Frontiers in sheep reproduction - making use of natural responses to environmental challenges to manage productivity

This review addresses advances, directions and opportunities for research on sheep reproduction in the context of the global challenges of food security and climate change, and demand for 'clean, green and ethical' (CGE) animal management. The foundation of CGE management is an understanding of the physiological processes through which the reproductive system responds to changes in the animal's environment. These days, to the main environmental factors (photoperiod, nutrition, pheromones), we need to add stress from extreme weather events. With respect to nutrition in rams, we now have a deeper understanding of the responses of the brain centres that control gonadotrophin secretion (the kisspeptin system). At testis level, we have found that nutrition affects non-coding RNAs in Sertoli cells and germ cells, thus affecting the balance between cell proliferation and apoptosis. This proliferation-apoptosis balance is also affected during prenatal development, when undernutrition or stress in pregnant ewes seems to elicit epigenetic changes in developing gonads that could affect offspring fertility in adult life. With respect to nutrition in ewes, metabolic signals act directly on ovarian follicles, and thus change ovulation rate, but the variety of signals now includes the adipokines. An early concern was that nutritional supplements that increase ovulation rate would also increase embryo mortality but we now know that embryo survival is improved under field conditions. Finally, we had always thought that the efficiency gains from early puberty in lambs could only be achieved by accelerating fat accumulation, but we now know that faster muscle growth will achieve the same goal, offering two advantages in meat production systems. With respect to pheromones ('ram effect'), we have a deeper understanding of the brain responses (kisspeptin system) but, most importantly, a realization that the response of ewes to the ram signal involves cell division in memory centres. Many opportunities remain.(AU)

Influence of eCG and reproductive management in the resynchronization of ovulation in dairy goats

Resynchronization protocols have been proposed as a way of shortening females' unproductive time in the flock, with good results in cattle and sheep. In goats, initial studies have shown that a second progestogen device inserted before luteolysis and pregnancy diagnosis does not interfere with the corpus luteum lifespan or functionality. This study aimed to evaluate the follicular growth, ovulation pattern and pregnancy rate after insertion of a second and new progestogen device for resynchronizing, with or without equine Chorionic Gonadotrophin (eCG), submitted to natural mating (NM) or artificial insemination (AI) to propose a viable resynchronization protocol for dairy goats. A total of 38 multiparous Saanen goats underwent a short-term progesterone protocol [six days exposed to medroxyprogesterone acetate (MAP) intravaginal sponges + 200 IU eCG and 0.12 mg of cloprostenol sodium on the 5th day + 0.025 mg of lecirelin 34 hours after sponge withdrawal] and, on day 16th after the ovulation, received a new MAP device which was retained until day 21. At this moment females were split into four groups: GeCG+NM ­ 100 IU eCG with NM; GSal+NM ­ saline solution with NM; GeCG+AI ­ 100 IU eCG with AI; and GSal+AI ­ saline solution with AI. Ultrasound scans were performed every 12 h from sponge withdrawal (day 21) until 108 h after sponge withdrawal (day 25) for follicular dynamics evaluation, at 240 h (day 31) for assessing the presence of active corpus luteum, and on day 60 for pregnancy diagnosis. No differences were found regarding ovulation time, synchronization and follicle size. However, GeCG+NM presented a greater estrus manifestation rate (100%) and pregnancy rate (62.5%) when compared to GSal+AI. In conclusion, resynchronization protocols in dairy goats may present satisfactory results.(AU)

Níveis de progesterona e os parâmetros reprodutivos no período periovulatório de vacas Nelore submetidas ao protocolo de IATF / Progesterone levels and reproductive parameters in the periovulatory period of Nellore cows under FTAI protocol

Background: Fixed Time Artificial Insemination (FTAI) has achieved a significant evolution in the last 18 years, however, despite the progress achieved by modern FTAI programs, the conception rates obtained are still low. Therefore, this study aimed to evaluate the interrelation between progesterone levels in the periovulatory period and reproductive parameters of Nellore cows submitted to an FTAI protocol. Materials, Methods & Results: On a random day, called day 0 (D0), 57 cows received a P4 device associated with the intramuscular (IM) application of 2.0 mg of estradiol benzoate. On D9, the P4 devices were removed and then were administered 500 µg of cloprostenol sodium IM; 0.6 mg of estradiol cypionate IM and 300 IUI of Equine Chorionic Gonadotrophin IM. Blood samples were collected for the determination of serum P4 concentrations on D9 and D11 of the protocol. The evaluations of follicular diameter (DFOL), follicular wall area (AFOL) and the vascularization area of the follicle wall (VFOL) were carried out on D11 using B-mode ultrasonography examination and colour Doppler, and then the artificial inseminations were performed. The evaluation of the corpus luteum diameter (CLD), of the total corpus luteum area (CLA), of the area of corpus luteum vascularization (CLV) and blood sampling for determination of postovulatory P4 levels (Post-P4) were performed on D24. For the analysis of the P4 concentration the chemiluminescence method was used, with a sensitivity of 0.1 ng/mL. According to the P4 concentrations on D11, cows were divided into 2 groups, LOW LEVELS OF P4 and HIGH LEVELS OF P4. The diagnosis of pregnancy was performed using transrectal ultrasonography on D45, at this point the cows were divided into 2 groups, PREGNANT and NON-PREGNANT. The correlation between DFOL and P4 dosage on D11 was moderate, negative and significant and between the AFOL and the serum P4 levels on D9, was moderate, negative and significant. As for the other correlations between follicular and luteal parameters and serum P4 levels, these were low to moderate, negative and not significant. Cows in the LOW LEVELS OF P4 group had significantly larger diameter and follicular areas than the cows in the HIGH LEVELS OF P4 group, the other follicular and luteal parameters showed no statistical difference. Of the total 57 cows that were inseminated, 30 cows became pregnant. Cows in the PREGNANT group had serum P4 levels on D9 equivalent to that obtained by the NON-PREGNANT group. However, at D11 the cows that became pregnant presented significantly lower serum P4 levels than cows that did not become pregnant. Discussion: The results of the interrelation between follicular parameters and P4 levels obtained in the present study, pointed out that the lower the levels of P4, the higher the follicular parameters, corroborating with other authors. Thus, larger preovulatory follicles provided high ovulation rates. Periovulatory serum P4 levels did not significantly affect the morphofunctional parameters of the CL. Such findings may be justified by high periovulatory P4 levels resulting from less efficient luteolysis, exert a negative effect on the results of FTAI protocols, because progesterone inhibits the release of LH pulses. It is concluded that lower periovulatory P4 levels established a favourable condition for follicular development and fertility, however, morphofunctional parameters of the corpus luteum were not affected.

Association Analysis Between Polymorphism of Gonadotrophin Releasing Hormone Genes and Growth Traits of Quail (Coturnix Coturnix)

This study investigated SNP mutation sites of Gonadotrophin releasing hormone (GnRH) gene in China yellow quail, Beijing white quail and Korean quail through PCR amplification and DNA sequencing technologies. Moreover, polymorphism of GnRH gene and its association with growth traits of quail were analyzed, aiming to get molecular markers associated to growth traits of quail, which could provide references for breeding of new quail species. According to research results, a total of 14 SNP mutation sites of GnRH were detected in China yellow quail, Beijing white quail and Korean quail, which were C71T, C108T, C168T, C178T, A184G, C206T, A209C, C215T, A252G, A279T, C281T, C293G, C339T and C458T. Except that only 2 genotypes were detected for A209C and C281T in China yellow quail and Beijing white quail, 3 genotypes were detected for all of the remaining 12 SNP mutation sites in three quail species. Of the 14 SNP sites, C71T, A209C, C215T, C281T, C293G, C339T and C458T were significantly associated with body weight (p 0.05), C71T, C108T, C168T, C178T, A184G, C206T, C215T, A252G, C293G, C339T and C458T were significantly associated with shank length (p 0.05), C71T, C215T, C293G and C458T were significantly associated with breastbone length (p 0.05), A209C and C281T were significantly associated with shank circumference (p 0.05).(AU)

Association Analysis Between Polymorphism of Gonadotrophin Releasing Hormone Genes and Growth Traits of Quail (Coturnix Coturnix)

This study investigated SNP mutation sites of Gonadotrophin releasing hormone (GnRH) gene in China yellow quail, Beijing white quail and Korean quail through PCR amplification and DNA sequencing technologies. Moreover, polymorphism of GnRH gene and its association with growth traits of quail were analyzed, aiming to get molecular markers associated to growth traits of quail, which could provide references for breeding of new quail species. According to research results, a total of 14 SNP mutation sites of GnRH were detected in China yellow quail, Beijing white quail and Korean quail, which were C71T, C108T, C168T, C178T, A184G, C206T, A209C, C215T, A252G, A279T, C281T, C293G, C339T and C458T. Except that only 2 genotypes were detected for A209C and C281T in China yellow quail and Beijing white quail, 3 genotypes were detected for all of the remaining 12 SNP mutation sites in three quail species. Of the 14 SNP sites, C71T, A209C, C215T, C281T, C293G, C339T and C458T were significantly associated with body weight (p 0.05), C71T, C108T, C168T, C178T, A184G, C206T, C215T, A252G, C293G, C339T and C458T were significantly associated with shank length (p 0.05), C71T, C215T, C293G and C458T were significantly associated with breastbone length (p 0.05), A209C and C281T were significantly associated with shank circumference (p 0.05).

Use of estradiol cypionate to induce ovulation in buffalo raised in floodplain areas of Itacoatiara, Amazonas / [Uso do cipionato de estradiol na indução da ovulação de búfalas criadas em várzea da região de Itacoatiara, Amazonas]

This study aimed to determine the efficiency of estradiol cypionate (EC) as an ovulation inducer in a Timed Artificial Insemination protocol. 69 buffalo cows received an intravaginal progesterone device and 2mg of estradiol benzoate (EB) at D0. On D9, the intravaginal device was removed and 0.53mg of prostaglandin (PGF2α) and 400UI of equine chorionic gonadotrophin (eCG) were applied. The cows were distributed into two groups: the first group received 1mg of EC (ECG) in D9, and the second group received 1mg of EB (EBG) in D10. Inseminations occurred on D11. Ovarian activity and pregnancy diagnosis were analyzed by ultrasonography. There was no difference (P>0.05) in follicular diameter (9.6 ± 0.89mm vs. 10.7 ± 1.12mm; P=0.06), in ovulation rate (90.9% vs. 90.9%; P=1) and pregnancy rate (58.8% vs. 62.9%; P=0.79), however, buffalo cows from the ECG treatment have less time between P4 removal and ovulation when compared to EBG buffalos (37.4h vs. 52.8h; P=0.001), respectively. Thus, it was concluded that the implantation of TAI in the floodplain of Amazonas is feasible and the use of EC results in successful rates, similar to EB.(AU)

O objetivo deste trabalho foi determinar a eficiência do cipionato de estradiol (CE) como indutor de ovulação em um protocolo de inseminação artificial de tempo fixo. Para isso, 69 búfalas receberam no D0 um dispositivo intravaginal de progesterona e 2mg de benzoato de estradiol (BE). No D9, o dispositivo intravaginal foi removido e foram aplicados 0,53mg de prostaglandina (PGF2α) e 400UI de gonadotrofina coriônica equina (eCG), para, então, os animais serem divididos em dois grupos: um deles (GCE) recebeu 1mg de CE no D9, e o outro (GBE) recebeu 1mg de BE 24h após. As inseminações ocorreram no D11. A atividade ovariana e o diagnóstico de prenhez foram avaliados por ultrassonografia. Não houve diferença (P>0,05) no diâmetro folicular (9,6 ± 0,89mm vs. 10,7 ± 1,12mm; P=0,06), na taxa de ovulação (90,9% vs. 90,9%; P=1) e na taxa de prenhez (58,8% vs. 62,9%; P=0,79), no entanto búfalas do tratamento GCE apresentaram menor tempo entre a remoção da P4 e a ovulação, quando comparadas com as búfalas do GBE (37,4h vs. 52,8h; P=0,001), respectivamente. A implantação da IATF nas várzeas do Amazonas é viável e a utilização do CE resulta em taxas de sucesso similares ao BE.(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...

Hormônios utilizados na indução da ovulação em bovinos Artigo de revisão / Hormones used as ovulation inducers in cattle A review

Diversos hormônios podem ser utilizados em protocolos que visam otimizar biotécnicas reprodutivas como a inseminação artificial (IA) e inseminação artificial em tempo fixo (IATF), que exigem controle preciso do ciclo estral e da ovulação. Alguns hormônios possuem ação central no eixo hipotalâmico-hipofisário, como o hormônio liberador de gonadotrofinas (GnRH) e os ésteres de estradiolcomo o benzoato (BE) e o cipionato de estradiol (CE), enquanto outros como a gonadotrofina coriônica humana (hCG) e o hormônio luteinizante (LH) apresentam ação local, a nível ovariano. Atualmente os protocolos mais utilizados para indução da ovulação utilizam GnRH e estrógenos. Recentemente, foi demonstrado que as prostaglandinas possuem efeitos positivos na indução do processo ovulatório, mas seu mecanismo de ação não está totalmente esclarecido. A presente revisão tem por objetivo abordar os principais indutores da ovulação utilizados em protocolos para controle do ciclo estral em bovinos, relatando o período de ocorrência das ovulações após a sua aplicação.(AU)

Several hormones may be used in protocols aimed to optimize reproductive biotechniques such as artificial insemination (AI) and fixed-timed artificial insemination (FTAI) which require precise control of the estrous cycle and the ovulation. Some hormones act on the hypothalamic-pituitary axis, such as the gonadotrophin releasing hormone (GnRH) and estradiol esters such as estradiol benzoate (EB) and cypionate (EC), whereas others act directly on the ovaries, such as human chorionic gonadotrophin (hCG) and luteinizing hormone (LH). Currently, the most commonly used protocols for ovulation induction use GnRH or estrogen. Prostaglandins have recently been shown to have positive effects on induction of the ovulatory process, but their mechanism of action is not fully understood. The present review aims to address the main ovulation inducers used in protocols to control the estrous cycle in cattle, emphasizing the period between their administration and the occurrence of ovulation.(AU)

Hormônios utilizados na indução da ovulação em bovinos – Artigo de revisão / Hormones used as ovulation inducers in cattle – A review

Diversos hormônios podem ser utilizados em protocolos que visam otimizar biotécnicas reprodutivas como a inseminação artificial (IA) e inseminação artificial em tempo fixo (IATF), que exigem controle preciso do ciclo estral e da ovulação. Alguns hormônios possuem ação central no eixo hipotalâmico-hipofisário, como o hormônio liberador de gonadotrofinas (GnRH) e os ésteres de estradiolcomo o benzoato (BE) e o cipionato de estradiol (CE), enquanto outros como a gonadotrofina coriônica humana (hCG) e o hormônio luteinizante (LH) apresentam ação local, a nível ovariano. Atualmente os protocolos mais utilizados para indução da ovulação utilizam GnRH e estrógenos. Recentemente, foi demonstrado que as prostaglandinas possuem efeitos positivos na indução do processo ovulatório, mas seu mecanismo de ação não está totalmente esclarecido. A presente revisão tem por objetivo abordar os principais indutores da ovulação utilizados em protocolos para controle do ciclo estral em bovinos, relatando o período de ocorrência das ovulações após a sua aplicação.

Several hormones may be used in protocols aimed to optimize reproductive biotechniques such as artificial insemination (AI) and fixed-timed artificial insemination (FTAI) which require precise control of the estrous cycle and the ovulation. Some hormones act on the hypothalamic-pituitary axis, such as the gonadotrophin releasing hormone (GnRH) and estradiol esters such as estradiol benzoate (EB) and cypionate (EC), whereas others act directly on the ovaries, such as human chorionic gonadotrophin (hCG) and luteinizing hormone (LH). Currently, the most commonly used protocols for ovulation induction use GnRH or estrogen. Prostaglandins have recently been shown to have positive effects on induction of the ovulatory process, but their mechanism of action is not fully understood. The present review aims to address the main ovulation inducers used in protocols to control the estrous cycle in cattle, emphasizing the period between their administration and the occurrence of ovulation.

Ciclicidade pós-desmame e protocolos de inseminação artificial em fêmeas suínas / Post-weaning cyclicity and artificial insemination protocols in swine females

O prolongamento do intervalo desmame-estro (IDE) tem impacto sobre os protocolos de inseminação artificial (IA) e sobre a eficiência reprodutiva, devido ao acúmulo de dias não produtivos. Além de fatores estacionais e de manejo, protocolos baseados em hormonioterapia podem ser usados no controle da ciclicidade das fêmeas. A administração das gonadotrofinas coriônicas equina (eCG) e humana (hCG) após o desmame pode reduzir o IDE. A inseminação artificial em tempo fixo (IATF) é baseada na sincronização da ovulação, para que uma única IA seja executada por fêmea. Protocolos para leitoas exigem sincronização prévia do estro com análogos de progesterona seguida de um indutor de ovulação, como o hormônio luteinizante suíno (pLH) ou um agonista do hormônio liberador de gonadotrofinas (GnRH). Os protocolos para porcas desmamadas podem ser conduzidos apenas com análogos de GnRH, aplicados por via intramuscular ou intravaginal. O uso da IATF associado às técnicas de IA intrauterina e IA homospérmica poderá resultar em substancial benefício econômico e genético devido à redução no número de espermatozoides em cada IA.(AU)

A prolonged WEI has an impact on artificial insemination (AI) management and reproductive efficiency due to the accumulation of non-productive days. Besides seasonal and management factors, hormone-based protocols can be used on the control of female cyclicity. Administration of equine and human chorionic gonadotrophins (eCG and hCG, respectively) after weaning can shorten the WEI. Fixed-time artificial insemination (FTAI) is based on synchronization of the ovulation, allowing a single AI to be conducted per female. Protocols of FTAI for gilts require previous estrous synchronization with progesterone analogs followed by an ovulation inductor, such as the porcine luteinizing hormone (pLH) or a gonadotrophin releasing hormone (GnRH) agonist. Protocols of FTAI for weaned sows can be conducted only using a GnRH agonist, applied either intramuscularly or intravaginally. The use of FTAI combined with both intrauterine and homospermic AI may result in substantial financial and genetic benefits due to the reduction in the number of spermatozoa per AI.(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)

Ciclicidade pós-desmame e protocolos de inseminação artificial em fêmeas suínas / Post-weaning cyclicity and artificial insemination protocols in swine females

O prolongamento do intervalo desmame-estro (IDE) tem impacto sobre os protocolos de inseminação artificial (IA) e sobre a eficiência reprodutiva, devido ao acúmulo de dias não produtivos. Além de fatores estacionais e de manejo, protocolos baseados em hormonioterapia podem ser usados no controle da ciclicidade das fêmeas. A administração das gonadotrofinas coriônicas equina (eCG) e humana (hCG) após o desmame pode reduzir o IDE. A inseminação artificial em tempo fixo (IATF) é baseada na sincronização da ovulação, para que uma única IA seja executada por fêmea. Protocolos para leitoas exigem sincronização prévia do estro com análogos de progesterona seguida de um indutor de ovulação, como o hormônio luteinizante suíno (pLH) ou um agonista do hormônio liberador de gonadotrofinas (GnRH). Os protocolos para porcas desmamadas podem ser conduzidos apenas com análogos de GnRH, aplicados por via intramuscular ou intravaginal. O uso da IATF associado às técnicas de IA intrauterina e IA homospérmica poderá resultar em substancial benefício econômico e genético devido à redução no número de espermatozoides em cada IA.

A prolonged WEI has an impact on artificial insemination (AI) management and reproductive efficiency due to the accumulation of non-productive days. Besides seasonal and management factors, hormone-based protocols can be used on the control of female cyclicity. Administration of equine and human chorionic gonadotrophins (eCG and hCG, respectively) after weaning can shorten the WEI. Fixed-time artificial insemination (FTAI) is based on synchronization of the ovulation, allowing a single AI to be conducted per female. Protocols of FTAI for gilts require previous estrous synchronization with progesterone analogs followed by an ovulation inductor, such as the porcine luteinizing hormone (pLH) or a gonadotrophin releasing hormone (GnRH) agonist. Protocols of FTAI for weaned sows can be conducted only using a GnRH agonist, applied either intramuscularly or intravaginally. The use of FTAI combined with both intrauterine and homospermic AI may result in substantial financial and genetic benefits due to the reduction in the number of spermatozoa per AI.

Effect of eCG on the follicular dynamics and vascularization of crossbred cows with different circulating progesterone concentrations during synchronization of ovulation in an FTAI protocol / Efeito do eCG na dinâmica e na vascularização folicular de vacas mestiças com diferentes concentrações circulantes de progesterona durante a sincronização de ovulação em um protocolo IATF

This study aimed to evaluate the effect of treatment with equine chorionic gonadotrophin (eCG) on the follicular dynamics and function of crossbred cows with different circulating progesterone (P4) concentrations during synchronization of ovulation in a fixed-time artificial insemination (FTAI) protocol. To this end, 30 crossbred cows were submitted to a pre-synchronization protocol to ensure that all of them presented corpus luteum (CL) at the beginning of the protocol, and were evaluated by transrectal ultrasonography (TRUS) to verify the presence of CL. After that, the animals underwent an ovulation synchronization protocol and evaluation of follicular dynamics and vascularization by B-mode and power-Doppler ultrasound (US). High plasma P4 concentrations at the time of ovulation synchronization negatively influenced follicle diameter on day 10 (D10), preovulatory follicle diameter, and preovulatory follicle wall vascularization area (p<0.05). Cows with high P4 concentration at the time of ovulation synchronization that were treated with eCG showed follicle diameter on D10 and preovulatory follicle diameter and wall vascularization area (p>0.05) similar to those of animals with low P4 concentration at the time of ovulation synchronization. Therefore, high P4 concentrations at the time of ovulation synchronization negatively influence follicular diameter and vascularization, and eCG can be used as a strategy to favor better follicular and luteal response in crossbred cows with high P4 concentrations submitted to an FTAI protocol.(AU)

Objetivou-se neste estudo avaliar o efeito do tratamento com gonadotrofina coriônica equina (eCG) sobre a dinâmica e função folicular em fêmeas mestiças com diferentes concentrações circulantes de P4 durante a sincronização da ovulação em um protocolo de IATF. Para tanto, foram utilizadas 30 fêmeas mestiças e submetidas a um protocolo de pré-sincronização para garantir que todos os animais apresentassem corpo lúteo (CL) no início do protocolo, sendo avaliadas por ultrassonografia (US) transretal para a verificação da presença ou não de CL. Em seguida foram submetidas a um protocolo de sincronização da ovulação e avaliação da dinâmica e vascularização folicular por ultrassonografia (US) em modo B e Doppler colorido. Altas concentrações de P4 no momento da sincronização da ovulação impactaram negativamente no diâmetro do folículo no D10, o diâmetro do folículo pré-ovulatório e na área de vascularização da parede do folículo pré-ovulatório (P<0,05). As vacas com alta concentração de P4 no momento da sincronização da ovulação e que foram tratadas com eCG apresentaram diâmetro do folículo no D10 e no diâmetro e a área de vascularização da parede do folículo pré-ovulatório (P>0,05), semelhantes às vacas que com baixa concentração de P4 no momento da sincronização da ovulação. Conclui-se que elevadas concentrações de P4 no momento da sincronização da ovulação impactam negativamente no diâmetro e vascularização folicular e que o eCG pode ser utilizado como uma estratégia para favorecer uma melhor resposta folicular e luteal em fêmeas mestiças com altas concentrações de P4 submetidas a um protocolo de IATF.(AU)

Effect of eCG on the follicular dynamics and vascularization of crossbred cows with different circulating progesterone concentrations during synchronization of ovulation in an FTAI protocol / Efeito do eCG na dinâmica e na vascularização folicular de vacas mestiças com diferentes concentrações circulantes de progesterona durante a sincronização de ovulação em um protocolo IATF

This study aimed to evaluate the effect of treatment with equine chorionic gonadotrophin (eCG) on the follicular dynamics and function of crossbred cows with different circulating progesterone (P4) concentrations during synchronization of ovulation in a fixed-time artificial insemination (FTAI) protocol. To this end, 30 crossbred cows were submitted to a pre-synchronization protocol to ensure that all of them presented corpus luteum (CL) at the beginning of the protocol, and were evaluated by transrectal ultrasonography (TRUS) to verify the presence of CL. After that, the animals underwent an ovulation synchronization protocol and evaluation of follicular dynamics and vascularization by B-mode and power-Doppler ultrasound (US). High plasma P4 concentrations at the time of ovulation synchronization negatively influenced follicle diameter on day 10 (D10), preovulatory follicle diameter, and preovulatory follicle wall vascularization area (p<0.05). Cows with high P4 concentration at the time of ovulation synchronization that were treated with eCG showed follicle diameter on D10 and preovulatory follicle diameter and wall vascularization area (p>0.05) similar to those of animals with low P4 concentration at the time of ovulation synchronization. Therefore, high P4 concentrations at the time of ovulation synchronization negatively influence follicular diameter and vascularization, and eCG can be used as a strategy to favor better follicular and luteal response in crossbred cows with high P4 concentrations submitted to an FTAI protocol.(AU)

Objetivou-se neste estudo avaliar o efeito do tratamento com gonadotrofina coriônica equina (eCG) sobre a dinâmica e função folicular em fêmeas mestiças com diferentes concentrações circulantes de P4 durante a sincronização da ovulação em um protocolo de IATF. Para tanto, foram utilizadas 30 fêmeas mestiças e submetidas a um protocolo de pré-sincronização para garantir que todos os animais apresentassem corpo lúteo (CL) no início do protocolo, sendo avaliadas por ultrassonografia (US) transretal para a verificação da presença ou não de CL. Em seguida foram submetidas a um protocolo de sincronização da ovulação e avaliação da dinâmica e vascularização folicular por ultrassonografia (US) em modo B e Doppler colorido. Altas concentrações de P4 no momento da sincronização da ovulação impactaram negativamente no diâmetro do folículo no D10, o diâmetro do folículo pré-ovulatório e na área de vascularização da parede do folículo pré-ovulatório (P<0,05). As vacas com alta concentração de P4 no momento da sincronização da ovulação e que foram tratadas com eCG apresentaram diâmetro do folículo no D10 e no diâmetro e a área de vascularização da parede do folículo pré-ovulatório (P>0,05), semelhantes às vacas que com baixa concentração de P4 no momento da sincronização da ovulação. Conclui-se que elevadas concentrações de P4 no momento da sincronização da ovulação impactam negativamente no diâmetro e vascularização folicular e que o eCG pode ser utilizado como uma estratégia para favorecer uma melhor resposta folicular e luteal em fêmeas mestiças com altas concentrações de P4 submetidas a um protocolo de IATF.(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.

Effect of hCG application at different moments of the estrous cycle on corpus luteum and uterine vascularization and serum progesterone concentration in mares

Establishment of pregnancy after embryo transfer is the ultimate goal of an embryo transfer program and increasing pregnancy rates and reducing pregnancy loss are mandatory. The utilization of treatments to improve conception rates in recipient mares has been the focus of several research groups over the last years and the results are controversial. Some studies using human chorionic gonadotrophin (hCG) found promising results. Our hypothesis was that hCG administration would cause an additional stimulation on luteal function, uterine and luteal vascularization and progesterone concentration, and the mares would have increased uterine and cervix tone. Therefore, in the present study the effects of hCG administration to induce ovulation, on day 0 (day of ovulation) or day 5 postovulation were evaluated on corpus luteum characteristics, reproductive tract vascularization, and serum progesterone concentration from ovulation until day 15 postovulation. Groups were: G1: (control) - no hCG; G2: 2500 IU of hCG to induce ovulation when a follicle greater than 35mm and uterine edema were detected; G3: 2500 IU hCG on day 0; G4: 2500 IU hCG on day 5 postovulation. Twelve mares were randomly assigned to each group, during consecutive cycles, in a Latin Square experimental design, in a total of 48 cycles. Doppler ultrasound evaluations were performed daily from day 0 until day 15 postovulation, including mesometrial vascularity, endometrial vascularity and corpus luteum vascularity. Blood samples were collected for serum progesterone concentration. Data was analyzed using the Proc Glimmix SAS Procedure for nonparametric variables and Proc Mixed for parametric parameters. There was no treatment effect for all variables studied (P > 0.05). Characteristics were only affected by day (P < 0.05). It can be concluded that hCG administration at the time points suggested in the current study did not alter the characteristics evaluated.