Luteal function in cyclic goats treated with human chorionic gonadotropin administered by intramuscular or intravaginal routes at the time of artificial insemination.

Human chorionic gonadotropin (hCG) has been used to improve goats reproductive efficiency. This study aimed to (i) evaluate if hCG administered by the intramuscular (i.m.) or intravaginal (i.vag.) route can be detected by a rapid ß-hCG test in blood plasma samples and (ii) document ovarian effects of hCG administered by both routes at the time of artificial insemination (AI) performed 60 h after oestrus synchronization in goats. Twenty-two Alpine goats received two i.m. injections of 30 µg of d-cloprostenol (Prolise®, Tecnopec, São Paulo, Brazil) 7.5 days apart. One day after the onset of oestrus (at the time of AI), the goats were randomly allocated to one of the three groups that received: control (n = 7): 0.3 ml of saline solution intravaginally; hCGi.m. (n = 7): 300 IU of hCG (Vetecor®; Hertape-Calier, São Paulo, Brazil) i.m. and hCGi.vag. (n = 8): 300 IU of hCG deposited intravaginally. Blood samples were drawn at -1, 3, 6, 9 and 24 h after as well as on days 3, 7, 10, 13, 17 and 21 after hCG treatment/AI. All animals tested negative for hCG (ECO Diagnóstica, Corinto, Brazil) at -1 h, and all control animals tested negative throughout the entire blood collection period. All hCGi.m. animals tested positive from 3 h until D3 post-AI but only 50% of hCGi.vag. goats tested positive during the present study. In all animals studied, mean circulating P4 concentrations increased (p < .05) from D3 to D7 after AI and then declined (p < .05) from D10 to D17 in control and hCGi.m. groups and from D17 to D21 in the hCGi.vag. group. Total cross-sectional luteal area (CLA), mean colour Doppler area (DA), DA/CLA, mean high-velocity Doppler area and HVDA/CLA all declined (p < .05) by D17-D21 in all animals studied. In summary: (i) human chorionic gonadotropin could consistently be detected in blood samples using the rapid ß-hCG test only in the hCGi.m. group; and (ii) there were no significant differences in the mean pregnancy rate, circulating P4 concentrations and various luteal parameters studied among Control, hCGi.m. and hCGi.vag. dose.

Use of meloxicam with or without dipyrone in non-surgical embryo recovery in hair sheep: Effects on animal welfare.

The aim of this study was to determine the effectiveness of meloxicam with or without dipyrone on the welfare of ewes subjected to non-surgical embryo recovery (NSER). Two studies were carried out using 51 multiparous Santa Inês ewes. All animals received a standard oestrous synchronization treatment and a superovulatory protocol. In Study 1, 12 ewes received meloxicam (GM) before cervical transposition (1 mg kg-1 , i.v.), repeated 24 h after (1 mg kg-1 , i.m.), while the other 10 received a saline solution, remaining as a control group (GC1). In Study 2, ewes were allocated into a group of 15 ewes treated as GM of Study 1 associated with dipyrone (GMD; 50 mg kg-1 , i.m.) before cervical transposition, 12 h, and 24 h after, or a control group (GC2) of 14 ewes treated with saline solution. In both studies, heart and respiratory rates (RR), cortisol, glucose, total proteins, albumin and globulins blood concentration were recorded before sedation (BS), after sedation (AS), after cervical transposition, immediately after collection (IAC), and 0.5, 1.5, 3, 6, 12, 24 and 48 h after embryo collection (hAC). In Study 1, RR tended to be greater in GC1 (p = .08), serum total proteins and globulins values were lower and serum albumin values were greater in this group than GM (p = .003, p < .0001, and p < .0001, respectively). In Study 2, treatment of GMD tended to reduce the glycaemia at AS (p = .052) and reduced it at 3hAC (p < .0001), and 6hAC (p = .03). It also tended to reduce cortisol concentrations (p = .10). The other variables varied with NSER without interaction with the experimental treatments. In conclusion, in this study condition, NSER in sheep induced transient changes indicative of stress and possibly pain, therefore, affecting animal welfare. The administration of meloxicam was ineffective to reduce those responses, and the association of dipyrone had only slight effects without modifying the main welfare indicative responses in ewes subjected to NSER.

Climatic seasons and time of the day influence thermoregulation and testicular hemodynamics in Santa Inês rams raised under humid tropical conditions.

This study evaluated the possible association between the diurnal variations of climatic factors during the rainy (RS) or less rainy (LS) seasons on the testicular hemodynamics and thermoregulatory responses of hair sheep rams raised in a humid tropical climate. Santa Inês rams (n = 6) underwent evaluation of general and testicular physiological parameters (heart and respiratory rates, internal and scrotal temperatures, internal-scrotal temperature gradient, scrotal distention, and color Doppler ultrasound evaluation of the spermatic cords and spectral analyses of testicular arteries) over six consecutive weeks per season at three separate times daily (morning = 8:00 a.m., noon = 12:00 p.m., and afternoon = 5:00 p.m.) during the RS and LS. Climatic air temperature and relative humidity data were recorded, and the temperature and humidity index (THI) was calculated. Higher thermal challenge was observed in LS relative to RS (air temperature = 28.0 vs. 30.9 °C; relative humidity = 84.1 vs. 69.9%; THI = 80.0 vs. 82.5; P < 0.05). In both seasons, respiratory rate and internal temperature were normal, demonstrating the animals' adaptability. In RS, however, a higher scrotal temperature was recorded in relation to LS (35.0 vs. 34.7 °C; P < 0.05), with a gradual increase from morning to afternoon. Lower resistivity (0.40 vs. 0.64; P < 0.05) and pulsatility (0.55 vs. 1.14; P < 0.05) indices, and a higher rate of high-velocity blood flow of testicular arteries (71.1 vs. 60.6%; P < 0.05) were observed in RS compared to LS. The lowest correlations between testicular hemodynamic, physiological variables, and environmental parameters (P < 0.05) were observed in the morning. In conclusion, testicular thermoregulation and testicular hemodynamics were influenced by the climatic seasons and time of the day, being more efficient in the LS season and with less interference from environmental factors in the morning.

Study of the factors affecting embryo yields and quality in superovulated Morada Nova ewes that underwent non-surgical uterine flushing.

The present study compared the outcomes of in vivo embryo production in Morada Nova ewes subjected to either 9-day (G-9SOV , n = 21) or 12-day (G-12SOV , n = 21) progesterone (P4 )-based estruses synchronization protocol coupled with superovulatory treatment with decreasing doses of porcine follicle-stimulating hormone (133 mg of pFSH given over 3 days). Non-surgical embryo recovery (NSER) was performed 6-7 days after the onset of oestrus. Total antral follicle count doubled from the first to the sixth pFSH dose in both groups (p < .05). Oestrus responses did not vary between the two groups of animals (95.2%). Corpora lutea (CL) were detected in 85.0% and 60.0% of ewes that previously manifested oestrus behaviour in G-9SOV and G-12SOV respectively. NSER was successfully completed in 86.2% of ewes that had CL (p > .05). The mean number of CL per ewe/successfully flushed donor ewe was greater (p < .05) in G-12SOV (12.3 ± 1.7/12.1 ± 1.9) than in G-9SOV (7.9 ± 1.4/8.2 ± 1.6). Mean numbers of retrieved blastocysts and viable embryos were greater (p > .05) in G-12SOV (5.8 ± 1.9 and 3.7 ± 1.7) than G-9SOV (3.5 ± 1.1 and 0.8 ± 0.3 respectively). The total follicle count (all follicles ≥2 mm in diameter) at the sixth pFSH dose (at P4 -device removal) was positively correlated (p < .05) with the number of CL (r = .95) and viable embryos (r = .91) in G-12SOV . The ewes with ≥10 Cl (48% of all flushed donors) yielded 80.5% of viable embryos. In summary: (a) Morada Nova ewes from G-12SOV group had better superovulatory responses compared with G-9SOV group; (b) total follicle count at the last pFSH dose was a good predictor of superovulatory responses only in the ewes primed with P4 for 12 days; and (c) animals with ≥10 ovulations are main contributors to viable embryo production in Morada Nova ewes.

Effect of eCG in a short-term synchronization treatment on ovarian status, estrus synchrony, and ovulation in dairy goats managed under tropical conditions.

The aim of this study was to assess the need of using eCG on short-term estrus synchronization protocol in nulliparous (NUL) and multiparous (MULT) dairy goats during the breeding season. Alpine (n = 20), Nubian (n = 20), and Saanen (n = 16) goats received 60 mg medroxyprogesterone acetate intravaginal sponges for 6 days plus 30 µg d-cloprostenol and 200 IU eCG (G-eCG, n = 28) or saline (G-Control, n = 28) 24 h before sponge removal. The NUL and MULT goats of each breed were equally assigned into the two treatments. Transrectal ultrasonography was used to evaluate ovulatory parameters, and teaser goats were used for estrus detection every 12 h from sponge removal to ovulation. eCG did not affect (P > 0.05) estrus response (~86%), diameter of ovulatory follicles (~6.8 mm), and number of ovulations (~1.6). Nevertheless, eCG led to earlier (P < 0.05) ovulation (G-eCG = 65.1 and G-Control = 73.2 h) and increased (P < 0.05) the ovulation rate (G-eCG = 96.4% and G-Control = 67.9%). In the absence of eCG, no differences regarding reproductive parameters (P > 0.05) were found between parity orders. Alpine MULT goats underwent a superior (P < 0.05) number of ovulations (2.2) in comparison to NUL goats (1.3). In conclusion, the exclusion of eCG from short-term estrus synchronization protocol did not interfere with estrus response but decreased the ovulation rate.

Vaginal cytology and cervical mucus as tools to predict ovulation time in small ruminants.

The possibility of using cervical mucus and vaginal cytology as tools to predict ovulation time was assessed in 11 ewes and 11 does raised under tropical conditions. Every 12 h from progesterone removal to ovulation, estrus behavior, cervical mucus, vaginal cytology, and ovarian ultrasound exams were performed. In goats, vaginal cytology had 88% of accuracy on detecting the ovulation time. However, in sheep, there was no cell pattern in the vaginal cytology and cervical mucus varied at ovulation. In conclusion, both vaginal cytology and mucus evaluation may be useful tools to determine the ovulation time in goats; however, both strategies are less accurate in sheep.

Ultrasonographic cervical evaluation: A tool to select ewes for non-surgical embryo recovery.

This study assessed the cervical ultrasonography mapping as a tool to select donor ewes for non-surgical embryo recovery (NSER). Lacaune ewes had their cervix evaluated by ultrasonography 12 hr after induced oestrus onset (Trial 1, n = 24) or 30 min before NSER (Trial 2, n = 17). Cervical rings were longitudinally evaluated and classified by their degree of misalignment on ultrasonography (DMUS) into: DMUS-1-cervix rectilinear, DMUS-2-intermediate and DMUS-3-highly asymmetrical. For predicting cervical transposing, only DMUS-1 and DMUS-2 were considered suitable. Similar ranking was attributed to degree of misalignment on the cervical map (DMCM 1-3), established immediately before NSER, which was performed at days 6 to 7 after oestrus. In Trial 1, cervical retraction for NSER was not possible only in three ewes classified as DMUS-3 (3/14, 21.4%). No difference (p > .05) was observed in the cervical transposing rates between ewes with different DMUS (ranged from 80% to 100%). In Trial 2, DMUS-1 and DMUS-2 reached 100% of transposing, and the only DMUS-3 ewe has not been transposed. In Trial 1, the prediction performance for successful cervical transposing showed low sensitivity (45%) and no specificity due to a high incidence of false negatives (52%). However, in Trial 2, sensitivity and specificity were both 100%. The DMCM and DMUS were uncorrelated, probably due to cervical stretching required to perform NSER. In conclusion, cervical ultrasound assessment immediately before NSER was more efficient to predict the cervical transposing than at induced oestrus, allowing the classification and selection of ewes eligible for NSER.

Use of two cloprostenol administrations 11.5 days apart efficiently synchronizes oestrus in photostimulated multiparous dairy goats in the non-breeding season.

This study assessed the efficiency of synchronous oestrous induction by light programme followed by two doses of cloprostenol in acyclic Saanen goats of different parity orders. Primiparous (n = 22) and multiparous (n = 33) goats were subjected to 16 hr of light and 8 hr of darkness for 60 days (D0-D60), starting 10 days after the winter solstice. All goats received 120 µg cloprostenol doses on D130 (morning) and D141.5 (afternoon) (11.5 days apart). Oestrus behaviour, ovarian follicular dynamics and serum progesterone (P4) analyses were recorded from D0 to D174 at different intervals. Animals in oestrus after D141.5 were randomly assigned into two groups: assisted natural mating (NM) or artificial insemination (AI; 10-24 hr after oestrus onset with frozen-thawed semen). From D57 to D120, 89.0% of goats presented large follicles (5-8 mm) and P4 concentrations were subluteal from D0 to D120. More multiparous compared to primiparous goats (54.5%, 18/33 vs. 18.2%, 4/22) exhibited oestrus after both injections. More primiparous compared to multiparous goats (54.5%, 12/22 vs. 12.1%, 4/33) did not exhibit oestrus after any injection. A total of 35 goats (64%) were in oestrus after the second prostaglandin injection and were subjected to NM or AI. The conception rate was similar among primiparous (70.0%, 7/10) and multiparous (68.0%, 17/25) goats but the pregnancy rate differed, being 31.8% (7/22) and 51.5% (17/33), respectively. No interaction was found between parity order and P4 concentrations in does that became pregnant or not. Thus, the association between light programme (60 days, starting at the beginning of winter) and two cloprostenol administrations 11.5 days apart (starting 70 days after the end of the light treatment) resulted in sufficient synchronous oestrous response in multiparous acyclic Saanen goats to reach satisfactory fertility levels after both NM and AI.

Successful transcervical uterine flushing can be performed without or reduced dose of oestradiol benzoate in cervical relaxation protocol in Dorper ewes.

This study assessed the efficiency of cervical relaxation protocol using none, half or full dose (1.0 mg) of oestradiol benzoate in Dorper ewes subjected to non-surgical embryo recovery (NSER). Thirty-six pluriparous ewes received progestogen sponge (60 mg) for 9 days plus eCG administration (300 IU i.m.) 24 hr before sponge removal. Ewes were not mated and were randomly assigned to receive at 16 hr before NSER 37.5 µg d-cloprostenol i.m. and different doses of oestradiol benzoate: 0.0 mg (0EB group; n = 12); 0.5 mg (0.5EB group; n = 12) or 1.0 mg of oestradiol (1.0EB group, n = 12). All ewes received oxytocin (50 IU) i.v. 20 min before NSER, which was performed 8 days after sponge removal. Corpora lutea were counted by transrectal ultrasonography 24 hr before NSER. After procedure, the ewes were kept in natural breeding period to check their post-NSER fertility. NSER was performed in 91.7% (33/36) of the animals with overall fluid recovery efficiency over 97% (p > .05). The cervical transposing with Hegar dilator was longer (p < .05) in 0EB (4.2 ± 0.3 min) compared to 0.5EB (1.7 ± 0.3 min) and 1.0EB group (1.5 ± 0.3 min). The cervical transposing with mandrel/catheter was longer (p < .05) in 0EB (2.4 ± 0.5 min) than 1.0EB group (1.3 ± 0.5 min). Overall duration of uterine flushing was 25.4 min with structure recovery rate of 43.5%, with no difference among groups (p > .05). The post-NSER fertility was higher (p < .05) in 0.0EB (90%) than 0.5EB group (36.4%). In conclusion, NSER can be successfully performed in Dorper ewes by using a cervical relaxation protocol without oestradiol benzoate.

Pregnancy rate after fixed-time transfer of cryopreserved embryos collected by non-surgical route in Lacaune sheep.

This study investigated the feasibility of applying fixed-time (cryopreserved) embryo transfer in ewes. Embryos (n = 106) were non-surgically recovered from superovulated donors (n = 39) on day 6-7 after oestrus. Straws containing one or two embryos (morulae and/or blastocysts) subjected to either slow freezing (SF, n = 62) or vitrification (VT, n = 44) were randomly used within fixed-time embryo transfer on Day 8.5. Recipient ewes were nulliparous (n = 58) bearing corpora lutea after synchronous oestrous induction protocol. The pregnancy rate was higher (p = .03) in SF (39.4%) than VT (16.9%) and survival rate tended (p = .08) to be higher in SF than in VT (25.8% vs. 15.9%). Lambing rates were similar (p = .13) between SF (20.9%) and VT (15.9%). Embryos recovered by non-surgical route after cervical dilation treatment and later cryopreserved by either slow freezing or vitrification produced reasonable pregnancy rates after FTET.

Combined treatment with oestradiol benzoate, d-cloprostenol and oxytocin permits cervical dilation and nonsurgical embryo recovery in ewes.

This study examined the feasibility of transcervical embryo recovery after the hormonal treatment to induce cervical dilation, following the 7-day oestrous synchronization protocol in multiparous Santa Inês ewes. A total of 23 cyclic ewes received two doses of 37.5 µg of d-cloprostenol by latero-vulvar route 7 days apart. After the second injection of d-cloprostenol, the ewes were checked for oestrus (every 12 hr) and then mated by fertile rams throughout the oestrous period. All ewes received 37.5 µg of d-cloprostenol (latero-vulvar) and 1 mg of oestradiol benzoate by either intramuscular (EBim group; n = 12) or intravaginal (EBivg group; n = 11) route 16 hr before embryo flushing. Twenty minutes before the flushing, 50 IU of oxytocin were administered intravenously. The oestrous response (i.e., the percentage of ewes that showed signs of oestrous behaviour after the second d-cloprostenol injection) was 91.3% (21/23). The proportion of successfully penetrated ewes (81.8% compared with 80.0%), the mean duration of embryo flushing (24.7 ± 2.0 min compared 26.2 ± 1.9 min), the flushing fluid recovery rate (94.8 ± 1.3% compared with 91.0 ± 2.9%) and the average number of structures recovered per ewe (0.5 ± 0.4 compared with 0.8 ± 0.4) did not vary (p > 0.05) between the EBim and EBivg groups. Viable embryos were recovered from 41.2% (7/17) of successfully penetrated ewes. It can be concluded that nonsurgical (i.e., transcervical) embryo collection can be performed in oestrous-synchronized Santa Inês ewes pretreated with d-cloprostenol, oxytocin and oestradiol benzoate, with the latter hormone administered by either the intramuscular or intravaginal route.

Cervical transposition test using Hegar dilator at oestrus as a tool to select ewes for transcervical embryo collection.

This study evaluated the cervical transposition method as a tool to select ewes for embryo collection by transcervical route. Adult Santa Inês ewes (n = 50) received Day 0 protocol for superovulation treatments. The cervix transposition test was performed both at oestrus and at the embryo collection time. The latter was preceded by hormonal cervical dilation. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 85.7%, 66.6%, 85.7%, 66.6% and 80.0%, respectively. The kappa index yielded a moderate score (κ = 0.52). In conclusion, the high sensitivity and accuracy indicate that the cervical transposition test is a screening option to select ewes for embryo collection by transcervical route.

Comparison of the intravenous and intravaginal route of oxytocin administration for cervical dilation protocol and non-surgical embryo recovery in oestrous-induced Santa Inês ewes.

This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous-induced Santa Inês ewes (6-day treatment with progestin-releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6-7 days after oestrous onset and mating. All ewes received 37.5 µg of d-cloprostenol via latero-vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non-surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17-40 min) and ~96% of flushing fluid could be recovered (range: 85%-100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep.

Use of two doses of cloprostenol in different intervals for estrus synchronization in hair sheep under tropical conditions.

This study evaluated the effect of two doses of prostaglandin at different intervals on reproductive parameters of crossbred ewes. In Experiment 1, 30 ewes received two doses of 120 µg cloprostenol at 7 (G 7 days), 9 (G 9 days), or 11.5 (G 11.5 days) days apart. Ultrasound assessments were performed from the first and second cloprostenol administration for 5 days or ovulation detection. Estrus signs were checked by a teaser male. Plasma progesterone concentration was measured before each cloprostenol dose. In Experiment 2, 95 ewes were allocated into the same treatments and after the second dose, ewes in estrus were mated. At 30 days after breeding, pregnancy diagnosis was conducted and prolificacy was evaluated at lambing. In Experiment 1, at the first cloprostenol administration, 50% of ewes had an active CL and all showed estrus. At the second administration, 66.7% of ewes had an active CL and one did not present estrus. There was no difference (P > 0.05) after the second dose for as follows: overall estrous response (90%), interval from cloprostenol administration to estrous onset (42.0 ± 4.9 h), estrus duration (31.5 ± 2.1 h), ovulation rate (100.0%), and number of ovulations (1.5 ± 0.3). In Experiment 2, both pregnancy and prolificacy rates were similar (P > 0.05) for G 7 days (73.3; 145%), G 9 days (75.9; 125%), or G 11.5 days (75.9; 145%), leading to an overall pregnancy rate of 75.0% (66/88) and prolificacy rate of 137%. Therefore, the three treatments proposed were able to promote high pregnancy and prolificacy rates in crossbred ewes.

Efficiency of different hormonal treatments for estrus synchronization in tropical Santa Inês sheep.

The aim of this study was to evaluate the effect of (i) the duration of hormone treatment with progestogen sponges during the seasonal anestrus and (ii) the administration of two doses of prostaglandin at 7 days apart during the breeding season on reproductive parameters of Santa Inês ewes. In experiment 1, 32 ewes received intravaginal MAP sponges for 6 (G6 days), 9 (G9 days), or 12 (G12days) days and 75 µg D-cloprostenol i.m. and 300 IU eCG i.m. 1 day before sponge removal. In experiment 2, 23 ewes received two doses of 0.48-mg sodium cloprostenol i.m. 7 days apart. Ovarian follicular dynamic was assessed through transrectal ultrasonography. Blood samples were collected daily to determine progesterone concentrations. In experiment 1, estrus and ovulation rates did not differ (P > 0.05) among protocols and between cyclic and acyclic ewes at the beginning of the experiment. The G9 days treatment showed a lower dispersion of ovulations in relation to onset of estrus when compared to G6 days and G12 days. In experiment 2, all ewes exhibit estrus and ovulated after the second dose of prostaglandin, although ewes that were in diestrus at D0 showed subluteal concentrations of progesterone during the follicle development stage of the treatment. In conclusion, the use of progestogen device during 9 days promotes lower dispersion of ovulation when compared to its use for 6 or 12 days, and the protocol of two doses of prostaglandin 7 days apart synchronizes estrus efficiently but results in follicular development under low progesterone concentrations.

Reproductive performance, metabolic and hormonal profiles of Santa Inês ewes in winter and summer under tropical conditions.

The study aimed to evaluate the reproductive, metabolic and hormonal profiles of Santa Inês ewes during winter and summer in the tropical climate of Rio de Janeiro State, Brazil. The ewes (n = 16) were prepared for induction of synchronised oestrus with a short-term hormonal treatment, and follicular dynamics were assessed with ultrasonography. Blood samples for biochemical and hormonal analyses were collected on days zero, six and eight of the protocol at 7, 13 and 19 h. Reproductive behaviour did not differ (P > 0.05) between seasons. Based on ultrasonography data, the ovulation rate was 100% in summer and 81.3% in winter. Most of the ewes showed double ovulation in summer, and the diameter of the largest and second largest follicles differed (P < 0.05) between seasons. Among the biochemical parameters, plasma glucose, plasma urea and serum albumin differed (P < 0.05) between the study periods. Regarding the hormonal profile, higher serum triiodothyronine, thyroxine and prolactin concentrations (P < 0.05) were observed in summer. The average progesterone concentrations demonstrated low reproductive seasonality. In conclusion, the reproductive performance of the ewes was superior in summer, and higher levels of plasma glucose and serum albumin during this season may have played a role in the observed ovulation rates. The higher levels of serum prolactin and serum thyroxine in summer demonstrated that these compounds were not involved in the regulatory mechanisms underlying the onset of anoestrus in these Santa Inês ewes under tropical conditions.

Is the Santa Inês sheep a typical non-seasonal breeder in the Brazilian Southeast?

This study aimed to characterize the annual reproductive cycle of Santa Inês sheep in the Fluminense lowland region (latitude 22° 27' 45″ south, Rio de Janeiro, Brazil) between September 2011 and August 2012. Ten ewes were maintained in a semi-intensive system under natural photoperiods with access to pasture and shelter. Blood samples were collected every 2 weeks to determine plasma progesterone concentrations. The body condition score (BCS) was determined each month. There was no seasonal variation in the plasma progesterone concentration from the months of September to January, April, and May to August. In the months of February and April, the plasma hormone levels were higher than August to November. Seventy percent (7/10) of the sheep studied had short seasonal anestrus. The periods of anestrus were concentrated between the months of September and December (spring season) in 85.7 % (6/7) of the cases evaluated. In these cases, 57.1 % (4/7) also had short periods of reproductive inactivity during other months of the year. The progesterone values obtained in the spring corroborate the higher reproductive anestrus observed in this season. Higher plasma progesterone values were found in summer and autumn with reduction in the winter to lower values in the spring. No changes in the BCS during the study period were observed. Under the studied conditions, the Santa Inês sheep showed a low degree of reproductive seasonality. However, some individual ewes had seasonal anestrus during the spring. Further studies that include management techniques are needed to improve reproductive efficiency without hormone therapy in this breed under tropical conditions.

The presence of estradiol benzoate in the cervical relaxation treatment for non-surgical embryo collection does not impair embryonic morphological quality, cryosurvival, and gene expression profile.

Non-surgical embryo recovery (NSER) is usually preceded by a cervical relaxation in ovine donors, based on estradiol benzoate (EB), prostaglandin (PGF), and oxytocin (OT). However, it is hypothesized that, due to poorly understood mechanisms, EB can result in embryotoxic actions. To evaluate this, 20 min before NSER superovulated sheep were induced to cervical relaxation with 0.0 (G0.0), 0.5 (G0.5), or 1.0 mg (G1.0) of EB associated with 37.5 µg of PGF 16 h before NSER and 50 IU of OT. In doing so, the efficiency and duration of the NSER procedure showed no compromise (P > 0.05). Additionally, the presence of EB did not affect (P > 0.05) the embryo's morphological quality, the development dynamics, or the abundance of transcripts associated with embryonic quality (OCT4 and NANOG), cellular stress (HSP90 and PRDX1), and apoptosis (BCL2 and BAX). A similar result (P > 0.05) was also observed when comparing embryonic cryosurvival at 24 (52.0, 52.0, and 54.0) and 48 h (60.0, 54.0, and 58.0) of in vitro culture (G0.0, G0.5, and G1.0, respectively). Thus, we can conclude that EB use does not compromise embryonic quality and cryoresistance.

Luteal tissue characteristics of Morada Nova ewes with hCG application 7.5 days after the end of estrus synchronization protocol in the breeding season.

Results with the use of hCG after synchronization protocol are still inconsistent, which may vary according to breed, season, day of application and dose of the drug used. The aim of the present study was to evaluate the functionality of luteal tissue and ovarian perfusion after hCG treatment during early luteal phase. Estrus-synchronized ewes were randomly assigned to receive i.m. injection of 300 IU of hCG (G-hCG; n = 40) or 1 mL of saline (G-Control; n = 32) on Day 7.5 after progesterone withdrawal. Ultrasonographic evaluations of the ovaries and ovarian and iliac arteries were performed on Days 7.5, 10.5, 13.5, and 21.5. The accessory corpus luteum (aCL) formation rate was 52.5% for G-hCG. There was interaction (p > 0.05) for treatment (G-hCG and G-Control), days (7.5, 10.5, 13.5 and 21.5) and PD (Pregnant and Non-pregnant) for the variables of biometric characteristics of the corpus luteum B-Mode and Color Doppler on days 7.5, 10.5, 13.5 and 21.5. There was no difference (p > 0.05) for pregnancy rates and mean fetuses per ewe between the treatment groups. It is concluded that the application of hCG 7.5 days after the hormonal protocol in Morada Nova ewes in a breeding season is efficient in inducing aCL formation and increasing luteal tissue biometry. However, there was no effect on pregnancy rate.

The pFSH dose affects the efficiency of in vivo embryo production in Santa Inês ewes.

This study compared the follicular growth, superovulatory response, and in vivo embryo production after administering two doses of porcine follicle-stimulating hormone (pFSH) in Santa Inês ewes. The estrous cycle of 36 multiparous ewes was synchronized with the Day 0 protocol and superovulated with 133 mg (G133, n=18) or 200 mg (G200, n=18) of pFSH. Ultrasonographic evaluations of the ovaries were performed, ewes were mated and submitted to non-surgical embryo recovery. Viable blastocysts were stained with Nile Red and Hoechst. The G200 had a greater number of medium and large follicles, as well as a larger size of the third largest follicle. A total of 97.2% (35/36) of the ewes came into estrus and it was possible to transpose cervix in 80.6% (29/36). There were no effects of treatments in the response to superovulation, the proportion of ewes in which was possible to transpose the cervix, the number of corpora lutea, the number of anovulatory follicles, the proportion of ewes flushed with at least one recovered structure, number of recovered structures, number of viable embryos, viability rate, and recovery rate. The G200 ewes were in estrus for a longer period of time than the G133 ewes (54.0 ± 4.5 h vs. 40.3 ± 3.6 h) and produced more freezable embryos (6.5 ± 1.6 vs. 2.3 ± 0.7) than G133. Both doses promoted an efficient superovulatory response and did not affect embryonic lipid accumulation. The dose of 200 mg of pFSH showed greater potential to increase the superovulatory response, as it increased follicular recruitment and the recovery of freezable embryos.