Evaluation of corpus luteum vascularization in recipient mares by using color Doppler ultrasound

Background: Embryo transfer is one of the most commonly used reproductive biotechnique. The success of embryotransfer is also affected by the synchrony of estrus and ovulation between donor and recipient animals. In horse reproduction, ultrasonography has been used, among other purposes, to diagnose early pregnancy. However, only the color Dopplerimaging mode makes it possible to evaluate the vascular architecture and the hemodynamic aspects of the vessels in severalorgans, especially the corpus luteum. The objective of this study was to evaluate, based on the color Doppler ultrasound,the corpus luteum vascularization and function from recipient mares at embryo transfer timing.Materials, Methods & Results: Mangalarga Machador mares from 5 to 10-year-old and a range of live weights of between350 to 450 kg were used for this experiment, kept in pasture-based on mombaça grass (Panicum maximum) and were givenad libitum access to water and mineral supplementation. The animals (n = 15) were gynecologically examined and uterineconsistency was evaluated by rectal palpation the same operator using an ultrasound system (SonoScape®) with a lineartransducer, and operating frequency ranging from 5 to 10 Mhz. The uterine tone was classified between grades 1 and 4 andsubjected to ovulation induction. The objective and subjective vascular perfusion of the corpus luteum was evaluated bycolor Doppler ultrasound on the day of embryo transfer and endometrium. The determination progesterone concentrationon the day of the embryo transfer was performed by direct chemiluminescence assay. The arcsine (√P/100) transformation was applied to the percentage data, and the results were expressed as mean (.) ± standard error of the mean (SEM).Further, the assumptions of normality and homoscedasticity were verified, respectively, based on the Shapiro-Wilk and...

Evaluation of corpus luteum vascularization in recipient mares by using color Doppler ultrasound

Background: Embryo transfer is one of the most commonly used reproductive biotechnique. The success of embryotransfer is also affected by the synchrony of estrus and ovulation between donor and recipient animals. In horse reproduction, ultrasonography has been used, among other purposes, to diagnose early pregnancy. However, only the color Dopplerimaging mode makes it possible to evaluate the vascular architecture and the hemodynamic aspects of the vessels in severalorgans, especially the corpus luteum. The objective of this study was to evaluate, based on the color Doppler ultrasound,the corpus luteum vascularization and function from recipient mares at embryo transfer timing.Materials, Methods & Results: Mangalarga Machador mares from 5 to 10-year-old and a range of live weights of between350 to 450 kg were used for this experiment, kept in pasture-based on mombaça grass (Panicum maximum) and were givenad libitum access to water and mineral supplementation. The animals (n = 15) were gynecologically examined and uterineconsistency was evaluated by rectal palpation the same operator using an ultrasound system (SonoScape®) with a lineartransducer, and operating frequency ranging from 5 to 10 Mhz. The uterine tone was classified between grades 1 and 4 andsubjected to ovulation induction. The objective and subjective vascular perfusion of the corpus luteum was evaluated bycolor Doppler ultrasound on the day of embryo transfer and endometrium. The determination progesterone concentrationon the day of the embryo transfer was performed by direct chemiluminescence assay. The arcsine (√P/100) transformation was applied to the percentage data, and the results were expressed as mean (.) ± standard error of the mean (SEM).Further, the assumptions of normality and homoscedasticity were verified, respectively, based on the Shapiro-Wilk and...(AU)

Functional assessment of diluent choice for semen cryopreservation from stallions with high and low freezability

Background: Fertility using horse frozen-thawed semen remains lower than in other livestock species. This fact suggeststhat horse semen hold intrinsic sensitivity to cryoinjury that must be investigated. Moreover, there is substantial evidenceof genetic factors upon horse cryopreservation outcome. Nonetheless, diluent and cryoprotectant choice for horse semencryopreservation are under intense research. Thus these factors could be explored to identify conditions that may increasesemen viability after thawing. The aim of this work was to evaluate the effect of diluents Botu-Crio®,Lactose-EDTA®, andINRA-82® on cryopreserved semen from stallions with high (HFA) and low freezability (LFA).Materials, Methods & Results: Frozen-thawed semen was evaluated for motility and membrane integrity using computerassisted semen analysis (CASA), and also inferred for sperm DNA fragmentation by sperm chromatin structure assay during the thermoresistance test (TRT). Comparisons for each parameter were done in a pair-wise fashion between HFA andLFA semen at one-hour intervals during the TRT (0 h - 4 h). Sperm motility in HFA, regardless of the diluent, was larger(P 0.05)at 0 h and 3 h. Sperm DNA fragmentation was lower (P < 0.05) in HFA semen at 0 h and 1 h.Discussion: Artificial insemination in horses using frozen-thawed semen is gaining wider acceptance under commercialsettings, although its current limited outreach due to low semen viability after thawing. Therefore, several efforts weremade toward ...

Functional assessment of diluent choice for semen cryopreservation from stallions with high and low freezability

Background: Fertility using horse frozen-thawed semen remains lower than in other livestock species. This fact suggeststhat horse semen hold intrinsic sensitivity to cryoinjury that must be investigated. Moreover, there is substantial evidenceof genetic factors upon horse cryopreservation outcome. Nonetheless, diluent and cryoprotectant choice for horse semencryopreservation are under intense research. Thus these factors could be explored to identify conditions that may increasesemen viability after thawing. The aim of this work was to evaluate the effect of diluents Botu-Crio®,Lactose-EDTA®, andINRA-82® on cryopreserved semen from stallions with high (HFA) and low freezability (LFA).Materials, Methods & Results: Frozen-thawed semen was evaluated for motility and membrane integrity using computerassisted semen analysis (CASA), and also inferred for sperm DNA fragmentation by sperm chromatin structure assay during the thermoresistance test (TRT). Comparisons for each parameter were done in a pair-wise fashion between HFA andLFA semen at one-hour intervals during the TRT (0 h - 4 h). Sperm motility in HFA, regardless of the diluent, was larger(P < 0.05) than LFA, both on 0h and 1h. In the 2h evaluation, sperm motility using Botu-Crio® and Lactose-EDTA® wasgreater (P < 0.05) for HFA. Analysis of sperm membrane integrity was similar between HFA and LFA semen (P > 0.05)at 0 h and 3 h. Sperm DNA fragmentation was lower (P < 0.05) in HFA semen at 0 h and 1 h.Discussion: Artificial insemination in horses using frozen-thawed semen is gaining wider acceptance under commercialsettings, although its current limited outreach due to low semen viability after thawing. Therefore, several efforts weremade toward ... (AU)

Induction of ovulation in Mangalarga Marchador mares by hCG or GnRH

Background: Induction of ovulation is a key procedure for horse assisted reproduction technologies, such as for artificial insemination (AI) and embryo transfer. The application of hCG remains as the primary ovulation-inducing agent for horse assisted reproduction, but alternatives are in demand to avoid its adverse effects, such as loss of ovulation-inducing efficiency over multiple applications by hCC-antibody production. Despite reports on alternative ovulation-inducing agents, pair-wise comparisons of such agents under similar conditions have been limited. Under such scenario, the work was aimed to determine the efficiency of both hCG and Buserelin at inducing ovulation in Mangalarga Marchador mares raised in the Northeast of Brazil under an AI program.Materials, Methods & Results: Mares were initially selected based on their reproductive performance, the absence of clinical-reproductive alterations and adequate body condition score. Mares in diestrus were randomly distributed in three experimental conditions, received 5 mg of Dinoprost and were monitored daily for estrus detection. After estrus detection, ovaries were monitored by ultrasonography, in 12-h intervals, until the follicle reached 35 mm. At this time-point, ovulation was induced with 0.042 mg of Buserelin endovenously, with 3,000 IU hCG by an intramuscular shot, and control mares received 2 mL of saline solution, also by an intramuscular shot. Both hCG and Buserelin displayed similar efficiencies (P > 0.05) for induction of ovulation and that both agents were effective (P 0.05) from those found in the Control. All ovulations occurred within a 72-h period after treatment.[...]

Induction of ovulation in Mangalarga Marchador mares by hCG or GnRH

Background: Induction of ovulation is a key procedure for horse assisted reproduction technologies, such as for artificial insemination (AI) and embryo transfer. The application of hCG remains as the primary ovulation-inducing agent for horse assisted reproduction, but alternatives are in demand to avoid its adverse effects, such as loss of ovulation-inducing efficiency over multiple applications by hCC-antibody production. Despite reports on alternative ovulation-inducing agents, pair-wise comparisons of such agents under similar conditions have been limited. Under such scenario, the work was aimed to determine the efficiency of both hCG and Buserelin at inducing ovulation in Mangalarga Marchador mares raised in the Northeast of Brazil under an AI program.Materials, Methods & Results: Mares were initially selected based on their reproductive performance, the absence of clinical-reproductive alterations and adequate body condition score. Mares in diestrus were randomly distributed in three experimental conditions, received 5 mg of Dinoprost and were monitored daily for estrus detection. After estrus detection, ovaries were monitored by ultrasonography, in 12-h intervals, until the follicle reached 35 mm. At this time-point, ovulation was induced with 0.042 mg of Buserelin endovenously, with 3,000 IU hCG by an intramuscular shot, and control mares received 2 mL of saline solution, also by an intramuscular shot. Both hCG and Buserelin displayed similar efficiencies (P > 0.05) for induction of ovulation and that both agents were effective (P < 0.05) for such purpose, since greater percentages (P < 0.05) of induction on mares treated from those of the control. Moreover, the total number of ovulations in mares treated at the end of the experiment was not different (P > 0.05) from those found in the Control. All ovulations occurred within a 72-h period after treatment.[...](AU)

Influence of male to female ratio on hormone profiles and reproductive performance of anestrus postpartum ewes subjected to the male effect

Background: Complete isolation of genders allows intense estrous induction and synchronization once rams are introduced in ewe flocks at the onset of the breeding season (BS). This management practice, defined as the male effect, results from a neuroendocrine process mediated by pheromones. The male effect is a straightforward procedure to induce estrous in noncycling ewes, but conditions for its use have not been fully explored. Thus, this study aimed to evaluate hormone levels and ovarian activity of postpartum ewes in anestrus which are subjected to the male effect under different male to female ratios. Material, Methods & Results: Pospartum females were selected according to body condition score and cyclicity status. Females were kept apart from males during 30 days at a distance of 10 m. Anestrus and ovulation were determined by P4 measures on days 10, 20 and 30 after isolation from males. After P4 concentration diagnosis, anestrus ewe (n = 99) were subjected to male to ewe ratios (MFR) of 1:20 (MFR20), 1:30 (MFR30) and 1:40 (MFR40). Santa Inês rams (n = 3) of proven fertility were used. Three females of each group were randomly subjected to blood collection for LH concentration analysis. Ovarian activity was performed by ultrasonography after estrus manifestation in six ewe of each group. Estrus events were observed twice a day during the BS of 35 days, and estrus [...](AU)

Influence of male to female ratio on hormone profiles and reproductive performance of anestrus postpartum ewes subjected to the male effect

Background: Complete isolation of genders allows intense estrous induction and synchronization once rams are introduced in ewe flocks at the onset of the breeding season (BS). This management practice, defined as the male effect, results from a neuroendocrine process mediated by pheromones. The male effect is a straightforward procedure to induce estrous in noncycling ewes, but conditions for its use have not been fully explored. Thus, this study aimed to evaluate hormone levels and ovarian activity of postpartum ewes in anestrus which are subjected to the male effect under different male to female ratios. Material, Methods & Results: Pospartum females were selected according to body condition score and cyclicity status. Females were kept apart from males during 30 days at a distance of 10 m. Anestrus and ovulation were determined by P4 measures on days 10, 20 and 30 after isolation from males. After P4 concentration diagnosis, anestrus ewe (n = 99) were subjected to male to ewe ratios (MFR) of 1:20 (MFR20), 1:30 (MFR30) and 1:40 (MFR40). Santa Inês rams (n = 3) of proven fertility were used. Three females of each group were randomly subjected to blood collection for LH concentration analysis. Ovarian activity was performed by ultrasonography after estrus manifestation in six ewe of each group. Estrus events were observed twice a day during the BS of 35 days, and estrus [...]

Role of male effect on reproductive efficiency of nulliparous Santa Inês and Morada Nova ewes raised in different regions / Ação do efeito macho sobre a eficiência reprodutiva de ovelhas nulíparas das raças Santa Inês e Morada Nova criadas em diferentes regiões

Background: The male effect is an attractive strategy to increase herd production by concentrating mating events and deliveries and further allowing the adoption of genetic improvement programs. It holds similar efficiency to those chemically based estrous synchronization methods, but has the advantage of being a natural method. The work was aimed to evaluate the influence of male effect on estrous induction and synchronization, pregnancy and prolificacy of nulliparous Santa Inês and Morada Nova ewes raised in Semiarid and Zona da Mata regions of Pernambuco state. Materials, Methods & Results: Santa Inês (n = 80) and Morada Nova (n = 80) females, with age from 11 to 12 months, after being evaluated and selected, were identified with plastic ear tags, weighted and maintained isolated from males, during 30 days before experiment onset, without any physical, visual, olfactive and auditive contact. Estrous events were observed twice a day (6:00 and 16:00 h) by trained personnel, during a breeding season of 60 days, and estrous were considered synchronized when detected, within first five days of breeding season. Rams of Santa Inês (n = 2) and Morada Nova (n = 2) breeds were selected based upon reproductive capacity by an andrology exam, and were marked on the externum bone region with a wax and ink (4:1) mixture, and were marked in female lots in order to identify females in [...](AU)

Role of male effect on reproductive efficiency of nulliparous Santa Inês and Morada Nova ewes raised in different regions / Ação do efeito macho sobre a eficiência reprodutiva de ovelhas nulíparas das raças Santa Inês e Morada Nova criadas em diferentes regiões

Background: The male effect is an attractive strategy to increase herd production by concentrating mating events and deliveries and further allowing the adoption of genetic improvement programs. It holds similar efficiency to those chemically based estrous synchronization methods, but has the advantage of being a natural method. The work was aimed to evaluate the influence of male effect on estrous induction and synchronization, pregnancy and prolificacy of nulliparous Santa Inês and Morada Nova ewes raised in Semiarid and Zona da Mata regions of Pernambuco state. Materials, Methods & Results: Santa Inês (n = 80) and Morada Nova (n = 80) females, with age from 11 to 12 months, after being evaluated and selected, were identified with plastic ear tags, weighted and maintained isolated from males, during 30 days before experiment onset, without any physical, visual, olfactive and auditive contact. Estrous events were observed twice a day (6:00 and 16:00 h) by trained personnel, during a breeding season of 60 days, and estrous were considered synchronized when detected, within first five days of breeding season. Rams of Santa Inês (n = 2) and Morada Nova (n = 2) breeds were selected based upon reproductive capacity by an andrology exam, and were marked on the externum bone region with a wax and ink (4:1) mixture, and were marked in female lots in order to identify females in [...]

Male effect and breeding season shortening under contrasting climatic conditions upon reproduction of nulliparous Anglo-Nubians / Efeito do macho e redução das estações de monta em diferentes condições climática a reprodução de nulíparas Anglo-Nubiana

This study was aimed to evaluate breeding seasons of different durations under contrasting climatic conditions upon reproductive performance of nulli­parous does submitted to male effect. A total of 240 Anglo-Nubian females at 8 to 12 months of age were used and were kept away from all three bucks at a distance of 300 m for 60 days, which avoided any physical, visual, olfactory or hearing contact between genders. Estrus were visually detected and pregnancy rates were determined by ultrasonography 60 days after the last mating. Breeding season duration and climatic condition did not influence estrus incidence, where 70% does had estrus detected at the dry season, 80% of does cycled at the rainy season within breeding seasons of 25 days. Moreover, 80% of does cycled at the dry season and 95% at the rainy season during breeding seasons of 35 days and 45 days. After breeding seasons of 25 days, pregnancy rate was lower at the dry season (55.0%) compared to the rainy season (80.0%). Mean birth weight of resulting offspring was lower during the rainy season (2.94 kg ± 0.26) than during the dry season (3.03 kg ± 0.16). The results show that estrus onset is affected by breeding season durations and climatic conditions tested, although dry season lowered pregnancy rates. In conclusion, 25-day breeding seasons are recommended to improve standardization of offspring lots, to reduce costs with food supplementation and estrus detection, while preserving pregnancy and kidding rates.

Male effect and breeding season shortening under contrasting climatic conditions upon reproduction of nulliparous Anglo-Nubians / Efeito do macho e redução das estações de monta em diferentes condições climática a reprodução de nulíparas Anglo-Nubiana

This study was aimed to evaluate breeding seasons of different durations under contrasting climatic conditions upon reproductive performance of nulli­parous does submitted to male effect. A total of 240 Anglo-Nubian females at 8 to 12 months of age were used and were kept away from all three bucks at a distance of 300 m for 60 days, which avoided any physical, visual, olfactory or hearing contact between genders. Estrus were visually detected and pregnancy rates were determined by ultrasonography 60 days after the last mating. Breeding season duration and climatic condition did not influence estrus incidence, where 70% does had estrus detected at the dry season, 80% of does cycled at the rainy season within breeding seasons of 25 days. Moreover, 80% of does cycled at the dry season and 95% at the rainy season during breeding seasons of 35 days and 45 days. After breeding seasons of 25 days, pregnancy rate was lower at the dry season (55.0%) compared to the rainy season (80.0%). Mean birth weight of resulting offspring was lower during the rainy season (2.94 kg ± 0.26) than during the dry season (3.03 kg ± 0.16). The results show that estrus onset is affected by breeding season durations and climatic conditions tested, although dry season lowered pregnancy rates. In conclusion, 25-day breeding seasons are recommended to improve standardization of offspring lots, to reduce costs with food supplementation and estrus detection, while preserving pregnancy and kidding rates.(AU)

Double ovulation induction using low dose of Deslorelin in mares / Indução de ovulações duplas utilizando baixa dose de deslorelina em éguas

The wok was aimed to induce multiple ovulations in mares using low doses of deslorelin acetate (GnRH) to enhance the reproductive efficiency. A total of 15 mares of the quarter horse breed were used as embryo donors in a cross over 15 x 2 experimental design (fifteen animals x two treatments), where animals were monitored for two consecutive cycles. On the control group (CG), the estrous of donors occurred on its natural form and follicular development was monitored by ultrasonography. Ovulation was induced with 2500 IU hCG intravenously, when the follicle reached 35 mm in diameter, moment when artificial insemination was performed. On day 8 (D8) after ovulation, donors were submitted to embryo collection. On Treated Group 2 (TG), donors received, by intramuscular shot, 7.5 mg dinoprost thrometamine and after 48 hours of its administration follicular development was monitored twice a day byultrasound, until the larger follicle reached 23 to 25 mm and the second follicle reached at least 18 mm. Moreover, a super-ovulation protocol was performed with 100 g deslorelin in 12 diâmehour intervals until larger follicle reached 33 to 35 mm. The ovulation was induced with 1000 g deslorelin acetate, by an intramuscular shot, concomitant with 1000 IU hCG intravenously. Artificial insemination was performed immediately after ovulation and embryo collection was on D8. The percentage of mares with multiple ovulations on CG was 13.33% (2/15) and TG of 86.66% (13/15), with diference between groups (P < 0.05). The mean number of embryos per donor was 1.066±0.497 on TG and 0.6±0.48 on CG (P < 0.05). The percentage of embryos per ovulation was 52.94% on CG and 57.14% on TG, with diference between groups (P < 0.05). The percentage of embryos per flushing was 60.00% on CG and 80.00% on TG, with diference between groups (P > 0.05). The percentage of embryo recovery per flushing was 60% CG and 80% on TG (P<0.05).[...](AU)

Objetivou-se induzir ovulações múltiplas em éguas utilizando baixas doses de acetato de deslorelina (GnRH) visando aumentar a eficiência reprodutiva nessa espécie. Foram utilizadas 15 éguas doadoras de embriões da raça Quarto de Milha, em sistema cross over 15 x 2 (quinze animais x dois tratamentos), no qual cada uma foi monitorada por dois ciclos consecutivos. No Grupo Controle (GC), o estro das doadoras ocorreu de forma natural e o desenvolvimento folicular foi monitorado por ultrassonografia. A ovulação foi induzida com 2500 UI de hCG por via intravenosa, quando o foliculo alcançou diâmetro de 35 mm, momento em que se procedeu a inseminação artificial. No oitavo dia (D8) após ovulação, as doadoras foram submetidas aos procedimentos de colheita embrionária. No Grupo Tratado (GT), as doadoras receberam, por via intramuscular, 7,5 mg de dinoprost-trometamina e após 48 horas de sua administração foi realizado o monitoramento folicular duas vezes ao dia com auxilio de ultrassom, até que o maior folículo atingisse o diâmetro de 23 a 25 mm e o segundo do que 18 mm. Posteriormenteiniciou-se o protocolo de superovulação com a administração de 100 g de GnRH em intervalo de 12 horas até que o maior folículo atingisse o diâmetro entre 33 de 35 mm. A ovulação foi induzida com 1000 µg de GnRH, por via intramuscular, associado a 1000 UI de hCG aplicado por via intravenosa. Imediatamente após a ovulação efetuou-se a inseminação artificial e a colheita de embriões realizada no D8. O percentual de éguas com ovulações múltiplas no GC foi de 13,33% (2/15) e no GT de 86,66% (13/15), havendo diferença (P<0,05). O número médio de embrião por doadora foi de 1,066±0,497 no GT e de 0,6±0,48 no GC, registrando-se diferença (P < 0,05). A porcentagem de embrião por ovulação foi de 52,94% no GC e 57,14% no GT, existindo diferença (P < 0,05). A porcentagem de embrião por lavado foi de 60,00% no GC e de 80,00% no GT, havendo diferença (P > 0,05). [...](AU)

Influence of male-to-female ratio and climatic conditions on the reproductive performance of Anglo Nubian goats / Influência da proporção macho/fêmea e condições climáticas sobre a performance reprodutiva de caprinos Anglo-Nubianos

The objective of this study was to test the “male effect” on the reproductive performance of Anglo Nubian does (n = 180), aged between 24 and 60 months, under different male-to-female ratios (1:20 – T20, 1:30 – T30, and 1:40 – T40) and climatic conditions (dry season – DS, and rainy season – RS). Does were randomly distributed into three groups (T20, T30, and T40) and were isolated from bucks at a distance of 300 m for 60 days before the start of the experiments. The first manifestation of estrous during the DS occurred 6.83 ± 4.54 (T20), 6.72 ± 4.56 (T30) and 7.05 ± 5.23 (T40) days following the onset of the breeding season (P>0.05). In the RS, onset of estrous was observed 6.60 ± 4.74 (T20), 6.70 ± 4.43 (T30) and 7.46 ± 4.54 (T40) days after the beginning of the breeding season (P>0.05). Estrous induction in females during the DS occurred in 95% (T20), 80% (T30), and 75.5% (T40) of all females. During the RS, estrous detection reached 100% (T20), 100% (T30), and 97.5% (T40) of all females, with no difference between all RS and DS groups. Estrous synchronization during the DS occurred in 35.00% (T20), 36.66% (T30), and 32.50% (T40) of all females, for an average occurrence of 34.72%. During the RS, synchronization occurred in 65% (T20), 70% (T30) and 62.25% (T40) of all females, for an average occurrence of 65.75%; no difference was detected between the RS and the DS. Pregnancy rates in the DS groups were 65.0% (T20), 70.0% (T30), and 62.5% (T40), while pregnancy rates in the RS were 90.0% (T20), 86.6% (T30), and 95.0% (T40). No difference was observed for conception rates between any of the RS and DS groups. Prolificacy during the DS was 1.30 (T20), 1.30 (T30) and 1.35 (T40), while in the RS prolificacy was 1.29 (T20), 1.25 (T30) and 1.30 (T40). Thus, the male effect can be used effectively for goats under 1:20–1:40 male-to-female ratios in a 45-day mating season under varying climatic conditions.

O objetivo do presente trabalho foi testar o “efeito macho” sobre o desempenho reprodutivo de cabras Anglo Nubianas (n = 180), com idade entre 24 e 60 meses, sob diferentes proporções macho:fêmea (1:20 - T20, 1:30 - T30, e 01:40 - T40) e condições climáticas (estação seca - ES, e estação chuvosa - EC). As fêmeas foram distribuídas aleatoriamente em três grupos (T20, T30 e T40), e foram mantidas separadas dos machos a distância de 300 m por 60 dias antes do início do experimento. A primeira manifestação de estro na ES ocorreu 6,83 ± 4,54 (T20), 6,72 ± 4,56 (T30) e em 7,05 ± 5,23 (T40) dias após o início da época de reprodução (P>0,05). Na EC, o início do estro foi observado 6,60 ± 4,74 (T20), 6,70 ± 4,43 (T30) e 7,46 ± 4,54 (T40) dias após o início da época de reprodução (P>0,05). A indução de estro na ES chegou em 95% (T20), 80% (T30), e 75,5% (T40) das fêmeas. Na EC, a detecção do estro atingiu 100% (T20), 100% (T30), e 97,5% (T40), sem diferença entre as épocas do ano. Sincronização de estro durante ES ocorreu em 34,72%, 35,00% (T20), 36,66% (T30), e 32,5 % (T40) das fêmeas. Na EC, a sincronização ocorreu em 65,75% das fêmeas, 65% (T20), 70% (T30) e 62,25% (T40), sem apresentar diferença estatística (P>0,05) entre EC e ES. A taxa de gestação nos grupos ES foi de 65,0% (T20), 70,0% (T30), e 62,5% (T40), enquanto que em EC foi de 90,0% (T20), 86,6% (T30), e de 95,0% (T40), sem diferença estatística (P>0,05) entre EC e ES. A prolificidade durante ES foi 1,30 (T20), 1,30 (T30) e 1,35 (T40) e na EC foi 1,29 (T20), 1,25 (T30) e 1,30 (T40). Em conclusão, o efeito macho pode ser utilizado com as proporções 1:20-1:40 macho:fêmea, em estação de monta de 45 dias de duração sob condições climáticas diferentes.

Double ovulation induction using low dose of Deslorelin in mares / Indução de ovulações duplas utilizando baixa dose de deslorelina em éguas

The wok was aimed to induce multiple ovulations in mares using low doses of deslorelin acetate (GnRH) to enhance the reproductive efficiency. A total of 15 mares of the quarter horse breed were used as embryo donors in a cross over 15 x 2 experimental design (fifteen animals x two treatments), where animals were monitored for two consecutive cycles. On the control group (CG), the estrous of donors occurred on its natural form and follicular development was monitored by ultrasonography. Ovulation was induced with 2500 IU hCG intravenously, when the follicle reached 35 mm in diameter, moment when artificial insemination was performed. On day 8 (D8) after ovulation, donors were submitted to embryo collection. On Treated Group 2 (TG), donors received, by intramuscular shot, 7.5 mg dinoprost thrometamine and after 48 hours of its administration follicular development was monitored twice a day byultrasound, until the larger follicle reached 23 to 25 mm and the second follicle reached at least 18 mm. Moreover, a super-ovulation protocol was performed with 100 g deslorelin in 12 diâmehour intervals until larger follicle reached 33 to 35 mm. The ovulation was induced with 1000 g deslorelin acetate, by an intramuscular shot, concomitant with 1000 IU hCG intravenously. Artificial insemination was performed immediately after ovulation and embryo collection was on D8. The percentage of mares with multiple ovulations on CG was 13.33% (2/15) and TG of 86.66% (13/15), with diference between groups (P 0.05). The percentage of embryo recovery per flushing was 60% CG and 80% on TG (P<0.05).[...]

Objetivou-se induzir ovulações múltiplas em éguas utilizando baixas doses de acetato de deslorelina (GnRH) visando aumentar a eficiência reprodutiva nessa espécie. Foram utilizadas 15 éguas doadoras de embriões da raça Quarto de Milha, em sistema cross over 15 x 2 (quinze animais x dois tratamentos), no qual cada uma foi monitorada por dois ciclos consecutivos. No Grupo Controle (GC), o estro das doadoras ocorreu de forma natural e o desenvolvimento folicular foi monitorado por ultrassonografia. A ovulação foi induzida com 2500 UI de hCG por via intravenosa, quando o foliculo alcançou diâmetro de 35 mm, momento em que se procedeu a inseminação artificial. No oitavo dia (D8) após ovulação, as doadoras foram submetidas aos procedimentos de colheita embrionária. No Grupo Tratado (GT), as doadoras receberam, por via intramuscular, 7,5 mg de dinoprost-trometamina e após 48 horas de sua administração foi realizado o monitoramento folicular duas vezes ao dia com auxilio de ultrassom, até que o maior folículo atingisse o diâmetro de 23 a 25 mm e o segundo do que 18 mm. Posteriormenteiniciou-se o protocolo de superovulação com a administração de 100 g de GnRH em intervalo de 12 horas até que o maior folículo atingisse o diâmetro entre 33 de 35 mm. A ovulação foi induzida com 1000 µg de GnRH, por via intramuscular, associado a 1000 UI de hCG aplicado por via intravenosa. Imediatamente após a ovulação efetuou-se a inseminação artificial e a colheita de embriões realizada no D8. O percentual de éguas com ovulações múltiplas no GC foi de 13,33% (2/15) e no GT de 86,66% (13/15), havendo diferença (P 0,05). [...]

Influence of male-to-female ratio and climatic conditions on the reproductive performance of Anglo Nubian goats / Influência da proporção macho/fêmea e condições climáticas sobre a performance reprodutiva de caprinos Anglo-Nubianos

The objective of this study was to test the “male effect” on the reproductive performance of Anglo Nubian does (n = 180), aged between 24 and 60 months, under different male-to-female ratios (1:20 T20, 1:30 T30, and 1:40 T40) and climatic conditions (dry season DS, and rainy season RS). Does were randomly distributed into three groups (T20, T30, and T40) and were isolated from bucks at a distance of 300 m for 60 days before the start of the experiments. The first manifestation of estrous during the DS occurred 6.83 ± 4.54 (T20), 6.72 ± 4.56 (T30) and 7.05 ± 5.23 (T40) days following the onset of the breeding season (P>0.05). In the RS, onset of estrous was observed 6.60 ± 4.74 (T20), 6.70 ± 4.43 (T30) and 7.46 ± 4.54 (T40) days after the beginning of the breeding season (P>0.05). Estrous induction in females during the DS occurred in 95% (T20), 80% (T30), and 75.5% (T40) of all females. During the RS, estrous detection reached 100% (T20), 100% (T30), and 97.5% (T40) of all females, with no difference between all RS and DS groups. Estrous synchronization during the DS occurred in 35.00% (T20), 36.66% (T30), and 32.50% (T40) of all females, for an average occurrence of 34.72%. During the RS, synchronization occurred in 65% (T20), 70% (T30) and 62.25% (T40) of all females, for an average occurrence of 65.75%; no difference was detected between the RS and the DS. Pregnancy rates in the DS groups were 65.0% (T20), 70.0% (T30), and 62.5% (T40), while pregnancy rates in the RS were 90.0% (T20), 86.6% (T30), and 95.0% (T40). No difference was observed for conception rates between any of the RS and DS groups. Prolificacy during the DS was 1.30 (T20), 1.30 (T30) and 1.35 (T40), while in the RS prolificacy was 1.29 (T20), 1.25 (T30) and 1.30 (T40). Thus, the male effect can be used effectively for goats under 1:20–1:40 male-to-female ratios in a 45-day mating season under varying climatic conditions.(AU)

O objetivo do presente trabalho foi testar o “efeito macho” sobre o desempenho reprodutivo de cabras Anglo Nubianas (n = 180), com idade entre 24 e 60 meses, sob diferentes proporções macho:fêmea (1:20 - T20, 1:30 - T30, e 01:40 - T40) e condições climáticas (estação seca - ES, e estação chuvosa - EC). As fêmeas foram distribuídas aleatoriamente em três grupos (T20, T30 e T40), e foram mantidas separadas dos machos a distância de 300 m por 60 dias antes do início do experimento. A primeira manifestação de estro na ES ocorreu 6,83 ± 4,54 (T20), 6,72 ± 4,56 (T30) e em 7,05 ± 5,23 (T40) dias após o início da época de reprodução (P>0,05). Na EC, o início do estro foi observado 6,60 ± 4,74 (T20), 6,70 ± 4,43 (T30) e 7,46 ± 4,54 (T40) dias após o início da época de reprodução (P>0,05). A indução de estro na ES chegou em 95% (T20), 80% (T30), e 75,5% (T40) das fêmeas. Na EC, a detecção do estro atingiu 100% (T20), 100% (T30), e 97,5% (T40), sem diferença entre as épocas do ano. Sincronização de estro durante ES ocorreu em 34,72%, 35,00% (T20), 36,66% (T30), e 32,5 % (T40) das fêmeas. Na EC, a sincronização ocorreu em 65,75% das fêmeas, 65% (T20), 70% (T30) e 62,25% (T40), sem apresentar diferença estatística (P>0,05) entre EC e ES. A taxa de gestação nos grupos ES foi de 65,0% (T20), 70,0% (T30), e 62,5% (T40), enquanto que em EC foi de 90,0% (T20), 86,6% (T30), e de 95,0% (T40), sem diferença estatística (P>0,05) entre EC e ES. A prolificidade durante ES foi 1,30 (T20), 1,30 (T30) e 1,35 (T40) e na EC foi 1,29 (T20), 1,25 (T30) e 1,30 (T40). Em conclusão, o efeito macho pode ser utilizado com as proporções 1:20-1:40 macho:fêmea, em estação de monta de 45 dias de duração sob condições climáticas diferentes.(AU)

Avaliação de oócitos caprinos submetidos à estresse calórico induzido durante a maturação in vitro / Evaluation of Goat Oocytes Subjected to Heat Stress Induced During Maturation In Vitro

Background: The low productivity of Northeast goat herds has been circumvented by the importation of exotic species; however, caution is needed due to the susceptibility of these breeds to the high temperatures found in this region. It is now known that the oocyte and the embryo are the primary targets of the deleterious effects induced by heat stress, causing cellular damage that triggers the cascade of apoptosis. Therefore, the purpose of this study was to evaluate the effect of thermal heat stress during in vitro maturation of oocytes and its effects on embryo production in goats. Materials, Methods & Results: The ovaries were collected in a slaughterhouse and transported to the Laboratory of Biotechnical Reproduction of UFRPE. The cumulus oophorus complexes (COCs) were collected by the technique of slicing the follicles from 2 to 6 mm in diameter, selected based on morphology and placed in a basic medium for maturation. In 10 replications, the COCs were submitted to the thermal heat stress at 41°C for 0 (thermoneutrality at 39°C), 3, 6, 12, 18, and 24 h of maturation in vitro. The data was evaluated in maturation, fertilization, cleavage (D-3), stage of 8-16 cells (D4), morula (D-5), and blastocyst (D-8) after fertilization and blastocysts positive for apoptosis through the TUNEL test. For statistics, the results were expressed as mean and standard deviation. Also considering the measurements addressed in percentages, a comparison of variances was carried out, F-test for variances to the level of signifi cance 5% (P < 0.05). Then, a t-test to compare averages was conducted, to the significance level of 5%, for equivalent variances or distinct variances, according to what was observed in the F-test for variances. A signifi cant difference (P < 0.05) was observed during all time periods studied for heat stress on maturation, fertilization, D-3, D-4, and D-5. On D-8 no significant difference (P > 0.05) was observed between the periods of 3 vs 6 and 18 vs 24 h, and in the blastocysts positive by the TUNEL test for the periods of 0 vs 3, 3 vs 6, 12 vs 18, and 18 vs 24 h of heat stress. Discussion: When applying a thermal shock that produces damage to the oocyte maturation in vitro, the characteristic membrane, chromatin configuration, and meiotic spindles are changed, and thus, the developmental potential of oocytes after fertilization is compromised. It was observed in this study that there was a gradual reduction in the number of oocytes as the time of exposure to heat shock increased, reflecting directly on each stage of IVP embryos. These stages are most vulnerable during maturation in vivo (ovulation), fertilization, within two days after fertilization, and in the first division of cleavage, as evidenced in this study in vitro after heat stress, reducing the number of blastocysts. This suggests that apoptosis can be induced in pre-implantation of embryos exposed to maternal hyperthermia. Moreover, the degree of apoptosis experienced by IVP embryos generally reflects the severity of thermal shock. In this study, the percentage of cells that were TUNEL positive increased with the prolongation of thermal shock. Induction of apoptosis was time dependent and the number of apoptotic cells increased proportionally after 6, 12, 18, and 24 h of exposure. Under the conditions observed in this study, the results indicate that the time in which the oocyte is exposed to heat stress during maturation in vitro is of great importance for embryonic development and their level of apoptotic cells.

Influência das estações seca e chuvosa na capacidade de desenvolvimento de oócitos e produção in vitro de embriões da espécie caprina / Influence of dry and rainy seasons on oocyte maturation and in vitro embryo production in goats

Objetivou-se com este estudo determinar a influência das estações seca e chuvosa na maturação de oócitos e produção in vitro (PIV) de embriões na espécie caprina. Os ovários das cabras nas estações seca (outubro a março) e chuvosa (abril a setembro) foram colhidos em abatedouro e transportados ao Laboratório de Biotécnicas da Reprodução da UFRPE. Os complexos cumulus oophorus (CCOs) foram colhidos pela técnica de "slicing" dos folículos entre 2 a 6 mm de diâmetro e selecionados com base na classificação morfológica. Foram realizadas 12 repetições, nas quais os CCOs foram submetidos à maturação, fertilização e cultivo in vitro dos embriões. A média e desvio padrão da taxa de clivagem foi determinada no dia 3 (D-3) e dos embriões que se desenvolveram aos estádios de 8-16 células, mórula e blastocisto foi determinada nos dias 4 (D-4), 5 (D-5) e 8 (D-8) após a fecundação, respectivamente. A quantidade de blastômeros foi determinada com o corante DAPI e os blastômeros positivos para apoptose por meio do teste de TUNEL. A produção de embriões no D-3 e mórulas foram inferiores ao obtido no período chuvoso (P 0,05) quanto às fases de maturação, fertilização, cultivo no D-4 e blastocisto. Os embriões produzidos na estação seca apresentaram maior incidência de apoptose (P < 0,05). Nas condições descritas neste estudo, os resultados permitem concluir que as fases iniciais do desenvolvimento embrionário sofrem maior impacto negativo durante a estação seca em protocolos de PIV na espécie caprina.

This study aimed to determine the influence of dry and rainy seasons on oocyte maturation and in vitro production (IVP) of embryos in goats. The ovaries of does in dry (October to March) and rainy season (April-September) were collected at a slaughterhouse and transported to the Laboratory of Biotechnical Reproduction of UFRPE. The cumulus oophorus complexes (COCs) were collected by the technique of slicing of the follicles from 2 to 6 mm in diameter, and selected based on morphologic classification. We used 12 replicates, in which the COCs were submitted to maturation, fertilization and in vitro culture. The cleavage rate was determined on day 3 (D-3) and embryos that developed to 8-16 cells (D-4), morulae (D-5) and blastocyst (D-8) stages after fertilization. The number of blastomeres was assessed with DAPI staining, and the determination of apoptotic blastomeres was performed by TUNEL assay. In the dry season, D-3 embryos and morulae development was lower than that obtained in the rainy season (P0.05) were observed on oocyte maturation, fertilization, D-4 embryo yield and blastocyst development. Embryos produced during the dry season had a higher incidence of apoptosis on D- 3 and at the morulae stage (P<0.05). Under the conditions described in this study, the results suggest that the early stages of embryonic development suffer greater negative impact during the dry season in IVP protocols in goats.

Avaliação de embriões ovinos provenientes de oócitos submetidos a estresse calórico durante a maturação in vitro / Evaluation of sheep oocytes submitted to heat stress induced during in vitro maturation

Neste trabalho foi avaliado o efeito do estresse calórico durante a maturação de oócitos sobre a produção in vitro de embriões ovinos. Os ovários foram obtidos em abatedouro e os oócitos colhidos de folículos de 2 a 6 mm de diâmetro. Após seleção, os oócitos, em 10 replicações, foram colocados para maturação in vitro (MIV) durante 24 horas. Os oócitos submetidos ao estresse térmico de 41º C durante 3, 6, 12, 18 e 24 horas foram posteriormente transferidos para completar a MIV a 39 ºC, mesma temperatura utilizada para maturação dos oócitos do grupo controle. O desenvolvimento dos embriões foi determinado nos dias 3, 4, 5 e 8 pós-fecundação. A avaliação da qualidade dos embriões foi efetuada através da contagem total de células coradas pelo DAPI e da determinação do número de blastômeros positivos para apoptose através do teste de TUNEL. Observou-se que o estresse térmico diminuiu (P 0,05) somente até 18 horas de incubação. Os resultados permitem concluir que o estresse calórico durante a maturação in vitro de oócitos reduz a quantidade e a qualidade dos embriões ovinos produzidos in vitro determinadas pela alta incidência de apoptose.

The aim of this work was evaluate the effect of heat stress during oocyte maturation on ovine in vitro embryo production. Ovaries were collected at abattoirs and oocytes retrieved from follicles ranging from 2 and 6 mm in diameter. After selection, all oocytes, in 10 replicates, were placed in in vitro maturation (IVM) during 24 hours. The oocytes were submitted to heat stress of 41º C during 3, 6, 12, 18 and 24 hours and were further transferred to 39º C in order to complete IVM, which was the temperature of maturation of control oocytes. Embryonic development was determined on days 3, 4, 5, and 8 post-fertilization. Embryo evaluation was performed as total cell count by DAPI staining and determination of positive blastomere for apoptosis by the TUNEL assay. We observed that heat stress diminishes (P 0.05) only up to 18 hours of incubation. The results allow the conclusion that heat stress during oocyte in vitro maturation reduces the quantity and quality of ovine embryos produced in vitro determined by the high incidence of apoptosis.

Avaliação de embriões ovinos provenientes de oócitos submetidos a estresse calórico durante a maturação in vitro / Evaluation of sheep oocytes submitted to heat stress induced during in vitro maturation

Neste trabalho foi avaliado o efeito do estresse calórico durante a maturação de oócitos sobre a produção in vitro de embriões ovinos. Os ovários foram obtidos em abatedouro e os oócitos colhidos de folículos de 2 a 6 mm de diâmetro. Após seleção, os oócitos, em 10 replicações, foram colocados para maturação in vitro (MIV) durante 24 horas. Os oócitos submetidos ao estresse térmico de 41º C durante 3, 6, 12, 18 e 24 horas foram posteriormente transferidos para completar a MIV a 39 ºC, mesma temperatura utilizada para maturação dos oócitos do grupo controle. O desenvolvimento dos embriões foi determinado nos dias 3, 4, 5 e 8 pós-fecundação. A avaliação da qualidade dos embriões foi efetuada através da contagem total de células coradas pelo DAPI e da determinação do número de blastômeros positivos para apoptose através do teste de TUNEL. Observou-se que o estresse térmico diminuiu (P < 0,05) a capacidade de maturação dos oócitos de acordo com o tempo de exposição à temperatura de 41º C. No grupo de oócitos incubados a 39 C, 70,70% maturou, enquanto que nos grupos expostos ao estresse térmico, apenas 45,28%, 35,17%, 12,30%, 9,74% e 4,60% maturaram, respectivamente, após 3, 6, 12, 18 e 24 horas de incubação. A duração de exposição dos oócitos ao estresse calórico é inversamente proporcional (P < 0,05) à capacidade de desenvolvimento embrionário e diretamente proporcional (P < 0,05) ao número de blastocistos positivos para apoptose. Todavia, o efeito deletério do estresse térmico sobre a clivagem e os embriões nos estádios de 8 a 16 células e de mórula foi crescente (P > 0,05) somente até 18 horas de incubação. Os resultados permitem concluir que o estresse calórico durante a maturação in vitro de oócitos reduz a quantidade e a qualidade dos embriões ovinos produzidos in vitro determinadas pela alta incidência de apoptose.(AU)

The aim of this work was evaluate the effect of heat stress during oocyte maturation on ovine in vitro embryo production. Ovaries were collected at abattoirs and oocytes retrieved from follicles ranging from 2 and 6 mm in diameter. After selection, all oocytes, in 10 replicates, were placed in in vitro maturation (IVM) during 24 hours. The oocytes were submitted to heat stress of 41º C during 3, 6, 12, 18 and 24 hours and were further transferred to 39º C in order to complete IVM, which was the temperature of maturation of control oocytes. Embryonic development was determined on days 3, 4, 5, and 8 post-fertilization. Embryo evaluation was performed as total cell count by DAPI staining and determination of positive blastomere for apoptosis by the TUNEL assay. We observed that heat stress diminishes (P < 0.05) oocyte maturation capacity in accordance with exposure time of 41º C. In the group of oocytes incubated at 39 ºC, 70.70% matured, while in the groups exposed to heat stress of 41º C, only 45.28%, 35.17%, 12.30%, 9.74% and 4.60% matured, respectively, after 3, 6, 12, 18 and 24 hours of incubation. The duration of exposure to heat stress is inversely proportional (P < 0.05) to embryonic developmental capacity directly proportional (P < 0.05) to the number of blastocysts positive to apoptosis. However, the cleavage rate and embryonic development from 8 to 16 cells and morulae stages were affected by heat stress (P > 0.05) only up to 18 hours of incubation. The results allow the conclusion that heat stress during oocyte in vitro maturation reduces the quantity and quality of ovine embryos produced in vitro determined by the high incidence of apoptosis.(AU)