The study was aimed to test the effect of the separation distance between males and females during the preconditioning period on the reproductive performance of Santa Inês ewes after the male effect. Santa Inês ewes were kept at distances of 3000 m (T1), 3 m (T2), and 300 m (T3) from rams for 60 days before starting 45-day mating seasons during the dry period (DP) and rainy periods (RP). Mating events were observed daily at 6:00 h and 16:00 h by trained personnel for one hour intervals. Estrous were scored as synchronized when observed until day 5 after breeding season start. Pregnancy diagnosis was performed by ultrasonography. In the DP, the first estrous averaged at 15.45±10.36 (T1), 9.25±6.41 (T2) and 13.05±10.24 (T3) days and in RP was 8.73±5.84 (T1), 9.30±5.62 (T2) and 6.10±5.66 (T3) days. All females cycled during both DP and RP. Estrous synchronization occurred in 20% of the females during DP (T1: 30%, T2: 15%, and T3: 15%). In the RP, estrous synchronization occurred in 40% of all females (T1: 30%, T2: 35%, and T3: 45%). The pregnancy rates in DP and RP were T1: 85%, T2: 80%, and T3: 75%. The results show that the male effect can be obtained simply by avoiding physical contact between males and females throughout the year under tropical conditions.

The objective of this study was to test the €œmale 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.

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) . 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.Keywords: bioestimulation, goat, small ruminants. DESEMPENHO REPRODUTIVO USANDO DISTÂNCIAS DIFERENTES PARA O PRÉ-CONDICIONAMENTO DO EFEITO MACHO EM CAPRINOS DURANTE DOIS PERÍODOS CLIMÁTICOS DISTINTOSRESUMO: O objetivo do presente estudo foi determinar se a distância de isolamento entre machos e fêmeas avaliado durante dois períodos climáticos distintos afeta o desempenho reprodutivo de caprinos submetidos a uma estação de monta (EM) de 45 dias. Fêmeas Anglo Nubianas (n = 120) foram afastadas dos machos por distâncias de 2 m (T1), 300 m (T2) e 2000 m (T3) por 60 dias antes da EM de 45 dias sob diferentes condições climáticas [estação seca (ES, Fevereiro a Março) e estação chuvosa (EC, Setembro a Outubro)] em Sertânia, estado de Pernambuco, Brasil. Não houve efeito da distância de pré-condicionamento entre machos e fêmeas em nenhuma variável avaliada. No entanto, durante a ES, a média da primeira manifestação de estro variou (P>0,05) entre os grupos [7,13±4,49 (T1)

The aim of the present study was to identify the migration period of the genital tubercle and its later differentiation into external genital structures in fetuses derived from natural mating and fetuses from fresh, frozen and vitrified embryo transfer. A transrectal ultrasound with a double-frequency linear transducer (6.0 and 8.0 MHz) was used to monitor 123 goat fetuses, which were allocated to one of four groups: fetuses originating from controlled natural mating (G1, n = 32) and fetuses derived from fresh (G2, n = 34), frozen (G3, n = 30) and vitrified (G4, n = 27) embryo transfer. The transferable embryos were collected 7 days after mating by laparoscopy. Migration of the genital tubercle occurred significantly earlier (P < 0.05) in G1 than in G2, G3 and G4. The visualisation of the scrotum, prepuce and vulva occurred significantly earlier (P < 0.05) in G1 than in G2, G3 and G4. Our results show that fetal sexing is feasible after 55 days for fetuses from natural mating and after 60 days in fetuses from fresh and cryopreserved embryos. Thus, real-time ultrasonography is a reliable tool for fetal sex determination in goats after Day 50 of pregnancy, taking into account both the location of the genital tubercle and the identification of external genital structures.

The study was aimed to evaluate the effect of breeding season (BS) duration on goat reproduction during dry (DS) and rainy (RS) periods. Females were kept 300 m apart from bucks for 60 days. Females were randomly distributed among BS groups of 25 (BS25), 35 (BS35), and 45 (BS45) days during DS and RS. All females cycled, except during BS45 in DS (95%). The duration of BS did not affect estrous incidence during DS and RS. The percentage of females with two estrous was similar in RS (BS25: 30%, BS35: 35%, BS45: 35%) and DS (BS25: 25%, BS35: 30%, BS45: 25%). Three estrous were observed in BS35 and BS45 during RS (5%). First estrous (FE) and second estrous (SE) were detected from days in BS25 (FE: 1-21, SE: 7-21), BS35 (FE: 1-23, SE: 6-27), and BS45 (FE:1-23, SE: 9-20) during RS. During DS, estrous were detected within days BS25 (FE: 1-17, SE: 6-23), , and BS45 (FE: 2-21, SE: 6-21). Pregnancy rates were similar in RS (BS25: 90%, BS35: 95%, BS45: 95%) and DS (BS25: 75%, BS35: 80%, BS45: 75%). In conclusion, goat BS can be shorten despite weather without any effect on reproduction.