RESUMEN
To compare the reproductive performance after TAI in ewes synchronized with mid (12 or 13) or long (14-16 d) interval prostaglandin (PG) or progesterone plus eCG (P4-eCG) based protocols, 440 multiparous Corriedale ewes were synchronized with two PG injections administered 12-16 d apart (PG12, PG13, PG14, PG15 and PG16 respectively), or P4-eCG (MAP sponges 14 d and eCG). Cervical TAI (Day 0) was performed with fresh semen. It was evaluated the ovulated ewes (OE, %) and the ovulation rate (OR) on Day 8 by trans-rectal ultrasonography, the rate of non-return to service between Days 13 and 21 by painted rams, and the pregnancy rate, prolificacy and fecundity on Day 60 by trans-abdominal ultrasonography. No significant differences were found in OE among groups (P>0.05), but P4-eCG achieved higher OR (P<0.05) compared to PG protocols, without differences among them (P>0.05). Similar NRR-21, pregnancy and fecundity were observed among PG15 (64.3, 62.9 and 84.3), PG16 (59.7, 59.7 and 77.8) and P4-eCG (70.3, 66.2 and 95.9), but higher compared to PG12 (42.5, 39.7 and 52.1) and PG13 group (44.0, 40.0 and 48.0, respectively; P<0.05). PG14 achieved intermediate results compared to other groups. No differences were found in prolificacy among groups (P>0.05), except PG13 that was lower compared to P4-eCG (P<0.05). In conclusion, long interval between PG injections (15 or 16 d) determined better reproductive outcome that mid interval (12 or 13 d), equating the P4-eCG based protocol after cervical TAI with fresh semen during the breeding season in sheep.
Asunto(s)
Dinoprost/análogos & derivados , Inseminación Artificial/veterinaria , Prostaglandinas F Sintéticas/farmacología , Ovinos/fisiología , Administración Intravaginal , Animales , Gonadotropina Coriónica , Dinoprost/administración & dosificación , Dinoprost/farmacología , Esquema de Medicación , Femenino , Acetato de Medroxiprogesterona/administración & dosificación , Acetato de Medroxiprogesterona/farmacología , Embarazo , Progesterona/farmacología , Prostaglandinas F Sintéticas/administración & dosificaciónRESUMEN
The objective of this experiment was to study the reproductive performance obtained after a short-interval prostaglandin (PG) F2α-based protocol for timed artificial insemination (TAI) in sheep (Synchrovine®: two injections of PG 7 d apart), including a GnRH analogue at 24 or 36h after the second PG injection. The experiment involved 296 Corriedale ewes (206 multiparous and 90 nulliparous) grazing natural pastures during the breeding season (March-April; UTU "La Carolina", Flores Uruguay, 33° S-57° W). Ewes were assigned to three treatment groups: a) Synchrovine® (Control, n=101): two injections of D-Cloprostenol 75µg, 7 d apart, b) Synchrovine®+GnRH24 (n=98): Synchrovine® plus GnRH (busereline acetate 8.4µg) 24h after the second PG injection, and c) Synchrovine®+GnRH36 (n=97): Synchrovine® plus GnRH 36h after the second PG injection. All ewes were subjected to cervical TAI (Day 0), 44 to 47h after second PG injection, with fresh extended semen pool from six rams. Reproductive performance of ewes having ovulations and ovulation rate on Day 10, estrous cycle length in ewes that returned to estrus and non-return rate to estrus up to Day 22, fertility, prolificacy and fecundity on Day 70 were analyzed. Ewes having ovulations, ovulation rate, estrous cycle length and prolificacy did not differ between groups (P>0.05). However, non-return to estrus, fertility and fecundity was decreased in Synchrovine®+GnRH24 (P<0.05) and similar between Synchrovine® and Synchrovine®+GnRH36 (P>0.05). It was concluded that the reproductive performance obtained by Synchovine® TAI protocol was impaired by GnRH at 24h and not improved by GnRH administered at 36h after the second PG injection.
Asunto(s)
Dinoprost/administración & dosificación , Hormona Liberadora de Gonadotropina/administración & dosificación , Inseminación Artificial/métodos , Reproducción/efectos de los fármacos , Oveja Doméstica , Animales , Esquema de Medicación , Sincronización del Estro/métodos , Femenino , Fármacos para la Fertilidad Femenina/administración & dosificación , Inseminación Artificial/veterinaria , Masculino , Inducción de la Ovulación/métodos , Inducción de la Ovulación/veterinaria , Reproducción/fisiología , Oveja Doméstica/fisiología , Resultado del TratamientoRESUMEN
The objective was to improve the reproductive performance of a prostaglandin (PG) F(2α)-based protocol for timed artificial insemination (TAI) in sheep (Synchrovine®: two doses of 160 µg of delprostenate 7 d apart, with TAI 42 h after second dose). Three experiments were performed: Experiment 1) two doses of a PGF(2α) analogue (delprostenate 80 or 160 µg) given 7 d apart; Experiment 2) two PGF(2α) treatment intervals (7 or 8 d apart) and two times of TAI (42 or 48 h); and Experiment 3) insemination 12 h after estrus detection or TAI with concurrent GnRH. Experiments involved 1131 ewes that received cervical insemination with fresh semen during the breeding season (32/34 °S-58 °W). Estrous behaviour, conception rate, prolificacy, and fecundity (ultrasonography 30-40 d), were assessed. In Experiment 1, ewes showing estrus between 25 and 48 h or at 72 h after the second PGF(2α) did not differ between 80 and 160 µg of delprostenate (73 vs 86%, P = 0.07; and 92 vs 95%, P = NS, respectively). Conception rate and fecundity were lower (P < 0.05) using 80 vs 160 µg (0.24 vs 0.42, and 0.27 vs 0.47, respectively). In Experiment 2, giving PGF(2α) 7 d apart resulted in higher (P < 0.05) rates of conception (0.45 and 0.51) and fecundity (0.49 and 0.53) than treatments 8 d apart (conception: 0.33 and 0.29; fecundity: 0.33 and 0.34) for TAI at 42 and 48 h, respectively. In Experiment 3, rates of conception, prolificacy and fecundity were similar (NS) between Synchrovine® with TAI at 42 h (0.50, 1.13, and 0.56) and AI 12 h after estrus detection (0.47, 1.18, and 0.55), and Synchrovine® plus GnRH at TAI (0.38, 1.28, and 0.49). However, all TAI treatments had lower (P < 0.05) prolificacy and fecundity compared to AI following detection of spontaneous estrus (1.39 and 0.83, respectively). In conclusion, the Synchrovine® protocol was: a) more successful using 160 vs 80 µg delprostenate; b) more successful with a 7 d than 8 d PGF(2α) interval; c) similarly effective for TAI versus AI 12 h after estrus detection; and d) not improved by giving GnRH at TAI.
Asunto(s)
Dinoprost/análogos & derivados , Dinoprost/farmacología , Sincronización del Estro/métodos , Fármacos para la Fertilidad Femenina/farmacología , Inseminación Artificial/veterinaria , Prostaglandinas F Sintéticas/farmacología , Ovinos/fisiología , Animales , Dinoprost/administración & dosificación , Femenino , Fármacos para la Fertilidad Femenina/administración & dosificación , Inseminación Artificial/métodos , Embarazo , Índice de Embarazo , Prostaglandinas F Sintéticas/administración & dosificación , Factores de TiempoRESUMEN
Two experiments were conducted to determine the effects of prostaglandin administration on ovarian follicular dynamics, conception, prolificacy, and fecundity in sheep. During the breeding season, multiparous Corriedale ewes were randomly allocated to two groups: 1) PG group (n = 15 and n = 135 in Experiments I and II, respectively): synchronized with two injections of DL-Cloprostenol (125 µg) given 7 d apart, and inseminated at a fixed time (Day 0), 48 h after the second injection; and 2) Control group (n = 15 and n = 73 in Experiments I and II): ewes in spontaneous estrus inseminated at detected estrus. Ewes received 100 × 10(6) sperm by intrauterine AI. Ultrasonography was used to evaluate growth of the ovulatory follicle, ovulation rate (OR), conception rate, and prolificacy on Days 30 and 60. Ewes from the group PG had a larger (4.8 ± 0.5 mm, mean ± SEM; P < 0.05) ovulatory follicle that grew faster (1.2 ± 0.3 mm/d, P = 0.08), and a lower OR (1.37 ± 0.1, P < 0.05), compared to ewes from the Control group (3.9 ± 0.2 mm, 0.7 ± 0.2 mm/d, and 1.61 ± 0.1 respectively). Plasma progesterone concentrations from Days -6 to 1 were lower in the PG group (P < 0.05), but plasma estradiol concentrations were similar between groups (P > 0.05). Progesterone concentrations were similar between groups during the early luteal phase and on Days 12 and 17 (P > 0.05). The embryo recovery rate (Day 7) tended to be lower in the PG group (39 vs 64%, P = 0.08), but embryo quality did not differ between groups. Conception, prolificacy and fecundity, were lower in the PG than in the Control group (P < 0.05). Cumulative reproductive losses were similar between groups, but more twins were lost in the PG group (P < 0.05). We concluded that in ewes synchronized with PGF(2α) given twice, 7 d apart, lower reproductive performance was associated with an environment dominated by lower progesterone concentrations that stimulated the preovulatory follicle to grow faster and become larger; this was associated with lower rates of ovulation, conception, prolificacy, and fecundity.
Asunto(s)
Cloprostenol/farmacología , Luteolíticos/farmacología , Folículo Ovárico/efectos de los fármacos , Folículo Ovárico/fisiología , Ovinos/fisiología , Animales , Estradiol/sangre , Femenino , Fertilidad/efectos de los fármacos , Fertilidad/fisiología , Inseminación Artificial/veterinaria , Masculino , Folículo Ovárico/diagnóstico por imagen , Embarazo , Progesterona/sangre , Distribución Aleatoria , UltrasonografíaRESUMEN
The objective was to compare the reproductive performance of a new PGF(2α)-based timed artificial insemination (TAI) protocol in sheep (Synchrovine®: two doses of PGF(2α), 7 d apart) to a traditional progesterone-eCG (P4-eCG) protocol, considering the effects of seminal state, AI-times, and AI-pathway. Three experiments involving 1297 multiparous Australian Merino ewes were done during the physiologic breeding season (location 32 °S-57 °W). Reproductive performance was assessed as non-return rate to service 21 d after AI (NRR21d), based on detection with androgenized wethers, as well as Fertility (pregnant/inseminated ewes), Prolificacy (fetuses/pregnant ewe), and Fecundity (fetuses/inseminated ewe), which were based on transabdominal ultrasonography 50 d after TAI. In Experiment 1, Synchrovine® treated ewes TAI cervically with fresh semen at 42, 48, or 54 h had similar NRR21d (0.51, 0.46, 0.57), Fertility (0.27, 0.31, 0.26), and Fecundity (0.29, 0.32, 0.27), all of which were lower (P < 0.05) than in a control P4-eCG group inseminated at 54 h (0.61, 0.48, 0.52, NRR21d, Fertility and Fecundity respectively). In Experiment 2, using chilled semen and cervical TAI, Synchrovine® treated ewes inseminated at 42 h yielded lower (P < 0.05) NRR21d, Fertility and Fecundity (0.28, 0.06, 0.06) compared to 48 (0.43, 0.24, 0.24) and 54 h (0.44, 0.22, 0.23). In Experiment 3 with chilled semen, Synchrovine® treated ewes TAI into the cervix at 51 or 57 h were similar in NRR21d (0.16 vs 0.20), Fertility (0.12 vs 0.14), and Fecundity (0.12 vs 0.15), respectively; but lower (P < 0.05) than P4-eCG treated ewes TAI at 54 h (0.34, 0.28, and 0.33 for NRR21d, Fertility and Fecundity respectively). Synchrovine® treated ewes intrauterine TAI at 51 or 57 h yielded similar NRR21d (0.51 vs 0.58), Fertility (0.43 vs 0.51), and Fecundity (0.45 vs 0.56) respectively, but lower (P < 0.05) results compared to P4-eCG treated ewes (0.75, 0.71, and 0.88 for NRR21d, Fertility and Fecundity respectively). In conclusion, AI-time in Synchrovine® treated ewes with fresh semen might be extended (42 to 54 h after the second PGF(2α)), but should be delayed to 48-54 h with chilled semen and cervical AI. Independent of the seminal state, AI-time or AI-pathway, Synchrovine® yielded lower reproductive results than a conventional P4-eCG protocol.
Asunto(s)
Dinoprost/administración & dosificación , Sincronización del Estro/métodos , Inseminación Artificial/veterinaria , Progesterona/administración & dosificación , Ovinos , Animales , Esquema de Medicación , Femenino , Fertilidad/efectos de los fármacos , Fertilidad/fisiología , Fármacos para la Fertilidad Femenina/administración & dosificación , Inseminación Artificial/métodos , Masculino , Embarazo , Índice de Embarazo , Ovinos/fisiología , Factores de TiempoRESUMEN
This study aimed at comparing in vitro, ultra-heat-treated (UHT) skim milk and INRA-96(®) -based extenders supplemented or not with 5% egg yolk and/or 2% glycerol on sperm quality parameters along 72 h of preservation at 5 °C, using a factorial design. Semen from six healthy mature Merino rams was pooled and extended in each medium using a split sample procedure (six replicates) and chilled. Subjective motility (SM) (%), membrane integrity (MI) (%) and uncapacitated spermatozoa (US) (× 10(6) spermatozoa/AI dose) were used to assess the semen quality at 0, 12, 24, 48 and 72 h of preservation. UHT-based extenders yielded better (p<0.05) SM and MI than INRA-96(®) -based extenders (59.7% vs 57.9%; 60.2% vs 55.8%, respectively) but similar numbers of US (64.2% vs 62.3 × 10(6) sperm/AI dose, respectively) along the preservation time. Egg yolk-glycerol or just egg yolk as additives improved (p<0.05) the results compared with the base extenders without additives or just with glycerol. The sperm parameters assessed decline slowly from 0 to 48 h, with a sharp decline (p<0.05) at 72 h of preservation. In conclusion, UHT and INRA-96(®) were similar as base extenders, and the addition of 5% egg yolk plus 2% glycerol or just 5% egg yolk improved the quality of ram semen preserved at 5 °C, at least for 48 h. The combination of egg yolk-glycerol might provide extra protection in case of fluctuation of temperatures below 5 °C, commonly seen under field conditions.
Asunto(s)
Frío , Yema de Huevo , Glicerol , Leche , Preservación de Semen/veterinaria , Ovinos , Animales , Crioprotectores , Inseminación Artificial/veterinaria , Masculino , Preservación de Semen/métodos , Motilidad Espermática , Espermatozoides/fisiologíaRESUMEN
This study aimed at comparing the effect of ram semen preserved at 5 °C on two milk-based extenders (UHT skim milk or INRA-96(®) , 5% egg yolk) supplemented with 2% glycerol, and the preservation time (24 and 48 h) on conception rates after cervical AI of ewes. In two field trials, 1198 Merino ewes were cervical AI in spontaneous oestrus. In Experiment 1, pooled semen (6 rams) was extended in UHT-base (fresh, control) or chilled for 24 h in UHT5Y (UHT-base 5% egg yolk), INRA5Y (INRA-96(®) 5% egg yolk), UHT5Y2G (UHT5Y 2% glycerol) or INRA5Y2G (INRA5Y 2% glycerol). In Experiment 2, AI was performed with pooled semen (7 rams) used fresh (extended in UHT-base or UHT5Y2G, control groups) or chilled (extended in UHT5Y2G) for 24 or 48 h. Conception rate was determined by ultrasound 40 days after AI. INRA-96(®) - had similar conception as UHT-preserved semen (56.7 vs 55.4%, p>0.05). Addition of 2% glycerol did not modify the results (56.8 vs 55.2%, p>0.05). Fresh semen extended in UHT-base, and UHT5Y2G yielded similar conception rates (60 vs 64%, p>0.05). Preservation for 24 or 48 h in UHT5Y2G gave similar results (49 vs 47%; p>0.05). In conclusion, ram semen chilled for 24 h in UHT- or INRA-96(®) -based extenders yielded similar results, and glycerol addition did not have a detrimental effect. UHT5Y2G might be used to extend ram semen for fresh AI, or to preserve it for 24 or 48 h with acceptable results.