Prolonging the time of semen deposition increases the pregnancy rates of ewes subjected to fixed time cervical insemination during the breeding season.

The main limiting factor of artificial cervical insemination in ewes is the long and narrow fibrous cervical canal, which impedes the transport of spermatozoa and leads to lower pregnancy rates. The hypothesis that prolonging the time of semen deposition during ovine cervical insemination can increase pregnancy rates was investigated in this study. Estrus was synchronized in 150 multiparous Ujimqin ewes using a polyurethane intravaginal sponge impregnated with 45 mg of flurogestone acetate. The sponge was left in the vagina for 12 days followed by an injection of 330 IU of eCG at sponge removal. After the exclusion of two ewes due to sponge loss, the remaining 148 ewes were divided into the Treatment group (n = 75) and the Control group (n = 73). Each ewe was inseminated once between 56 and 60 h after the removal of sponges, using a new type of insemination device containing 0.25 ml of diluted semen. Semen was collected from eight Black Suffolk rams and all the ejaculates were pooled and diluted in ultra-high temperature-treated commercial skimmed milk. The time of semen deposition was prolonged to 60 s in the Treatment group, while ewes were given traditional insemination in the Control group. Pregnancy status was determined by transabdominal ultrasound examination 45 days after insemination. Lambing performance was calculated after all the ewes had been delivered. Significant differences were observed between the Treatment group and the Control group in terms of the pregnancy rate and the fecundity rate (73.3% and 93.3% vs 56.2% and 71.2%, p < .05 and p < .01, respectively). In conclusion, prolonging the time of semen deposition significantly increased pregnancy and fecundity rates in estrus-synchronized Ujimqin ewes subjected to fixed time cervical insemination.

Approaches of estrous synchronization in sheep: developments during the last two decades: a review.

The objective of the current review was to summarize the protocols used for estrous synchronization in ewes during the last two decades. Progesterone (P4) is a major hormone used in most protocols. P4 in the form of a controlled internal drug releasing (CIDR) device, medroxyprogesterone acetate (MAP), and fluorogestone acetates (FGA) has been used for estrous synchronization. Also, gonadotropins such as equine chorionic gonadotropin (eCG) and gonadotropin-releasing hormone (GnRH) are often administered at the end of P4-based protocols to improve fertility. Moreover, the administration of prostaglandins (PG) and ram effects have been used for estrus induction and synchronization of ewes. The findings of previous studies indicate that the outcome of administering various synthetics P4 analogues (CIDR, MAP, and FGA) in ewes is comparable in terms of estrous synchronization/induction. The supplementation of P4-based protocols with eCG, however, improves the estrus response and pregnancy rate during breeding and non-breeding season. On the other hand, PG is effective for successful estrous synchronization during the breeding season only. Often, two injections of PG are administered either 11 or 14 days apart along with P4-based protocols to lyse ovine corpus luteum (CL) when it is receptive to PG i.e., 3 days post-ovulation. Alternatively, the "ram effect" has been shown to improve the efficacy of P4-based protocols and can be used as an alternative to eCG in ewes. The current review describes the methods of synchronization and their outcomes during breeding and a non-breeding season in ewes.

Oxytocin increases pregnancy rates after fixed time artificial insemination in Kazak ewes.

It is probable that reduced pregnancy rates in ewes after fixed time artificial insemination (FTAI) is attributable, in part, to the reduced number of normal spermatozoa that colonize the oviduct. Administration of oxytocin stimulates both cervical dilation and uterine/oviductal contractility. The hypothesis that oxytocin can enhance sperm transport into the uteri and the oviducts, and thereby increase pregnancy rates, was tested in the present study. Oestrus was synchronized in 199 multiparous Kazak ewes using intravaginal flurogestone-impregnated sponge. The sponge was left in the vagina for 12 days followed with an injection of 330 IU of eCG at sponge removal. Each ewe was intracervically inseminated twice at 50 hr and 62 hr after the removal of sponges using an insemination catheter containing 0.25 ml of diluted semen. Semen was collected from seven Texel rams and all the ejaculates were pooled and diluted in ultra-high temperature-treated commercial skimmed milk without (Control group, 0.05 ml of saline per mL milk, n = 144) or with oxytocin supplement (Oxytocin group, 0.5 U of oxytocin per ml milk, n = 55). Pregnancy status was determined by transabdominal ultrasound examination 45 days after insemination. Lambing performance was recorded at delivery. Significant differences were observed between the Oxytocin group and the Control group in terms of the pregnancy rate and the fecundity rate (85.5% and 92.7% versus 68.8% and 72.9%, respectively). In conclusion, low dose oxytocin supplementation of semen extender significantly increased pregnancy and fecundity rates in oestrus-synchronized Kazak ewes after FTAI.

Presence of a sexually active goat buck enhances ovulation occurrence in seasonally anestrous does after ovulation and luteolysis induction in hormonally-treated goats in seasonal anestrus.

In seasonally anestrous goat does, ovulations can be induced by combining a treatment regimen including progestagen, eCG and prostaglandins. Nonetheless, ovulations occur only once and then does return to a seasonally anestrous state. This study was performed to determine whether the presence of a sexually active buck can stimulate a second ovulation after induced luteolysis using prostaglandins following the first ovulation. Three groups of seasonally anestrous does were treated to induce ovulations using an intra-vaginally inserted sponge containing a progestin combined with eCG and prostaglandin administrations. Goats that had ovulations were treated with a prostaglandin 11 days after progestin sponge removal. After the prostaglandin injection, does continued to be isolated from bucks (n = 8), were penned with a control buck (n = 9), or were penned with a sexually active buck (n = 10). The proportion of goats having ovulations after imposing the ovulation-induction protocol was greater than 80% and did not differ among treatment groups (P >  0.05). The proportion of does having ovulations after injecting prostaglandins was greater when does were penned with a sexually active buck (8/10) than does penned with a control buck (0/9) or that were isolated from bucks (0/8; P < 0.05). It is concluded that in seasonally anestrous goat does induced to have ovulations using a hormonal treatment regimen, the presence of a sexually active buck can induce a second ovulation when there is an induced luteolysis.

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

The efficacy of eight combinations of fluorogestone acetate (FGA, 20 or 40 mg as intravaginal device during 11 days), equine chorionic gonadotropin (eCG, 300 or 500 UI injected 48 hr before FGA removal) and prostaglandin F2α (cloprostenol, 0 or 50 µg injected 48 hr before FGA removal) aiming at induction and synchronization of oestrus and ovulation was evaluated during the anoestrus season in spring and during the breeding season in autumn in adult Beni Arouss goats. Oestrous behaviour was recorded between 12 and 60 hr after FGA removal. Blood samplings allowing to assess onset of the pre-ovulatory LH surge and increase of progesterone as sign of an active corpus luteum were performed, respectively, between 20 and 60 hr and 3, 5, 8 and 15 days after FGA removal. No season-related differences (spring vs. autumn) were observed for oestrous response (95% vs. 93%), pre-ovulatory LH surge (94% vs. 84%) and luteal response after 3-8 and 11-15 days post-treatment (respectively 92% vs. 66% and 92% vs. 98%). The onset of oestrus (21 [13-53] vs. 32 [12-54] hr) and LH surge (26 [20-60] vs. 38 [22-60] hr) occurred significantly later in autumn. FGA (40 vs. 20 mg) in autumn significantly delayed the onset of oestrus (36 [16-54] vs. 23 [12-47] hr) and LH surge (44 [26-58] vs. 33 [22-60] hr). Significant treatment-related differences were recorded for onset of LH surge (earliest for 20 mg FGA, 300 IU eCG, 50 µg PGF2α ) and onset of luteal phase (latest for 40 mg FGA, 300 IU eCG, 50 µg PGF2α ). In conclusion, the hormone combinations tested appeared equally effective in terms of oestrous and ovulation rates. Season has influenced significantly the onset of oestrus and LH surge, and the high dose regimen of FGA delayed the ovarian response in autumn.

Vulvar thermal pattern following synchronization of estrus is linked to fertility after timed artificial insemination in goat.

Aim of this study was to study the vulvar thermal pattern variation during the timed artificial insemination protocol in Angora goat and identify the relationship with the successful rate. Does (36 adult healthy females) were synchronized using PGF2α at the day 0, 11 days of progesterone impregnated sponges intra-vaginally, PMSG 48 h before sponges withdraw (day 11) and the intra-cervical inseminations were carried out 48 h later (Timed Artificial Insemination: TAI) with chilled semen. Vulvar (VST) and perivulvar (PST) areas were considered to evaluate the thermal pattern during the protocol at the day 0 and at the TAI using a thermo camera (E60, FLIR System). Differences of temperature (ΔT) between the surfaces were calculated for each time. The does were monitored for pregnancy, delivery time and prolificacy. Pregnant (P) and non-pregnant (NP) does were compared in terms of VST, PST and ΔT using two ways ANOVA considering time and pregnancy as sources of variability. VST was lower than PST in all the monitored does (P < 0.05) (34.79 ± 0.14 vs 36.58 ± 0.14 °C) and without differences between P and NP at day 0 (35 ± 0.18 vs 36.39 ± 0.22 °C). Significant difference (P < 0.05) between P and NP does was recorded at TAI in terms of VST (33.89 ± 0.31 vs 35.40 ± 0.24 °C) and ΔT (-3.16 ± 0.34 vs -1.62 ± 0.26 °C). In conclusion thermal emission by glabrous surfaces in goat may be used to identify the right response induced by hormonal treatments and to optimize the application of assisted reproductive techniques at the field level.

Influence of short-term energy supplementation on estrus, ovarian activity, and blood biochemistry in Ossimi ewes synchronized with fluorogestone acetate in the subtropics.

The objective of this study was to evaluate if short-term high-energy diet treatments have any overstimulatory effects on ovarian function and metabolic status in Ossimi ewes synchronized with progesterone sponge. Thirteen ewes were divided into high-energy (HEG; n = 7) and normal-energy or control (NEG; n = 6) groups. Progesterone sponges were placed intravaginally for 14 days during the winter breeding season (December-February). Four days before the removal of the sponges, a high-energy diet (130% of maintenance) was fed to HEG, whereas NEG was offered maintenance diet throughout the experiment. Ovarian performance and progesterone, estradiol, and blood metabolites were assessed daily starting from the day of removal of the sponges. Estrus period was longer in HEG (P < 0.05) when compared with NEG. Ovulation took place considerably longer with larger ovulatory follicles in HEG (P < 0.05). A marked increase in the level of total protein, albumin, glucose, and blood urea during the first 2 days following the removal of progesterone sponge was noticed in HEG when compared with NEG ewes. Eighty-five percentage (85.7%; 6/7) and 66.6% (4/6) had ovulation for the HEG and NEG, respectively. Dietary energy had a nonsignificant effect on the number of the recruited follicles, whereas a significant effect was observed for the diameter of the ovulatory follicle and ovulation rate (HEG, 2.3 ± 0.1 vs. NEG, 1.2 ± 0.3). It is concluded that short-term energy supplementation improves estrus expression and ovarian activity in fluorgestone acetate (FGA)-synchronized Ossimi ewes.

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

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

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.

Reproductive performance of seasonally anovular mixed-bred dairy goats induced to ovulate with a combination of progesterone and eCG or estradiol.

Adult goats (n = 32) were randomly assigned to one of four treatments (n = 8, each): (i) progesterone (P4 ) + equine chorionic gonadotropin (eCG), treated with 25 mg progesterone intramuscularly (i.m.) + 250 IU eCG 24 h later; (ii) cronolone + eCG, treated with vaginal sponges - 20 mg cronolone × 7 days + 250 IU eCG at pessary removal; (ii) P4 + estradiol (E2 ), treated with 25 mg progesterone i.m. + 1 mg estradiol 24 h later; (iv) cronolone + E2 , treated with vaginal sponges - 20 mg cronolone × 7 days + 1 mg of estradiol i.m. at pessary removal. Goats were tested for estrus throughout the presence of a buck. Seven days prior and after treatment, an ovarian ultrasonographic scanning was performed to determine ovarian function and structures. An ultrasonographic pregnancy diagnosis was performed on day 30 post-service. In all groups, 100% estrus response was observed within 96 h post-treatment. While ovulation occurred in 100% of P4 + eCG and cronolone + eCG treated goats, the other groups only depicted 50% ovulatory activity (P < 0.05). Pregnancy rate was higher (P <0.05) in the P4 + eCG and cronolone + eCG groups (88 and 100%, respectively), compared with 38% in P4 + E2 and cronolone + E2 groups. The best treatments were those in which eCG was applied. The P4 + eCG treatment was a pessary-free, cheaper and effective protocol to induce ovulation in goats during the seasonal anovulatory period.

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.

Modifications of carbohydrate residues in the sheep oviductal ampulla after superovulation.

Epithelium of oviductal ampulla was studied in normal and in superovulated sheep using morphologic analysis and lectin glycohistochemistry. The lining epithelium consisted of two types of cells, ciliated and nonciliated cells. Unlike superovulated samples, the nonciliated cells from control ewes showed apical protrusions indicating an apocrine secretory activity. The ciliated cells showed lectin-binding sites mainly at the level of the cilia which bound all the used lectins except Peanut agglutinin, suggesting the lack of glycans terminating with Galß1,3GalNAc. In superovulated specimens, the ciliated cells with high mannosylated glycans Concanavalin A (Con A) and GlcNAc and GalNac termini Griffonia simplicifolia agglutinin II (GSA II) and Dolicurus biflorus agglutinin (DBA) decreased. The luminal surface of nonciliated cells showed all investigated sugar residues in controls, whereas it was lacking in high mannosylated (Con A) and terminal GalNAcα1,3(LFucα1,2)Galß1,3/4GlcNAcß1 sequence (DBA) in superovulated ewes. Apical protrusions from control ampullae nonciliated cells showed glycans containing mannose, GlcNac, GalNAc, galactose, and α2,3-linked sialic acid (Con A, KOH-sialidase- Wheat germ agglutnin [WGA], GSA II, SBA, Griffonia simplicifolia agglutinin-isolectin B4 [GSA I-B4], Maackia amurensis agglutinin II [MAL II]). The supranuclear cytoplasm of nonciliated cells expressed terminal GlcNAc (GSA II) in all specimens, also O-linked glycans (mucin-type glycans) with GalNAc and sialic acid termini (Helix pomatia agglutinin [HPA] and MAL II) in control animals, and also N-linked glycans with fucose, galactose, lactosamine, and α2,3-linked sialic acid termini (Ulex europaeus agglutinin I [UEA I], GSA I-B4, Ricinus communis agglutinin120 [RCA120], and Sambucus nigra agglutinin [SNA] ) in superovulated ewes. These results report for the first time that the superovulation treatment affects the secretory activity and the glycan pattern of the epithelium lining the sheep oviductal ampulla.

Effect of intravaginal fluorogestone acetate sponges on prolactin levels of Damascus-local cross breed goats.

The effect of intravaginal fluorogestone acetate (FGA) sponges on prolactin levels (PRL) and correlations between PRL and milk somatic cell count (SCC) and steroid hormones levels of Damascus-local cross goats during transitional period to anestrous were investigated in this study. Fifty-six goats were assigned to three groups. Group 1 (FGA, n = 19) was treated with 40 mg FGA and equine chorionic gonadotropin (600 IU, i.m.) at time of sponge withdrawal (day 0). Group 2 (FGA-PGF; n = 19) was treated similar to group 1 but was also injected with dinoprost tromethamine (naturally occurring PGF2α) (10 mg, i.m.) on day 0. Control goats (n = 18) were left untreated. On day 0, five fertile bucks were turned in with all goats. Milk and blood samples were collected on days -13 (day of sponge insertion), -6, 0, 1, 2, 7, 13, and 20. Prolactin levels were at lowest values on day -13 of the study and increased (p < 0.05) from day -6 to day 20 in all groups. A significant positive correlation (p < 0.05) between PRL and progesterone and between PRL and estradiol levels was found in this study. No significant correlation was found between PRL and SCC of all groups during the study except on days 2 and 20 where PRL levels were correlated (p < 0.05) with SCC of left udder halves of FGA group. In conclusion, estrus induction with FGA resulted in significant increase in PRL. A positive correlation was found between PRL and steroid hormones, but there was no correlation between PRL and goat milk SCC.

Short communication: estrus synchronization using progestogens or cloprostenol in tropical hair sheep.

The objective of the experiment was to compare the use of a PGF2α analogue (Cloprostenol) IM, with an intravaginal progestagen sponge, flurogestone acetate (FGA), and equine chorionic gonadotropin (eCG) IM application protocol. A total of 30 cyclical hair ewes (54.07 ± 0.5 kg live weight, body condition score 3.5 ± 0.5, and age 3 ± 1 years) were used. For the control group ewes (n = 15), intravaginal sponges (IS) impregnated with 20 mg of FGA were inserted for 12 days with 500 IU of eCG IM at sponges withdrawal. For the PG group ewes (Treatment group n = 15), two injections of Cloprostenol (75 mcg) were given 12 days apart. The presence of estrus was detected using two rams with 8 h interval beginning at the end of the treatment. Progesterone concentrations in blood were measured by solid phase radioimmunoassay. A student's t test was performed to analyze the duration of estrus and the interval between the ends of the treatment and the onset of estrus (ET-OE) presentation. Progesterone levels were compared with two-way ANOVA, with treatment, and day of menstrual cycle as fixed factors. Treatment costs ratio was calculated by dividing the total costs of FGA IS application between total costs of Cloprostenol application. Significant differences (P < 0.05) were found in the (ET-OE) interval and estrus duration. For the control group, estrus was presented at 30 + 8.2 h; in treatment group, at 44 h after the last application, duration of estrus was 54.9 + 8.34 h, and 41 + 1.83 h for the control and treatment group, pregnancy rates were 53.3 and 60.0 %, respectively. Significant differences (P < 0.001) were found from days 9 to 13 on Progesterone levels in both treatments. Treatment costs of Cloprostenol protocol were 2.63 cheaper than FGA including disposable material, biological products, and labor. It was concluded that Cloprostenol could be an effective tool in estrus synchronization in hair sheep in tropical areas.

Influence of the FecX(R) allele in heterozygous ewes on follicular population and outcomes of IVP and ET using LOPU-derived oocytes.

Ewes heterozygous for the FecX(R) allele (R+) in the bone morphogenetic protein 15 (BMP15) gene display increased ovulation rate and prolificacy. Besides this phenotypic advantage, the influence of the FecX(R) allele on follicle number and size, oocyte competence and in vitro production (IVP) remains undefined. With these aims, 8 R+ and 8 wild-type (++) ewes were subjected to 2 laparoscopic ovum pick-up (LOPU) trials (four sessions per trial; two with and two without FSH) and subsequent IVP and fresh embryo transfer. All follicles >3 mm were punctured (n = 1673). Genotype did not significantly affect the number of punctured follicles per ewe and session (10.4 and 10.2 in R+ and ++ untreated ewes, 17.4 and 14.3 in R+ and ++ FSH-treated ewes, respectively), but follicular diameter of R+ ewes was significantly reduced compared with ++ ewes (-0.2 mm in untreated and -0.8 mm in FSH-treated ewes; p < 0.01). R+ ewes showed higher recovery rate and increased numbers of total and suitable cumulus-oocyte complexes for in vitro maturation (IVM). Similar rates of day 8 blastocysts were observed in R+ (36.1%, 147/407) and ++ (32.6%, 100/307) ewes, but the final output of day 8 blastocysts per ewe and session was higher in R+ ewes (+0.75; p < 0.005), without differences in survival rate at birth of the transferred embryos (40.4%, 21/52 vs 36.4%, 16/44, respectively). In conclusion, a higher number of oocytes proven to be competent for in vitro development and embryo survival after transfer are recovered from R+ ewes, despite the lower mean size of their follicles at puncture.

Estrus response and follicular development in Boer does synchronized with flugestone acetate and PGF2α or their combination with eCG or FSH.

The effects of different estrus synchronization techniques on follicular development and estrus response were studied in 81 nulliparous Boer does. The does were divided into nine groups. Eight of the nine groups were synchronized with prostaglandin F2-alpha (PGF(2α)) or flugestone acetate (FGA) or their combinations, and the ninth group was a control group. In addition to the above combinations, four of the eight synchronized groups were given 5 mg follicle-stimulating hormone (FSH) and the remaining four groups were administered 300 IU equine chorionic gonadotrophin (eCG). Posttreatment follicular development was monitored until ovulation occurred using a real-time B-mode ultrasound scanner (Aloka, 500 SSD, Japan), with a 7.5-MHz transrectal linear probe. All the does from the synchronized groups that were given eCG exhibited oestrus while only 88.9% of the does synchronized with FSH showed estrus. The estrus response was observed to be the least among the does synchronized with PGF(2α) + FSH (33.3%) combination followed closely by the FGA + FSH (42.9%) combinations. It was observed that the combinations of FGA + PGF(2α) + FSH resulted in increased percentage of estrus response, duration of estrus, and ovulation. The number of follicles was higher (P < 0.05) in FSH-synchronized groups than the eCG-synchronized groups. It was concluded that the best estrus synchronization protocol in goats is the FGA + eCG with or without PGF(2α). However, the PGF(2α) + FGA + FSH method of estrus synchronization is the most promising combination for further development as a better alternative to estrus synchronization with eCG in does.

Response of fat-tailed Syrian Awassi ewes to accelerated lambing systems.

Fifty cyclic fat-tailed Syrian Awassi ewes aged 2-4 years, with a mean weight of 51.4 kg, were used for 4 years to assess the accelerated lambing system (three lambings in 2 years). Ewes were divided into two groups: treated (T) and untreated (C). Ewes in the T group were treated with flugestone acetate for 14 days and injected intramuscularly at sponge withdrawal with 500 IU of equine chorionic gonadotropin (eCG). Results indicated that ewes in the T group exhibited oestrus and were mated within 5 days post sponge removal compared to 11 days for ewes in the C group, and the difference in oestrus response between the two groups was significant (P < 0.001). Repeated hormonal treatments had no significant (P > 0.05) effect on the lamb birth weight. However, significant (P < 0.001) differences in the lamb birth weight were observed between singles and multiple births. In the treated ewes, the total number of lambs born was 211-157 parturitions, and the multiple birth rate reached 27.4%, whereas the rate in the untreated group was 6.3% with the difference being significant (P < 0.05). In the untreated ewes, the total number of lambs born was 14-13 parturitions (12 singles and 1 twin). Fecundity rates were 135.1% and 106.3% in the treated and untreated ewes, respectively, and the difference was significant (P < 0.05). Repeated administration of eCG had no negative effect on fertility of Syrian Awassi ewes. However, anti-eCG antibodies were produced following eCG injections with extremely high individual differences in the immune response among ewes.

The effects of time and dose of pregnant mare serum gonadotropin (PMSG) on reproductive efficiency in hair sheep ewes.

The aim of this study was to evaluate the effects of dose and application time of pregnant mare serum gonadotropin (PMSG) on reproductive performance of hair sheep ewes synchronized with fluorogesterone acetate (FGA) under tropical conditions of Northeastern Mexico. Ninety-nine hair ewes (63 Blackbelly and 36 Pelibuey) were treated with intravaginal sponges during 10 days. After insertion of FGA sponges, ewes were divided into four groups, and PMSG was injected intramuscularly at doses of 100, 200, and 400 IU. Relative to FGA sponge removal, PMSG was administrated at -48 h, -24 h, and at sponge removal. PMSG was not administered to the control group. Control ewes had similar (P > 0.05) lambing rate, fertility, and fecundity than those treated with 100 IU of PMSG, but lower (P < 0.05) percentages to these variables than those treated with 200 and 400 IU of PMSG. Time to estrus decreased linearly, and ovulation rate increased quadratically as PMSG dose increased (0 to 400 IU). Administration of PMSG before sponge removal increased (P < 0.01) response to estrus and decreased (P < 0.01) interval to estrus compared with control. Ovulation rate, lambing rate, fertility, and fecundity were not affected (P > 0.05) by administration time of PMSG. Both dose and time of PMSG application did not affect (P > 0.05) pregnancy rate, percentage of single and multiple lambing, and prolificacy. In conclusion, results show that the dose of 400 IU of PMSG administered before sponge withdrawal in an estrus synchronization protocol improved reproductive efficiency of hair sheep ewes.

Characterization of oestrous induction response, oestrous duration, fecundity and fertility in Awassi ewes during the non-breeding season utilizing both CIDR and intravaginal sponge treatments.

The aim of this study was to investigate characterization of oestrous response, onset of induced oestrus, oestrous duration, fecundity and fertility in Awassi ewes treatment with intravaginal sponges and Controlled Intravaginal Drug Release (CIDR) devices in combination with pregnant mare serum gonadotropin (PMSG) under local environmental conditions during the non-breeding season. A total of 62 ewes were divided into three groups. Group CIDR (n = 20) was treated with CIDR devices for 12 days and 400 IU PMSG was injected upon removal of the CIDR. For ewes in Group Sponge (SP) (n = 24), 30 mg fluorogestone acetate was administered to the sheep for 12 days and 400 IU PMSG was injected upon withdrawal of the sponge. Group Control (CON) (n = 18) served as a control group and received no treatment. Adult, intact and sexually experienced Awassi rams were introduced to all groups at the time when the intravaginal devices were removed. There were no significant differences in terms of oestrous response (CIDR: 90%, SP: 87.5%), time to onset of oestrus and duration of induced oestrus between the CIDR and SP groups. The oestrous response of treatment groups was significantly greater (p < 0.05) than in the control ewes. There were no significant differences in pregnancy (CIDR: 70%, SP: 70.8%), lambing (CIDR: 85%, SP: 79.2%) and fecundity rates between ewes treated with CIDR and those treated with sponges. However, pregnancy and lambing rates were significantly (p < 0.05) higher in ewes treated with CIDR or sponges when compared with those in the control group. It was concluded that it is possible to induce fertile oestrus, successful pregnancy and lambing with the treatment of either CIDR or intravaginal sponge in combination with PMSG in Awassi ewes during the non-breeding season.

Short-term undernutrition affects final development of ovulatory follicles in sheep synchronized for ovulation.

The objective of this study was to determine, in sheep, the effect of a short-term undernutrition on growth dynamics and competence of pre-ovulatory follicles. Synchronization of sexual cycles and induction of ovulation were performed, with progestagens and gonadotrophins, in 14 adult female sheep. Morphological characteristics and developmental competence of ovarian follicles to achieve ovulation were determined by imaging techniques (ultrasonography and laparoscopy) and blood sampling. All the animals ovulated and mean ovulation rates were similar between groups (2.0 ± 0.6 corpora lutea in control ewes and 2.2 ± 0.8 in undernourished sheep). However, nutritional restriction, even during a short period, was related to the presence of large follicles in static growing phase which, despite reaching ovulation, persisted static during the induced follicular phase and evidenced functional alterations as there was no inhibition of the development of subordinate follicles. Thus, this study suggests the existence of deleterious effects from short-term undernutrition on functionality of pre-ovulatory follicles, which can compromise fertility.