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Background and Aim: Estrus synchronization of ewes has been accomplished using several protocols with various degrees of success in improving reproductive efficiency and obtaining the most effective protocol used in sheep farming. This study aimed to compare the effectiveness of three treatment protocols and to record the intensity and duration of estrus signs and pregnancy rate in Barbados Black Belly (BBB) sheep. Materials and Methods: Thirty-two primipara BBB ewes aged 18-24 months were equally divided into three treatment groups. T1: the ewes were injected intramuscularly with 2 mL Lutalyse (PGF2α) (10 mg) on days 0 and 10. T2: 1 mL Fertiline (50 µg; Gonadorelin acetate) on day 0 and 2 mL lutalyse (10 mg) on day 7. T3: 1 mL fertiline (50 µg) on day 0, 2 mL lutalyse (10 mg) on day 7, and 1 mL Fertiline (50 µg) on day 9. Estrus response was assessed using naturally mating rams and ewes. Pregnancy was determined using ultrasonography between 55 and 80 days after the last hormonal injection. The following estrus signs were noted: Swollen vulva, mucus discharge, sniffing, excitement, loss of appetite, mounting, and rapid tail movement. Results: Of the expressed signs, swollen vulva was most frequent, whereas loss of appetite and mucus discharge were the least overt signs recorded. The estrus response (%), onset (%), and duration (h) in ewe synchronization of the three treatment protocols were 100%, 58.3 ± 23.4%, and 48.0 ± 18.2 h (T1), 100%, 61.7 ± 41.2%, and 45.0 ± 27.0 h (T2), and 37.5%, 32.1 ± 1.7%, and 29.2 ± 1.25 h (T3), respectively. The pregnancy rates were 87.5%, 87.5%, 37.5%, and 50.0% in T1, T2, T3, and T4, respectively. Conclusion: Prostaglandin F2α+PGF2α and GnRH+PGF2α synchronization protocols were more effective in the fertilization of BBB ewes with better expression of estrus signs compared with the GnRH+PGF2α+GnRH (OVS) protocol.

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Fixed-timed artificial insemination (FTAI) protocols for beef cattle in South America are primarily based on estradiol esters and intravaginal progesterone-releasing devices (IVPD). The objective of this study was to determine the optimal gonadotropin-releasing hormone (GnRH)-based protocol as an alternative to the use of estrogen-based protocols in grazing Bos taurus suckling beef cows. All cows received an IVPD on the day of protocol initiation and prostaglandin F2α (PG) plus equine chorionic gonadotropin (eCG) treatments at the time of IVPD removal. In Experiment 1, cows (n = 235) were randomly assigned to one of four treatments: (i) 7-day estradiol = 2 mg of estradiol benzoate (EB) at IVPD insertion on Day 9 and 1 mg of estradiol cypionate (ECP) at IVPD removal on Day 2; (ii) 7-day GnRH = 10 µg of GnRH at IVPD insertion on Day 10, IVPD removal on Day 3 and GnRH at FTAI; (iii) 7 & 7 estradiol = PG at IVPD insertion on Day 16, EB on Day 9 and ECP at IVPD removal on Day 2; (iv) 7 & 7 GnRH = PG at IVPD insertion on Day 17, GnRH on Day 10, IVPD removal on Day 3 and GnRH at FTAI. In Experiment 2, cows (n = 462) were randomly assigned to one of four treatments: (i) 6-day estradiol = EB at IVPD insertion on Day 9, IVPD removal on Day 3 and GnRH at FTAI; (ii) 7-day estradiol; (iii) 7-day GnRH; (iv) 7 & 7 GnRH. In Experiment 1, plasma progesterone concentrations and percentage of cows with a corpus luteum (CL) at IVPD removal, and pregnancy per AI (P/AI) were greater for cows subjected to GnRH-based protocols compared with cows subjected to estrogen-based protocols (p < 0.01). In Experiment 2, cows subjected to the 7 & 7 GnRH protocol had the greatest P/AI (p < 0.01). In summary, GnRH-based FTAI protocols resulted in similar or greater P/AI compared to estrogen-based FTAI protocols in grazing postpartum Bos taurus suckled beef cows. The greatest P/AI was attained with the 7 & 7 GnRH protocol.

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Nos últimos anos, observou-se um aumento no tamanho do rebanho ovino no país, indicando uma retomada na ovinocultura. Para melhorar a eficiência reprodutiva desses animais, a utilização de biotécnicas tem se mostrado uma ferramenta importante. Dentre essas biotécnicas, destacam-se os protocolos de sincronização do ciclo estral, os quais frequentemente utilizam progesterona associada a gonadotrofinas ou análogos da prostaglandina em duas aplicações. Este artigo tem como objetivo revisar os protocolos de sincronização utilizados em ovinos e apresentar atualizações relevantes sobre os mesmos.(AU)

In recent years, there has been an increase in the size of the sheep herd in the country, indicating a recovery in sheep farming. To improve the reproductive efficiency of these animals, the use of biotechniques has been shown to be an important tool. Among these biotechniques, estrous cycle synchronization protocols stand out, which frequently use progesterone associated with gonadotropins or prostaglandin analogues in two applications. This article aims to review the synchronization protocols used in sheep and present relevant updates about them.(AU)

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This study aimed to evaluate the reproductive performance of ewes submitted to timed AI protocol with 7 (D7) or 9 (D9) days of progesterone. A total of 220 crossbred ewes (Doper × Santa Ines) were distributed in the treatments according to body weight (52.67 ± 11.76 kg), body condition score (2.5 ± 0.8; scale of 1-5), and the female category (multiparous, nulliparous and primiparous). Ewes received an intravaginal device of 0.3 g of progesterone (CIDR® Easy breed) on day 0, keeping in ewes for 7 or 9 days, which were the experimental treatments. At the time of P4 withdrawal, ewes received 300 IU of eCG (Novormon®) and 6.70 mg of dinoprost tromethamine (Lutalyse®). Insemination by laparoscopy was performed between 46 and 59 h after device removal, lasting from 1 to 5 min/ewe, which did not differ between protocols. The estrus detection rate was higher in the 9-day protocol compared to the 7-day protocol (82% and 65%, respectively, P = 0.0096). However, the 7-day protocol tended to increase pregnancy rate on the TAI compared to the 9-day protocol (45% and 33%, respectively, P = 0.09). The plasma concentration of progesterone at device removal was higher in the 7-day protocol than in the 9-day protocol (2.35 and 1.22 ng/mL, respectively, P = 0.04). We conclude that reducing the length of the estrus synchronization protocol to 7 days is recommended, which improved the reproductive response in ewes.

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Background: The intensive reproductive management in the dairy farms requires inclusion of a large group of replacement heifers in the breeding program for a shorter period. In this aspect, a creation of effective estrus synchronization protocols with timed artificial insemination (TAI) by sexed semen and optimization of the current ones have a crucial role for obtaining high pregnancy rate. These protocols are beneficial, because they led to reduced interval to first AI, lack of need for estrus detection, and allow obtaining a large group of female calves for on time. Because of limited fertilizing potential of sexed spermatozoa this type of semen is applied mainly for heifers, as fertility is higher compared to lactating cows. The main objective of the present study was to investigate the effect of ovarian status on the reproductive performance in dairy heifers subjected to estrus synchronization and timed artificial insemination with sexed semen. Materials, Methods & Results: Forty-eight Holstein healthy heifers separated in 2 groups were subjected to PGF2α-GnRH pre-treatment and Ovsynch or PRID-5-day estrus synchronization protocol and timed artificial insemination (TAI) with sex-sorted semen, staring 6 days after end of the hormonal pre-treatment. The ovarian status (presence of follicles with or not a corpus luteum) of the heifers at the begin of the treatment, on day of TAI and pregnancy rate in different groups were determined and compared. Additionally, the ovarian status at the begin of the treatment, ovarian status and size of preovulatory follicle (PF) on day of TAI and total values for both groups according to reproductive performance (pregnant or non-pregnant) were also analyzed. On day of TAI the animals with PF and a lack of corpus luteum (CL) in both groups were more that those with PF and CL (39.3% and 30% vs. 60.7 % and 70%), with significant (P < 0.05) difference in PRID-5-day group. The pregnancy rate tended to be higher in PRID-5 day than Ovsynch treatment (65% vs. 35.7%). A higher percentage (100% and 67.9%) of the pregnant animals in both treatments had not CL on day of TAI, and the size of the PF (1.58 ± 0.12 cm and 1.64 ± 0.13 cm) was increased (P < 0.05). Similar effects of the ovarian status on reproductive performance were obtained after a comparison of the total values between pregnant and non-pregnant animals. The percentage of heifers with observed PF without CL on day of TAI was significantly greater (P < 0.05) in pregnant compared to non-pregnant group (91.3% vs. 40%). The opposite dependence was determined for the parameter presence of follicles and corpus luteum (8.7% vs. 60%; P < 0.05). Furthermore, the size of the PF measured immediately before TAI was increased in animals became pregnant (1.60 ± 0.12 cm vs. 1.34 ± 0.17 cm; P < 0.05). Discussion: The analysis of the obtained results showed that the ovarian status on day of TAI affects the reproductive performance in dairy heifers subjected to estrus synchronization and timed artificial insemination with sexed semen. Hormonal pre-treatment with onset of PRID-5-day protocol 6 days later and TAI with sex-sorted semen ensure acceptable pregnancy rate. The greater preovulatory follicle and a lack of corpus luteum before insemination provide significantly (P < 0.05) more pregnant animals, compared to the cases when CL is presented. Ultrasound determination of the ovarian function before insemination can be used in selection of heifers for TAI with sex-sorted semen.

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There is still a lack of information on estrus synchronization in goats. Understanding the estrus synchronization protocols and the subsequent effects is important to improve the efficiency of assisted reproductive technologies (ARTs) and subsequently would improve the breeding procedures. This study will help in determining the most suitable estrus synchronization protocol and understand better the effect on the sexual behaviour and hormonal effects in goats. A total of 127 Boer does were used and divided into three groups with different duration of CIDR insertion intravaginally either for 14 (two groups) or 9 days (one group). Approximately 0.5 ml Estrumate® (PG) was administered intramuscularly to all groups at CIDR removal, and only groups PMSG14 and PMSG9 were administered with 200IU of Pregnant Mare Serum Gonadotropin (PMSG) intramuscularly. Estrus signs were observed at 4 h intervals and blood samples were collected for progesterone and luteinizing hormone determination. The percentage of does in estrus within 24 to 72 h post CIDR removal was significantly higher (P<0.05) in groups with PMSG compared to the group without the PMSG. The numbers of does display estrus signs within 24 to 28 h post CIDR removal were significantly higher (P<0.05) in group shorter period (9 days) compared to groups with 14 days CIDR. The P4 concentrations at 24 hours post CIDR removals and LH concentration was not significantly different (P>0.05) in all groups. The time of the LH peak in the group without the PMSG was significantly delayed (P<0.05) when compared to group 9 days CIDR and administered with PMSG. It is recommended to use the treatment for 9 days CIDR since the estrous cycle can be shortened.

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The objective of this study was to compare the reproductive efficiency of dairy buffaloes undergoing fixed-time artificial insemination (FTAI) protocols based on progesterone/estrogen (P4/E2) and eCG during unfavorable breeding season using cooled (CS) and frozen semen (FS). A total of 446 buffaloes (> 40 days postpartum) were randomly distributed into four blocks (years): B1-2014 (n = 143), B2-2015 (n = 34), B3-2016 (n = 90), and B4-2017 (n = 179). Each block was subdivided into two (AI with CS and FS using the same ejaculate of each bull). Thus, the block subdivision was as follows: B1 (CS = 71 and FS = 72); B2 (CS = 18 and FS = 16); B3 (CS = 47 and FS = 43); and B4 (CS = 90 and FS = 89). The ejaculates of eight Murrah bulls collected using an artificial vagina were divided into two aliquots: one aliquot was diluted in Botu-Bov® commercial extender and cooled (BB-CS), and the other was diluted in the same extender and frozen (BB-FS). BB-CS aliquots were cooled at 5 °C/24 h using a refrigerator. BB-FS group aliquots were also cooled, and after equilibrating at 5 °C for 4 h, were placed in a 21-L Styrofoam box, 5 cm above the surface of liquid nitrogen. In the afternoon (A) on D0 (2:00 p.m.) the animals received EB 2.0 mg IM (Estrogin®) and an ear implant (CRESTAR® 3.0 mg P4). At D9 (A), the implant was removed, and the animals received eCG 400 IU IM (Folligon® 5000) + Cloprostenol PGF2α 0.530 mg IM (Sincrocio®). At D10 (A), the animals received EB 1.0 mg IM (Estrogin®), and at D12 (8:00 a.m.), AI was performed. At D42, pregnancy was diagnosed via ultrasonography. Total CRs were 48.2% CS and 34.6% FS for years 2014 to 2017, with a significant difference of 13.7% (P<0.05). In conclusion, cooled semen resulted in higher CR than frozen semen in dairy buffaloes under the P4/E2 and eCG FTAI during the unfavorable reproductive season.(AU)

O objetivo deste estudo foi comparar a eficiência reprodutiva de búfalas leiteiras submetidas a protocolos de inseminação artificial em tempo fixo (IATF) à base de progesterona/estrogênio (P4/E2) e eCG, durante a estação reprodutiva desfavorável, usando-se sêmen resfriado (SR) e congelado (SC) Um total de 446 búfalas (> 40 dias após o parto) foi distribuído aleatoriamente em quatro blocos (anos): B1-2014 (n = 143), B2-2015 (n = 34), B3-2016 (n = 90) e B4-2017 (n = 179). Cada bloco foi subdividido em dois (IA com SR e SC utilizando-se a mesma ejaculação de cada touro). Assim, a subdivisão do bloco foi a seguinte: B1 (SR = 71 e SC = 72); B2 (SR = 18 e SC = 16); B3 (SR = 47 e SC = 43); e B4 (SR = 90 e SC = 89). Os ejaculados de oito touros Murrah coletados com vagina artificial foram divididos em duas alíquotas: uma alíquota diluída em diluente comercial Botu-Bov® e resfriada (BB-SR), e a outra diluída no mesmo diluente e congelada (BB-SC). As alíquotas de BB-SR foram resfriados a 5°C/24h usando-se um refrigerador. As alíquotas do grupo BB-SC também foram resfriadas e, após equilíbrio a 5°C por 4h, foram colocadas em uma caixa de isopor de 21L, 5 cm acima da superfície do nitrogênio líquido. À tarde (A), no D0 (14h), os animais receberam BE 2,0 mg IM (Estrogin®) e um implante auricular (Crestar® 3,0 mg P4). No D9 (A), o implante foi retirado e os animais receberam eCG 400 UI IM (Folligon® 5000) + cloprostenol PGF2α 0,530 mg IM (Sincrocio®). No D10 (A), os animais receberam BE 1,0mg IM (Estrogin®), e, no D12 (8h da manhã), foram realizadas as IAs. No D42, a gestação foi diagnosticada por ultrassonografia. As taxas de concepção (TC) totais foram 48,2% SR e 34,6% SC para os anos de 2014 a 2017, com uma diferença significativa de 13,7% (P<0,05). Em conclusão, o sêmen resfriado resultou em maior TC do que o sêmen congelado em bubalinos leiteiros sob P4/E2 e eCG FTAI durante a estação reprodutiva desfavorável.(AU)

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Currently, there is an intense effort to find an alternative hormone to eCG to induce ovulation after estrus synchronization treatments in sheep. One of the proposed alternatives is based on the use of hCG, but the results are controversial since fertility rates are commonly affected. The present study aims to evaluate, therefore, the adequacy of hCG in protocols for the synchronization of estrus and ovulation. Ovarian follicle dynamics, occurrence of estrus behavior and subsequent ovulation, quality of corpora lutea, and pregnancy rate after controlled natural mating were assessed in two consecutive trials. The findings indicate that the low fertility rates reported for the protocols based on the administration of hCG for inducing ovulation during estrus synchronization in sheep may be related to a high occurrence of abnormal follicular growth patterns, disturbances, and retardments of ovulation and concomitant formation of follicular cysts in the treated females. These results preclude their practical application to induce ovulation concomitantly to estrous synchronization treatments.

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There is still a lack of information on estrus synchronization in goats. Understanding the estrus synchronization protocols and the subsequent effects is important to improve the efficiency of assisted reproductive technologies (ARTs) and subsequently would improve the breeding procedures. This study will help in determining the most suitable estrus synchronization protocol and understand better the effect on the sexual behaviour and hormonal effects in goats. A total of 127 Boer does were used and divided into three groups with different duration of CIDR insertion intravaginally either for 14 (two groups) or 9 days (one group). Approximately 0.5 ml Estrumate® (PG) was administered intramuscularly to all groups at CIDR removal, and only groups PMSG14 and PMSG9 were administered with 200IU of Pregnant Mare Serum Gonadotropin (PMSG) intramuscularly. Estrus signs were observed at 4 h intervals and blood samples were collected for progesterone and luteinizing hormone determination. The percentage of does in estrus within 24 to 72 h post CIDR removal was significantly higher (P0.05) in all groups. The time of the LH peak in the group without the PMSG was significantly delayed (P

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There is still a lack of information on estrus synchronization in goats. Understanding the estrus synchronization protocols and the subsequent effects is important to improve the efficiency of assisted reproductive technologies (ARTs) and subsequently would improve the breeding procedures. This study will help in determining the most suitable estrus synchronization protocol and understand better the effect on the sexual behaviour and hormonal effects in goats. A total of 127 Boer does were used and divided into three groups with different duration of CIDR insertion intravaginally either for 14 (two groups) or 9 days (one group). Approximately 0.5 ml Estrumate® (PG) was administered intramuscularly to all groups at CIDR removal, and only groups PMSG14 and PMSG9 were administered with 200IU of Pregnant Mare Serum Gonadotropin (PMSG) intramuscularly. Estrus signs were observed at 4 h intervals and blood samples were collected for progesterone and luteinizing hormone determination. The percentage of does in estrus within 24 to 72 h post CIDR removal was significantly higher (P0.05) in all groups. The time of the LH peak in the group without the PMSG was significantly delayed (P(AU)

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A research career is not only built on ideas and publishable results; it is more often the product of determination, hard work, collegiality and collaboration. It is through our collaborators, family and friends that we really become better persons, and scientists. It is also a matter of being at the right place at the right time. My work in bovine reproduction has progressed from an interest in superovulation and embryo transfer before I became a veterinarian, to the development and application of this technology and fixed-time artificial insemination in beef and dairy herds. Everything that I have done has been possible because of the people that I have worked with over the years. This manuscript combines some of the very exciting things that I have learned about bovine reproduction over the last 30 years and personal stories behind the projects and ideas that we have pursued during that time.

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In bovine estrus synchronization, intravaginal devices made of silicone are used to administer exogenous progesterone with the aim of maintain plasmatic levels above 2 ng ml-1 during the treatment. After their use, devices must be discarded. There is an important concern on the environmental impact of the disposal of these used products due mainly to the non-degradability of the silicone and to the residual content of the hormone. Different alternatives are being studied, and the use of ecological materials appears as the more important. The objective of the present contribution was to design and evaluate a recyclable intravaginal prototype using ethylene vinyl acetate copolymer (EVA). Devices were fabricated by an injection-molding technique and characterized in terms of dimensions, loading efficiency, release rate, and wing tension. An analysis was first conducted to compare three different matrices and two supports. Secondly, the best candidate prototype was assayed in both beef and dairy cattle. Finally, used matrices were recycled measuring the progesterone content in the resulting devices and testing them in vitro. According to release tests, no differences were observed between the three matrices both in vitro and in vivo. On the contrary, a better performance was achieved when a support with a more flexible Y shape was used in comparison with a rigid T geometry. Successful results were observed in non-lactating cows, with plasma concentrations above the threshold value defined for the synchronization therapy. However, lower progesterone levels resulted when devices were tested in animals with large milk production. By last, recycled matrices presented a similar initial content and in vitro release rate than original matrices. These findings could open the possibility to use recyclable EVA devices as an alternative to the non-degradable silicone intravaginal inserts. Future research must be carried out to optimize the performance of the recycled matrices in dairy cattle. Modifications of the release surface and/or the initial loading can give a solution to the lower values observed in these animals. Graphical abstract.

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Abstract Background: Coffee pulp has a high content of antioxidants capable of modifying the oxidative status in small ruminants. However, high amounts for a prolonged time can reduce fertility. Objective: To determine the effect of two inclusion levels of coffee pulp during estrous synchronization on reproductive variables and oxidative status of primiparous ewes. Methods: Sixty Suffolk x Dorset primiparous ewes were distributed into three treatments in a completely randomized design; T0: (n=20) 1.5 kg balanced diet, T1: (n=20) 1.5 kg balanced diet and 5% coffee pulp, T2: (n=20) 1.5 kg balanced diet and 10% coffee pulp. Supplementation was given for 16 days before estrus synchronization and until the beginning of the breeding season. A progestogen (CIDR®) was inserted for 11 days and a dose of PGF2α was applied two days prior to its withdrawal. Estrus detection started 12 hours after CIDR withdrawal. Blood samples were obtained during the supplementation period to measure oxidative status, antioxidant capacity, glucose and insulin, and up to 9 days after breeding to determine progesterone concentration. Pregnancy diagnosis was performed at 30 and 60 days post-breeding. An analysis of repeated measures of mixed effects and frequency analysis were carried out. Results: Inclusion of coffee pulp for a short period prior to breeding did not affect reproductive parameters, nor progesterone, glucose or insulin concentrations (p>0.05); however, antioxidant capacity increased, while lipid oxidation showed an opposite trend (p<0.05). Conclusion: Inclusion of up to 10% coffee pulp in the diet of ewe lambs for 16 days prior to breeding improves oxidative status without causing adverse effects on pregnancy, estrus or prolificacy.

Resumen Antecedentes: La pulpa de café tiene un alto contenido de antioxidantes capaces de modificar el estado oxidativo en pequeños rumiantes. Sin embargo, a dosis elevadas y por un tiempo prolongado puede reducir la fertilidad. Objetivo: Determinar el efecto de dos niveles de inclusión de pulpa de café durante la sincronización del estro en variables reproductivas y el estado oxidativo de ovejas primerizas. Métodos: Se utilizaron 60 ovejas primalas Suffolk x Dorset fueron distribuidas en tres tratamientos en un diseño completamente al azar; T0: (n=20) con 1,5 kg de dieta integral, T1: (n=20) con 1,5 kg de dieta integral y 5% de pulpa de café, T2: (n=20) con 1,5 kg de dieta integral y 10% de pulpa de café. La suplementación se realizó por 16 días, previo a la sincronización del estro y hasta el empadre. El progestágeno (CIDR®) se insertó en las ovejas por 11 días y se aplicó una dosis de PGF2α dos días antes de su retiro. La detección de estro comenzó a las 12 horas post-retiro del CIDR®. Se obtuvieron muestras sanguíneas durante el periodo de suplementación para medir estado oxidativo, capacidad antioxidante, glucosa e insulina, y hasta 9 días posteriores al empadre para determinar las concentraciones de progesterona. El diagnóstico de gestación se realizó a los 30 y 60 días post-monta. Se realizaron análisis de medidas repetidas utilizando un modelo de efectos mixtos, además de análisis de frecuencias. Resultados: La inclusión de pulpa por un periodo corto previo al empadre no afectó los parámetros reproductivos ni las concentraciones de progesterona, glucosa o insulina (p>0,05); sin embargo, la capacidad antioxidante se incrementó, mientras que la oxidación lipídica siguió una tendencia inversa (p<0,05). Conclusión: La inclusión hasta de 10% de pulpa de café en la dieta de ovejas por 16 días previo al empadre mejora el estado oxidativo sin ocasionar efectos adversos en el porcentaje de preñez, estro o prolificidad.

Resumo Antecedentes: A polpa de café tem alto conteúdo de antioxidantes capazes de modificar o estado oxidativo em pequenos ruminantes; no entanto, em doses elevadas e por um tempo prolongado reduz a fertilidade. Objetivo: Determinar o efeito de diferentes níveis de inclusão de polpa de café durante a sincronização do estro em diferentes variáveis reprodutivas e estado oxidativo das ovelhas primíparas. Métodos: Sessenta ovelhas primíparas dos cruzamentos Suffolk x Dorset foram distribuídas em três tratamentos em um design completamente aleatório; T0: (n=20) com 1,5 kg de dieta completa, T1: (n=20) com 1,5 kg de dieta completa contendo 5% de polpa de café, T2: (n=20) com 1,5 kg de dieta completa contendo 10% de polpa de café. A suplementação realizou-se por 16 dias, antes do início da sincronização de estros e até o momento do acasalamento. O progestogênio (CIDR) foi inserido nas ovelhas durante 11 dias e uma dose de PGF2α foi aplicada dois dias antes da sua retirada. Doze horas após a retirada do CIDR iniciou-se a detecção de estros. Foram obtidas amostras de sangue durante o período de suplementação, para medição do estado oxidativo, capacidade antioxidante, glicose e insulina e até 9 dias posteriores ao início da estação de monta para determinar as concentrações de progesterona. O diagnostico de gestação realizou-se aos 30 e 60 dias post-monta. Uma análise de medidas repetidas de efeitos mistos e análise de freqüência foi realizada. Resultados: A inclusão de polpa por um período curto antes da estação de monta não afetou os parâmetros reprodutivos nem as concentrações de progesterona, glicose e insulina (p>0,05); porém, a capacidade antioxidante nas ovelhas foi aumentada, enquanto a oxidação lipídica seguiu uma tendência inversa (p<0,05). Conclusão: Inclusão de polpa de café na dieta de ovelha até 10% durante 16 dias antes do acasalamento melhora o estado oxidativo, sem causar efeitos adversos na porcentagem de gravidez, estro e prolificidade.

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This study aimed to evaluate the effect of progesterone (P4) device reutilization in long and short protocols for transcervical timed artificial insemination (TAI) in Santa Inês ewes. A total of 275 multiparous lactating ewes were blocked according to body weight (BW, 49.1 ± 7.3 means ± SE), body condition score (BCS, 2.9 ± 0.4; scale of 1-5), and days postpartum (50 ± 8.2 days), and allocated to one of the treatments. The treatments were arranged in a factorial design, in which the factor 1 was the P4 device type (new or a device of 0.3 g of P4 previously used by 11 days), and the factor 2 was the short or long TAI protocol (P4 device remained by 7 or 11 days, respectively). At device removal, all ewes received 300 IU eCG and 6.70 mg of Dinoprost tromethamine. After TAI protocol, ewes remained with ram by 21 days. There was no interaction between factors in any variables. Ewes that received a new P4 device delayed (P = 0.05) to show estrus compared with ewes receiving a previously used P4 device, but it did not affect pregnancy rate. The long protocol tended to increase pregnancy rate compared with short protocol (33% vs. 24%, respectively; P = 0.07). However, the pregnancy rate at the end of reproductive period was similar in both groups (about 84%). Thus, the use of long protocols tended to improve reproductive performance, and the reused P4 device did not affect pregnancy rate.

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A resposta ovariana de catetos tratados com eCG/hCG foi analisada pelo desenvolvimento folicular e pela expressão gênica. O tratamento DS (dose utilizada em suínos) e DA (dose ajustada alometricamente) foram comparados. Todas as fêmeas apresentaram corpos hemorrágicos (CHs) e as taxas de ovulação foram semelhantes entre DS (4,00±1,17) e DA (2,50±0,43). O número de folículos por animal e as quantidades de folículos P (≤3mm), M (3-5mm) e G (≥5mm) foram similares entre os grupos. Os folículos ovarianos do mesmo tamanho expressaram FSHR e LHCGR em níveis similares entre os grupos. FSHR foi mais expresso na fase inicial, e LHCGR, na fase tardia da foliculogênese ovariana de cateto. A expressão de LHCGR nos CHs foi igual entre os tratamentos e entre os ovários direito e esquerdo.

The ovarian response of catches treated with eCG/hCG was analyzed by follicular development and gene expression. The treatment DS (dose used in pigs) and AD (dose adjusted alometrically) were compared. All females showed hemorrhagic bodies (CHs) and ovulation rates were similar between DS (4.00±1.17) and AD (2.50±0.43). The number of follicles per animal and the numbers of follicles P (≤3mm), M (3-5mm) and G (≥5mm) were similar between the groups. Ovarian follicles of the same size expressed FSHR and LHCGR at similar levels between groups. FSHR was more expressed in the early phase, and LHCGR, in the late phase of ovarian catheter folliculogenesis. LHCGR expression in CHs was equal between treatments and between right and left ovary.

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A resposta ovariana de catetos tratados com eCG/hCG foi analisada pelo desenvolvimento folicular e pela expressão gênica. O tratamento DS (dose utilizada em suínos) e DA (dose ajustada alometricamente) foram comparados. Todas as fêmeas apresentaram corpos hemorrágicos (CHs) e as taxas de ovulação foram semelhantes entre DS (4,00±1,17) e DA (2,50±0,43). O número de folículos por animal e as quantidades de folículos P (≤3mm), M (3-5mm) e G (≥5mm) foram similares entre os grupos. Os folículos ovarianos do mesmo tamanho expressaram FSHR e LHCGR em níveis similares entre os grupos. FSHR foi mais expresso na fase inicial, e LHCGR, na fase tardia da foliculogênese ovariana de cateto. A expressão de LHCGR nos CHs foi igual entre os tratamentos e entre os ovários direito e esquerdo.(AU)

The ovarian response of catches treated with eCG/hCG was analyzed by follicular development and gene expression. The treatment DS (dose used in pigs) and AD (dose adjusted alometrically) were compared. All females showed hemorrhagic bodies (CHs) and ovulation rates were similar between DS (4.00±1.17) and AD (2.50±0.43). The number of follicles per animal and the numbers of follicles P (≤3mm), M (3-5mm) and G (≥5mm) were similar between the groups. Ovarian follicles of the same size expressed FSHR and LHCGR at similar levels between groups. FSHR was more expressed in the early phase, and LHCGR, in the late phase of ovarian catheter folliculogenesis. LHCGR expression in CHs was equal between treatments and between right and left ovary.(AU)

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RESUMO

PURPOSE: Planned reproduction in cattle involves regulation of estrous cycle and the use of artificial insemination. Cycle control includes the administration of exogenous progesterone during 5-8 days in a controlled manner allowing females to synchronize their ovulation. Several progesterone delivery systems are commercially available but they have several drawbacks. The aim of the present contribution was to evaluate chitosan microparticles entrapping progesterone as an alternative system. METHODS: Microparticles were prepared by spray drying. The effect of formulation parameters and experimental conditions on particle features and delivery was studied. A mathematical model to predict progesterone plasma concentration in animals was developed and validated with experimental data. RESULTS: Microparticle size was not affected by formulation parameters but sphericity enhances as Tween 80 content increases and it impairs as TPP content rises. Z potential decreases as phosphate content rises. Particles remain stable in acidic solution but the addition of surfactant is required to stabilize dispersions in neutral medium. Encapsulation efficiencies was 69-75%. In vitro delivery studies showed burst and diffusion-controlled phases, being progesterone released faster at low pH. In addition, delivery extend in cows was affected mainly by particle size and hormone initial content, while the amount injected altered plasma concentration. Theoretical predictions with excellent accuracy were obtained. CONCLUSION: The mathematical model developed can help to find proper particle features to reach specific delivery rates in the animals. This not only save time, money and effort but also minimized experimentation with animals which is desired from an ethical point of view.

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RESUMO

Paraoxonase-1 (PON1) activity has been associated with improvement in ovarian function in early postpartum dairy cows and improved in vitro embryo development. The aim of the current study was to evaluate the potential association among PON1 activity and follicular growth, diameter of the preovulatory follicle and pregnancy per artificial insemination (AI) service in cattle. In Experiment 1, cows (n=33) were subjected to an estradiol-progesterone based protocol to control time of ovulation. Starting on Day 8 of the protocol, follicular growth and serum PON1 activity were monitored. Cows were separated according to the occurrence of ovulation into two groups: Ovulatory (Ov; n=22) and Anovulatory (Anov; n=11). The serum activity of PON1 was not different between Ov and Anov cows (P=0.94). In addition, using a regression model there was no effect of serum PON1 activity on the diameter of dominant follicle (r2=0.00; P=0.99). In Experiment 2, cows (n=193) were submitted to the same hormonal protocol as in Experiment 1. On the day of the timed artificial insemination (TAI), the diameter of dominant follicle was evaluated and blood samples were collected for analysis of PON1 activity. According to the serum PON1 activity, cows were divided into three groups: Low (<70U/mL), Medium (70-90U/mL) or High (>90U/mL) PON1 activity. The overall pregnancy rate was 62.7% (121/193), with no difference among PON1 activity groups. Additionally, using a regression model there was no effect of serum PON1 activity on the diameter of the preovulatory follicle (r2=0.03; P=0.65) and pregnancy rate (r2=0.005; P=0.94). The results of this study indicate that there is no effect of serum PON1 activity on the diameter of preovulatory follicle or establishment of pregnancy in cows submitted to time of ovulation synchronization protocols.

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RESUMO

As our understanding of ovarian function in cattle has improved, our ability to control it has also increased. Luteal function in cattle has been studied in detail, and prostaglandin F2α has been used for several years for the elective induction of luteal regression. More recently, follicle wave dynamics has been studied and protocols designed to induce follicular wave emergence and ovulation have reduced, and even eliminated, the need for estrus detection. The addition of progestin-releasing devices, estradiol, GnRH and equine chorionic gonadotropin (eCG) have provided opportunities for fixed-time AI (FTAI) and possibilities for increased pregnancy rates. In embryo transfer programs, these same treatments have eliminated the need for estrus detection, permitting fixed-time embryo transfer and the initiation of superstimulatory treatments without regard to day of the estrous cycle. Collectively, new treatment protocols have facilitated the application of assisted reproductive technologies, and this is especially true in South America. Over the last 20 years, the use of AI in South America has increased, due largely to the use of FTAI. There has been more than a 10-fold increase in the use of FTAI in Brazil with more than 11 million treatments in 2016, representing 85% of all AI. Similar trends are occurring in Argentina and Uruguay. Production of in vivo-derived (IVD) embryos has remained relatively stable over the years, but in vitro embryo production (IVP) has increased dramatically over the past 10 to 15 years, especially in Brazil where more than 300,000 IVP embryos were produced in 2010. World-wide, more than 666,000 bovine IVP embryos were produced in 2016, of which more than 57% were produced in South America. The use of assisted reproductive technologies has facilitated the dissemination of improved genetics and increased reproductive performance; other South American countries are now following suit.

RESUMO

As our understanding of ovarian function in cattle has improved, our ability to control it has also increased. Luteal function in cattle has been studied in detail, and prostaglandin F2α has been used for several years for the elective induction of luteal regression. More recently, follicle wave dynamics has been studied and protocols designed to induce follicular wave emergence and ovulation have reduced, and even eliminated, the need for estrus detection. The addition of progestin-releasing devices, estradiol, GnRH and equine chorionic gonadotropin (eCG) have provided opportunities for fixed-time AI (FTAI) and possibilities for increased pregnancy rates. In embryo transfer programs, these same treatments have eliminated the need for estrus detection, permitting fixed-time embryo transfer and the initiation of superstimulatory treatments without regard to day of the estrous cycle. Collectively, new treatment protocols have facilitated the application of assisted reproductive technologies, and this is especially true in South America. Over the last 20 years, the use of AI in South America has increased, due largely to the use of FTAI. There has been more than a 10-fold increase in the use of FTAI in Brazil with more than 11 million treatments in 2016, representing 85% of all AI. Similar trends are occurring in Argentina and Uruguay. Production of in vivo-derived (IVD) embryos has remained relatively stable over the years, but in vitro embryo production (IVP) has increased dramatically over the past 10 to 15 years, especially in Brazil where more than 300,000 IVP embryos were produced in 2010. World-wide, more than 666,000 bovine IVP embryos were produced in 2016, of which more than 57% were produced in South America. The use of assisted reproductive technologies has facilitated the dissemination of improved genetics and increased reproductive performance; other South American countries are now following suit.

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