Reproductive outcomes using different distances for preconditioning for the male effect in Anglo Nubian goats during two distinct climate seasons

Alves, Carlos Geraldo Tenório; Ferreira-Silva, José Carlos; Almeida-Irmão, José Monteiro; Moura, Marcelo Tigre; Bartolomeu, Cláudio Coutinho; Lima, Paulo Ricardo Silva; Oliveira, Marcos Antônio Lemos

doi:10.17523/bia.v72n1p69

Cited by 3 publications

(3 citation statements)

References 19 publications

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“…This fact is in accordance with previous data in goats and sheep (aLvEs et al, 2014;CaLdas et al, 2015), as described by CusHwa et al (1992) and pEarCE and oLdHaM (1988), who reported efficient estrous detection. In accordance with Martin et al (1986), two peaks of estrous detection were observed when males were introduced into the ewe herd, which was in seasonal anestrous.…”

Section: Discussionsupporting

confidence: 93%

Male effect associated with suckling interruption on the reproductive performance of Santa Inês ewes

et al. 2015

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This study aimed to evaluate the effect of temporary suckling interruption associated with the male effect on reproductive performance of pluriparous Santa Inês ewes. The females were kept apart from the males for 60 days and then randomly distributed into three treatments associated with the male effect (DT0, DT24 and DT48); in DT0, there was no suckling interruption; in DT24, suckling was interrupted for 24 hours, and in DT48, sucking was interrupted for 48 hours. Estrous distribution was observed within 31 (DT0), 27 (DT24) and 38 (DT48) days of the breeding season. Estrous synchronization up to the 5th day of the mating season was observed in 15% (DT0), 30% (DT24) and 25% (DT48) of the females, with no difference among treatments. Estrous percentages were 90% (DT0), 100% (DT24) and 100% (DT48), with no difference among treatments. Pregnancy rates were 38.4% (DT0), 60.0% (DT24) and 45.0% (DT48) with no difference among treatments. Prolificacy was 1.43 (DT0), 1.17 (DT24) and 1.22 (DT48) and did not differ between treatments. In conclusion, temporary suckling interruption associated with the male effect is efficient to induce estrous but not to synchronize estrous or increase the pregnancy rates and prolificacy of Santa Inês ewes during a 45-day breeding season.Keywords: anestrous, biostimulation, reproduction, sheep. EFEITO MACHO ASSOCIADO AO DESMAME TEMPORÁRIO NO DESEMPENHO REPRODUTIVO DE OVELHAS SANTA INÊSRESUMO: O estudo teve como objetivo avaliar o efeito do desmame temporário associado ao efeito macho sobre o desempenho reprodutivo de ovinos Santa Inês. As fêmeas foram mantidas distantes dos machos por 60 dias e aleatoriamente distribuídas em três tratamentos associados ao efeito macho (DT0, DT24 e DT48), no qual em DT0, não houve interrupção da amamentação; em DT24, amamentação interrompida por 24 horas e em DT48, interrupção da amamentação por 48 horas. Distribuição de estro foi observada em 31 (DT0), 27 (DT24) e 38 (DT48) dias da estação de monta. Sincronização de estro até o quinto dia da estação de monta foi observada em 15% (DT0), 30% (DT24) e 25% (DT48) das fêmeas, não havendo diferença entre os tratamentos. Percentagens de estro foram de 90% (DT0), 100% (DT24) e 100% (DT48), não havendo diferença entre os tratamentos. As taxas de prenhez foram de 38,4% (DT0), 60,0% (DT24) e 45,0% (DT48), sem diferença entre os tratamentos. A prolificidade foi de 1,43 (DT0), 1,17 (DT24) e 1,22 (DT48), e não diferiu entre os tratamentos. Em conclusão, o desmame temporário associado ao efeito macho é eficiente na indução do estro, embora não seja eficiente na sincronização de estros e não aumente as taxas de gestação e prolificidade das ovelhas Santa Inês durante uma estação de monta de 45 dias.Palavras-chave: anestro, bioestimulação, ovinos, reprodução.

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Section: Discussionsupporting

confidence: 93%

Male effect associated with suckling interruption on the reproductive performance of Santa Inês ewes

et al. 2015

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“…Thus, prolonged anestrus postpartum is a limiting factor to livestock production as it negatively affects reproductive rates and overall profitability. On the other hand, anestrus can be easily minimized by adopting appropriate management practices such as the male effect [7,22], which is low cost, easily implemented and fits within animal welfare criteria [1,2,4,5,9,13]. Additionally, the male effect may be used as a breeding tool to select females with higher reproductive potential as it has been shown to be associated with reduced age at first delivery and interval between deliveries and increased number of multiple deliveries [3,19].…”

Section: Introductionmentioning

confidence: 99%

Influence of Male to Female Ratio on Hormone Profiles and Reproductive Performance of Anestrus Postpartum Ewes Subjected to the Male Effect

Ferreira-Silva

Burnett

Souto

et al. 2017

Acta Scientiae. Vet.

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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 were considered synchronized when it occured within the initial five days of the BS. Pregnancy diagnosis was performed by ultrasonography on days 35 and 60 after the last mating. All ewe were in a non-cycling condition before BS onset, based upon P4 analysis. After initiation of the BS, P4 concentrations increased for all groups. Irrespectively of male to female ratio, male effect induced LH pre-ovulatory peaks within the initial 26 to 86 h of the BS. Synchronization of estrus reached 50% for MFR20, 40% for MFR30 and 20% for MFR40 for all ewe. Moreover, overall estrus incidence was 100% (MFR20), 90% (MFR30) and 65% (MFR40) within the initial 15 days of the BS. However, incidence of ewe that had repeated estrus events was lower for MFR20 than for MFR30. Follicular growth and number of ovulations was similar between groups. Conception rates on first service was higher than that of second service for MFR20 and MFR30, although there was no difference between services for MFR40. In contrast, overall conception rates, delivery type and prolificacy were similar between groups.Discussion: P4 increased to cyclicity levels after contact between genders, demonstrating the potential of the male effect to induce estrus in non-cycling ewes. Most ewe ovulated within three days after the male effect, possibly due to elevated basal LH levels. Moreover, the LH preovulatory peak varied within groups, possibly due to greater interactions between genders, which ultimately may have led to earlier ovulation anticipation under lower MFR. Estrus parameters were similar between groups, suggesting low or negligible effects of MFR. Ovulatory follicle size and growth and the number of ovulations were similar between all groups; previous reports have suggested that this may be due to a strong effect of their genetic background. Conception rates were higher at first than second services, demonstrating the potential of male effect. In conclusion, male to female ratio affects the efficiency of the male effect to induce and synchronize estrus in ewes under postpartum anestrus, but it does not affect conception rates and prolificacy.

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“…Por isso é importante racionalizar a eficiência reprodutiva dos rebanhos através do desenvolvimento de estraté-gias que sejam de baixo custo e fácil execução [4]. Nesse contexto, o controle dos eventos reprodutivos contribui para maximizar o manejo reprodutivo, a correta indução e sincronização do estro, seja através de fármacos [11,26] ou por métodos naturais, como o efeito macho [1][2][3]5], que são ferramentas para acelerar o melhoramento genético tendo em vista que permitem concentrar as coberturas em curto período de tempo, os partos ocorrem em épocas favoráveis, além de contribuírem para implementação de programas de reprodução assistida, como a inseminação artificial [23,25] e a transferência de embriões [17].…”

Section: Introductionunclassified

Role of Male effect on Reproductive Efficiency of Nulliparous Santa Inês and Morada Nova ewes raised in Different Regions

Filho

Ferreira-Silva

Nascimento

et al. 2016

Acta Scientiae. Vet.

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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 estrous. After ten days of breeding season onset, rams were again marked with the same wax and ink mixture, but with a different ink color. Pregnancy diagnosis was performed on day 30 by ultrasonography and confirmed on day 60 after the last mating. The statistical analysis was performed using SAS, version 8. Differences of 5% (P < 0.05) or lower were considered significant. The results show that estrous synchronization in the semiarid region in both breeds was detected in 10% of females. The total pregnancy on first service was 45.00% and on second was 52.94%, with 85.18% of singleton and 14.81% twin deliveries, with prolificacy de 1.15 ± 0.38. In the Zona da Mata region 10% Santa Inês and 15% Morada Nova females had synchronized estrous (P > 0.05). The total pregnancy was 42.50% on first, 64.70% on second service and total delivery was 86.20% singletons, 12.06% twins and 3.33% triples with prolificacy of 1.15 ± 0.31. On both Semiarid and Zona da Mata regions, the majority of estrous events occurred between the11th and 15th day of the breeding season for Santa Inês ewes and between 6th and 10th day for Morada Nova ewes. Discussion: The occurrence of estrous, for both breeds, in both regions, were detected throughout the breeding seasons, despite most estrous detections were within the initial fifteen days, which normally happens with cycling pluriparous females, in disagreement with findings in the literature that young females display lower reproductive performance on the first breeding season. However, the sexual inexperience of young females is not equivalent to lack of male receptivity, since then, could not be responsible for late ...

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Reproductive outcomes using different distances for preconditioning for the male effect in Anglo Nubian goats during two distinct climate seasons

Cited by 3 publications

References 19 publications

Male effect associated with suckling interruption on the reproductive performance of Santa Inês ewes

Male effect associated with suckling interruption on the reproductive performance of Santa Inês ewes

Influence of Male to Female Ratio on Hormone Profiles and Reproductive Performance of Anestrus Postpartum Ewes Subjected to the Male Effect

Role of Male effect on Reproductive Efficiency of Nulliparous Santa Inês and Morada Nova ewes raised in Different Regions

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