between artificially inseminated and naturally bred goats in group I (72% vs. 42.9%) and group II (19% vs. 73%) were registered (P<0.05). Additionally, considerable differences (P<0.05) between the values after first natural breeding (9.6% and 46.6%) were detected. The total pregnancy rate (84%) in dry goats was higher (P<0.05) than that (54%) in lactating animals. The interestrus intervals were similar (P=0.2). In conclusion, the current data could be used for optimisation of the pregnancy rate and the reproductive efficiency in local goat breeds.

Returning of cyclicity in infertile Corriedale sheep with natural progesterone and GnRH based strategies

Abstract Objective To evaluate the return of ovarian cyclicity with four hormone based protocols during non-breeding season in infertile Corriedale sheep. Methods The return to ovarian cyclicity was considered in terms of percent estrus response rate (ERR). The time of exhibition of estrus after either sponge removal or last PGF2α injection, was considered as time to onset of estrus. Infertile Corriedale ewes were randomly selected and distributed into four groups corresponding to four hormonal protocols such as PsE (intravaginal progesterone sponges for 12 days and eCG (equine chorionic gonadotropin) at 24 h before sponge removal; n = 6), GP (GnRH on day 0 and PGF2α on day 5; n = 7), GPG (GnRH on day 0, PGF2α on day 5 and second injection of GnRH on day 7; n = 7) and PsPG (Intravaginal progesterone sponges for 12 days, PGF2α and gonadotropin-releasing hormone (GnRH) respectively, at 24 h before and after sponge removal; n = 8). Results PsPG protocol produced significantly (P 0.05) higher than GP (85.71%) and PsE (66%). Estrus was compact and more synchronized in PsPG group because 75% of ewes exhibited estrus during the first 48 h. The collective incidence of estrus (78.94%) was also maximum during the first 48 h. Conclusion PsPG estrus induction strategy has a potential to replace eCG based protocols for returning of ovarian cyclicity in infertile Corriedale sheep.

Short communication: Drug residues in goat milk after prophylactic use of antibiotics in intravaginal sponges for estrus synchronization

The aim of this study was to determine whether the prophylactic use of antibiotics in intravaginal sponges used for estrus synchronization in goats may result in the presence of inhibitors in milk and, therefore, of positive results by microbial screening tests. Ninety-eight Murciano-Granadina goats were used, divided into 7 groups of 14 animals. Intravaginal sponges were placed in 6 groups using 2 concentrations of 3 different antibiotics: doxycycline, oxytetracycline, and sulfathiazole-framycetin. The sponges of the control group were placed without antibiotics. Milk samples were collected daily until 7 d posttreatment and analyzed using 3 microbial tests. Positive samples were retested by specific receptor-binding assays to confirm the positive results. Vaginal status was evaluated by visual assessment of the external aspect of the sponges after removal. The microbial test response was not affected by either day posttreatment or dose of antibiotic used, except for oxytetracycline at the higher concentration. Moreover, no positive results were obtained using receptor-binding assays, suggesting that residues, if present in milk, did not exceed the regulatory (safety) levels established for these drugs. The occurrence of soiled sponges was higher in the control group. With respect to the dose of antibiotics used, no significant differences were found for the lower dose administered. However, a significant increase in the percentage of clean sponges was observed for the higher dose of doxycycline. We conclude that the prophylactic use of low doses of doxycycline, oxytetracycline, or sulfathiazole in intravaginal sponges used for synchronization of estrus helps to reduce clinical vaginitis in dairy goats and does not seem to be the cause of positive results in microbial inhibitor tests used to detect antibiotics in goat milk.

Vaginal mucus from ewes treated with progestogen sponges affects quality of ram spermatozoa

The use of intravaginal sponges (IS) to synchronize estrous onset in ewes provokes vaginitis, an increase in the vaginal bacterial load, and growth of bacterial species that are not present during spontaneous estrous behavior. The objective of the study was to compare the functional sperm parameters after incubating it with mucus collected from the vagina of ewes during spontaneous estrus or estrous synchronized with IS. Pooled spermatozoa were co-incubated with: (1) vaginal mucus collected from ewes in spontaneous estrus; (2) vaginal mucus collected from ewes in estrus pretreated with progestogen-impregnated IS; (3) synthetic mucus; and (4) medium without mucus as a control group. Sperm samples were evaluated after incubating it for 30 and 90 minutes. The number of colony-forming units (CFUs/mL), pH, and osmolality were greater in the mucus collected from ewes treated with IS than from those untreated (P = 0.046; P < 0.0001, and P < 0.0001, respectively). The percentage of sperm with progressive motility was lower after incubation with vaginal mucus collected from estrous ewes treated with IS than in the other three treatments both, 30 and 90 minutes after incubation (P = 0.0009 and P < 0.0001, respectively). The sample incubated for 30 minutes with mucus from ewes treated with IS had a lower percentage of sperm with intact plasma membrane than all the other treatments (P < 0.0001). The percentage of sperm with functional membrane was significantly lower in the sample incubated for 30 minutes with vaginal mucus from ewes treated with IS than in the other three treatments (P < 0.0001). After 90 minutes, the percentage was still lower than that in the sample collected from ewes during their spontaneous estrus (P = 0.0005). The lowest percentages of sperm with acrosome damage were observed in sperm incubated with mucus collected from sheep in spontaneous estrus for 30 and 90 minutes (P < 0.0001 and P = 0.008, respectively). The percentage of apoptotic spermatozoa was greater in samples incubated during 30 minutes with vaginal mucus collected from ewes treated with IS than in the other three groups (P = 0.0005). The functionality and the viability of ram sperm is negatively affected by the cervical mucus of ewes pretreated with progestagen-impregnated IS used in estrous synchronization treatments. This may partially explain the decrease in conception rate obtained with treatments with IS.

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.

The effect of estrus synchronization programmes on parturition time and some reproductive characteristics of Saanen goats

ABSTRACTThe aim of the present study was to determine the effect of estrus synchronization programmes on parturition time and some reproductive characteristics of Saanen goats. Estrus of Saanen goats was synchronized as follows: by use of intravaginal sponges containing 30 mg flugestone acetate for 11 days following IM injection of 500 IU PMSG (group PP; n = 80) or only intravaginal sponges (group P; n = 80) and natural estrus (control; C, n = 50). Forty-eight hours after removing intravaginal sponges, all goats were introduced to Saanen bucks. Kidding rate and litter size of goats in the PP group were higher than those of goats in the C and P groups (P < .05). Neonatal mortality rate of kids from goats in the PP group was found higher than those of goats in the C and P groups (P < .05). The length of kidding period in goats of group C was longer than goats in the P and PP groups (P < .05). Births showed a unimodal distribution, with maximum parturition at midday and minimum parturition at midnight in all goats. The parturition that occurred during daytime hours in goats of P and PP groups was more than goats in the C group (P < .05). The results of this study may suggest that estrus synchronization shortened the length of the kidding period, concentrated parturition time during daylight hours and increased reproductive performance in Saanen goats.

Comparison of the effects of pretreatment with Veramix sponge (medroxyprogesterone acetate) or CIDR (natural progesterone) in combination with an injection of estradiol-17β on ovarian activity, endocrine profiles, and embryo yields in cyclic ewes superovulated in the multiple-dose Folltropin-V (porcine FSH) regimen

Follicular wave status at the beginning of exogenous FSH administration is an important contributor to variability in superovulatory responses in ruminants. Studies in ewes have shown a decrease in the number of ovulations when superovulation is initiated in the presence of ostensibly ovulatory-sized ovarian follicles. Hormonal ablation of large antral follicles with the progestin–estradiol (E2-17β) treatment significantly reduces this variability in superovulated anestrous ewes, but the effects of the treatment in cycling ewes have not yet been assessed. Sixteen Rideau Arcott × Polled Dorset ewes (November–December) received either medroxyprogesterone acetate (MAP)–releasing intravaginal sponges (60 mg) or controlled internal drug release (CIDR) devices (containing 300 mg of natural progesterone) for 14 days (Days 0–14), with a single intramuscular injection of 350 μg of E2-17β on Day 6. The superovulatory treatment consisted of six injections of porcine FSH (Folltropin-V) given twice daily, followed by a bolus GnRH injection (50 μg intramuscular) on Day 15. There were no differences (P < 0.05) in the ovulatory responses and embryo yields between the two groups of ewes. In both subsets of animals, the next follicular wave emerged ∼2.5 days after an E2-17β injection (P > 0.05). A decline in maximum follicle size after an E2-17β injection was more abrupt in CIDR- compared with MAP-treated animals, and the ewes pretreated with exogenous progesterone had significantly more 3-mm follicles at the start of the superovulatory treatment. The metabolic clearance rate of exogenous E2-17β appeared to be greater in MAP-treated ewes, but circulating concentrations of porcine FSH failed to increase significantly after each Folltropin-V injection in CIDR-treated animals. The CIDR-treated ewes exceeded (P < 0.05) their MAP-treated counterparts in serum E2-17β concentrations during superovulation. In spite of differences in antral follicle numbers and endocrine profiles between MAP- and CIDR-treated cyclic ewes receiving E2-17β before ovarian superstimulation, there were no differences in superovulatory responses.

Synchronization Protocols in Spanish Merino Sheep: Reduction in Time to Estrus by the Addition of eCG to a Progesterone-Based Estrus Synchronization Protocol

Abstract An appropriate management of reproduction allows ewes to breed at a more intensive rhythm, more compatible with economic efficiency of farms. Hence, the objectives of the present work were to evaluate a traditional estrus synchronization protocol (based on medroxyprogesterone acetate-impregnated intravaginal sponges combined or not with equine chorionic gonadotropin) on a Merino sheep herd during the breeding season, in order to determine the best working protocol for this breed. A total of 277 sheep, blocked by age (200 ewes and 77 ewe lambs) were randomly allocated to four groups, two of ewes (E and Ee) and two of ewe lambs (L and Le). All females received 60 mg MAP (medroxyprogesterone acetate) sponges on the first day. At the day of removal the animals of groups Ee and Le received 450 IU of eCG (equine chorionic gonadotropin). Mean estrus synchronization rate was 92.06% and similar among groups. Time to estrus was shorter for Ee (46.93±12.44 h) and Le (44.34±10.76 h), when compared to treatments without eCG (60.60±20.46 h and 58.68±17.72 h for E and L, respectively; P&lt;0.05 for both). Pregnancy rates were 71.35 and 72.86% for ewes and ewe lambs, respectively, and similar among groups. Lambing rates were lower in ewes (1.36) than in ewe lambs (1.85) with no significant effect of eCG. The study demonstrates the efficacy of the synchronization method with MAP and the reduction in the time to estrus induced by eCG in Spanish Merino ewes and ewe lambs during the breeding season.

Determination of the proper time for mating after oestrous synchronisation during anoestrous or oestrous by measuring electrical resistance of cervical mucus in ewes

The purpose of the present study was to investigate whether the electrical resistance values of the cer - vical mucus and/or blood οestradiol-17β and progesterone concentrations at mating, after oestrous synchronisation during the anoestrous or oestrous period in ewes, are related to fertility. Oestrus was induced by medroxyprogesterone acetate-impregnated intravaginal sponges (Veramix, Upjohn, USA), either for 12 days (12-day group; 24 Kymi and 28 Chios) or for 14 days (14-day group; 24 Kymi and 28 Chios), plus 400 IU equine chorionic gonadotropin (Intergonan, Intervet, the Netherlands) i.m., at the time of sponge removal. In each case, one blood sample was collected from all ewes at sponge insertion, at sponge removal and at oestrus, for the determination of serum οestradiol-17β and progesterone concentrations, using a radioimmunoassay. The electrical resistance of the cervical mucus was meas - ured once, just after oestrus detection by teaser rams, using a digital heat detector. All ewes found to be in oestrus were mated to fertile rams. Pregnancy was determined by transabdominal ultrasonography 35-40 days after mating. Kymi ewes were in anoestrous, while those of Chios were in the oestrous period. The 14-day treatment resulted in better outcome as concerns oestrus detection and pregnancy rate than the 12-day treatment, in either oestrous or anoestrous period ewes. Oestradiol-17β concentrations at sponge removal and at oestrus were lower ( P < 0.05) in the 14-day group than in the 12-day group, in both oestrous or anoestrous period ewes. Progesterone concentrations at sponge insertion and removal were higher ( P < 0.05), while progesterone concentrations and electrical resistance values of the cervical mucus at oestrus were lower ( P < 0.05) in ewes of both groups who conceived compared to those that did not, either in oestrous or in the anoestrous period. Linear regression analysis revealed a positive relation between the electrical resistance values of the cervical mucus and blood serum progesterone concentrations in both oestrous or anoestrous period ewes. The electrical resistance of cervical mucus could be useful for the detection of the proper time for mating after oestrous synchronisation in ewes.

Vaginal Histological Changes after Using Intravaginal Sponges for Oestrous Synchronization in Anoestrous Ewes

To characterize the histological and cytological vaginal changes generated by the use of intravaginal sponge (IS) applied in oestrous synchronization treatments in ewes during mid-non-breeding season. Thirty-five multiparous ewes were allocated to three experimental groups according to the moment in which the samples were taken: (i) ewes treated with IS containing 60 mg of medroxyprogesterone acetate for 14 days, sampled the day of IS removal (group ISR; n = 10), (ii) or after sponge removal at time of oestrus or 72 h after removal (group AR; n = 14) and (iii) ewes without sponge treatment that were sampled at the day of IS removal of the other groups (group CG; n = 11). Vaginal biopsies and cytological samples were taken from the anterior vaginal fornix area. The vagina of the CG group had a stratified squamous epithelium with a moderate degree of cellular infiltration with lymphocytes and plasma cells in the lamina propia. Treated ewes (ISR and AR) had epithelial hyperplasia and hypertrophy. ISR ewes had haemorrhage and perivascular infiltrate and an increased number of epithelial cells, neutrophils, macrophages and erythrocytes at IS removal. The use of IS generated histological and cytological alterations in the vaginal wall when used for oestrous synchronization in anoestrous ewes.

Induction of Estrus and Fertility Response in True Anoestrus Buffaloes Using Intravaginal Progesterone Sponge During Summer

Present study was carried out to study the efficacy of intravaginal progesterone sponge for induction of estrum in post partum anoestrus buffaloes during summer. True anoestrus animals were identified by repeated rectal examinations twice at 10 days interval apart having the small and smooth ovaries without any follicular activity. Out of 40 animals identified, 30 were treated with intravaginal progesterone sponge for 10 days and PGF2 injection was given one day prior to removal of sponge. Remaining 10 animals were kept as anoestrus control without treatment. The animals were watched closely for change in external gentallia after sponge removal and for estrus symptoms. The animals exhibiting estrus were inseminated artificially. Estrus was induced in 80% of animals (24/30) and the conception rate was 66.66% (16/24). This result indicates the better possibilities of inducing ovarian cyclicity in functionally anoestrus buffaloes by cost effective intravaginal progesterone sponge.