Atualizações no controle do ciclo estral em ovinos / Updates on the control of the estrous cycle in sheep

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

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

Full confluency, serum starvation, and roscovitine for inducing arrest in the G0/G1 phase of the cell cycle in puma skin-derived fibroblast lines

The puma population is constantly decreasing, and cloning by somatic cell nuclear transfer can be used to conserve the species. One of the factors determining the success of the development of cloned embryos is the cell cycle stage of the donor cells. We evaluated the effects of full confluency (~100%), serum starvation (0.5% serum), and roscovitine (15 µM) treatments on the cell cycle synchronization in G0/G1 of puma skin-derived fibroblasts by flow cytometric analysis. Also, we assessed the effects of these synchronization methods on morphology, viability, and apoptosis levels using microscopy tools. The results showed that culturing the cells to confluence for 24 h (84.0%), 48 h (84.6%), and 72 h (84.2%) and serum starvation for 96 h (85.4%) yielded a significantly higher percentage of cells arrested in the G0/G1 (P < 0.05) phase than cells not subjected to any cell cycle synchronization method (73.9%). Nevertheless, while serum starvation reduced the percentage of viable cells, no difference was observed for the full confluence and roscovitine treatments (P > 0.05). Moreover, roscovitine for 12 h (78.6%) and 24 h (82.1%) was unable to synchronize cells in G0/G1 (P > 0.05). In summary, full confluency induces puma fibroblast cell cycle synchronization at the G0/G1 stage without affecting cell viability. These outcomes may be valuable for planning donor cells for somatic cell nuclear transfer in pumas.(AU)

Recent advances in treatments for resynchronization of ovulation in small ruminants: a review

Hormonal methodologies to control small ruminants' estrous cycle are worldwide used and evolved, adjusting the application to the precise female physiological moments to enhance reproductive performance. The estrous cycle can be induced and/or synchronized, aiming for fixed-time artificial insemination, or based on estrus behavior signs for insemination, natural or guided mating. Successive protocols can be performed to resynchronize ovulation and increase reproductive outcomes in females that failed to conceive. These recently developed treatments aim to resynchronize the ovulation as earlier as non-pregnancy is detected. The present review aimed to summarize the recent advances and main findings regarding resynchronization protocols used in small ruminants. Lastly, we present future perspectives and new paths to be studied in the subject. The resynchronization treatment is still a growing field in small ruminant reproduction, nevertheless, some enhancements are found in the reproductive outcome, showing that such protocols can be successfully used in sheep and goat production.(AU)

Efeito da progesterona na sincronização de vacas de leite / Effect of progesterone on synchronization of dairy cows

Diversos fatores impactam os índices reprodutivos em vacas leiteiras, como a produção de leite, o manejo nutricional e o programa reprodutivo implementado. Em vacas leiteiras de alta produção, o maior catabolismo de esteróides, como a progesterona, devem ser levados em consideração ao escolher o tratamento hormonal a ser realizado. Assim, estratégias com a suplementação de progesterona previamente e ao início do protocolo foram desenvolvidas e descritas.(AU)

Milk production, nutritional management and the implemented reproductive program impact reproductive rates in dairy cows. The greater catabolism of steroids such as progesterone in high producing dairy cows must be considered when choosing the hormonal treatment to be used. Thus, strategies with progesterone supplementation before and at the beginning of the protocol were developed and described.(AU)

Farmacopuntura em protocolos de sincronização de estro em pequenos ruminantes / Pharmacopuncture in estrus synchronization protocols in small ruminants

O objetivo com essa revisão foi realizar o levantamento da produção científica disponível e articular saberes a respeito do uso da farmacopuntura associada à protocolos de sincronização de estro principalmente em caprinos e ovinos, como também, em outras espécies de interesse. Ao analisar as pesquisas realizadas nos últimos 10 anos com a utilização de subdoses hormonais associada à farmacopuntura em programas de inseminação artificial em tempo fixo (IATF), nota-se que a farmacopuntura vem se tornando uma ferramenta promissora para viabilizar a redução das doses hormonais administradas e potencializar o efeito do fármaco aplicado, o que eleva a eficiência dos programas de sincronização de estro/ovulação ao reduzir os custos desses protocolos. Além de diminuir o custo desses protocolos para os produtores, nosso grupo de pesquisa realizou uma série de estudos nessa área, visando a busca por protocolos com menores doses hormonais, o que consequentemente reduz a quantidade de resíduos produzidos e promove manejos mais sustentáveis. Baseado nas publicações, pode-se afirmar que a farmacopuntura apresenta resultados satisfatórios e coloca-se como uma via de aplicação de sub-doses ou micro-doses hormonais em protocolos de controle do ciclo estral em caprinos e ovinos, como também, para outras espécies domésticas.(AU)

The objective of this review was to compile information regarding the use of pharmacopuncture associated with estrus synchronization protocols, mainly in goats and sheep, as well as in other species of interest, with the aim of updating and providing information on the subject. When analyzing the research carried out in the last 10 years with the use of hormonal underdoses associated with pharmacopuncture in fixed-time AI programs, these have become a promising tool to enable the reduction of administered hormonal doses and to potentiate the effect of the applied drug, the that increases the efficiency of estrus/ovulation synchronization programs by reducing the costs of these protocols. In addition to reducing the cost of these protocols for producers, our research group carried out a series of studies in this area, aiming at the search for protocols with lower hormonal doses, less waste produced and more sustainable management. Based on the publications, it can be stated that pharmacopuncture presents satisfactory results and is a way of applying sub-doses or micro-doses of hormones in protocols for controlling the estrous cycle in goats and sheep, as well as for other domestic species.(AU)

Fatores que impactam na eficiência reprodutiva de vacas de corte / Factors that impact the reproductive efficiency of beef cows

A maior produtividade na pecuária está correlacionada com a eficiência reprodutiva do rebanho. As biotécnicas da reprodução, principalmente os protocolos de sincronização da ovulação, são de grande importância para otimizar a produção e acelerar o ganho genético em rebanhos de corte e de leite. No entanto, alguns fatores como a categoria animal, o manejo reprodutivo implementado na propriedade e o reprodutor utilizado podem afetar os resultados de fertilidade nos protocolos de IATF. Dessa maneira, algumas estratégias foram desenvolvidas para contornar alguns desafios inerentes a vacas de corte em anestro pós-parto e aumentar a eficiência reprodutiva dessas fêmeas. Dentre as estratégias, destacam-se a utilização de progesterona e a suplementação energética/proteica previamente ao início do protocolo de IATF.(AU)

The reproductive efficiency of the herd is correlated with higher productivity in livestock. Reproduction biotechniques as ovulation synchronization protocols are important to optimize production and accelerate genetic profit in beef and dairy herds. However, some factors such as the animal category, the reproductive management implemented on the farm and the sire used can affect the fertility results in the TAI protocols. In this way, some strategies were developed to overcome some challenges of postpartum anestrus beef cows and to increase the reproductive efficiency of these cows. The use of progesterone and energy/protein supplementation before starting the TAI protocol stand out are the strategies.(AU)

How does reproduction account for dairy farm sustainability?

Sustainability - the new hype of the 21st century has brought discomfort for the government and society. Sustainable agriculture is essential to face our most concerning challenges: climate change, food security, and the environmental footprint, all of which add to consumers' opinions and choices. Improvements in reproductive indexes can enhance animal production and efficiency, guaranteeing profit and sustainability. Estrus detection, artificial insemination (AI), embryo transfer (ET), estrus synchronization (ES), and multiple ovulations are some strategies used to improve animal reproduction. This review highlights how reproductive strategies and genetic selection can contribute to sustainable ruminant production. Improved reproductive indices can reduce the number of nonproductive cows in the herd, reducing methane emissions and land use for production while preserving natural resources.(AU)

Maternal and fetal ultrasonography, vulvar temperature and vaginal mucous impedance for the prediction of parturition in Saanen does

The aim of this study was to evaluate and correlate modifications of vaginal mucous impedance, vulvar temperature and ultrasonographic measurements (echobiometric parameters) to parturition in pregnant Saanen does. 30 does were selected for the study and submitted to an estrus synchronization protocol and natural mating. The females were evaluated daily from Day 143 of pregnancy to parturition. For the sonographic evaluations, the following structures were measured: biparietal diameter, thoracic diameter, abdominal diameter, ocular orbit, kidney length, kidney height, cardiac area, placentome length, cervical measurement and fetal heart rate; by means of two different approaches: transrectal and transabdominal, using a 7.5 MHz linear transducer. The vaginal mucous impedance was assessed using an electric estrous detector and vulvar temperature was measured using a non-contact infrared thermometer. Statistical analysis was performed using the R-project software and the significance level was set at 5% for all tests. 25 Saanen does became pregnant, resulting in 80.33% pregnancy rate. Fetal heart rate was negatively correlated to the hours to parturition (p<0,001; r-Pearson= -0,451), as well as vaginal temperature (p= 0,001; r-Pearson= -0,275), while cervical thickness was positively correlated to hours to parturition (p<0,001; r-Pearson= 0,490). The echobiometric parameters (biparietal diameter, thoracic diameter, abdominal diameter, ocular orbit, kidney length and height, cardiac area, placentome length), as well as vaginal mucous impedance did not vary throughout the timepoints of evaluation and did not correlate to the moment of parturition. It was concluded that the parameters of fetal heartbeat, vaginal temperature and cervical effacement in the last week of pregnancy provide valuable information regarding the proximity of parturition.(AU)

Effect of GnRH administration on pregnancy-associated glycoproteins in dairy sheep with different reproductive status

Background: Measurement of pregnancy-associated glycoproteins (PAGs) by radioimmunoassay or enzyme-linked immunosorbent assay has been commonly used for early pregnancy diagnosis in ruminants. However, an accurately pregnancy detection depends on test antibody, breed and number of embryos. Only few studies have conducted to detect or predict animals at risk of late embrionic mortality (LEM) and to use hormonal interventions for embryo losses reducing, but this area is still open in sheep. The current study aimed to evaluate the effect of gonadotropin releasing hormone (GnRH) administration on Day 4 after artificial insemination on the pregnancy-associated glycoproteins in dairy sheep with different reproductive status in relation to pregnancy and late embrionic mortality detection. Materials, Methods & Results: Sixty-five East Friesian sheep were divided in 2 groups - I (Control group, n = 35) and II (GnRH group, n = 30) and sublected to estrus synchronization and artificial insemination (AI). Group I was not treated and Group II received 50 µg GnRH on Day 4 after AI. PAGs in blood serum were measured by Alertys Ruminant Pregnancy test on Days 4, 12, 20, 25 and 35 after AI and ultrasound pregnancy test was conducted on Days 20, 25, 35 and 60. Reproductive status (non-pregnant, pregnant and animals with LEM) was determined by ultrasound and the results between different groups were compared. The PAGs mean values according to reproductive status and Day after AI were analysed. Accuracy, sensitivity and specificity of the PAGs test for pregnancy diagnosis on Day 35 were calculated. On Day 20 after AI the pregnat sheep (83.3%) in group I tended to be higher than those (77.1%) in group II with decrease of 25.7% and 20% for the same groups on Day 25. On day 25 LEM was recorded in 33.3% and 24% in group I and II, respectively. The ultrasound exams on Day 60 confirmed the results from Day 25 after AI. A total value of non-pegnant, pregnant animals and LEM was 20%, 56.9% and 28.8%, respectively. The mean values of PAGs in animals with the same reproductive status in group I and II no differed statistically between Days 4 and 35 after AI. On Day 25 the PAGs values in LEM groups (0.126 ± 0.072 and 0.179 ± 0.029) were higher than those (0.062 ± 0.038 and 0.083 ± 0.023) in the non-pregnant groups, but no significan difference was deternined. On Day 35 after AI the mean values of PAGs (0.414 ± 0.125 and 0.421 ± 0.121) for the pregnant groups were significantly (P < 0.05) higher than those (0.078 ± 0.053 and 0.093 ± 0.034) for the non-pregnant groups. The values of PAGs in LEM groups on Day 25 (0.099 ± 0.062 and 0.113 ± 0.058) were decreased and close to the mean values in non-pregnant sheep. A significant effect of the day after AI on the PAGs values was evidenced in pregnant animals only (control r = 0.97 and GnRH r = 0.98; P < 0.05). The PAGs started to rise rapidly between Days 25 and 35 after AI. On Day 35 the accuracy (98%), the sensitivity (97.3%) and the specificity (100%) of the PAG test for pregnancy diagnosis were similar to the values (100%) for ultrasound method. Discussion: The gonadotropin treatment on Day 4 after AI tended to improve the reproductive performance in the sheep, but no significant effect of GnRH on the PAGs values in the animals with different reproductive status was found. The PAGs profiles in non-pregnant and LEM sheep were close and distinguishing between non-pregnant and LEM ewes on Day 35 was impossible. The PAGs values in pregnant sheep showed significantly (P < 0.05) increase between Days 25 and 35 after AI with higher mean values in pregnant than non-pregnant groups on Day 35 (P < 0.05). Alertys Ruminant Pregnancy test was a reliable for pregnancy detection in sheep on Day 35 after artificial insemination.

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons

This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons

This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.(AU)

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons

Abstract This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.

Effect of ovarian status on reproductive performance in dairy heifers inseminated with sexed semen

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

Correlation between estrus onset and ovarian parameters in dairy goats / Início do estro e sua correlação com os parâmetros ovarianos em cabras leiteiras

This study assessed the effects of social dominance on the behavioral estrus and ovarian parameters of dairy goats subjected to synchronous estrus induction during the non-breeding season. Synchronous estrus was induced in 23 dairy goats allocated to collective pens. Ovarian ultrasonography was performed at 12 h intervals from device removal to ovulation. Upon estrus onset (EO) detection, the goats were immediately removed from the pens. Dominance was scored according to EO in relation to device removal in each pen, with HD - high dominants (<36 h; n = 8), MD - medium dominants (36 to 48 h; n = 10) and LD - low dominants (>48 h; n = 5). Goats in estrus underwent flexible time artificial insemination (FxTAI) according to EO. The estrus response was 100.0%. The interval to estrus was longer (P<0.05) in LD (53.7 ± 6.5 h) than in MD (37.9 ± 5.5 h) and HD goats (32.3 ± 6.6 h), while the interval from device removal to ovulation was similar (P>0.05) among all groups. The interval from EO to FxTAI was longer in HD goats compared to the other groups (P<0.05). In conclusion, although social hierarchy influenced the time of EO, the ovarian parameters, including ovulation, were not affected.

Este estudo avaliou os efeitos da dominância social sobre o comportamento do estro e os parâmetros ovarianos de cabras leiteiras submetidas à indução sincronizada do estro durante a estação não reprodutiva. A sincronização foi induzida em 23 cabras leiteira alocadas em baias coletivas. A ultrassonografia foi realizada em intervalos de 12 horas desde a remoção do dispositivo até a ovulação. Após a detecção do início do estro (EO), as cabras foram imediatamente removidas dos currais. A dominância foi pontuada de acordo com EO em relação à remoção do dispositivo, sendo: HD - alto dominante (<36 h; n = 8), MD - médio dominante (36 a 48 h; n = 10) e LD - baixo dominante (>478 h; n = 5). As cabras em estro foram inseminadas artificialmente em tempo flexível (FxTAI). O intervalo de estro foi maior (P<0,05) em LD (53,7 ± 6,5 h) do que em MD (37,9 ± 5,5 h) e cabras HD (32,3 ± 6,6 h), por sua vez, o intervalo entre a remoção do dispositivo e a ovulação foi semelhante (P> 0,05) em todos os grupos. O intervalo de EO a FxTAI foi maior em cabras HD quando comparado aos outros grupos (P<0,05). Em conclusão, embora a hierarquia social tenha influenciado o tempo de início do estro, os parâmetros ovarianos incluindo a ovulação não foram afetados.

Effect of 20 mg fluorogestone acetate (FGA) sponges on reproductive parameters of dairy ovine breeds in Southern Italy

Background: Intravaginal devices containing progestins are widely used for oestrus synchronization in sheep. Progestins give economic benefits to farmers but may have some limitations and the efficacy strictly depends on farm management. There are different devices, with different molecules (progesterone, medroxyprogesterone acetate, fluorogestone acetate), different dosages and long (12-14 days) and short-term (5-7 days) protocols. Experimental studies often include a limited number of animals and are held at different latitudes and with different system of management. To our knowledge, there are few reports in the literature on field application of the recently licensed 20 mg fluorogestone acetate (FGA) sponges in large ewe flocks, excluding the registration trials. Materials, Methods & Results: This study was designed to evaluate oestrous synchronization in 2 different breeds. A total of 1100 Lacaune (L) and 618 Sarda (S) were assigned to 8 groups, comparing multiparous (M) and nulliparous (N) and those synchronized in November (n) and May (m). The groups were: LMm (n. 556), LNm (n. 180), SMm (n. 70), SNm (n. 32), LMn (n. 242), LNn (n. 222), SMn (n. 440) e SNn (n. 76). The intravaginal sponge was inserted for 14 days. At sponge withdrawal, eCG (400 IU, IM) was injected, and rams were joined into flocks 30 h later with a male/female ratio of 1:8. Transrectal ultrasonography was performed for pregnancy diagnosis after 30 days. Fertility parameters such as oestrus (OR), pregnancy (PR), lambing rates (LR) and prolificacy were calculated. Fisher exact test was used to compare parameters of each group with the corresponding and significance was set at P < 0.01. The use of intravaginal sponges in this study was easily performed in all animals. In nulliparous groups, digital insertion of the sponge, instead of the applicator, was preferred to avoid discomfort. Sponge loss was observed in 2% of treated ewes. At the removal of the sponge, mild vaginal contamination was observed in 90% of the ewes. Ultrasound finding of embryo resorption, pseudopregnancy and pyometra were found in rates under 2%. The loss of pregnancy ranged from 0 to 3.6% without significant differences among groups. The SMn group showed the best performances (0.91 OR, 0.88 PR, 0.85 LR), significantly higher than the other groups. Prolificacy was maximum in the LMn (1.68) and minimum in the SNm group (1.06), without significant differences among groups. Discussion: The 14-day regimen based on 20 mg FGA-releasing intravaginal devices is an easy and satisfactory synchronization regimen to improve the productivity and the fertility of sheep farm, and this can be managed and optimized in different breeding conditions. In this study, Sarda breed shows a good adaption to the environment with adult ewes giving the best results in reproductive season. However young Sarda ewes were less productive especially in non-breading season. Lacaune showed good reproductive potential, young and adult ewes responded to progestins in reproductive and non-reproductive season. It was confirmed that the reproductive performance is affected by season, age, and breed. This study encourages the breeding of indigenous breeds by implementing the management with modern technologies. The imported highly productive breeds, if well managed, can give a production less influenced by seasonal variables and age.

Hormonal induction and synchronization in the reproduction of Nile tilapia (Oreochromis niloticus) / Sincronização e indução hormonal na reprodução de tilápia do nilo (Oreochromis niloticus)

The present study aims to evaluate the sexual synchronization of Nile tilapia (Oreochromisniloticus) breeding herds under different distributions and days. This study was carried out during, a period of 21 experimental days. It was conducted in a randomized block design (DBC), in a factorial scheme 2 × 2 × 3, (male and female, with and without hormone induction, and three times blocks of 7, 14 and 21 days). A total of 324 fish were used, 180 females and 144 males, previously microchipped with approximately 250 ± 12.25 g of body weight.. Each tank contained 36 animals, with every three tanks comprising a block of which were repeated in time. Each of the tanks was composed of only males, another with 12 males and 24 females separated by a glass and a screen on the bottom and the third tank with only females. In each treatment, half of the animals (male and female) were applied the hCG hormone, in a single dose at a concentration of 5 IU / gram fish live weight. The animals were evaluated at 7, 14, and 21 days. After 667 hours-degree after application of the hormone was made extrusion and spermatozoa by celomatic massage. It was observed females that showed ease of extrusion of gametes. For the females, spawning index, absolute and relative fecundity, oocyte weight per 1 g, diameters, and germinal vesicle peripheral position were evaluated; the sperm concentration, volume (ml), motility (%), duration of sperm motility (min) and integrity were evaluated in males. The data were submitted to analysis of variance at the 5% level of significance. For females at 14 days there was greater ease of extrusion when separated from males, with hormone application . The distribution influenced the spawning weight, the larger diameter, and for the diameters smaller the days and induction presented interference. In males, the days interfered in the increase in volume and duration of semen motility independent of induction and environment, and finally, the environment interfered significantly in semen concentration.

O presente estudo tem como objetivo avaliar a sincronização sexual de reprodutores de tilápias do Nilo (Oreochromis niloticus) em cativeiro sob diferentes distribuições e dias. Este estudo foi realizado por um período de 21 dias experimentais. Foi conduzido num delineamento de blocos casualizados (DBC), num esquema fatorial 2×2×3, (sendo macho e fêmea, com e sem indução hormonal) e três tempos, 7, 14 e 21 dias (blocos). Foram utilizados 324 peixes, sendo 180 fêmeas e 144 machos, com aproximadamente 250 ± 12,25g de peso corporal, previamente microchipados. Cada tanque continha 36 animais, sendo que a cada três tanques compreendia um bloco do qual foram repetidos no tempo. Cada um dos tanques esteve composto por: somente machos, outro com 12 machos e 24 fêmeas separados por um vidro e uma tela na parte de baixo e o terceiro tanque com apenas fêmeas. Em cada tanque, metade dos peixes (macho e fêmeas) recebeu indução hormonal com hCG (CHORULON®), na concentração de 5000UI/grama de peso vivo por peixe. Os animais foram avaliados aos 7, 14, e 21 dias. Passado 667 horas-grau após aplicação do hormônio foi feita extrusão e espermeação mediante massagem celomática. Foram observadas fêmeas que apresentaram facilidade de extrusão de gametas. Para asfêmeas foram avaliadas as seguintes variáveis: índice de desova, fecundidade absoluta e relativa, o peso dos ovócitos por cada 1g, os diâmetros, e posição periférica da vesícula germinativa; nos machos, foram avaliados a concentração espermática, o volume (ml), motilidade (%), tempo de duração de motilidade espermática (min) e integridade. Os dados obtidos foram submetidos a análise de variância ao nível de 5% de significância. Observou-se para fêmeas aos 14 dias, mantidas separada dos machos e com aplicação de hormônios, maior facilidade de extrusão, peso da desova diâmetro dos ovócitos. Nos machos, os dias interferiram no aumento dovolume e na duração de motilidade do sêmen independente da indução e ambiente, e por fim, o ambiente interferiu significativamente na concentração do sêmen.

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)

Efficiency and accuracy of different ovulation inducers after progesterone device removal in crossbred multiparous cows / Eficiência e acurácia de diferentes indutores de ovulação após a remoção do dispositivo de progesterona em vacas mestiças multíparas

The aim of this study was to verify the efficiency and ovulation time after the administration of different inducers for synchronization of ovulation in beef cows. One hundred and eight non-lactating cows were distributed into the control group (CG; untreated; n=28), estradiol benzoate (EB) group (EBG; n=28); 17 beta-estradiol (17ßE) group (17ßEG; n=28), and deslorelin (DES) group (DESG; n=24). On day minus 11 (D-11) of the protocol, the CG underwent application of cloprostenol and ultrasound examination (US); on D0, progesterone (P4) was inserted plus EB; on D7, cloprostenol was applied; on D9, P4 was removed and cloprostenol plus 400 IU of equine chorionic gonadotropin (eCG) was injected. The EBG was subjected to treatment identical to that of the CG, except on D10, when the cows received EB. The 17ßE was subjected to the same protocol used in the CG except for the administration of 17ßE on D10. And, the DESG was subjected to the same treatment as the CG, except on D10, when the group received DES acetate. Twelve hours after the administration of EB, 17ßE and DES, ovarian US were performed every 6 hours. The preovulatory follicle (POF) diameters measured before ovulation were 19.5; 14.7; 18.7 and 19.8 mm respectively for CG, EBG, 17ßEG and DESG; and the time intervals between inducer application and ovulation were 20.2; 18.9; 21.0 and 22.5 hours respectively. In conclusion, all ovulation inducers were efficient in promoting ovulation; the inducers caused ovulation between 18.9 and 22.5 hours; EB promoted ovulation in a shorter time (P<0.05); 17ßE and DES showed greater variation in application/ovulation time between groups.

O objetivo do estudo foi verificar a eficiência e a ovulação após a administração de diferentes indutores para a sincronização da ovulação em vacas de corte. Cento e oito vacas não-lactantes foram distribuídas em grupo controle (GC; não tratadas; n=28); grupo benzoato de estradiol (BE) (GBE; n=28); grupo 17 beta-estradiol (17ßE) (G17ßE; n=28) e grupo deslorelina (DES) (GDES; n=24). No dia menos 11 (D-11) do protocolo, o GC recebeu cloprostenol e exame ultrassonográfico (US); ao D0, dispositivo de progesterona (P4) foi inserido mais BE; ao D7, cloprostenol foi aplicado; ao D9, a P4 foi removida e cloprostenol mais 400 UI de gonadotrofina coriônica equina (eCG) foi injetada. O GBE foi submetido a tratamento idêntico ao do GC, exceto ao D10, quando as vacas receberam BE. o G17ßE foi submetido ao mesmo protocolo usado no CG exceto pela administração de 17ßE ao D10. E, o GDES foi submetido ao mesmo tratamento que o CG, exceto ao D10, quando o grupo recebeu o acetato de DES. Doze horas após a administração de BE, 17ßE e DES, US ovarianos foram realizados a cada 6 horas. O diâmetro do folículo pré-ovulatório (FPO) medido antes da ovulação foi de 19,5; 14,7; 18,7 e 19,8 mm respectivamente para GC, GBE, G17ßE e GDES; e o intervalo de tempo entre a aplicação do indutor e ovulação foi 20,2; 18,9; 21;0 e 22,5 horas respectivamente. Em conclusão, todos os indutores da ovulação foram eficientes em promover a ovulação; os indutores acarretaram ovulação entre 18,9 e 22,5 horas; o BE promoveu a ovulação em menor espaço de tempo (P<0,05); 17ßE e DES demonstraram maior variação em aplicação/tempo de ovulação entre os grupos.

Conception rate according to sire, body condition score and estrus occurrence of suckled Bos taurus beef cows submitted to timed artificial insemination / Taxa de concepção de acordo com o touro, escore de condição corporal e ocorrência de estro em vacas de corte Bos taurus lactantes submetidas à inseminação artificial em tempo fixo

The objective of this study was to investigate the effect of estrus expression, body condition score (BCS), different sires and semen batches on the conception rate of suckled Bos taurus beef cows submitted to timed artificial insemination (TAI). Data from 7,737 TAI were obtained from five farms in South Brazil. Cows received an estradiol plus progesterone-based estrous synchronization protocol. Only sires (n = 13) with at least two semen batches and 50 AI in two different lots were included in the study. Conception rate was higher for cows in estrus (66.8% vs. 26.3%) or with BCS ≥ 3 (57.2% vs. 51.6%) than in cows without estrus or BCS < 3, respectively (P≤0.001). Conception rate per sire ranged from 42.6% (Sire L) to 74.3% (Sire K). Conception rate in cows with BCS ≥ 3 and estrus occurrence varied from 47.4% (Sire L) to 86.1% (Sire A) among sires. Conception rate differed among semen batches of the same sire (B1 = 58.5%, B2 = 62.5%, and B3 = 83.2%). In conclusion, there was individual variation in conception rate among AI sires and semen batches within sires. The conception rate was increased by estrus occurrence and greater BCS.

O objetivo deste estudo foi investigar o efeito da manifestação de estro, o escore de condição corporal (ECC), os diferentes touros e partidas de sêmen na taxa de concepção de vacas Bos taurus lactantes de corte submetidas à inseminação artificial em tempo fixo (IATF). Dados de 7.737 IATF foram obtidos em cinco fazendas do sul do Brasil. As vacas receberam um protocolo de sincronização de estro à base de estradiol e progesterona. Somente touros (n=13) com no mínimo duas partidas e 50 inseminações em dois lotes diferentes foram incluídos no estudo. A taxa de concepção foi maior nas vacas em estro (66,8% vs. 26,3%) ou com ECC ≥ 3 (57,2% vs. 51,6%) do que em vacas sem estro ou com menor ECC, respectivamente (P≤0,001). A taxa de concepção por touro variou de 42,6% (Touro L) a 74,3% (Touro K). A taxa de concepção em vacas que demonstraram estro e com ECC ≥3 variou de 47,4% (Touro L) a 86,1% (Touro A) entre os touros. A taxa de concepção diferiu entre partidas de um mesmo touro (B1=58,5%, B2=62,5% e B3=83,2%). Em conclusão, houve variação individual na taxa de concepção entre touros e entre as partidas de sêmen de um mesmo touro. A taxa de concepção foi aumentada pela ocorrência de estro e maior ECC.

Does combining estradiol cypionate and GnRH for ovulation induction in recipient cows increase pregnancy rate after timed embryo transfer?

Estradiol cypionate (EC) or GnRH have been widely used for ovulation induction in timed embryo transfer (TET). EC administration increases the proportion of cows that show estrus, whereas GnRH promotes more synchronized ovulations. The aim of the present study was to evaluate the potential beneficial effects of combining EC and GnRH in TET. In experiment 1, no difference was observed on serum progesterone concentrations on Day 6 and 13 after GnRH treatment between GnRH and EC+GnRH groups. In experiment 2, pregnancy per embryo transfer (P/ET) did not differ (p = 0.69) between GnRH (62.8%) and EC+GnRH (58.7%) groups. In conclusion, combining EC and GnRH for ovulation induction does not increase progesterone secretion and pregnancy rate after TET in cattle.(AU)