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The production of kilograms of weaned calf per cow is a variable that depends on multiple factors, with fertility being a determining factor in the final result. When a greater proportion of females are pregnant and more pregnancies are obtained in the first month of breading season, the number of kilograms of calf weaned at a fixed date per cow included in the breeding season is greater. FTAI allows to increase the kilograms of weaned calves due to the shortening of the average interval between the beginning of breading season and conception, the increase in pregnancy percentage and the impact in the genetic improvement achieved through AI on weaning weight. The objective of this work is to compare, using simulation models, the productive impact of the implementation of a FTAI protocol in two cow-calf systems with different levels of cyclicity at the beginning of the service (50 vs 20%) and in the same farm with a low level of cyclicity at the beginning of the service (20%) with two criteria for including animals in the protocol. The productivity benefits achieved by the application of FTAI according to the simulation model were 34.7 kilos and 17.3 kilos for the conditions of 20% and 50% of cyclicity, respectively. This increase represents between 11 and 22% of the average weight at weaning compare to the NS strategy. In cases of initial cyclicity of 20%, the difference in kilos of weaned calf per cow between including all animals regardless of cyclicity vs including 70% of cyclic and in superficial anestrus, excluding those in deep anestrus, was 4.5 kg per cow. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate serum concentrations of P4 at the time of removal of the intravaginal device (DIV), time of detection of estrus (CD), Fixed Time Insemination (FTAI), and at day 7 post-FTAI, in sheep. The Huayrapungo Farm located in the parish of Malchinguí, with an altitude of 2600 to 2800 m.s.n.m; temperature between 7 and 17 0C, has multíparas sheep in production, breeds (Merino x Suffolk) f1, with body condition (2.5 / 5), 90 days open, and an age of 2 to 4 years. Divided into two treatments, (T1= 400 IU PMCG - 10 sheep), and (T2= 500 IU PMCG - 10 sheep). In a conventional protocol, in which, at day 0, CDR, 60mg P4 (Zoetis) was applied at day 10 was applied T1=400 IU; and T2=500 IU of PMCG i.m. (NOVORMON - PMCG 5000, Zoetis), plus 250 μg of Cloprostenol (PG2α, Ciclase DL, Zoetis), at day 12 DIV, day 13 AD, and day 14 IATF with laparoscopy method. At day 35 pregnancy was confirmed by ultrasonography. There was no significant difference in the pregnancy rate between treatments (60%) (P=0.073), similar in serum P4 concentrations at the time of DIV, DC, and IATF withdrawal (P=0.49). Not so, the day 7 post IATF, (P=0.020*). However, serum concentrations of P4 did not differ in the sheep's reproductive state (not pregnant or pregnant). [ABSTRACT FROM AUTHOR]

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El estudio evaluó cómo el diámetro de los cuernos uterinos y la actividad cíclica de vaquillas para carne influye en su comportamiento estral y tasas de gestación con inseminación artificial a tiempo fijo (IATF). Se usaron 100 vaquillas Bos taurus (cruzas no definidas de Angus, Charolais y Gelbvieh) de 300 ± 32 kg, evaluadas en su condición corporal (escala 1 a 5), el diámetro del cuerno uterino (1: menor a 1 cm; 2: 1 a 1.5 cm; 3: mayor a 1.5 cm) y su actividad cíclica al inicio del protocolo. La actividad cíclica se clasificó en: ciclando (C), anestro superficial (AS), o anestro profundo (AP). Se utilizó el protocolo J–Synch para sincronización de la ovulación, con seguimiento de la actividad estral mediante la pintura en la base de la cola. Los resultados mostraron que un 81 % de las vaquillas ciclando (C), exhibieron estro dentro de 72 h de finalizado el protocolo, superando significativamente a las vaquillas AS y AP (P≤0,001). La presencia de estro en vaquillas con un mayor diámetro uterino fue superior a las de menor diámetro (P≤0,001). Además, la intensidad del estro influyó en las tasas de gestación 30 días después de la IATF (P≤0,003). La actividad cíclica y el diámetro de los cuernos uterinos al inicio del tratamiento también afectaron las tasas de preñez (P≤0,05). Se concluye que, el diámetro de los cuernos uterinos y la actividad cíclica inicial en vaquillas para carne impacta la respuesta al protocolo J–Synch y las tasas de preñez pos–IATF.

Reproductiveperformance is crucialforprofitabilityofdual-purpose cow-calfproduction in the Ecuadorian Amazon. To evaluate three different fixed-time artificial insemination (FTAI) protocols in suckled, dual-purpose cows in the Ecuadorian Amazon. Lactating, Brown Swiss cows (n=301) received 2 mg estradiol benzoate (EB) and an intravaginal device containing 0.5 g of progesterone (P4) on Day 0. They were allocated randomly into the following three treatment groups: Cows in the EB group received 500 μg cloprostenol (PGF2α), and P4 devices were removed on Day 7, and 1 mg EB was administered on Day 8. Cows in the ECP group were treated as those in the EB group, except that they received 0.5 mg estradiol cypionate (ECP) at the time of P4 device removal on Day 7 instead of EB on Day 8. Cows in the J-Synch group had the P4 device removed and PGF2α administered on Day 6. All cows were FTAI on Day 9; cows in the J-Synch group also received 100 µg gonadorelin at that time. Although the diameter of the dominant follicle and the resulting CL were greater (P<0.05) in cows in the J-Synch group, pregnancies per AI did not differ (P>0.2) among groups (EB: 51.0%, ECP: 53.0% and J-Synch: 59.4%). The three protocols tested were applied successfully in suckled, dual-purpose cows with no differences in pregnancies per AI. [ABSTRACT FROM AUTHOR]

The objectives of the study were to evaluate: I. the predictive value of estrus expression on pregnancy rate at timed artificial insemination (TAI); II. the causal effect of administering GnRH at the time of TAI on the pregnancy rate in cows that did not express estrus; III. if GnRH administration in cows that do not exhibit estrus allows achieving pregnancy rates at TAI similar to those obtained in cows that exhibit estrus. A total of 406 suckled Angus cows were synchronized using a protocol based on intravaginal progesterone devices (IVPD), estradiol benzoate, a luteolytic agent, and estradiol cypionate (CPE). All animals were painted in the sacro-coccygeal region upon removal of the IVPD, and they were considered to be in estrus if they had at least 30% of the tail-paint rubbed-off. The cows that did not exhibit estrus were randomly allocated to receive or not receive a dose of gonadorelin acetate (GnRH) at the time of timed artificial insemination (TAI). All cows were inseminated within 48 to 54 hours after removal of the IVPD. Pregnancy diagnosis was performed 37 days post-TAI by ultrasonography. Estrus expression was associated with a higher pregnancy rate at TAI [56.1% (148/264) vs. 29.6% (21/71); P< 0.001]. GnRH administration improved the pregnancy rate at TAI in cows that had not expressed estrus [49.3% (35/71) vs. 29.6% (21/71); P= 0.026]. GnRH administration in cows that had not exhibited estrus allowed achieving pregnancy rates closer to those obtained in cows that exhibited estrus [56.1% (148/264) vs. 49.3% (35/71); P= 0.312]. In conclusion, estrus expression between IVPD removal and TAI is associated with a higher pregnancy percentage at TAI. Moreover, treatment based on GnRH application in cows that do not exhibit estrus improves the pregnancy rate at TAI, approaching the pregnancy rate achieved in cows that exhibit estrus. [ABSTRACT FROM AUTHOR]

Se realizó una investigación en la “Hacienda Manantiales del Rocío S.A.”, provincia de Manabí, Ecuador, dirigida a evaluar la respuesta de vacas de la raza Girolando a la administración de la hormona coriónica equina (eCG) posterior a la inseminación artificial a tiempo fijo (IATF). Se comparó un tratamiento testigo sin aplicación de la hormona contra un tratamiento con administración de 400 UI de eCG 20, 30 y 40 días después de la IATF (dd IATF). Se utilizó el mismo protocolo de inseminación para ambos grupos de animales. Se utilizó un diseño experimental completamente aleatorizado. Cada grupo contó con 29 animales. Las unidades experimentales estuvieron constituidas por una vaca Girolando. Se determinó el porcentaje de preñez por medio de análisis ecográfico en tres periodos distintos (30, 40 y 50 dd IATF). Las pérdidas embrionarias se cuantificaron por diferencia entre los periodos evaluados. Se utilizó la prueba de t Student para realizar comparaciones entre tratamientos. Los resultados evidenciaron que la aplicación de la hormona eCG posterior a la inseminación artificial no tuvo un impacto significativo sobre el porcentaje de preñez ni sobre las pérdidas por muerte embrionaria en las vacas de la raza Girolando.

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A pecuária de corte brasileira destaca-se no cenário econômico nacional quanto internacional, devido as melhorias nos índices de produção alcançados nos últimos anos. O melhoramento genético é uma das principais ferramentas que garantem o crescimento e o desenvolvimento da pecuária, enquanto, as biotécnicas da reprodução, tais como inseminação artificial, produção in vitro de embriões e transferência de embriões são utilizadas com o intuito de aumentar a eficiência da seleção genética e consequentemente acelerar o melhoramento genético no rebanho. Diante da importância do melhoramento genético e das biotécnicas da reprodução, nesta revisão serão apresentados dados sobre ferramentas para serem utilizadas na pecuária de corte afim de elevar os níveis de produção, visando impacto positivo no rebanho.

La iatf es una herramienta biotecnológica que permite el control del ciclo estral de la hembra a través de la incorporación de compuestos hormonales que precisan el momento exacto del celo y la ovulación. La combinación de estos compuestos ha permitido el surgimiento de innumerables protocolos hormonales que buscan mejorar la sincronización. El objetivo de este estudio fue evaluar el uso de protocolos hormonales a base de la hormona liberadora de gonadotropina (GnRH) sobre la fertilidad de novillas Bos indicus. Se sincronizaron 180 novillas (cíclicas y acíclicas) de la raza Brahman. Los tratamientos experimentales correspondieron a tres protocolos que incluyeron las siguientes hormonas: GNRH-PGF2-GNRH (T1 y T2), DIB-GNRH-PGF2-GNRH (T3 y T4) y DIB-GNRH-PGF2-eCG-GNRH (T5 y T6). A los animales se les evaluó el tamaño del folículo preovulatorio y el diagnóstico de preñez por medio de ultrasonografía, con los protocolos de sincronización se obtuvo una tasa de preñez total de: 10,7 % (T1), 16,6 % (T2), 36,8 % (T3), 41,9 %(T4), 38,7 % (T5) y 27,68 % (T6). Se encontró un efecto (p = 0,0803) entre los tratamientos al realizar la comparación de proporciones de preñez y se encontró que el T1 y el T2 fueron estadísticamente iguales (p > 0,05) y lo mismo sucedió con los tratamientos T3, T4, T5 y T6, pero se encontraron diferencias (p ≤ 0,05) entre los tratamientos T1 y T2 al compararlos con los tratamientos T3, T4, T5 y T6; por otro lado, no hubo diferencias (p ≥ 0,05) en el promedio del tamaño de folículo preovulatorio, siendo estos de 10,28 mm, 11,21 mm y 11,77 mm para las novillas sincronizadas con los tratamientos 1, 2 y 3, respectivamente. El uso de la hormona GnRH en combinación con la progesterona en protocolo Cosynch mejora significativamente las tasas de preñez en novillas Bos indicus, en comparación al protocolo Cosynch tradicional.

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The objective was to compare estrus expression and pregnancy to TAI in cyclic heifers treated or not with 300 IU of eCG at intravaginal progesterone device (IPD) removal. A total of 1049 heifers with reproductive tract score (STR) 4 and 5 received a 0,5 g IPD and 2 mg of estradiol benzoate (BE). Eight days later, 150 μg of D-Cloprostenol and 0,5 mg of estradiol cypionate (CE) were administered and paint was applied in the lumbosacral area. At this time heifers were randomly assigned to receive 300 IU of eCG (n = 524) or remained as non-treated controls (n = 525). At TAI, 48 h after IPD removal, heifers with more than 50% of paint removed were considered in estrus and the rest received 10,5 μg of busereline acetate. TAI was performed by two technicians using three bulls of proven fertility. Pregnancy diagnosis was conducted at 40 and 120 days. The effect of independent variables (group, STR, bull and inseminator) on dependent variables (estrus expression, pregnancy to TAI and pregnancy losses) was evaluated by multiple logistic regression. Estrus expression was greater (P=0,04) in heifers with STR 5 (65,0%) than in heifers STR 4 (56,4%) and there was no effect of treatment group (P=0,20) and interactions (P>0,10). Pregnancy to TAI was similar (P=0,76) for Treatment group (61,4%) than for Control group (63,2%) and there was not significant effect of STR (P=0,95) and interactions (P>0,10). Pregnancy losses between 40 and 120 days were similar (P=0,22) in the Treatment group (3,1%) and Control group (4,8%). In conclusion, in cyclic Aberdeen Angus heifers using a TAI protocol that includes GnRH in animals not showing estrus, treatment with eCG at the time of progesterone device removal did not affect fertility. [ABSTRACT FROM AUTHOR]

A expansão, o desenvolvimento e o embasamento das cadeias produti vas ligadas à pecuária estabeleceram um novo perfil de produção no Oeste Catarinense. Por conseguinte, os avanços técnicos realizados nessa cadeia resultaram na transformação desta mesorregião em um centro com elevada capacidade produtiva de proteína animal. Atualmente, a bovinocultura de corte está distribuída em diversas propriedades rurais, mas ela ainda não é autossuficiente nesse segmento e depende de avanços tecnológicos como a aplicação de biotecnologias da reprodução. Nesse sentido, a aplicação de inseminações em sequência permite um sistema de manejo intensivo sem o uso de touros, trazendo diversas vantagens comerciais e de manejo ao pequeno produtor rural. A tecnologia chamada de “Ressinc” é apresentada neste informati vo técnico.

Copyright of Revista Cientifica de la Facultade de Veterinaria is the property of Universidad del Zulia, Facultad de Ciencias Veterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Protocols using estradiol, GnRH, prostaglandin, and progesterone are used to conduct timed-artificial insemination (TAI). Follicular development, progesterone, and ovulation in Bos taurus (Experiment 1, n = 46) and pregnancy in Bos taurus (Experiment 2, n = 130) and Bos taurus x Bos indicus crossbred (Experiment 3, n = 499) heifers was compared between protocols J-Synch and COSynch. J-Synch protocol consisted in estradiol benzoate and an intravaginal progesterone device (IPD) on day 0, removal of IPD and prostaglandin on day 6, and GnRH/TAI on day 9. CO-Synch protocol consisted in a IPD on day 1, removal of IPD and prostaglandin on day 6, and GnRH/TAI on day 9. The size of the dominant follicle (P = 0,01) and plasmatic progesterone at IPD removal (P = 0,02) was greater for CO-Synch. There was no difference in time of ovulation (P = 0,70). Pregnancy per TAI was 52,38 % for J-Synch and 46,27 % for CO-Synch in Bos taurus heifers (P = 0,50) and 37,80 % for J-Synch and 40,41 % for COSynch (P = 0,60) in Bos taurus x Bos indicus crossbred heifers. In conclusion, no differences in fertility were detected in beef heifers synchronized with a J-Synch or CO-Synch protocol. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the effect of the dose of estradiol cypionate (ECP; 0.5 vs 1.0 mg) administered at the removal of the intravaginal progesterone releasing device (IVD) on estrus expression (EE) and pregnancy proportion (PP) in suckled Angus cows submitted to fixed-time artificial insemination (FTAI). Also, the role of the body condition score (BCS) as an effect modifier of the dose of CPE was explored. Four replicates of the experiment were carried out, using a total of 456 multiparous Angus cows, with a BCS of 4 and 5 (1 to 9 scale) and a postpartum interval of 42 to 113 days. On day 0, IVDs with 0.6 g of progesterone was inserted and 2 mg of estradiol benzoate were injected. On day 7, IVDs were removed, 150 µg of D+ cloprostenol and 400 IU of equine chorionic gonadotropin were administered, and tail-paint was applied to all the cows. At that moment animals were randomized to receive 0.5 or 1.0 mg of ECP. After 48 h of DIV removal, the amount of tail-paint rubbed-off was assessed (estrus detection) and the FTAI was performed. Pregnancy diagnosis was made on days 38-40 after FTAI, by ultrasonography. The application of 1.0 mg of ECP was associated with higher EE [87.2% (197/226) vs. 78.3% (180/230), P = 0.002], regardless of the BCS. However, the BCS conditioned the effect of the ECP dose on the PP (P = 0.048). It is concluded that the administration of 1.0 mg of ECP at DIV removal is associated with a greater EE at FTAI. Also, the effect of the dose of ECP on PP at FTAI would be conditioned by the BCS. In cows with BCS 5 a greater reproductive response is obtained when 1.0 mg of ECP is administered, while in cows with BCS 4 there are no differences between the evaluated ECP doses. [ABSTRACT FROM AUTHOR]

Con el objetivo de evaluar el efecto de la utilización de la gonadotrofina coriónica equina (eCG) en un protocolo de inseminación artificial a tiempo fijo (IATF) a base de progesterona (P4) y la condición corporal (CC), sobre la fertilidad de vacas mantenidas bajo un sistema de producción tradicional (SPT); se desarrolló una investigación, empleando un diseño completo al azar, con arreglo factorial 2×2, siendo los factores la CC (3,00 ≤ CC ≤ 2,75) y la administración de 400 Unidades Internacionales (UI) de eCG, formando cuatro tratamientos (T) con 50 animales cada uno. T1 vacas sincronizadas con CC ≤ 2,75 y sin aplicación de eCG; T2 vacas sincronizadas con CC ≤ 2,75 y con aplicación de eCG; T3 vacas sincronizadas con CC ≥ 3,00 y sin aplicación de eCG; T4 vacas sincronizadas con CC ≥ 3,00 y con aplicación de eCG. El protocolo base fue: Día cero, aplicación del dispositivo intravaginal (DIV) de progesterona, más 2 miligramos (mg) de benzoato de estradiol (BE), el día 7, retiro del DIV más 500 microgramos (µcg) de cloprostenol sódico, día 8, 1 mg de BE, Día 9 la IATF, 56 horas de haber retirado el DIV. La eCG se administró al momento de retirar el DIV. Los valores de fertilidad fueron para el T1: 22,0 %; T2: 44,0 %; T3: 46,0 % y T4: 48,0 %, con diferencias significativas (P

In this study a new treatment protocol named Web-Synch for synchronization of ovulation was evaluated by the determination of the ovulation time and pregnancy rate at fixed-time artificial insemination (FTAI) in suckled beef cows. In Experiment 1, all cows (n=52) were randomly divided into three treatment groups. The Web-Synch treatment (n=19), Day 0: Prostaglandin F2α (PGF) + insertion of a progesterone (P4) - releasing device, Day 5: 0.02 mg busereline acetate (GnRH).The J-Synch treatment (n=15), Day 5: 2 mg estradiol benzoate (BE) + P4 device. The Co-Synch 6 d treatment (n=18), Day 5: GnRH + P4 device. On Day 11 devices were removed from all cows and received PGF and 105 IU of reCG. All animals that expressed estrus were inseminated on Day 14 (72 hours after device removal) and those that did not express estrus received GnRH and were inseminated at the same time. Transrectal ultrasonographic examinations were carried out to determine follicular diameter, ovulation rate and CL size after ovulation. In Experiment 2, cows (n=19) were randomly divided to receive four treatment groups in 2 x 2 factorial design. The Web-Synch treatment, Day 0: PGF + device with 0.7 g of P4 (n=5) or with 1.0 g of P4 (n=5), Day 5: 0.02 mg GnRH. The J-Synch treatment, Day 5: 2 mg BE + device with 0.7 g of P4 (n=5) or with 1.0 g of P4 (n=4). On Day 11 devices were removed and all cows received PGF and 105 IU of reCG. Cows were inseminated and were examined by ultrasonography as in the Experiment 1 to determine follicular growth, ovulation time and ovulation rate. In Experiment 3, suckled beef cows (n=213) were divided in a 2 x 2 factorial design as in Experiment 2, and were inseminated and evaluated for estrus and pregnancy rates at FTAI. In Experiment 1, ovulation rate did not vary among treatments, being 100, 83.3 and 80.0% for Web-Synch, Co-Synch 6 d and J-Synch groups, respectively (P>0.1). Follicular diameter at FTAI was greater in the Web-Synch and Co-Synch 6 d groups (11.8 ± 0.4 and 11.7 ± 0.5 mm, respectively) than in the J-Synch group (9.8 ± 0.6 mm; P<0.05). Corpus luteum volume did not differ among Web-Synch, CoSynch 6 d and J-Synch treatments (3208.0 ± 436.4, 3315.2 ± 510.9 and 3369.3 ± 415.3 mm3, respectively; P>0.1). In Experiment 2, in cows treated with the Web-Synch protocol, the largest follicle diameter was greater at 60, 72 and 84 h in comparison with that observed in the J-Synch protocol (P<0.05). However, the maximum follicular diameter did not differ between treatments (P>0.1). Ovulation rate and ovulation time did not vary between protocols, being 80.0% and 94.5 ± 3.5 h for the Web-Synch protocol, and 100% and 96.7 ± 5.1 h for the J-Synch protocol (P>0.1). In Experiment 3, estrus and pregnancy rates at FTAI did not differ between treatments, being 66.0 and 58.7% for the Web-Synch treatment and 58.0 and 54.1% for the J-Synch treatment (P>0.1). In conclusion, the Web-Synch protocol could be consider as a new alternative for synchronization of ovulation and FTAI in suckled beef cows. The high ovulation rate at the end of treatment, the induction of a prolonged proestrus and the acceptable pregnancy outcome define it as an encouraging alternative to the conventional estradiol-based treatments. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of the use of tail-paint and artificial insemination after estrus detection on the pregnancy rate of lactating Holando Argentino cows subjected to fixed-time artificial insemination (FTAI) programs. Two experiments were conducted in two dairy farms (Farm I: n = 259 and Farm II: n = 252). On day 0, an intravaginal device (IVD) with 1.2 g of progesterone was inserted, and 2 mg of estradiol benzoate were applied to each animal. On day 7, the IVD was removed, and 150 μg of D-cloprostenol, 1 mg of estradiol cypionate and 500 IU of equine chorionic gonadotrophin were applied. At the device removal, cows were randomly assigned to two reproductive managements: 1) With use of tail-paint (WTP): at device removal, the animals were tail-painted, and those with ≥30% of the tail-paint rubbed off by 60 h after the device removal were inseminated, while those that did not show estrus received a dose of GnRH and were FTAI 72 h after the device removal. 2) Without use of tailpaint (WOTP): 48 h after the device removal, GnRH was administered and the FTAI was performed 60 h after the device removal. In Farm I, the use of tail-paint and artificial insemination after estrus detection during the FTAI program was associated with a numeric but non-significant (P = 0.266) improvement in the pregnancy rate [WTP: 47.2% (59/125), WOTP: 40.3% (54/134)]. However, the improvement was statistically significant (P = 0.001) in Farm II [WTP: 59.4 (76/128), SP: 37.1 (46/124)]. The use of tail-paint and artificial insemination after estrus detection during FTAI programs is in general associated with an increase in the pregnancy rate of Holando Argentino cows. However, the observed differences between dairy farms suggests that there is some other factors that modifies the effect of the reproductive management on the pregnancy rate. [ABSTRACT FROM AUTHOR]

The technique of timed artificial insemination (TAI) has been transformed into a tool to standardize the reproductive management of commercial beef and dairy herds. It has recently been shown an increase in pregnancy rates to TAI in dairy heifers using protocols that reduce the period of insertion of the device and prolong the proestrous period, called 5-day Co-Synch protocols. In South America, TAI protocols used mainly estradiol benzoate (EB) and progesterone devices. The J-Synch protocol is a protocol that uses estradiol and progesterone devices in which the device insertion period is reduced to 6 days and the proestrous period is prolonged by administering GnRH and perforoming the TAI at 72 hours after removal of the progesterone device. This protocol is presented as an interesting option for its practicality of implementation and the results are very encouraging in terms of pregnancy rates. The aim of this study was to compare the J-Synch protocol with the 5- day Co-Synch protocol (both have prolonged proestrus) to the conventional protocol (short proestrus), one of the most widely used TAI protocols in South America. The results confirm that the J-Synch protocol presents a proestrus that was, on average, 21 hours longer than the conventional protocol. Although, pregnancy rates were not significantly different between protocols, pregnancy results were higher in the J-Synch protocol than in the conventional protocol in all replicates performed. The J-Synch treatment was efficient to synchronize ovulation in dairy heifers and in addition, its application is practical because it requires to manage the animals only three times. [ABSTRACT FROM AUTHOR]

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O presente estudo teve como objetivo avaliar o uso de dispositivos intravaginais contendo doses altas ou baixas de progesterona (P4) na taxa de prenhez de novilhas zebuínas submetidas à inseminação artificial em tempo fixo (IATF). Novilhas Bos indicus (Nelore) receberam, no dia 0, uma injeção im de 2 mg de benzoato de estradiol (BE) e, em seguida, foram divididas aleatoriamente em três grupos. Nos grupos 1 (n = 80) e 2 (n = 79) foi colocado um dispositivo intravaginal contendo 1,9 g (grupo 1) e 0,75 g ( grupo 2) de P4, enquanto que o grupo 3 (n = 76) não recebeu dispositivo. Os dispositivos intravaginais foram removidos no dia 8, juntamente com a aplicação im de uma dose luteolítica de cloprostenol. Metade dos animais de cada grupo recebeu adicionalmente um injeção im de 300 UI de eCG. Vinte e quatro horas depois, todos animais receberam uma segunda aplicação im de 1 mg de BE e foram inseminados 54-56 horas após a aplicação de cloprostenol. O diagnostico de prenhez foi realizado 40 dias após a IATF, por meio de ultrassonografia transretal. Os dados foram analisados ​​por regressão logística. As taxas de prenhez foram de 27,5% , 30,4% e 28,9% para os grupos 1, 2 e 3, respectivamente (P> 0,05). A injeção de eCG, bem como outras variáveis tais como escore corporal, fazenda e presença de CL no início dos tratamentos não influenciaram esse resultado. Em conclusão, o uso de dispositivos intravaginas contendo alto (1,9 g) ou baixo (0,75 g) teor de P4 resultou em semelhantes taxas de prenhez após IATF de novilhas Nelore púberes.

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Copyright of Revista Brasileira de Reprodução Animal is the property of Revista Brasileira de Reproducao Animal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objetivou-se avaliar o efeito da administração de uma dose adicional de prostaglandina F2 alfa (PGF2) em protocolo de inseminação artificial em tempo fixo (IATF) sobre a fertilidade de fêmeas bovinas da raça Nelore. Foram realizados dois experimentos, sendo um (E1) no estado do Tocantins e o segundo (E2) no estado do Pará. No experimento 1 (E1) foram utilizadas 80 fêmeas bovinas distribuídas em três tratamentos (T1, T2 e T3), todos animais receberam o mesmo protocolo de IATF, diferindo no T1 (n=29), que recebeu 12,5 mg de Dinoprost no dia 9, T2 (n=28) recebeu a dose adicional no dia 10 e o T3 (n=23) - Grupo controle, que não recebeu a dose adicional de PGF2. O experimento 2 (E2) constituído por 147 fêmeas bovinas distribuídas em dois tratamentos. T1: com 72 animais, recebendo mesmo protocolo do T1 do E1. T2: constituído por 75 animais, com protocolo idêntico ao T3 do E1. A análise estatistica foi realizada no programa SAS, sendo no E1 utilizando-se o PROC NPARWAY e as médias comparadas pelo teste de Wilcoxon com nível de significância de 5%. No E2 os dados foram submetidos à análise de variancia pelo PROC GLIMMIX e as médias comparadas pelo teste T com nível de significância de 5%. No experimento 1 a taxa de prenhez no T1 foi de 62,06% (18/29), T2 de 57,14% (16/28) e T3 de 52,17% (12/23), não sendo observada diferença significativa entre os tratamentos. No experimento 2 a taxa de prenhez do T1 foi de 66,67% (48/72), enquanto T2 foi de 41,33% (31/75), verificando-se diferença significativa (P < 0,05). A dose adicional de PGF2 promoveu incremento na taxa de prenhez de fêmeas Nelore.

Diversos fatores podem influenciar os resultados de concepção dos programas de inseminação artificial em tempo-fixo (IATF), como por exemplo a qualidade dos materiais utilizados para a inseminação artificial (IA). Nesse contexto, três experimentos foram conduzidos para testar o efeito da bainha sobre o percentual de retenção residual de sêmen nos aplicadores de IA e nas taxas de concepção de vacas submetidas à IATF. No Experimento 1 foram descongeladas 400 palhetas de sêmen bovino criopreservado, que foram re-envasadas para compor amostras com características de peso e volume semelhantes. Cada nova dose de sêmen (n=300) foi montada em um dos três modelos de bainhas de inseminação artificial em teste (n=100 doses de sêmen/ bainha): marca líder no mercado global (G1), modelo líder no mercado brasileiro (G2), modelo comercializado como de baixa taxa de retenção residual de sêmen (G3), para determinação do percentual de eliminação seminal (PES). No Experimento-2 foram selecionadas 464 vacas Nelore, sincronizadas através de implantes intravaginais de progesterona e inseminadas empregando as mesmas bainhas do experimento anterior, porém agrupadas em classes (convencional: G1 e G2 [n = 225]; ou baixo refluxo: G3 [n = 239]). No Experimento-3 859 vacas Nelore foram sincronizadas e inseminadas com sêmen previamente selecionado, utilizando os mesmos modelos de bainhas testadas nos experimentos anteriores. Após cada IATF as bainhas foram inspecionadas visualmente para detecção de presença residual de sêmen e o diagnóstico de gestação foi realizado a partir de 35 dias após a IATF (Experimentos 2 e 3). O PES foi de 91,7%, 90,6% e 96,5%, respectivamente para os grupos G1, G2 e G3 (P = 0,05). As taxas de concepção no Experimento-2 foram de 53,33% e 58,16%, respectivamente para o modelo convencional e de baixo refluxo (P > 0,05), porém havendo diferenças (P = 0,05) de acordo com o modelo da bainha empregada para a IA (57,72% [71/123], 48,04% [49/102] e 58,16% [139/239], respectivamente para os grupos G1, G2 e G3). Menor incidência de refluxo de sêmen (P < 0,05) foi observado para o modelo de baixa retenção residual de espermatozoides (0,72%), frente aos modelos líderes do mercado internacional (10,42%) e nacional (22,99%; Experimento-3). Conclui-se que ocorre retenção residual de sêmen, independente do modelo de bainha utilizada para a IA. No entanto, a PES é influenciada pelo modelo e qualidade da bainha utilizada para inseminação artificial, fator que pode comprometer os índices de concepção de vacas sincronizadas para IATF.

Entre os anos de 2013 e 2016 foram utilizadas 31 fêmeas bovinas mestiças das raças Gir e Holandês, em diferentes estágios de gestação, multíparas com idade entre 4 e 8 anos e escore de condição corporal (ECC) médio 3 em escala que variou de 1 a 5 (1 muito magra e 5 muito gorda) do Setor de Bovinocultura de leite da Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, com o objetivo de avaliar o desenvolvimento embrionário e fetal comparativamente entre Inseminação Artificial convencional (IA) e Inseminação Artificial em Tempo Fixo (IATF). Foram avaliados parâmetros de desenvolvimento do esqueleto axial e apendicular, assim como do alantóide, âmnio e frequência cardíaca. Os dados obtidos ao longo dos três anos de avaliação neste estudo permitiram concluir que a ultrassonografia em modo B, por via transretal, representa uma ferramenta segura para o acompanhamento gestacional no primeiro trimestre de gestação das fêmeas avaliadas, sendo as variáveis analisadas de alta confiabilidade para o estudo da viabilidade embrionária e fetal bovina no primeiro trimestre de gestação. O uso de hormônios para sincronização da ovulação e IATF, não influenciou o desenvolvimento embrionário e fetal de vacas leiteiras mestiças, concluindo-se que produtos oriundos de IA convencional e IATF, apresentam padrão de desenvolvimento no primeiro trimestre de gestação sem diferenças significativas.

The objective of the study was to compare the effect of different doses of eCG (300 IU and 400 IU) upon pregnancy proportion (PP) at fixed-time artificial insemination (FTAI) in suckled Angus cows treated with an intravaginal progesterone device combined with estrogen salts and a luteolytic agent. Also, the effect of the treatment on the proportion of estrus manifestation (EP), and the effect of the body condition score (BCS) on the EP and the PP were evaluated. Two experiments were conducted: (Exp.1: n=233 y Exp.2: n=147). On day 0, an intravaginal device with 0.5 g of progesterone was inserted, and 2 mg of estradiol benzoate were applied to each animal. On day 8, intravaginal devices were removed, animals were injected with 500 μg of DL-cloprostenol and 0.5 mg of estradiol cypionate, and they were painted at the base of the tail. At that time, animals were randomly assigned to 3 groups to receive 300 IU or 400 IU of eCG or remained as untreated controls. The degree of paint removal was measured during the FTAI (48-56 h after device removal). Pregnancy diagnosis was performed by ultrasonography at day 41 post-FTAI. Different nutritional scenarios were observed in each of the experiments (Exp.1: BCS increase, Exp.2: BCS decrease). In the Exp.1 the treatment affected the EP (P<0.01) and marginally affected the PP (P=0.09), without differences between eCG doses (P>0,60). In the Exp.2, neither the treatment nor the eCG dose affected the evaluated reproductive outcomes (P>0.50). The BCS affected the EP in the Exp.1 (P<0.01) and affected the PP in both experiments (P<0.05). The results suggest that using eCG improves the EP and tends to improve the PP in animals that show and improve in their nutritional status, without differences between the two evaluated eCG doses. [ABSTRACT FROM AUTHOR]

In the period 1981-1989, companies associated with CABIA (Argentine Chamber of Reproduction Biotechnology and Artificial Insemination) traded an average of 542 thousand doses of semen per year. The most commonly used breeds were Angus (39.3%), Polled Hereford (31.4%) and Brangus (10.5%). It is estimated that the AI (Artificial Insemination) rate in cow-calf operations during this period was 3.5%. In the second half of the '90s, the average amount of semen doses sold by CABIA companies was 607 asothousand, being mostly Angus (47.2%), Polled Hereford (24.0%) and zebu composite breeds (23.8%). The insemination rate in the Buenos Aires province, during this period was 5.6%. From the total inseminated animals, 73.5% were heifers. Nationwide, it is estimated that the insemination rate was 4%. In the early 2000's, this rate continued to be around 4%. As of 2004, there was an increase in the use of AI, accentuated since 2010, mainly due to the growth of the FTAI (Fixed Time Artificial Insemination) technique. Angus (42.4%), Braford (19.7%) and Brangus (15.7%) were the most used breeds in the period. The amount of beef semen doses marketed annually by CABIA companies between years 2015-2018, was 2.5 million, mostly Angus (45.1%), Brangus (23.7%) and Braford (17, 9%). An average of 3 million FTAI treatments per year were carried out, which represented more than 90% of total AI in beef cattle. The AI rate during this period was 12.8%. The evolution analysis of the beef AI market in the last 40 years shows a significant growth, going from 3.5% to 13% rate. The growth of the FTAI led to a pronounced increase in the proportion of inseminated breeding cows with calf at foot. [ABSTRACT FROM AUTHOR]

Copyright of Revista Cientifica de la Facultade de Veterinaria is the property of Universidad del Zulia, Facultad de Ciencias Veterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Cientifica de la Facultade de Veterinaria is the property of Universidad del Zulia, Facultad de Ciencias Veterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study evaluated the pregnancy rate in Nelore cows (Bos indicus) that were subjected to fixed-time artificial insemination (FTAI) using different protocols consisting of injectable progesterone (P4) or an intravaginal device (impregnated with P4). Multiparous cows 72-84 months in age, 30-45 days postpartum, were selected on the basis of the absence of a corpus luteum (CL) and follicles < 8 mm after transrectal palpation and ultrasound examinations. On a random day of the estrus cycle (D0), the selected animals (n = 135) were randomly assigned to one of three experimental groups (n = 45 each). Group I (injectable P4/FTAI 36 hours) received 250 mg of injectable P4 and 2 mg EB on D0; on D7, they received 500 µg of cloprostenol; on D8, 300 IU of eCG and 1 mg of EB were administered; and finally, FTAI was performed 36 hours after the application of EB. Group II (injectable P4/FTAI 48 hours) received the same protocol as Group I, except that the FTAI was performed 48 hours after ovulation induction. The animals of Group III (Control/CIDR) received a conventional protocol for FTAI using an intravaginal device (D0: P4 and 2 mg EB; D8: device removal, 500 µg cloprostenol, 300 IU eCG, 1 mg EB; and FTAI performed 48 hours after removal of the device). The results showed that cows synchronized with the conventional protocol for FTAI (Control/CIDR) had a higher pregnancy rate (60 %, 27/45) than those synchronized with an injectable P4/FTAI 36 hours (33.33 %; 15/45, P = 0.010). However, the group receiving injectable P4 group/FTAI 48 hours had a similar pregnancy rate (48.9 %; 22/45; P = 0.290) when compared to both the group receiving the conventional protocol and that receiving injectable P4/FTAI 36 hours (P = 0.134). Although the injectable P4 may affect pregnancy rate with the FTAI performed in 36 hours, we found similar pregnancy rates from cows inseminated 48 hours after induction ovulation, considering injectable or intravaginal P4. Therefore, we suggest that injectable P4 represents an alternative source of progesterone for synchronization of cattle for FTAI.

This study aimed to evaluate the effects of gonadorelin (GnRH), used both at the outset of a timed artificial insemination (TAI) protocol to synchronize follicular wave recruitment and at the end to synchronize ovulation, on the conception rate (CR) in Nellore cows. The experiment was conducted on two beef cattle farms in the Vale do Araguaia, MT. The body condition score (BCS) evaluation and ultrasound examination to determine ovarian status [follicle diameter < 10 mm, ? 10 mm or presence of corpus luteum (CL)] were performed at the beginning (Day 0) of the TAI protocol. Multiparous cows (n = 494) were subjected to the following protocol: Day 0 – insertion of intravaginal progesterone device (P4 DIB®, MSD) previously used for 8 or 16 days and IM administration of 2.0 mg of estradiol benzoate (EB, Gonadiol®, MSD); Day 8 – P4 device withdrawal, IM injection of 300 IU of equine chorionic gonadotropin (eCG, Folligon®, MSD), 1.0 mg of estradiol cypionate (ECP®, Zoetis) and 0.265 mg of Sodium cloprostenol (PGF2?, Ciosin®, MSD); Day 10 – TAI, performed by a single inseminator. Animals were randomly assigned to one of four groups: control (n = 126), GnRH D0 (n = 123), GnRH D10 (n = 123) and GnRH D0 + D10 (n = 122). Animals treated with GnRH received 50 mcg of gonadorelin (GnRH, Cystorelin®, Merial). Pregnancy was diagnosed by ultrasound 39 ± 10 days after TAI. Data were analyzed using the GLIMMIX procedure of SAS program (P < 0.05). The overall CR was 42.71%. Effect of treatment was not detected (P = 0.2482) on CR, which was 36.89% ± 0.19 (47/126) for the control group, 46.08% ± 0.19 (56/123) for GnRH D0, 48.30% ± 0.18 (61/123) for GnRH D10 and 38.48% ± 0.19 (47/122) for GnRH D0 + D10. An effect of farm was detected; the CR was 47.32% ± 0.13 at Farm A and was 38.24% ± 0.13 at Farm B (P = 0.0249). No effects of the interaction between farm and treatment were observed (P = 0.7662), nor of those among ovarian condition and treatment (P = 0.1225) on CR. Cows with follicles < 10 mm had lower CR (16.44% ± 0.08; P = 0.0001) than cows with follicles ? 10 mm (46.15% ± 0.07) and cows with CL (48.35% ± 0.07). It was concluded that GnRH used to both synchronize the follicular wave recruitment and synchronize ovulation as part of a TAI protocol, did not improve the conception rate in Nellore beef cows.

The objective of this study was to evaluate the reproductive indices of different cattle herds submitted to a fixed-time artificial insemination program (FTAI) in the region of Piracicaba, SP. Twenty herds composed of 10 to 80 crossbred dairy cows were selected to participate in a breeding program through FTAI. First, a survey was conducted to determine the incidence of reproductive system diseases in the herds. For this purpose, blood samples were collected randomly from each herd for the serological diagnosis of brucellosis, leptospirosis, infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), enzootic bovine leukosis (EBL), and neosporosis. The laboratory tests were conducted according to the methods of the World Organisation for Animal Health. All herds had at least one animal that tested positive for one or more reproductive system diseases. Brucellosis was detected in 3/20 (15%) herds, IBR and BVD in 19/20 (95%), EBL in 20/20 (100%), neosporosis in 13/20 (65%), and tuberculosis in 8/8 (100%). Six months later, cows (n=203) of the different herds were submitted to hormone treatment consisting of estradiol-progesterone and PGF2α for heat synchronization and ovulation and subsequent FTAI. The data were analyzed by logistic regression and Fisher’s exact test. The pregnancy rates at 30 and 60 days after FTAI were 55.7% and 48.3%, respectively. These rates were not influenced by herd, inseminator, body score, post-calving days, or number of lactations. The calving rate (42.4%) differed from the pregnancy rate at 30 (P=0.01), but not at 60 (P=0.27) days after FTAI. The gestation loss until calving was 23.2% (26/112), but no exact cause of this event was identified. Despite the presence (seroreactivity) of reproductive diseases, cattle herds owned by small-scale producers exhibit acceptable pregnancy rates after FTAI. However, additional prophylactic measures such as vaccination and improvement of livestock management should be adopted.

O dispositivo de liberação de progesterona (DLP) é muito importante em protocolos de Inseminação Artificial em Tempo Fixo (IATF). Representa cerca de 43% dos custos e é objeto de estudos sobre a eficiência da sua reutilização. No entanto, perfis de liberação de progesterona (P4) em animais com diferentes concentrações endógenas desse esteroide não são claramente descritos. Este estudo teve como objetivo avaliar a concentração sérica de P4 em fêmeas com diferentes situações de atividade luteal, tratadas com DLP novo (1g de P4) por 8 dias. Trinta novilhas mestiças cíclicas foram divididas em três grupos: em G1 e G2, o DLP foi inserido (D0) sete dias após a ovulação induzida. Adicionalmente, 0,15mg de D-cloprostenol foi administrado três dias depois para promover a luteólise em G2. Para G3, o corpo lúteo foi lisado antes da inserção do DLP para que a P4 exógena fosse a única fonte desse hormônio. O sangue foi coletado no D0, D3, D5 e D8, e a P4 avaliada por RIA. Médias de P4 foram comparadas entre os grupos em cada dia e dentro do grupo, entre os dias, utilizando o teste Tukey. Antes da inserção do implante (D0), os níveis de P4 foram, nos grupos, semelhantes em G1 e G2, e superiores a G3 (5,3±3,1a e 5,3±1,4a vs 0,6±0.3bng/mL, respectivamente-P

The beef cattle rearing is an economic and social activity in La Pampa province, developed in an area of natural forages, with severe weather and edaphic limitations. The present trial was carried out on a beef farm with 320 British crossbreed cattle, at Toay Department, La Pampa. During a period of five years, a protocol as following was implemented: three-time estrous synchronization followed by fixed-time artificial insemination plus natural mating until the end of the breeding period. The protocol used for artificial insemination started 40 days post-partum and each cow was classified by a colour ear tag and by probable date of delivery. At day zero, an intra-vaginal progesterone dispositive (0.5 g, i.v., Dib, Sintex S.A., Argentina) was placed to all cows in combination with an estradiol benzoate dose, when the dispositive was removed, after 7 days, the animals received a dose of prostaglandin (Cloprostenol, 2 cc., i.m., Ciclase DL, Sintex S.A.) and estradiol cypionate (1 mg, i.m. Cipiosyn, Sintex S.A., Argentina), to finally be inseminated at day 9. Thereafter, the protocol finished with the incoming of 5% of bulls until the end of the predetermined breeding period. The pregnancy percentage of both cows and heifers increased through the study period to values of 90 and 91%, respectively. 70% of parturition was concentrated during the first month, 23% in the second and just 3% during the last month of calving season. The suggested system allows increasing the reproductive efficiency of the cattle herd, achieving both a higher percentage of early pregnancy and increasing interparturition interval allowing a better recovery of the reproductive tract. [ABSTRACT FROM AUTHOR]

Copyright of Revista Veterinária em Foco is the property of Universidade Luterana do Brasil and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Pesquisa Veterinaria Brasileira is the property of Colegio Brasileiro de Patologia Animal - CBPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Freezing produces biochemical and structural changes in spermatozoa that diminish their fertilization power. As a result, there has been interest in less invasive ways of preservation, such as fresh semen. This technology allows maintaining the semen, generally at 5°C for a maximum period of 72 hours, without affecting its fertilization power. The objective of this paper was to analyze available information on the use of fresh semen in fixed-time artificial insemination programs. The preservation modality mentioned has been used in Argentina, USA and Brazil. From the analysis made appears that there are differences in the percentage of pregnancy in favor of the frozen, although they are not always significant. Based on the premise that the main purpose of artificial insemination is genetic improvement, the bull should be selected based on its contribution to the improvement and not based on the availability or not of fresh semen. Taking the previous concept into the account, fresh semen is a valid alternative that has proven to be versatile. It can be successful independent of race, semen collection method, formulation of the semen diluent and ovulation control protocol. Also, it is effective with a wide range of variation in the number of spermatozoa contained in the inseminating dose. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the pregnancy rate of injectable progesterone (P4i) application in Nelore cows ten days before the start of the artificial insemination protocol (D-10). The experiment involved 436 Nelore cows, aged four to six years, with an average weight of approximately 450 kg, in the postpartum period ranging from 30 to 60 days. Among them, 253 were multiparous and 183 were primiparous, with a body condition score (BCS) between 2.5 and 4.5 (on a scale of 1-5), from two farms located in Cachoeiro de Itapemirim, ES, Brazil, and the state of Rondônia, Brazil. The animals were kept under the same grazing and nutritional conditions and were randomly divided into two groups: the P4i group, that received an injection of 150 mg of injectable progesterone 10 days before the start of the timed artificial insemination protocol (TAI), and the control group, that received no prior treatment before the protocol. The results showed that the control group had a higher pregnancy rate (54.8%) compared to the P4i group (45.2%); however, when comparing animals within the same category, there was no significant difference. In relation to BCS, the following pregnancy rates were obtained: ≥ 2.0 < 3.0 (49.8%), ≥ 3.0 < 4.0 (56.2%), and ≥ 4.0 (62.5%). In conclusion the application of P4i on D-10 did not result in an increased pregnancy rate. Regarding body condition (BCS), there was an increase in pregnancy rates as BCS increased, with the greatest difference observed in the highest BCS catego [ABSTRACT FROM AUTHOR]