Study of sexual behaviours with different types of estrus synchronization protocols in Boer goats

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

Study of sexual behaviours with different types of estrus synchronization protocols in Boer goats

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)

The effect of Gonadotropin releasing hormone administration on fertility and embryonic loss in goats during the anoestrus period

Following the induction of oestrus out of season in small ruminants, low fertility and variations in fertility rates are associated with embryonic losses. One of the main causes of embryonic loss is luteal dysfunction. Gonadotropin Releasing Hormone (GnRH) supports the luteal structure, and increasing progesterone levels may be beneficial in terms of promoting embryonic life. The main objective of the present study was to evaluate the efficacy of GnRH administration following an oestrus induction protocol in the anoestrus season for preventing embryonic loss in goats having failure to conceive during the season. In the study, 106 Damascus goats aged 3-5 years and weighing 45-60 kg were used. The oestrus of 106 goats in the anoestrous group was stimulated with progesterone and pregnant mare serum gonadotropin (PMSG) treatment. Out of breeding season, goats were divided into the 4 following groups: GnRH0 (n = 27), GnRH7 (n = 26), GnRH0+7 (n = 27) and control (n = 26). In each goat, an intravaginal sponge (IS) containing 20 mg of fluorogestone acetate (FGA) was placed into the vagina and left for 9 days. With the withdrawal of the sponge, 550IU PMSG and 125 µg of d-cloprostenol were injected intramuscularly. Oestrus detection was made via teaser bucks for 3 days starting 24 h after withdrawal of the IS. Eighteen bucks known to be fertile were used for breeding. Goats in the oestrus period were mated via natural breeding. The GnRH analogue lecirelin was injected intramuscularly at breeding in the GnRH0 group, on day 7 post-breeding in the GnRH7 group, and both at breeding and on day 7 post-breeding in the GnRH0+7 group. No injections were given to the control group. Blood samples for progesterone measurement were taken by jugular vena puncturing on days 3, 6, 7, 10, 13, 16, and 19 after breeding from 10 randomly chosen goats in all groups. The goats with a level of > 3.5 ng/mL of progesterone on day 21 post-breeding were evaluated as pregnant. Pregnancy was also viewed on day 50 after breeding by real-time ultrasonography (USG) with a 5-7.5 MHz convex probe. The oestrus rate was 96.23% (102/106) in the goats. The rates of onset of oestrus between 36-48 h, 48-60 h and 60 h and beyond were 38.7% (41/106), 21.7% (23/106) and 35.8% (38/106), respectively. The total pregnancy rate was 35.8% (38/106). There were no statistically significant differences (P > 0.05) found for the pregnancy rate, embryonic death rate or progesterone concentration of the groups. However, serum progesterone levels were statistically different in the GnRH7 group compared with the control group (P < 0.05). After synchronisation, various anti-luteolytic strategies can be used to support corpus luteum development and elevate progesterone concentration in the luteal phase to decrease embryonic loss and increase reproductive performance. Therefore, application of GnRH to support the luteal structure and to increase progesterone levels may be beneficial in terms of supporting embryonic life. The results showed that GnRH treatment on the day 7 post-breeding following oestrus induction, including FGA and PMSG, can increase serum progesterone levels in Damascus goats in the anoestrus period. However, following oestrus induction in the anoestrus period, it was seen that GnRH treatment at breeding or on day 7 after breeding did not have any positive effect on embryonic loss or reproductive performance. In conclusion, it was considered that this protocol could be implemented successfully, yielding a 35% pregnancy rate in Damascus goats in the anoestrus period, but embryonic loss must be deeply studied in detail.(AU)

Hormonal protocols for the synchronization and induction of synchronized estrus in dairy ewes kept under tropical conditions

Background: Lacaune is an important sheep breed and shows reproductive seasonality which affects dairy product supply. The most common hormonal protocols are based on progesterone-releasing devices in order to reach reproductive activity. Due to international consumer demand for natural, green, and clean methods, such issues encourage the minimal or absent use of synthetic hormones in livestock. In this sense, the present study tested the efficiency of induction and estrus synchronization protocols in lacaune ewes, considering: application interval of synthetic prostaglandin at the breeding season; length of synthetic progesterone exposure; and eCG dose at the outbreeding season. Materials, Methods & Results: In study 1: 52 ewes were submitted to estrus synchronization protocol using two doses of d-cloprostenol 7 or 9 days apart. In study 2: 47 ewes were submitted to estrus induction protocol using an intravaginal device containing 60 mg of medroxyprogesterone acetate maintained for 6, 9, or 12 days. In study 3: 46 ewes were submitted to synchronized estrus induction protocol using intravaginal progesterone device for six days. On the fifth day, d-cloprostenol and 300 IU or 400 IU of eCG were administered. For all studies, signs of estrus beginning/ending were recorded and natural mating was performed. After 30 days, transrectal ultrasound was performed for pregnancy diagnosis. In study 1, groups presented similar rate of estrus behavior (78.8%) and pregnancy (average 75.6%). Meanwhile, compared to G9days (37.8 ± 7.2 h), interval between the second dose of prostaglandin and beginning of estrus was smaller in G7days (31.5 ± 7.8 h). No difference was found among variables studied in study 2 (P > 0.05), nevertheless the SD for the estrus duration was shorter (P < 0.05) in G6days and G12 days when compared with the G9days . Equally, the SD...

Paeonia lactiflora improves ovarian function and oocyte quality in aged female mice

Although ovarian aging is a key cause of decreased ovarian function and oocyte quality, it remains a problem in infertility treatment. Therefore, this study is aimed to investigate whether Paeonia lactiflora (PL), a herb improves ovarian function and oocyte quality using aged female mice. C57BL/6 female mice aged 8 months were treated orally every day with PL of 26.5 mg/kg (n=7) and 53 mg/kg (n=7) of body weight for 4 weeks using an oral zoned needle. The control group (n=7) was treated with normal saline. Ovaries and serum were collected for the H&E stain and the evaluation of reactive oxygen species (ROS) levels, respectively. In the second experiment, female mice were orally administered with PL (26.5 mg/kg: n=12, 53 mg/kg: n=12, control: n=12) and then superovulated with PMSG and hCG, and mated with male mice. Zygotes were retrieved and cultured for 4 days. Ovaries were provided for examination of expressions of genes associated with angiogenesis (VEGF and visfatin), anti-aging (Sirt1 and Sirt2), and follicular development (c-Kit, BMP-15, and GDF-9). PL significantly increased numbers of surviving follicles (primordial, primary, secondary, and antral), numbers of zygotes retrieved, embryo development rate, and ovarian expression of VEGF, visfatin, c-Kit, BMP-15, and GDF-9 at both doses. However, ovarian expression of Sirt1 and Sirt2 was increased at 53.0 mg/kg of PL. ROS levels were not affected by PL. These results suggest that PL may possess beneficial effects regarding ovarian function and oocyte quality, possibly by activation of ovarian angiogenesis and follicular development.

Paeonia lactiflora improves ovarian function and oocyte quality in aged female mice

Although ovarian aging is a key cause of decreased ovarian function and oocyte quality, it remains a problem in infertility treatment. Therefore, this study is aimed to investigate whether Paeonia lactiflora (PL), a herb improves ovarian function and oocyte quality using aged female mice. C57BL/6 female mice aged 8 months were treated orally every day with PL of 26.5 mg/kg (n=7) and 53 mg/kg (n=7) of body weight for 4 weeks using an oral zoned needle. The control group (n=7) was treated with normal saline. Ovaries and serum were collected for the H&E stain and the evaluation of reactive oxygen species (ROS) levels, respectively. In the second experiment, female mice were orally administered with PL (26.5 mg/kg: n=12, 53 mg/kg: n=12, control: n=12) and then superovulated with PMSG and hCG, and mated with male mice. Zygotes were retrieved and cultured for 4 days. Ovaries were provided for examination of expressions of genes associated with angiogenesis (VEGF and visfatin), anti-aging (Sirt1 and Sirt2), and follicular development (c-Kit, BMP-15, and GDF-9). PL significantly increased numbers of surviving follicles (primordial, primary, secondary, and antral), numbers of zygotes retrieved, embryo development rate, and ovarian expression of VEGF, visfatin, c-Kit, BMP-15, and GDF-9 at both doses. However, ovarian expression of Sirt1 and Sirt2 was increased at 53.0 mg/kg of PL. ROS levels were not affected by PL. These results suggest that PL may possess beneficial effects regarding ovarian function and oocyte quality, possibly by activation of ovarian angiogenesis and follicular development.(AU)

Diferentes momentos de aplicação de gonadotrofina coriônica equina em protocolo de inseminação artificial em tempo fixo para vacas de leite / Different times of application of equine chorionic gonadotropin in fixed-time artificial insemination protocols for dairy cows

Avaliaram-se diferentes momentos de aplicação da gonadotrofina coriônica equina (eCG) em protocolos de inseminação artificial em tempo fixo (IATF) para vacas de leite. Foram utilizadas 76 fêmeas, as quais receberam, no dia zero (D0) do protocolo, dispositivos intravaginais de progesterona, sendo esses retirados no D9, e os animais foram, então, distribuídos aleatoriamente em três tratamentos: T1 - aplicação de eCG no momento da retirada dos dispositivos; T2 e T3 - aplicação de eCG 48h e 24h antes da retirada dos dispositivos, respectivamente. No D10 os animais receberam 1mg de GnRH, e a IATF foi realizada 52 horas após a retirada do implante. Não houve diferença (P>0,05) para intervalo entre a retirada do implante à ovulação (72,56±3,92h), o diâmetro do maior folículo no D9 (10,88±1,49mm), o diâmetro do folículo ovulatório (15,15±1,16mm) e do segundo maior folículo (7,49±0,52mm), a taxa de crescimento folicular (1,38±0,04mm/dia), a taxa de ovulação (96,67%), o intervalo entre diâmetro final e inicial do folículo dominante (73,49±3,84h), a área de corpo lúteo (2,27±0,43cm²), a porcentagem de CL no ovário direito (53,00%) e no esquerdo (26,33%) e a taxa de gestação (33,33%). O momento da aplicação da eCG não influenciou na eficiência do protocolo. Recomenda-se a utilização da eCG no momento da retirada do implante por otimização do manejo.(AU)

Different times of application of equine chorionic gonadotropin (eCG) in Fixed-Time Artificial Insemination (FTAI) protocols for dairy cows were evaluated. A total of 76 females were used, which received intravaginal progesterone devices on day zero (D0) of the protocol, which were withdrawn on D9, and the animals were then randomly distributed in three treatments: T1- application of eCG at the time of device withdrawal; T2 and T3 - application of eCG 48h and 24h before withdrawal of the devices, respectively. On D10 the animals received 1mg of GnRH and the FTAI was carried out 52 hours after the removal of the implant. There was no difference (P>0.05) for interval from implant removal to ovulation (72.56±3.92h), diameter of the largest follicle of D9 (10.88±1.49mm), diameters of ovulatory follicle (15.15±1.16mm) and of the second largest follicle (7.49±0.52mm), follicle growth rate (1.38±0.04mm/day), ovulation rate (96.67%), interval between final diameter and initial diameter of dominant follicle (73.49±3.84h), corpus luteum area (2.27±0.43cm²), percentage of CL in right ovary (53.00%) and in left ovary (26.33%) and pregnancy rate (33.33%). The time of the application of eCG did not influence the efficiency of the protocol. We recommend the use of eCG at the time of the removal of the implant for management optimization.(AU)

Farmacopuntura utilizando os acupontos Hou Hai e Bai Hui em protocolos de sincronização de estro em cabras / Pharmacopuncture using acupoints Hou Hai and Bai Hui in estrous synchronization protocols in goats

Avaliou-se a eficiência da administração de subdoses de eCG nos acupontos Bai Hui e Hou Hai em protocolos de sincronização de estro em cabras. Na primeira etapa, 57 cabras foram distribuídas aleatoriamente em quatro tratamentos: T1- 300UI de eCG intramuscular (IM); T2- 60UI de eCG no acuponto Hou Hai; T3- 60UI de eCG no acuponto Bai Hui e T4- 60UI de eCG IM; e na segunda etapa, 28 cabras foram distribuídas aleatoriamente em três tratamentos: T1- 300UI de eCG IM; T2- 30UI de eCG no acuponto Bai Hui e T3- 30UI de eCG IM. Ao final do tratamento hormonal, as cabras foram monitoradas para detecção do estro, realização das coberturas e avaliação do comportamento reprodutivo. Os dados foram submetidos à análise de normalidade, seguida dos testes estatísticos adequados para cada variável. Na primeira etapa experimental, obteve-se maior duração de estro nas cabras do T1 (P=0,009). Na segunda etapa experimental, obteve-se maior número de animais em estros no T1 (P=0,03). As demais variáveis para ambas as etapas não sofreram influência dos tratamentos (P>0,05), demonstrando que a administração de subdoses de eCG nos acupontos Bai Hui e Hou Hai foi eficiente para sincronizar o estro.(AU)

The efficiency of administration of subdoses of eCG in the Bai Hui and Hou Hai acupoints in oestrus synchronization protocols in goats was evaluated. In the first stage, 57 goats were randomly assigned to four treatments: T1- 300UI of intramuscular eCG (IM); T2- 60UI of eCG in acupoint Hou Hai; T3- 60UI of eCG in the Bai Hui acupoint and T4- 60UI of eCG IM; and in the second stage, 28 goats were randomly assigned to three treatments: T1-300UI of eCG IM; T2-30UI of eCG in the Bai Hui acupoint and T3- 30UI of eCG IM. At the end of the hormonal treatment the goats were monitored for estrus detection, and evaluation of reproductive behavior. The data were submitted to normality analysis, followed by appropriate statistical tests for each variable. In the first experimental stage, a longer duration of estrus in the T1 goats (P= 0.009) was obtained. In the second experimental stage, a greater number of animals were obtained in estrus at T1 (P= 0.03). The other variables for both experiments were not influenced by the treatments (P> 0.05), demonstrating that administration of eCG subdoses in the Bai Hui and Hou Hai acupoints was efficient to synchronize the estrus.(AU)

Diferentes momentos de aplicação de gonadotrofina coriônica equina em protocolo de inseminação artificial em tempo fixo para vacas de leite / Different times of application of equine chorionic gonadotropin in fixed-time artificial insemination protocols for dairy cows

Avaliaram-se diferentes momentos de aplicação da gonadotrofina coriônica equina (eCG) em protocolos de inseminação artificial em tempo fixo (IATF) para vacas de leite. Foram utilizadas 76 fêmeas, as quais receberam, no dia zero (D0) do protocolo, dispositivos intravaginais de progesterona, sendo esses retirados no D9, e os animais foram, então, distribuídos aleatoriamente em três tratamentos: T1 - aplicação de eCG no momento da retirada dos dispositivos; T2 e T3 - aplicação de eCG 48h e 24h antes da retirada dos dispositivos, respectivamente. No D10 os animais receberam 1mg de GnRH, e a IATF foi realizada 52 horas após a retirada do implante. Não houve diferença (P>0,05) para intervalo entre a retirada do implante à ovulação (72,56±3,92h), o diâmetro do maior folículo no D9 (10,88±1,49mm), o diâmetro do folículo ovulatório (15,15±1,16mm) e do segundo maior folículo (7,49±0,52mm), a taxa de crescimento folicular (1,38±0,04mm/dia), a taxa de ovulação (96,67%), o intervalo entre diâmetro final e inicial do folículo dominante (73,49±3,84h), a área de corpo lúteo (2,27±0,43cm²), a porcentagem de CL no ovário direito (53,00%) e no esquerdo (26,33%) e a taxa de gestação (33,33%). O momento da aplicação da eCG não influenciou na eficiência do protocolo. Recomenda-se a utilização da eCG no momento da retirada do implante por otimização do manejo.(AU)

Different times of application of equine chorionic gonadotropin (eCG) in Fixed-Time Artificial Insemination (FTAI) protocols for dairy cows were evaluated. A total of 76 females were used, which received intravaginal progesterone devices on day zero (D0) of the protocol, which were withdrawn on D9, and the animals were then randomly distributed in three treatments: T1- application of eCG at the time of device withdrawal; T2 and T3 - application of eCG 48h and 24h before withdrawal of the devices, respectively. On D10 the animals received 1mg of GnRH and the FTAI was carried out 52 hours after the removal of the implant. There was no difference (P>0.05) for interval from implant removal to ovulation (72.56±3.92h), diameter of the largest follicle of D9 (10.88±1.49mm), diameters of ovulatory follicle (15.15±1.16mm) and of the second largest follicle (7.49±0.52mm), follicle growth rate (1.38±0.04mm/day), ovulation rate (96.67%), interval between final diameter and initial diameter of dominant follicle (73.49±3.84h), corpus luteum area (2.27±0.43cm²), percentage of CL in right ovary (53.00%) and in left ovary (26.33%) and pregnancy rate (33.33%). The time of the application of eCG did not influence the efficiency of the protocol. We recommend the use of eCG at the time of the removal of the implant for management optimization.(AU)

Farmacopuntura utilizando os acupontos Hou Hai e Bai Hui em protocolos de sincronização de estro em cabras / Pharmacopuncture using acupoints Hou Hai and Bai Hui in estrous synchronization protocols in goats

Avaliou-se a eficiência da administração de subdoses de eCG nos acupontos Bai Hui e Hou Hai em protocolos de sincronização de estro em cabras. Na primeira etapa, 57 cabras foram distribuídas aleatoriamente em quatro tratamentos: T1- 300UI de eCG intramuscular (IM); T2- 60UI de eCG no acuponto Hou Hai; T3- 60UI de eCG no acuponto Bai Hui e T4- 60UI de eCG IM; e na segunda etapa, 28 cabras foram distribuídas aleatoriamente em três tratamentos: T1- 300UI de eCG IM; T2- 30UI de eCG no acuponto Bai Hui e T3- 30UI de eCG IM. Ao final do tratamento hormonal, as cabras foram monitoradas para detecção do estro, realização das coberturas e avaliação do comportamento reprodutivo. Os dados foram submetidos à análise de normalidade, seguida dos testes estatísticos adequados para cada variável. Na primeira etapa experimental, obteve-se maior duração de estro nas cabras do T1 (P=0,009). Na segunda etapa experimental, obteve-se maior número de animais em estros no T1 (P=0,03). As demais variáveis para ambas as etapas não sofreram influência dos tratamentos (P>0,05), demonstrando que a administração de subdoses de eCG nos acupontos Bai Hui e Hou Hai foi eficiente para sincronizar o estro.(AU)

The efficiency of administration of subdoses of eCG in the Bai Hui and Hou Hai acupoints in oestrus synchronization protocols in goats was evaluated. In the first stage, 57 goats were randomly assigned to four treatments: T1- 300UI of intramuscular eCG (IM); T2- 60UI of eCG in acupoint Hou Hai; T3- 60UI of eCG in the Bai Hui acupoint and T4- 60UI of eCG IM; and in the second stage, 28 goats were randomly assigned to three treatments: T1-300UI of eCG IM; T2-30UI of eCG in the Bai Hui acupoint and T3- 30UI of eCG IM. At the end of the hormonal treatment the goats were monitored for estrus detection, and evaluation of reproductive behavior. The data were submitted to normality analysis, followed by appropriate statistical tests for each variable. In the first experimental stage, a longer duration of estrus in the T1 goats (P= 0.009) was obtained. In the second experimental stage, a greater number of animals were obtained in estrus at T1 (P= 0.03). The other variables for both experiments were not influenced by the treatments (P> 0.05), demonstrating that administration of eCG subdoses in the Bai Hui and Hou Hai acupoints was efficient to synchronize the estrus.(AU)

Application of low dose of equine chorionic gonadotropin at acupoint Hou Hai for fixed-time artificial insemination in beef cows / Aplicação de baixa dose de gonadotrofina coriônica equina no acuponto Hou Hai em protocolos de inseminação artificial em tempo fixo para vacas de corte

This study evaluated the efficiency application of low dose of equine chorionic gonadotropin (eCG) using Hou Hai acupoint for fixed-term artificial insemination (FTAI) in beef cows. Seventy cows received intravaginal devices with progesterone, and 3 mg of estradiol benzoate on day zero (D0) of FTAI. On D9, the devices were removed, and 150 μg of prostaglandin F2α was applied; the animals were then randomly distributed to three treatment groups: T1 (n = 23), 300 IU of eCG intramuscularly (IM); T2 (n = 23), 90 IU of eCG at acupoint Hou Hai; and T3 (n = 25), 90 IU of eCG at false acupoint IM. On D10, the animals received 1 mg of gonadotropin-releasing hormone IM, and FTAI was performed, 52 h after the devices were removed. The quantitative variables with normal distribution were assessed using analysis of variance at 5% probability. For variables that did not show normal distribution, Kruskal-Wallis test at 5% probability was used. No significant difference was noted among the groups (P > 0.05) for the interval between device withdrawal at ovulation (58.2 ± 12.2 h), diameter of the largest follicle on D9 (9.9 ± 2.2 mm), diameters of the ovulatory follicle (12.2 ± 3.0 mm) and the second largest follicle (6.7 ± 2.1 mm), follicular growth rate (0.8 ± 0.3 mm/d), ovulation rate (82%), corpus luteum size (2.32 ± 0.35 cm2), and pregnancy rate (58.67%). The protocol cost per animal was US$ 10.67 (T1) and US$ 8.50 (T2 and T3). The use of 90 IU of eCG applied at Hou Hai acupoint or at false acupoint caused satisfactory synchronization of estrus in beef cows. In addition, this procedure was cost-effective.(AU)

Avaliou-se a eficiência da aplicação de subdose gonadotrofina coriônica equina (eCG) utulizando como via de administração o acuponto Hou Hai em protocolos de inseminação artificial em tempo fixo (IATF) para vacas de corte. Setenta vacas receberam no dia zero (D0) do protocolo dispositivos intravaginais com progesterona, e 3mg de benzoato de estradiol. No D9 foram retirados os dispositivos, aplicado 150µg de prostaglandina F2α e distribuídos os animais aleatoriamente em três tratamentos: T1 (n=23) - 300UI de eCG por via intra muscular (IM); T2 (n=23) - 90UI de eCG no acuponto Hou Hai e T3 (n=25) - 90UI de eCG em falso acuponto, IM. No D10 os animais receberam 1mg de GnRH por via IM e foi realizada a IATF, 52 horas após a retirada dos dispositivos. Para as variáveis quantitativas com distribuição normal foi utilizada ANOVA, a 5% de probabilidade. Para as variáveis que não apresentaram distribuição normal, utilizou-se o teste de Kruskal-Wallis, a 5% de probabilidade. Não houve diferença (P >0,05) para o intervalo entre a retirada do dispositivo à ovulação (58,2 ± 12,2h), diâmetro do maior folículo no D9 (9,9 ± 2,2mm), diâmetros do folículo ovulatório (12,2 ± 3,0mm) e do segundo maior folículo (6,7 ± 2,1mm), taxa de crescimento folicular (0,8 ± 0,3mm/d), taxa de ovulação (82%), área de corpo lúteo (2,32 ± 0,35 cm2) e taxa de prenhez (58,67%). O custo do protocolo por animal foi de US$ 10,67 (T1) e US$ 8,50 (T2 e T3). Sugere-se que a utilização de 90UI de eCG aplicada no acuponto Hou Hai ou em falso acuponto foram satisfatórios na sincronização de estro de vacas de corte. Além disso, possibilita a redução do custo do protocolo.(AU)

Application of low dose of equine chorionic gonadotropin at acupoint Hou Hai for fixed-time artificial insemination in beef cows / Aplicação de baixa dose de gonadotrofina coriônica equina no acuponto Hou Hai em protocolos de inseminação artificial em tempo fixo para vacas de corte

This study evaluated the efficiency application of low dose of equine chorionic gonadotropin (eCG) using Hou Hai acupoint for fixed-term artificial insemination (FTAI) in beef cows. Seventy cows received intravaginal devices with progesterone, and 3 mg of estradiol benzoate on day zero (D0) of FTAI. On D9, the devices were removed, and 150 μg of prostaglandin F2α was applied; the animals were then randomly distributed to three treatment groups: T1 (n = 23), 300 IU of eCG intramuscularly (IM); T2 (n = 23), 90 IU of eCG at acupoint Hou Hai; and T3 (n = 25), 90 IU of eCG at false acupoint IM. On D10, the animals received 1 mg of gonadotropin-releasing hormone IM, and FTAI was performed, 52 h after the devices were removed. The quantitative variables with normal distribution were assessed using analysis of variance at 5% probability. For variables that did not show normal distribution, Kruskal-Wallis test at 5% probability was used. No significant difference was noted among the groups (P > 0.05) for the interval between device withdrawal at ovulation (58.2 ± 12.2 h), diameter of the largest follicle on D9 (9.9 ± 2.2 mm), diameters of the ovulatory follicle (12.2 ± 3.0 mm) and the second largest follicle (6.7 ± 2.1 mm), follicular growth rate (0.8 ± 0.3 mm/d), ovulation rate (82%), corpus luteum size (2.32 ± 0.35 cm2), and pregnancy rate (58.67%). The protocol cost per animal was US$ 10.67 (T1) and US$ 8.50 (T2 and T3). The use of 90 IU of eCG applied at Hou Hai acupoint or at false acupoint caused satisfactory synchronization of estrus in beef cows. In addition, this procedure was cost-effective.

Avaliou-se a eficiência da aplicação de subdose gonadotrofina coriônica equina (eCG) utulizando como via de administração o acuponto Hou Hai em protocolos de inseminação artificial em tempo fixo (IATF) para vacas de corte. Setenta vacas receberam no dia zero (D0) do protocolo dispositivos intravaginais com progesterona, e 3mg de benzoato de estradiol. No D9 foram retirados os dispositivos, aplicado 150µg de prostaglandina F2α e distribuídos os animais aleatoriamente em três tratamentos: T1 (n=23) - 300UI de eCG por via intra muscular (IM); T2 (n=23) - 90UI de eCG no acuponto Hou Hai e T3 (n=25) - 90UI de eCG em falso acuponto, IM. No D10 os animais receberam 1mg de GnRH por via IM e foi realizada a IATF, 52 horas após a retirada dos dispositivos. Para as variáveis quantitativas com distribuição normal foi utilizada ANOVA, a 5% de probabilidade. Para as variáveis que não apresentaram distribuição normal, utilizou-se o teste de Kruskal-Wallis, a 5% de probabilidade. Não houve diferença (P >0,05) para o intervalo entre a retirada do dispositivo à ovulação (58,2 ± 12,2h), diâmetro do maior folículo no D9 (9,9 ± 2,2mm), diâmetros do folículo ovulatório (12,2 ± 3,0mm) e do segundo maior folículo (6,7 ± 2,1mm), taxa de crescimento folicular (0,8 ± 0,3mm/d), taxa de ovulação (82%), área de corpo lúteo (2,32 ± 0,35 cm2) e taxa de prenhez (58,67%). O custo do protocolo por animal foi de US$ 10,67 (T1) e US$ 8,50 (T2 e T3). Sugere-se que a utilização de 90UI de eCG aplicada no acuponto Hou Hai ou em falso acuponto foram satisfatórios na sincronização de estro de vacas de corte. Além disso, possibilita a redução do custo do protocolo.

Influence of follicular growth stimulation on fertility of beef cows treated with eCG or FSH in FTAI protocols / Influência da estimulação do crescimento folicular na fertilidade de vacas de corte tratadas com eCG ou FSH em protocolos de IATF

Background: The pregnancy rate in fixed-time insemination (FTAI) programs in beef cattle is affected by several factors, including the size of ovulatory follicle (OF). Induced ovulation of small OF (≤11 mm) reduces the chance of pregnancy after FTAI when compared to ovulation of larger follicles (≥12 mm). Hormonal treatments to enhance the follicle growth have been widely used in comercial beef cattle systems, aiming to improve the development of a dominant follicle. The objective of this experiment was to evaluate the effect of treatment with eCG or FSH at the time of progesterone implant removal on the diameter of OF, final follicle growth and pregnancy rate in beef cows.Materials, Methods & Results: Three hundred and seven suckled beef cows with body condition score 2.80 ± 0.24 (1 to 5 scale) and 45 to 70 days postpartum were synchronized to FTAI. On day 0, intravaginal implants containing 1 g of progesterone, were inserted and administered 2 mg of estradiol benzoate (EB), i.m. On day 7, intravaginal implants were removed and 150 µg of D-cloprostenol were administered i.m. At this time, three groups were assigned according to the treatments: eCG (400 UI eCG, i.m.), FSH (25 UI FSH, i.m.) and Control (1 mL Saline, i.m.). On day 8, all cows were injected with 1mg EB i.m. and were inseminated 52 to 56 h after the implant removal. Transrectal ultrasonography exams of ovaries were performed at the time of implant removal and before FTAI to determine the diameter of the largest follicle and the follicular daily growth. Pregnancy exams were conducted by transretal ultrasonography 30 days after FTAI. Statistical analyzes were performed by Chi-square test for pregnancy rate. Ovarian diameters and follicular daily growth were analyzed by ANOVA with means compared by Tukey test considering significant P value < 0.05.[...]

Influence of follicular growth stimulation on fertility of beef cows treated with eCG or FSH in FTAI protocols / Influência da estimulação do crescimento folicular na fertilidade de vacas de corte tratadas com eCG ou FSH em protocolos de IATF

Background: The pregnancy rate in fixed-time insemination (FTAI) programs in beef cattle is affected by several factors, including the size of ovulatory follicle (OF). Induced ovulation of small OF (≤11 mm) reduces the chance of pregnancy after FTAI when compared to ovulation of larger follicles (≥12 mm). Hormonal treatments to enhance the follicle growth have been widely used in comercial beef cattle systems, aiming to improve the development of a dominant follicle. The objective of this experiment was to evaluate the effect of treatment with eCG or FSH at the time of progesterone implant removal on the diameter of OF, final follicle growth and pregnancy rate in beef cows.Materials, Methods & Results: Three hundred and seven suckled beef cows with body condition score 2.80 ± 0.24 (1 to 5 scale) and 45 to 70 days postpartum were synchronized to FTAI. On day 0, intravaginal implants containing 1 g of progesterone, were inserted and administered 2 mg of estradiol benzoate (EB), i.m. On day 7, intravaginal implants were removed and 150 µg of D-cloprostenol were administered i.m. At this time, three groups were assigned according to the treatments: eCG (400 UI eCG, i.m.), FSH (25 UI FSH, i.m.) and Control (1 mL Saline, i.m.). On day 8, all cows were injected with 1mg EB i.m. and were inseminated 52 to 56 h after the implant removal. Transrectal ultrasonography exams of ovaries were performed at the time of implant removal and before FTAI to determine the diameter of the largest follicle and the follicular daily growth. Pregnancy exams were conducted by transretal ultrasonography 30 days after FTAI. Statistical analyzes were performed by Chi-square test for pregnancy rate. Ovarian diameters and follicular daily growth were analyzed by ANOVA with means compared by Tukey test considering significant P value < 0.05.[...](AU)

Eficácia da associação dupla dose PGF2 alfa-eCG no proestro de vacas leiteiras mestiças submetidas à IATF / Efficacy of the double PGF2 alpha dose-eCG association in proestrus of crossbred dairy cows submitted to IATF

Objetivou-se avaliar o efeito de uma ou duas doses de prostaglandina F2α (PGF2α) associada ou não a gonadotrofina coriônica equina (eCG) sobre a dinâmica folicular, a função luteal pré-ovulatória, assim como as características morfofuncionais pós-ovulatórias do corpo lúteo (CL) em fêmeas mestiças cíclicas submetidas a um protocolo de inseminação artificial em tempo fixo (IATF). Para tanto, 29 vacas 3/4 Gir x Holandês multíparas foram submetidas ao exame de ultrassonografia (US) transretal e após a detecção do CL iniciou-se um protocolo de IATF em um dia denominado zero (D0), por meio da inserção do implante de progesterona (P4) associado à aplicação de 2,0mg de benzoato de estradiol. No D7 esses animais receberam 12,5mg de dinoprost trometamina. No D9 realizou a remoção dos dispositivos de P4 e aplicou 0,6mg de cipionato de estradiol. Nesse momento, as fêmeas foram subdivididas nos seguintes tratamentos: Grupo Controle (n=7), foi administrado 2,5mL de solução fisiológica; Grupo 2PGF (n=7), aplicou 12,5mg de dinoprost trometamina; Grupo eCG (n=7), administrou-se 300UI de eCG; Grupo 2PGF+eCG (n=8), realizou a aplicação de 300UI de eCG e 12,5mg de dinoprost trometamina. Para avaliar a dinâmica folicular foram realizados exames de US em modo B e power doppler (Mindray Z5, Shenzhen, China) a cada 12h do D7 até o momento da ovulação ou 96h após a remoção dos implantes de P4, mensurando-se o diâmetro folicular (DFOL), a área da parede folicular (AFOL) e a área de perfusão sanguínea da parede folicular (VFOL). Concomitante a cada exame, foram coletadas amostras de sangue sendo determinada a concentração sérica de P4 pré-ovulatória por meio da metodologia de quimioluminescência. No D24 foi realizada a US modo B e doppler analisando-se o diâmetro luteal (DCL), área luteal (ACL) e área de perfusão sanguínea do CL (VCL), assim como, foi coletada amostra de sangue para averiguar a concentração sérica de P4 pós-ovulatória.(AU)

The study aimed to evaluate the effect of one or two prostaglandin doses F2α (PGF2a) with or without equine chorionic gonadotropin (eCG) in the follicular dynamics, the preovulatory luteal function, as well as the structural and functional characteristics post-ovulatory of the corpus luteum (CL) in cyclic crossbred females subjected to a fixed time artificial insemination (FTAI) protocol. For this, 29 multiparous 3/4 Gyr x Holstein cows were subjected to transrectal ultrasound examination (US) and upon detection of CL initiated a FTAI protocol on day called zero (D0) by the insertion of progesterone implant (P4) associated with the application of 2.0mg estradiol benzoate. On D7, these animals received 12.5mg of dinoprost tromethamine. At D9 happened the removal of the P4 devices and was applied 0.6mg of estradiol cypionate. At that time, the females were divided into the following treatments: control group (n=7) - which received 2.5mL of saline solution, 2PGF group (n=7) - received 12.5mg of dinoprost tromethamine, eCG group (n=7) - was administered 300IU eCG and eCG+2PGF group (n=8) - which received 300 IU eCG and 12.5mg of dinoprost tromethamine. To assess follicular dynamics were performed US scans B-mode and power doppler (Mindray Z5, Shenzhen, China) each 12h on D7 until the time of ovulation or until 96h after removal of the P4 implants, considering the follicular diameter (DFOL), the area of the follicular wall (AFOL) and the blood perfusion area of the follicular wall (VFOL). Concomitant with each test, blood samples were collected to determine the serum concentration of P4 preovulatory by chemiluminescence methodology. In D24 had held US B-mode and doppler to analyse the luteal diameter (DCL), luteal area (ACL) and blood perfusion area CL (VCL). (AU)

Eficácia da associação dupla dose PGF2 alfa-eCG no proestro de vacas leiteiras mestiças submetidas à IATF / Efficacy of the double PGF2 alpha dose-eCG association in proestrus of crossbred dairy cows submitted to IATF

Objetivou-se avaliar o efeito de uma ou duas doses de prostaglandina F2α (PGF2α) associada ou não a gonadotrofina coriônica equina (eCG) sobre a dinâmica folicular, a função luteal pré-ovulatória, assim como as características morfofuncionais pós-ovulatórias do corpo lúteo (CL) em fêmeas mestiças cíclicas submetidas a um protocolo de inseminação artificial em tempo fixo (IATF). Para tanto, 29 vacas 3/4 Gir x Holandês multíparas foram submetidas ao exame de ultrassonografia (US) transretal e após a detecção do CL iniciou-se um protocolo de IATF em um dia denominado zero (D0), por meio da inserção do implante de progesterona (P4) associado à aplicação de 2,0mg de benzoato de estradiol. No D7 esses animais receberam 12,5mg de dinoprost trometamina. No D9 realizou a remoção dos dispositivos de P4 e aplicou 0,6mg de cipionato de estradiol. Nesse momento, as fêmeas foram subdivididas nos seguintes tratamentos: Grupo Controle (n=7), foi administrado 2,5mL de solução fisiológica; Grupo 2PGF (n=7), aplicou 12,5mg de dinoprost trometamina; Grupo eCG (n=7), administrou-se 300UI de eCG; Grupo 2PGF+eCG (n=8), realizou a aplicação de 300UI de eCG e 12,5mg de dinoprost trometamina. Para avaliar a dinâmica folicular foram realizados exames de US em modo B e power doppler (Mindray Z5, Shenzhen, China) a cada 12h do D7 até o momento da ovulação ou 96h após a remoção dos implantes de P4, mensurando-se o diâmetro folicular (DFOL), a área da parede folicular (AFOL) e a área de perfusão sanguínea da parede folicular (VFOL). Concomitante a cada exame, foram coletadas amostras de sangue sendo determinada a concentração sérica de P4 pré-ovulatória por meio da metodologia de quimioluminescência. No D24 foi realizada a US modo B e doppler analisando-se o diâmetro luteal (DCL), área luteal (ACL) e área de perfusão sanguínea do CL (VCL), assim como, foi coletada amostra de sangue para averiguar a concentração sérica de P4 pós-ovulatória. Os dados foram avaliados pelo Two-way ANOVA e análise de medidas repetidas considerando os efeitos do eCG, 2PGF e interação eCG*2PGF, P<0,05. Não houve diferença significativa entre os protocolos de sincronização para as variáveis DFOL, AFOL e VFOL ao longo do tempo da dinâmica folicular. Os grupos experimentais apresentaram uma concentração sérica de P4 pré-ovulatória semelhante em cada momento da avaliação. Não foi observada distinção da ACL e VCL entre os tratamentos hormonais, contudo o Grupo eCG demonstrou tendência (P=0,08) a apresentar maior DCL em relação ao Grupo 2PGF e 2PGF+eCG. Adicionalmente a estes achados, também foi constatado tendência (P=0,07) a maiores concentrações de progesterona no dia 24 do protocolo nos animais do Grupo eCG (11,00±3,32ng/mL) em relação ao Grupo 2PGF (6,37±1,31ng/mL), enquanto o Controle e 2PGF+eCG demonstraram resultados intermediários que se assemelham a ambos os grupos, com concentrações de 8,43±3,85 e 9,18±2,82ng/mL, respectivamente. As tentativas de ajustes no proestro foram incapazes de melhorar a qualidade folicular e minimizar a função luteal pré-ovulatória, assim como não incrementaram a morfologia do CL e a função luteal pós-ovulatória, sugerindo que em animais cíclicos mestiços protocolos de IATF com a utilização de uma única dose PGF2α e sem o suporte gonadotrófico da eCG parece promover adequada resposta folicular e luteal.(AU)

The study aimed to evaluate the effect of one or two prostaglandin doses F2α (PGF2a) with or without equine chorionic gonadotropin (eCG) in the follicular dynamics, the preovulatory luteal function, as well as the structural and functional characteristics post-ovulatory of the corpus luteum (CL) in cyclic crossbred females subjected to a fixed time artificial insemination (FTAI) protocol. For this, 29 multiparous 3/4 Gyr x Holstein cows were subjected to transrectal ultrasound examination (US) and upon detection of CL initiated a FTAI protocol on day called zero (D0) by the insertion of progesterone implant (P4) associated with the application of 2.0mg estradiol benzoate. On D7, these animals received 12.5mg of dinoprost tromethamine. At D9 happened the removal of the P4 devices and was applied 0.6mg of estradiol cypionate. At that time, the females were divided into the following treatments: control group (n=7) - which received 2.5mL of saline solution, 2PGF group (n=7) - received 12.5mg of dinoprost tromethamine, eCG group (n=7) - was administered 300IU eCG and eCG+2PGF group (n=8) - which received 300 IU eCG and 12.5mg of dinoprost tromethamine. To assess follicular dynamics were performed US scans B-mode and power doppler (Mindray Z5, Shenzhen, China) each 12h on D7 until the time of ovulation or until 96h after removal of the P4 implants, considering the follicular diameter (DFOL), the area of the follicular wall (AFOL) and the blood perfusion area of the follicular wall (VFOL). Concomitant with each test, blood samples were collected to determine the serum concentration of P4 preovulatory by chemiluminescence methodology. In D24 had held US B-mode and doppler to analyse the luteal diameter (DCL), luteal area (ACL) and blood perfusion area CL (VCL). Also, a blood sample was collected to determine the serum concentration of P4 post-ovulatory. All data was evaluated by Two-way ANOVA and repeated measures analysis considering the effects of eCG, 2PGF and eCG*2PGF, P<0.05. There was not significant difference between the synchronization protocols for DFOL, AFOL and VFOL variables over time of follicular dynamics. Experimental groups had a serum concentration of P4 preovulatory similar in every moment of evaluation. There wasn't distinction of ACL and VCL between hormone treatments. However, the eCG group showed a tendency (P=0.08) to present higher DCL compared to the 2PGF and 2PGF+eCG groups. In addition to these findings, there was also a tendency (P=0.07) to higher concentrations of P4 on D24 of the protocol in the animals of the eCG group (11.00±3.32ng/mL) compared to the 2PGF group (6,37±1.31ng/mL), meanwhile the Control and 2PGF+eCG showed intermediate results that resembled both groups, with concentrations of 8.43±3.85 and 9.18±2.82ng/mL, respectively. Attempts to adjust proestrus were unable to improve follicular quality and minimize preovulatory luteal function, nor did they increase CL morphology and post-ovulatory luteal function, suggesting that in cyclic animals, FTAI protocols using a single PGF2α dose and without the gonadotrophic support of eCG seems to promote adequate follicular and luteal responses.(AU)

Inseminação Artificial Em Tempo Fixo Em Búfalos / Fixed-Time Artificial Insemination In Buffaloes / Inseminacción Artifical A Tiempo Fijo En Búfalos

A bubalinocultura brasileira apresenta um rebanho em pleno crescimento, visando tanto a produção de leite quanto de carne. Uma vez que esta espécie possui características reprodutivas que dificultam sua reprodução como maturidade sexual tardia, baixa expressão de estro, duração do estro muito variável, grande intervalo entre partos e anestro sazonal durante dias longos, estratégias que buscam melhores resultados reprodutivos vêm sendo aplicadas e estudadas. A principal biotecnologia implementada atualmente é a inseminação artificial, obtendo-se melhores resultados com o advento da inseminação artificial em tempo fixo. Diversos protocolos hormonais são utilizados para este fim, entre eles o Ovsynch, Doublesynch, Heatsynch, Estradoublesynch e protocolos hormonais à base de progesterona e estradiol com ou sem a administração de gonadotrofina coriônica equina (eCG). O Ovsynch e suas derivações apresentam resultados satisfatórios durante a estação reprodutiva favorável, porém as taxas reprodutivas são desastrosas durante a estação reprodutiva desfavorável. Dessa maneira, buscou-se alternativas visando melhores resultados neste período, sendo que a associação de progestágenos, estradiol, prostaglandina e eCG apresentou capacidade de desestacionalização nesta espécie, melhorando os resultados reprodutivos. Essa melhora reprodutiva deve-provavelmente devido ao maior diâmetro pré-ovulatório de seus folículos, que geram corpos lúteos mais robustos, capazes de produzir uma maior quantidade de progesterona, a qual será responsável pela manutenção da prenhez no início da gestação. Dessa maneira cabe ao profissional a escolha do protocolo hormonal mais adequado à realidade do rebanho, visando o aumento da produtividade de leite e carne.(AU)

The buffalo farming in Brazil is in full growth, aiming at both milk and meat production. Since this species has reproductive characteristics that make it difficult to reproduce as late sexual maturity, low estrous expression, very variable estrus duration, large interval between births and seasonal anestrous during long days, strategies that seek better reproductive results have been applied and studied. The main biotechnology reproductive rates are disastrous during the unfavorable reproductive season. In this way, alternatives were sought for better results in this period, and the association of progestogens, estradiol, prostaglandin and eCG showed the capacity of currently implemented is artificial insemination, obtaining better results with the advent of fixed-time artificial insemination. Several hormonal protocols are used for this purpose, among them Ovsynch, Doublesynch, Heatsynch, Estradoublesynch and hormonal protocols based on progesterone and estradiol with or without administration of equine chorionic gonadotrophin (eCG). Ovsynch and its derivations present satisfactory results during the favorable reproductive season, but deseasonalization, improving the reproductive results, probably due to the greater preovulatory diameter of its follicles, which generate more robust luteal bodies, capable of producing a greater amount of progesterone, which will be responsible for the maintenance of pregnancy at the beginning of gestation. In this way, it is up to the professional to choose the most appropriate hormonal protocol to the reality of the herd, aiming to increase the productivity of milk and meat.(AU)

La bubalinocultura brasileña presenta un rebaño en pleno crecimiento, buscando tanto la producción de leche y de carne. Una vez que esta especie posee características reproductivas que dificultan su reproducción como madurez sexual tardía, baja expresión del celo, duración del celo muy variable, gran intervalo entre partos y anestro estacional durante los días largos, estrategias que buscan mejores resultados reproductivos vienen siendo aplicadas y estudiadas. La principal biotecnología implementada actualmente es la inseminación artificial, obteniéndose mejores resultados con el advenimiento de la inseminación artificial a tiempo fijo. Varios protocolos hormonales se utilizan para este fin, entre ellos Ovsynch, Doublesynch, Heatsynch, Estradoublesynch y protocolos hormonales a base de progesterona y estradiol con o sin la administración de gonadotropina coriónica equina (eCG). El Ovsynch y sus derivaciones presentan resultados satisfactorios durante la estación reproductiva favorable, pero las tasas reproductivas son desastrosas durante la estación reproductiva desfavorable. De esta manera, se buscó alternativas visando mejores resultados en este período, siendo que la asociación de progestágenos, estradiol, prostaglandina y eCG presentó capacidad de desestacionalización en esta especie, mejorando los resultados reproductivos, probablemente debido al mayor diámetro preovulatorio de sus folículos, que generan cuerpos lúteos más robustos, capaces de producir una mayor cantidad de progesterona, la cual será responsable del mantenimiento de la preñez al inicio de la gestación. De esta manera cabe al profesional la elección del protocolo hormonal más adecuado a la realidad del rebaño, visando el aumento de la productividad de leche y carne.(AU)

Inseminação Artificial Em Tempo Fixo Em Búfalos / Fixed-Time Artificial Insemination In Buffaloes / Inseminacción Artifical A Tiempo Fijo En Búfalos

A bubalinocultura brasileira apresenta um rebanho em pleno crescimento, visando tanto a produção de leite quanto de carne. Uma vez que esta espécie possui características reprodutivas que dificultam sua reprodução como maturidade sexual tardia, baixa expressão de estro, duração do estro muito variável, grande intervalo entre partos e anestro sazonal durante dias longos, estratégias que buscam melhores resultados reprodutivos vêm sendo aplicadas e estudadas. A principal biotecnologia implementada atualmente é a inseminação artificial, obtendo-se melhores resultados com o advento da inseminação artificial em tempo fixo. Diversos protocolos hormonais são utilizados para este fim, entre eles o Ovsynch, Doublesynch, Heatsynch, Estradoublesynch e protocolos hormonais à base de progesterona e estradiol com ou sem a administração de gonadotrofina coriônica equina (eCG). O Ovsynch e suas derivações apresentam resultados satisfatórios durante a estação reprodutiva favorável, porém as taxas reprodutivas são desastrosas durante a estação reprodutiva desfavorável. Dessa maneira, buscou-se alternativas visando melhores resultados neste período, sendo que a associação de progestágenos, estradiol, prostaglandina e eCG apresentou capacidade de desestacionalização nesta espécie, melhorando os resultados reprodutivos. Essa melhora reprodutiva deve-provavelmente devido ao maior diâmetro pré-ovulatório de seus folículos, que geram corpos lúteos mais robustos, capazes de produzir uma maior quantidade de progesterona, a qual será responsável pela manutenção da prenhez no início da gestação. Dessa maneira cabe ao profissional a escolha do protocolo hormonal mais adequado à realidade do rebanho, visando o aumento da produtividade de leite e carne.

The buffalo farming in Brazil is in full growth, aiming at both milk and meat production. Since this species has reproductive characteristics that make it difficult to reproduce as late sexual maturity, low estrous expression, very variable estrus duration, large interval between births and seasonal anestrous during long days, strategies that seek better reproductive results have been applied and studied. The main biotechnology reproductive rates are disastrous during the unfavorable reproductive season. In this way, alternatives were sought for better results in this period, and the association of progestogens, estradiol, prostaglandin and eCG showed the capacity of currently implemented is artificial insemination, obtaining better results with the advent of fixed-time artificial insemination. Several hormonal protocols are used for this purpose, among them Ovsynch, Doublesynch, Heatsynch, Estradoublesynch and hormonal protocols based on progesterone and estradiol with or without administration of equine chorionic gonadotrophin (eCG). Ovsynch and its derivations present satisfactory results during the favorable reproductive season, but deseasonalization, improving the reproductive results, probably due to the greater preovulatory diameter of its follicles, which generate more robust luteal bodies, capable of producing a greater amount of progesterone, which will be responsible for the maintenance of pregnancy at the beginning of gestation. In this way, it is up to the professional to choose the most appropriate hormonal protocol to the reality of the herd, aiming to increase the productivity of milk and meat.

La bubalinocultura brasileña presenta un rebaño en pleno crecimiento, buscando tanto la producción de leche y de carne. Una vez que esta especie posee características reproductivas que dificultan su reproducción como madurez sexual tardía, baja expresión del celo, duración del celo muy variable, gran intervalo entre partos y anestro estacional durante los días largos, estrategias que buscan mejores resultados reproductivos vienen siendo aplicadas y estudiadas. La principal biotecnología implementada actualmente es la inseminación artificial, obteniéndose mejores resultados con el advenimiento de la inseminación artificial a tiempo fijo. Varios protocolos hormonales se utilizan para este fin, entre ellos Ovsynch, Doublesynch, Heatsynch, Estradoublesynch y protocolos hormonales a base de progesterona y estradiol con o sin la administración de gonadotropina coriónica equina (eCG). El Ovsynch y sus derivaciones presentan resultados satisfactorios durante la estación reproductiva favorable, pero las tasas reproductivas son desastrosas durante la estación reproductiva desfavorable. De esta manera, se buscó alternativas visando mejores resultados en este período, siendo que la asociación de progestágenos, estradiol, prostaglandina y eCG presentó capacidad de desestacionalización en esta especie, mejorando los resultados reproductivos, probablemente debido al mayor diámetro preovulatorio de sus folículos, que generan cuerpos lúteos más robustos, capaces de producir una mayor cantidad de progesterona, la cual será responsable del mantenimiento de la preñez al inicio de la gestación. De esta manera cabe al profesional la elección del protocolo hormonal más adecuado a la realidad del rebaño, visando el aumento de la productividad de leche y carne.

Taxa de prenhez em vacas leiteiras submetidas a inseminação artificial em tempo fixo utilizando gonadotrofina coriônica equin / Pregnancy rate in dairy cows submitted to fixed time artificial insemination using equine chorionic gonadotropin

This study aimed to evaluate the pregnancy rate in cyclic lactating dairy cows inseminated at fixed timeusing eCG in the withdrawal of progesterone implant. The experimental design was a randomized blocks, twotreatments with 32 repetitions for G1 and 31 repetitions for G2. The G1 control group: cows with hormonalprotocol with the use of eCG; G2: cows with hormonal protocol without using eCG. The study presented to theGroup eCG with pregnancy rate of 28.13%, while no eCG group had a 16.13% pregnancy rate. The statisticaldifference between the groups was not significant (p = 0.2522). In conclusion, the use of eCG had no influenceon the pregnancy rate.(AU)

Taxa de prenhez em vacas leiteiras submetidas a inseminação artificial em tempo fixo utilizando gonadotrofina coriônica equin / Pregnancy rate in dairy cows submitted to fixed time artificial insemination using equine chorionic gonadotropin

This study aimed to evaluate the pregnancy rate in cyclic lactating dairy cows inseminated at fixed timeusing eCG in the withdrawal of progesterone implant. The experimental design was a randomized blocks, twotreatments with 32 repetitions for G1 and 31 repetitions for G2. The G1 control group: cows with hormonalprotocol with the use of eCG; G2: cows with hormonal protocol without using eCG. The study presented to theGroup eCG with pregnancy rate of 28.13%, while no eCG group had a 16.13% pregnancy rate. The statisticaldifference between the groups was not significant (p = 0.2522). In conclusion, the use of eCG had no influenceon the pregnancy rate.