Reproductive handling strategies male effect associated in the Angle-Nubian goats raised in the semi-arid regions of the State of Pernambuco.

Objetivou-se avaliar estratégias de manejo reprodutivo associada ao efeito macho em cabras pluríparas (n = 184) da raça Anglo-Nubiana, com idade de 24 a 60 meses, criadas em regime semi-extensivo no semi-árido do Estado de Pernambuco. As cabras foram mantidas a 300 m de distância dos reprodutores (n = 3) em piquetes formados por vegetação nativa do tipo arbustiva. Antes de iniciar os experimentos, os reprodutores foram avaliados pelo exame clínico andrológico e as fêmeas foram selecionadas pelo escore de condição corporal, por meio de exames vaginoscópico e ultrassonográfico. A concentração de progesterona foi aferida para constatação da condição de ciclicidade. A prenhez foi diagnosticada por ultrassonografia após 60 dias da última cobertura. No primeiro experimento foi avaliada a influência da duração da estação de monta nos períodos seco (PS) e chuvoso (PC). As cabras (n = 120), equitativamente distribuídas nos tratamentos, foram submetidas à estação de monta de 25 (EM-25D), 35 (EM-35D) e de 45 (EM-45D) dias. As porcentagens de estro durante o PC e o PS foram de 100% nas EM-25D, EM-35D e EM-45D, excetuando-se aquela de 95% obtida na EM-45 durante o PS. Esses dados não revelaram influência (P > 0,05) da duração da estação de monta sobre a exibição de estro durante o PS e o PC. No PC foi observada presença de duplo estro em 30% das fêmeas na EM-25D, 35% na EM-35D e 35% na EM-45D, bem como 25% na EM-25D, 30% na EM-35D e 25% na EM-45D durante o PC. A presença de estro triplo foi somente registrada em 5% das fêmeas na EM-35D e EM-45D durante o PC. Não houve influência (P > 0,05) da duração da estação de monta sobre a repetição de estro no PS e no PC. Verificou-se que o intervalo entre os estros no PC variou de 1 a 21 dias no primeiro e de 7 a 21 dias no segundo estro da EM-25D. Na EM-35D variou de 1 a 23 no primeiro e de 6 a 27 no segundo estro. O terceiro estro ocorreu no 24o dia. Na EM-45D oscilou de 1 a 23 dias no primeiro e de 9 a 20 dias no segundo estro. O terceiro estro ocorreu no 30o dia. No PS variou de 1 a 17 dias no primeiro e de 6 a 23 dias no segundo estro da EM-25D. Na EM-35D variou de 1 a 20 no primeiro e de 6 a 24 no segundo estro. Na EM-45D oscilou de 2 a 21 dias no primeiro e de 6 a 21 dias no segundo estro. Não ocorreu o terceiro estro no PS. As porcentagens de prenhez no PC foram de 90,0% na EM-25D, 95% na EM-35D e 95% na EM-45D. No PS, essas porcentagens foram de 75% na EM-25, 80% na EM-35D e 75% na EM-D45, não sendo constatada influência (P > 0,05) da duração da estação de monta tanto no PC quanto no PS. No segundo experimento, avaliou-se o efeito do desaleitamento temporário. As cabras (n = 64) foram aleatoriamente distribuídas em três tratamentos (DT0, DT24, DT48). No DT0 (n = 20), não houve interrupção do aleitamento, no DT24 (n = 22), o aleitamento foi interrompido por 24 horas e no DT48 (n = 22) interrompido por 48 horas. A distribuição dos estros ocorreu de forma dispersa até o 16o dia no DT0, 13o dia no DT24 e 11o dia no DT48. A sincronização dos estros até o 5o dia da estação de monta foi de 70% (DT0), 80% (DT24) e de 72% (DT48), não havendo diferença entre os tratamentos. As porcentagens de estro de ciclo normal foram de 85% (DT0), 95,45% (DT24) e 100% (DT48), não diferindo (P > 0,05) entre os tratamentos. As porcentagens de estro de ciclo curto foram de 58,00% (DT0), 57,14% (DT24) e de 36,36% (DT48), não diferindo (P > 0,05) entre os tratamentos. As porcentagens de prenhez foram de 52,94% (DT0), 80,95% (DT24) e de 36,36% (DT48), constatando-se que a porcentagem do DT24 foi superior (P 0,05) entre as porcentagens do DT0 e do DT48. A prolificidade foi de 1,44 (DT0), 1,35 (DT24) e de 1,37 (DT48), não havendo diferença (P > 0,05) entre os tratamentos. Estes resultados permitem concluir que a duração da estação de monta no PC e no PS não exerce influência sobre as porcentagens de exibição de estro e de prenhez. Sendo assim, é possível recomendar a utilização da EM-25D, além de reduzir o tempo de acasalamento, padroniza os lotes das crias e os custos da propriedade com suplementação alimentar e pessoal habilitado para observação de estro e supervisão de partos. Além disso, é possível concluir que o desaleitamento temporário por 24 horas é eficiente como estratégia de manejo reprodutivo capaz para reduzir o período parto/concepção em cabras da raça Anglo-Nubiana sem interferir na prolificidade.This work aimed to evaluate reproductive handling strategies male effect associated in the goats pluriparous Anglo-Nubian goats (n = 184), aged 24 to 60 months old, raised in semi-extensive regime in the semi-arid region of the State of Pernambuco. The goats were kept 300 m away from the males (n = 3) which were maintained behind fences made of bush-type native vegetation. Before the start of the experiments, the males underwent fertility testing and the females were selected according to body condition score by both vaginoscopy and ultra-sound. Concentration of progesterone was measure to determine cyclicity conditions. Pregnancy was diagnosed by ultra-sound 60 days after the last mating. During the first experiment, the influence of duration of the mating season in the dry period (DP) and wet period (WP) was evaluated. The evenly distributed goats (n = 120), were submitted to mating seasons of 25 (MS-25D), 35 (MS-35D) and 45 (MS-45D) days. Estrous percentages during DP and WP were 100% at MS-25D, MS-35D e MS-45D, except for 95% obtained at MS-45D during DP. These data did not reveal any influence (P > 0.05) of the mating season during exhibition of estrous during DP and WP. During the DP, the presence of double estrous was observed in 30% of the females at the MS-25D, 35% at the MS-35D and 35% at the MS-45D, as well as 25% at the MS-25D, 30% at the MS-35 and 25% at the MS-45D during the WP. The presence of a triple estrous was only recorded in 5% of the females at the MS-35D and MS-45D during the WT. There was no influence (P > 0.05) of duration of the mating season on repetition of estrous during the DP or the WP. It was found that the intervals between estrous during the WS varied from 1 to 21 days in the first, and from 7 to 21 days during the second estrous at MS-25D. At MS-35D, it varied from 1 to 23 days, and from 6 to 27 days during the second. The third estrous occurred on the 24th day. At MS-45D, it varied from 1 to 23 days during the first and from 9 to 20 days during the second. The third estrous occurred on the 30th day. During the DS, it varied from 1 to 17 days during the first, and from 6 to 23 days during the second estrous at MS-25D. At MS-35D, it varied from 1 to 20 days in the first, and from 6 to 21 days during the second estrous. There was no third estrous during the DS. Pregnancy percentages during the WP were 90.0% at MS-25D, 95% at MS-35D and 95% an MS-45D. During the DP, these percentages were 75% at MS-25D, 80% at MS-35D and 75% at MS-45D, with no influence (P > 0.05) of duration of mating season both during the DP or WP. In the second experiment, the effect of temporary interrupted of suckling was evaluated. The goats (n = 64) were randomly distributed in three treatments (TS0, TS24, TS48). At TS0 (n = 20), there was no suckling interruption, while at TS24 (n = 22), suckling was interrupted for 24 hours and at TS48, (n = 22), interruption was for 48 hours. Estrous distribution was scattered up to the 16th day at TS0, 13th day at TS24 and 11th at TS48. Estrous synchronization at to the 5th day of the mating season was 70% (TS0), 80% (TS24) and 72% (TS48), with no difference between treatments. Estrous percentages in the normal cycle were 85% (TS0), 95.45% (TS24) and 100% (TS48), with no different (P > 0.05) among treatments. Short cycle estrous percentages were 58.00% (TS0), 57.14% (TS24) and 36.36% (TS48), with no difference among treatments. Pregnancy percentages were 52.94% (TS0), 80.95% (TS24) and 36.36% (TS48), and it was found that the percentage at TS24 was higher (P 0.05) between TS0 and TS48 percentages. Prolificacy was 1.44 (TS0), 1.35 (TS24) and 1.37 (TS48), with no difference (P > 0.05) among treatments. The results allow us to conclude that duration of the mating season during the DP and WP have no influence on the percentages of exhibit of estrous and pregnancy. Therefore, it is possible to recommend the use of MS-25D because, besides reducing mating time, it standardized the lot of offspring and costs such as supplementary feeding and skilled personnel to observe estrous and supervise deliveries. Moreover, it is also possible to conclude that the 24-hour suckling time can be recommended as a strategy for reproductive handling due to reducing the delivery/conception period in the Anglo-Nubian goats not intervening with the prolificness.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPE

Desempenho reprodutivo usando distâncias diferentes para o pré-condicionamento do efeito macho em caprinos durante dois períodos climáticos distintos

The objective of the present study was to determine if separation distance between bucks and does during two distinct climate seasons could affect the reproductive performance of goats subjected to a 45-day mating season (MS). Anglo Nubian does (n = 120) were kept apart from bucks at distances of 2 m (T1), 300 m (T2), and 2000 m (T3) for 60 days prior to the 45-day MS during two distinct climate seasons [dry season (DS, February to March) and rainy season (RS, September to October)] in Sertânia, Pernambuco state, Brazil. There were no effects of distance of separation between bucks and does in any response variable evaluated. However, during the DS, the mean of the first estrous manifestation varied significantly (P&gt;0.05) between groups [7.13±4.49 (T1), 8.84±5.64 (T2), and 6.37±4.21 (T3) days] and during the RS [7.33±5.74 (T1), 6.60±4.88 (T2) and 8.10±4.87 (T3) days]. Similar (P&gt;0.05) estrous induction rates were found during both the DS [100.00% (T1), 100.00% (T2) and 95.50% (T3)] and the RS [100.00% (T1), 100.00% (T2) and 100.00% (T3)]. The estrous synchronization rate was found to be lower during the DS [36.60%; 30.00% (T1), 35.00% (T2) and 45.00% (T3)] than during the RS [56.60%; 50.00% (T1), 60.00% (T2) and 60.00% (T3)]. Pregnancy rates during the DS [P&gt;0.05; 80.00% (T1), 70.00% (T2) and 75.00% (T3)] were lower than during the RS [P&gt;0.05; 90.00% (T1), 90.00% (T2) and 95.00%(T3)]. In summary, the separation distance between bucks and does did not affect the reproductive outcome of Anglo Nubian goats over a 45-day MS under tropical conditions. Greater reproductive outcome was observed during the RS than the DS regardless of the separation distance between bucks and does.</span

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

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). 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 estrous onset in a breeding season of young females. In agreement with this statement, and based on the data described here, it has been described that young ewes display estrous within the initial 18 days of breeding season onset. The estrous dispersion in biostimulation programs is normally due to female cyclicity, a physiological condition that lowers the sensibility to estradiol negative feedback response, but are still responsible to the presence of males

Influence of male-to-female ratio and climatic conditions on the reproductive performance of Anglo Nubian goats

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&gt;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&gt;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