Previous sexual experience does not improve estrous behavior and ovulatory activity in seasonally anestrous goats in contact with photostimulated bucks

Sexually inexperienced ewes display lower estrous behavior during the first contact with rams. The objective of this study was to determine whether sexually inexperienced anestrous females display estrous behavior and ovulatory activity as the sexually experienced females, and with restricted sexual experience exposed to photo-stimulated bucks. Six bucks were rendered sexually active during the non-breeding season by exposure to artificially long days (16 h of light and 8 h of darkness per day) for 2.5 months. The first group, sexually experienced females (n = 10) had physical contact with two vasectomized bucks, and mating was allowed; the second group, with restricted sexual experience (n = 10) had contact with two vasectomized bucks through a wire-mesh fence and mating was prevented; the third group, sexually inexperienced females (n = 9) was totally isolated from bucks. At 14-month-old the females were exposed to photostimulated bucks for 15 days. The proportion of females that displayed estrous behavior, ovulations, short and normal ovulatory cycles, and pregnancy rates did not differ between sexually experienced, with restricted sexual experience, and sexually inexperienced (P > 0.05, in all variables). Similarly, the ovulation rate did not differ between the three groups of females (P > 0.05). However, the interval from introduction of the bucks to the first estrus was shorter in sexually inexperienced females (P < 0.05). Therefore, sexually inexperienced anestrous females displayed estrous behavior, ovulation, and pregnancy rate similar to those displayed by sexually experienced and with restricted sexual experience when exposed to photo-stimulated bucks through the male effect.(AU)

Previous sexual experience does not improve estrous behavior and ovulatory activity in seasonally anestrous goats in contact with photostimulated bucks

Sexually inexperienced ewes display lower estrous behavior during the first contact with rams. The objective of this study was to determine whether sexually inexperienced anestrous females display estrous behavior and ovulatory activity as the sexually experienced females, and with restricted sexual experience exposed to photo-stimulated bucks. Six bucks were rendered sexually active during the non-breeding season by exposure to artificially long days (16 h of light and 8 h of darkness per day) for 2.5 months. The first group, sexually experienced females (n = 10) had physical contact with two vasectomized bucks, and mating was allowed; the second group, with restricted sexual experience (n = 10) had contact with two vasectomized bucks through a wire-mesh fence and mating was prevented; the third group, sexually inexperienced females (n = 9) was totally isolated from bucks. At 14-month-old the females were exposed to photostimulated bucks for 15 days. The proportion of females that displayed estrous behavior, ovulations, short and normal ovulatory cycles, and pregnancy rates did not differ between sexually experienced, with restricted sexual experience, and sexually inexperienced (P > 0.05, in all variables). Similarly, the ovulation rate did not differ between the three groups of females (P > 0.05). However, the interval from introduction of the bucks to the first estrus was shorter in sexually inexperienced females (P < 0.05). Therefore, sexually inexperienced anestrous females displayed estrous behavior, ovulation, and pregnancy rate similar to those displayed by sexually experienced and with restricted sexual experience when exposed to photo-stimulated bucks through the male effect.

Influence of male on estrus behavior, estradiol and progesterone release and puberty onset on prepubertal Saanen goats / Influência do reprodutor sobre o comportamento de estro, liberação de estrógeno, progesterona e início da puberdade em cabras Saanen pré-puberes

The present study investigated the male effect on the estrus behaviors, estradiol and progesterone release in prepubertal Saanen goats. Twenty-nine female Saanen goats at 135 ± 10 days old with body weight of 22.8 ± 3.3 Kg were randomly assigned to three treatments: exposure to sexually active male (male treatment), exposure to androgenized females (androgenized female treatment), and prepubertal goats isolated from active male and androgenized females (control treatment). Sexual behaviors associated with estrus were recorded daily, and blood samples were taken weekly to determine estradiol and progesterone concentrations over 24 weeks. The experimental goats subjected to male or androgenized female had significantly higher frequency of estrus (mount acceptance) (P ≤ 0,02), progesterone (P ≤ 0,01), and estradiol (P ≤ 0,01) release than the control goats. Furthermore, goats exposed to a male showed estrus behavior two weeks earlier and maintained this estrus behavior for three weeks more than goats of both female and control treatments. Estrus was observed in 70 % of goats in male and female treatments during the breeding season versus 44 % of the control goats. Finally, significantly more goats subjected to male treatment (60 % of goats) showed progesterone concentrations higher than 1 ng mL-1 (which indicates the presence of a functional corpus luteum) compared to the female and control treatment (40 and 22 % of goats, respectively). These results shows that male treatment significantly increased the number of females showing estrus behavior, estradiol and progesterone release, and the number of animals with a functional corpus luteum, anticipating puberty for experimental goats, suggesting that the male effect could be used to anticipate the onset of puberty in goats.(AU)

O presente estudo investigou o efeito do macho sobre o comportamento do estro, liberação de estradiol e progesterona em cabritas Sannen pré-púberes. Vinte e nove cabritas com 135 ± 10 dias de idade e peso corporal de 22,8 ± 3,3 kg foram submetidas à três tratamentos: macho; fêmeas androgenizadas; controle (mantidas isoladas do efeito macho ou de fêmeas androgenizadas) . Os comportamentos sexuais foram registrados diariamente e as amostras de sangue foram colhidas semanalmente ao longo de 24 semanas. Os tratamentos macho e fêmea androgenizada aumentaram significativamente a ocorrência comportamental do estro (P ≤ 0,02), a concentração de progesterona (P ≤ 0,01) e estradiol (P ≤ 0,01) em comparação ao tratamento controle. As cabritas expostas ao efeito macho anteciparam o comportamento de estro em duas semanas, e o mantiveram por mais três semanas quando comparado às cabritas dos tratamentos fêmea androgenizada e controle. Apenas 44% das cabritas controle foram observadas em estro, sendo que 70% das cabritas submetidas aos tratamentos macho e fêmea androgenizada foram observadas em estro. Além disso, 60% das cabritas expostas ao efeito macho, 40 % das cabritas expostas ao efeito fêmea androgenizada e 22% das cabritas controle apresentaram concentrações de progesterona superiores a 1 ng mL-1, o que indica a presença de corpo lúteo funcional. De fato, o efeito macho aumentou significativamente o número de fêmeas em estro, a concentração de estradiol e progesterona, o número de fêmeas com corpo lúteo funcional, sugerindo que o efeito macho pode ser usado para antecipar o início da puberdade em cabritas Saanen.(AU)

Sexually inexperienced anestrous goats are able to exhibit sexual behaviours exposed to sexually active bucks

The aim of this study was to determine whether sexually inexperienced females could display proceptivity and receptivity behaviours as the experienced, in the first exposure to males. Three groups of females (n=9 each) were used: i) sexually inexperienced, ii) with complete sexual experience, and iii) with limited sexual experience. Three male goats were subjected to photoperiodic treatment for 2.5 months of long days to stimulate their sexual activity during the natural sexual rest (March-April). During anestrous season, females were exposed to photo-stimulated males. Sexual behaviours were recorded during the first three days post-introduction of the males into female groups, in two daily periods of 20 min each. Sexually inexperienced females and those with complete sexual experience showed higher tail wagging than those with limited sexual experience (P<0.001). Sexually inexperienced females displayed higher female-female sniffing and emission of urine than those groups with complete and limited sexual experience (P<0.001 and P<0.05, respectively). Females with limited sexual experience displayed higher female-female mounts than those groups inexperienced and with complete sexual experience (P<0.05). In addition, females with complete sexual experience displayed higher female-male sniffing than those groups inexperienced and with limited sexual experience (P<0.001). Receptivity behaviour did not differ between female groups (P>0.05). We concluded that sexually inexperienced anestrous females display proceptivity and receptivity behaviours as those sexually experienced exposed to photo-stimulated males.(AU)

Sexually inexperienced anestrous goats are able to exhibit sexual behaviours exposed to sexually active bucks

The aim of this study was to determine whether sexually inexperienced females could display proceptivity and receptivity behaviours as the experienced, in the first exposure to males. Three groups of females (n=9 each) were used: i) sexually inexperienced, ii) with complete sexual experience, and iii) with limited sexual experience. Three male goats were subjected to photoperiodic treatment for 2.5 months of long days to stimulate their sexual activity during the natural sexual rest (March-April). During anestrous season, females were exposed to photo-stimulated males. Sexual behaviours were recorded during the first three days post-introduction of the males into female groups, in two daily periods of 20 min each. Sexually inexperienced females and those with complete sexual experience showed higher tail wagging than those with limited sexual experience (P0.05). We concluded that sexually inexperienced anestrous females display proceptivity and receptivity behaviours as those sexually experienced exposed to photo-stimulated males.

Plasma melatonin and progesterone profiles of Suffolk and Romney Marsh ewes implanted with melatonin during anoestrus season at lower latitudes in Southern hemisphere

Background: The subcutaneous implants of melatonin are stimulatory and mimic the positive effects of short photoperiod on reproduction in small ruminants. This study investigated the daily plasma melatonin profiles in ewes treated with melatonin implants and kept under natural photoperiod in Southeastern Brazil. The plasma progesterone concentrations were also investigated before and after melatonin implantation. Materials, Methods & Results: Romney Marsh (n = 11) and Suffolk (n = 10) ewes, which had been isolated from rams for at least 2 months prior to the beginning of the trial, were randomly allocated in two groups based on melatonin implant treatment (with or without melatonin implant). For plasma melatonin concentration, 43 days after melatonin implantation and 3 days before the ram introduction blood samples were collected every 2 hours during 24 hours. For plasma progesterone concentrations, blood samples were collected every once to twice a week for 2 different periods: prior to melatonin implantation and 46 days after the melatonin implantation and at the same day of the introduction of rams. The hormonal concentrations were determined by the radioimmunoassay method (RIA). The data were analyzed according to MIXED procedure (SAS) as repeated measurements for random animal effects. The effect of melatonin treatment on plasma melatonin 24-h period varied according [...](AU)

Plasma melatonin and progesterone profiles of Suffolk and Romney Marsh ewes implanted with melatonin during anoestrus season at lower latitudes in Southern hemisphere

Background: The subcutaneous implants of melatonin are stimulatory and mimic the positive effects of short photoperiod on reproduction in small ruminants. This study investigated the daily plasma melatonin profiles in ewes treated with melatonin implants and kept under natural photoperiod in Southeastern Brazil. The plasma progesterone concentrations were also investigated before and after melatonin implantation. Materials, Methods & Results: Romney Marsh (n = 11) and Suffolk (n = 10) ewes, which had been isolated from rams for at least 2 months prior to the beginning of the trial, were randomly allocated in two groups based on melatonin implant treatment (with or without melatonin implant). For plasma melatonin concentration, 43 days after melatonin implantation and 3 days before the ram introduction blood samples were collected every 2 hours during 24 hours. For plasma progesterone concentrations, blood samples were collected every once to twice a week for 2 different periods: prior to melatonin implantation and 46 days after the melatonin implantation and at the same day of the introduction of rams. The hormonal concentrations were determined by the radioimmunoassay method (RIA). The data were analyzed according to MIXED procedure (SAS) as repeated measurements for random animal effects. The effect of melatonin treatment on plasma melatonin 24-h period varied according [...]

Sudden introduction of bucks during the late luteal phase of isolated female goats induces a biphasic change in progesterone concentrations

The aim was to determine the progesterone profile after the introduction of bucks during the advanced luteal phase of does. Fourteen does received vaginal sponges impregnated with 40 mg fluorogestone acetate for 12 days, and a luteolytic dose of a prostaglandin analogue (75 μg of D-cloprostenol) 2 days before sponge removal. Fifteen days after sponge withdrawal one buck was introduced in one of the pens (BE group; n = 6), while the female goats in the other pen remained as controls (CON group; n = 8). The buck was replaced every 24 h, alternating their presence until the end of the experiment. Serum progesterone levels were used to monitor ovarian activity. Progesterone concentration from day 14 to 20 varied with time (P < 0.0001), and there was an interaction between treatment and day (P = 0.02). While progesterone concentration increased from day 15 to day 16 in BE does (P = 0.01), there were no changes in CON does on those days (P = 0.2). On the other hand, progesterone concentrations decreased in BE does from day 18 to day 19 (P = 0.02), without changes in CON does (P = 0.6). Finally, there was a sharp decrease from day 19 to day 20 in both BE (P = 0.0009) and CON (P < 0.0001) does. Overall, our results demonstrated that the introduction of bucks during the late luteal phase of isolated does can induce changes in the progesterone pattern, showing an early increase followed by a pronounced withdrawn.(AU)

Sudden introduction of bucks during the late luteal phase of isolated female goats induces a biphasic change in progesterone concentrations

The aim was to determine the progesterone profile after the introduction of bucks during the advanced luteal phase of does. Fourteen does received vaginal sponges impregnated with 40 mg fluorogestone acetate for 12 days, and a luteolytic dose of a prostaglandin analogue (75 μg of D-cloprostenol) 2 days before sponge removal. Fifteen days after sponge withdrawal one buck was introduced in one of the pens (BE group; n = 6), while the female goats in the other pen remained as controls (CON group; n = 8). The buck was replaced every 24 h, alternating their presence until the end of the experiment. Serum progesterone levels were used to monitor ovarian activity. Progesterone concentration from day 14 to 20 varied with time (P < 0.0001), and there was an interaction between treatment and day (P = 0.02). While progesterone concentration increased from day 15 to day 16 in BE does (P = 0.01), there were no changes in CON does on those days (P = 0.2). On the other hand, progesterone concentrations decreased in BE does from day 18 to day 19 (P = 0.02), without changes in CON does (P = 0.6). Finally, there was a sharp decrease from day 19 to day 20 in both BE (P = 0.0009) and CON (P < 0.0001) does. Overall, our results demonstrated that the introduction of bucks during the late luteal phase of isolated does can induce changes in the progesterone pattern, showing an early increase followed by a pronounced withdrawn.

Bioestimulação pelo efeito macho / Biostimulation by male effect

The male effect is a simple technique which aims the induction of estrus and ovulation, which is the reintroduction of male to a female group previously separated. This interaction leads to an increase in LH pulse followed by ovulation. One of the strategies for estrus induction is exposure of females to males. In all species there are communication strategies, many of them involving the use of chemoreceptor organs that enable the perception of pheromones, and these mediators in the interaction intra species related to recognition for mating. The synchronization of estrus by the male effect is an important step in the reproductive management of herds, since the advantages indicated by several authors reflect directly on reducing costs, avoid undesirable immune response by the use of chorionic gonadotropin, decreases hormone residues in treated females thus complying with ecological principles and sustainable production.

O efeito macho é uma técnica simples que objetiva a indução do estro e da ovulação, e consiste na reintrodução de machos a um grupo de fêmeas previamente separadas. Esta interação induz a um aumento dos pulsos de LH seguido da ovulação. Uma das estratégias para indução do estro é a exposição das fêmeas a machos. Em todas as espécies existem estratégias de comunicação, muitas delas envolvendo o uso de órgãos quimiorreceptores que possibilitam a percepção de feromônios, sendo estes mediadores na interação intraespécie relacionada ao reconhecimento para o acasalamento. A sincronização do estro de fêmeas pelo efeito macho constitui importante medida no manejo reprodutivo de rebanhos, uma vez que as vantagens indicadas por diversos autores refletem diretamente na redução de custos, evita resposta imunológica indesejável pelo uso das gonadotrofinas coriônicas, diminui resíduos hormonais nas fêmeas tratadas, cumprindo assim com preceitos ecológicos e de produção sustentável.

Bioestimulação pelo efeito macho / Biostimulation by male effect

The male effect is a simple technique which aims the induction of estrus and ovulation, which is the reintroduction of male to a female group previously separated. This interaction leads to an increase in LH pulse followed by ovulation. One of the strategies for estrus induction is exposure of females to males. In all species there are communication strategies, many of them involving the use of chemoreceptor organs that enable the perception of pheromones, and these mediators in the interaction intra species related to recognition for mating. The synchronization of estrus by the male effect is an important step in the reproductive management of herds, since the advantages indicated by several authors reflect directly on reducing costs, avoid undesirable immune response by the use of chorionic gonadotropin, decreases hormone residues in treated females thus complying with ecological principles and sustainable production.(AU)

O efeito macho é uma técnica simples que objetiva a indução do estro e da ovulação, e consiste na reintrodução de machos a um grupo de fêmeas previamente separadas. Esta interação induz a um aumento dos pulsos de LH seguido da ovulação. Uma das estratégias para indução do estro é a exposição das fêmeas a machos. Em todas as espécies existem estratégias de comunicação, muitas delas envolvendo o uso de órgãos quimiorreceptores que possibilitam a percepção de feromônios, sendo estes mediadores na interação intraespécie relacionada ao reconhecimento para o acasalamento. A sincronização do estro de fêmeas pelo efeito macho constitui importante medida no manejo reprodutivo de rebanhos, uma vez que as vantagens indicadas por diversos autores refletem diretamente na redução de custos, evita resposta imunológica indesejável pelo uso das gonadotrofinas coriônicas, diminui resíduos hormonais nas fêmeas tratadas, cumprindo assim com preceitos ecológicos e de produção sustentável.(AU)

Organic and conventional management in a Parda Alpina dairy goat production system in northeastern Brazil / Manejo orgânico e convencional do sistema de produção de cabras leiteiras Parda Alpina no Nordeste do Brasil

In this study, we compared organic and conventional management in a dairy goat production system in Angicos, Rio Grande do Norte, Northeastern Brazil. Twenty-six Parda Alpina dairy goats were used: 13 in organic management (OM) and 13 in conventional management (CM). The experimental design was completely randomized with two treatments and 13 repetitions. OM practices included estrus synchronization with the male effect, an herbal-based treatment against endoparasitoses (an extract of lemon [Citrus limonum] and garlic [Allium sativum]) and the control of mastitis using the Embrapa Kit for manual milking with a rosemary pepper (Lippia sidoides) tincture. CM animals received synthetic hormones (Promone®, Prolise®, and Novormon®) for synchronization of estrus, ivermectin for endoparasitoses, and iodized alcohol for mastitis prevention aided by the Embrapa Kit for manual milking. No significant differences were observed between the management types in the pregnancy rate, FEC, FAMACHA© (Faffa Malan Chart) scores, physico-chemical composition of the milk, or somatic cell count (SCC). Both OM and MC had pregnancy rates of 61.54%. The mean values of the egg counts observed in the OM and CM were 24 and 35 eggs g-1, respectively. The FAMACHA© scores were 1 or 2 and 2, 3, or 4 in OM and CM, respectively. The goats had average weights in OM of 48.53 kg and in CM of 55.92 kg. Milk production, fat, protein, lactose, total solids, and nonfat solids in OM (0.971 kg/day, 2,210, 2,322, 3,306, 7,866, 5,566, respectively) were slightly higher than those in CM (0.946 kg/day, 1,812, 1,812, 2.868, 6.74, 4.928). OM (904,860 cells/mL) and CM (1.02052 million cells/mL) SCC values were similar, with the OM within the acceptable range for milk goats.[...](AU)

Objetivou-se neste trabalho comparar o manejo orgânico e convencional de um sistema de produção de caprinos leiteiros em Angicos, Rio Grande do Norte, Nordeste do Brasil. Foram utilizadas 26 cabras da Raça Parda Alpina em lactação, sendo 13 em manejo orgânico (MO) e 13 em manejo convencional (MC). O delineamento experimental foi o inteiramente casualizado, com dois tratamentos e 13 repetições. Os animais do MO foram submetidos à sincronização de estro com efeito macho, tratamento à base de fitoterápicos contra endoparasitoses (Extrato de limão (Citrus Limonium) e alho (Allium sativum), e no controle de mastite usando o Kit Embrapa de ordenha manual à base de alecrim pimenta (Lippia sidoides). No MC os animais receberam hormônios sintéticos (Promone-e®, Prólise® e Novormon®) para a sincronização do estro, Ivermectina para endoparasitoses e álcool iodado para prevenção de mastite auxiliado pelo Kit Embrapa de ordenha manual. Não houve diferença significativa para os resultados de porcentagem de prenhezes, OPG, escores do FAMACHA©, composição físico-química do leite e Contagem de Células Somáticas (CCS) nos dois tipos de manejo. No MO e MC as cabras apresentaram médias de percentagem de prenhezes positiva de 61,54% em ambos os sistemas. Os valores médios da contagem de ovos observados nos MO e MC foram de 24 e 35 de OPG, respectivamente. Pelo método FAMACHA© observou-se escores de 1 e 2; 2, 3 e 4 no MO e MC respectivamente. As cabras apresentaram pesos médios no MO (48,53 Kg) e MC (55,92 Kg). A produção de leite, gordura, proteína, lactose, extrato seco total e extrato seco desengordurado no MO (0,971kg/dia; 2,210; 2,322; 3,306; 7,866; 5,566) foram ligeiramente superiores aos valores do MC (0,946 kg/dia 1,812; 1,812; 2,868; 6,74; 4,928). Para a CCS o MO (904.860 cel/mL) e MC (1.020.520 cel/mL) apresentaram valores próximos, estando o MO dentro dos valores aceitáveis para leite de cabra.[...](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.

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)

Desenvolvimento reprodutivo de cabritas Saanen submetidas ao efeito macho no período peri-púbere

O efeito macho, principal fator social associado a reprodução, é muito usado na estimulação da atividade cíclica durante o anestro em espécies sazonais. Há também referência da sua influência sobre a puberdade podendo acelerar idade em que esta ocorre, particularmente em suínos e ratos. O presente projeto tinha como objetivo estudar o efeito da exposição de cabritas Saanen peri-púbere ao efeito macho sobre o desenvolvimento reprodutivo em particular no padrão de comportamentos associados ao cio, perfil de estrógeno e progesterona e na expressão do gene kiss1, receptores de kisspeptinas, estrógeno e progesterona no hipotálamo, hipófise e ovário. No experimento 1, 29 cabritas Saanen entre 142,72 ± 10,61 dias idade e 24,9 ± 4,26 kg de peso, foram distribuídas aleatoriamente entre três tratamentos: 1) exposição ao macho sexualmente ativo (grupo macho); 2) exposição a fêmea androgenizada (grupo fêmea) e; 3) controle (grupo controle). Observação diária de comportamentos associados ao cio e coletas de sangue para determinação dos níveis de estradiol e progesterona foram realizadas de maio a outubro. Os grupos macho e fêmea registraram mais comportamentos associados ao cio que os animais do grupo controle. A interação social teve efeito sobre a posição da cauda, aspecto da vulva, vocalizar e deixar montar. Houve diferenças significativas entre os grupos nas médias de estradiol. O grupo macho registrou médias de estradiol superiores ao grupo controle. Houve interação grupo*coleta no perfil de progesterona. Os grupos macho e fêmea registraram médias significativamente mais altas comparado ao grupo controle durante o experimento. No experimento 2, 16 cabritas Saanen com 138,37 ± 3,59 dias de idade e 22,75 ± 2,43 kg de peso foram distribuídas aleatoriamente entre dois tratamentos: 1) exposição ao macho sexualmente ativo (grupo macho) e; 2) controle (grupo controle). Foram realizadas observações diárias de comportamentos associados ao cio, coletas de sangue duas vezes por semana para determinação dos níveis de estradiol e progesterona e coleta de tecidos hipotalâmico, hipofisário e ovárico (antes e 60 dias depois da exposição ao macho) para determinar a expressão do gene kiss1, receptores de kisspeptinas, estradiol e progesterona. Não houve diferença entre grupos no comportamento deixar montar. O grupo macho registrou maior frequência de comportamento montar, contudo o grupo fêmea registrou maior frequência na alteração do aspecto da vulva, deslocar e interagir. Foram encontradas diferenças significativas entre grupos para perfil de progesterona, a expressão de kiss1, kiss1R, ER, ER e PR no hipotálamo, expressão de ER na hipófise e ER, ER e PR no ovário. Em conjunto, os resultados encontrados indicam que o nível de expressão de mRNA das moléculas estudas varia entre animais sexualmente imaturos e maduros e é influenciado pela fase de desenvolvimento folicular em animais pós-pubere.

Male effect, major social factor associated to reproduction, is mainly used to stimulate cyclic activity during anestrus period in seasonal breeder species. There are references to the influence of male effect on puberty where it can advance the age at which puberty occurs. The present project aimed to study the effect of exposure of peri-pubertal Saanen goat kids to the male effect on Sexual maturation, in particular, estrus associated behaviors, estrogen and progesterone profiles and expression of kiss1 gene, kisspeptin receptor, estradiol receptor and progesterone receptor in the hypothalamus, pituitary and ovary. In the first experiment, 29 Saanen kids with 142,72 ± 10,61 days of age and 24,9 ± 4,26 kg weight were randomly assigned to three treatments namely: 1) exposure to active male (male group), 2) exposure to androgenized female (female group) and 3) control (control group). Daily observation to record estrus associated behaviors and weekly blood collections for estradiol and progesterone levels determination were made from May to October. Animals subjected to the male effect (active male or female) registered more estrus associated behavior than the control group. Social interaction had effect on tail position, vulva aspect, vocalization and mounts acceptance. There were significant differences among groups on estradiol levels. The male group registered higher estradiol concentrations than the control group. There was interaction group*collection on progesterone concentrations. Animals from the female group had significantly higher progesterone means in most collections than the other groups. The male group had statistically higher progesterone averages than the control group. In the second experiment, 16 Saanen kids at age of 138,37 ± 3,59 days and 22,75 ± 2,43 kg weight were randomly assigned to exposure to 1) active male (male group) and 2) control (control group). Animals were twice daily observed for 1 h: 30 minutes for registration of estrus associated behavior and twice weekly blood samples were collected for estradiol and progesterone assessment.Hypothalamic, pituitary and ovarian tissue samples were obtained before and sixty days after exposure to male effect for assessment of expression levels for kiss1 gene, kisspeptin receptor (kiss1R), estradiol receptor (ER) and progesterone receptor (PR). There were no differences among groups for standing mount. The male group registered higher frequency for mounting, however, the control group registered higher frequency for swelling vulva, restlessness and interacting. Progesterone concentrations and mRNA expression of kiss1, kiss1R, ERs and PR in the hypothalamus, ER in the pituitary, ER, ER and PR in the ovaries were significantly different among groups. The results suggest that mRNA expression of studied molecules differs between sexually immature and mature animals and the mRNA expression is influenced by the cyclic stage in post-pubertal animals.

Short-term exposure of high body weight heifers to testosterone-treated steers increases pregnancy rate during a late autumn-early winter natural service

Exposure to bulls seem to stimulate cyclic activity in postparitum beef cows, hasten puberty and increase pregnancy rate in heifers. The aim of this experiment was to determine if short-term exposure of pubertal beef heifers to testosterone-treated steers prior to late autumn-early winter bull breeding would increase pregnancy rates. An . Pregnancy was determined on Days 60 and 75. On Day 60, no differences were observed between groups in the frequency of pregnant heifers (18.2 vs 7.7% pregnant). On Day 75, more heifers in the biostimulation group that had an initial body weight ≥310 kg were pregnant (61.1 vs 32.4%, for stimulated and non-stimulated heifers respectively, P = 0.016), whereas there were no significant differences in heifers with lower initial body weight (17.9 vs 30.3% pregnant, for stimulated and non-stimulated heifers respectively). In conclusion, pregnancy rate was increased in high body weight heifers during late autumn-early winter natural service following pre-breeding exposure of the heifers to testosterone-treated steers.(AU)

Short-term exposure of high body weight heifers to testosterone-treated steers increases pregnancy rate during a late autumn-early winter natural service

Exposure to bulls seem to stimulate cyclic activity in postparitum beef cows, hasten puberty and increase pregnancy rate in heifers. The aim of this experiment was to determine if short-term exposure of pubertal beef heifers to testosterone-treated steers prior to late autumn-early winter bull breeding would increase pregnancy rates. An . Pregnancy was determined on Days 60 and 75. On Day 60, no differences were observed between groups in the frequency of pregnant heifers (18.2 vs 7.7% pregnant). On Day 75, more heifers in the biostimulation group that had an initial body weight ≥310 kg were pregnant (61.1 vs 32.4%, for stimulated and non-stimulated heifers respectively, P = 0.016), whereas there were no significant differences in heifers with lower initial body weight (17.9 vs 30.3% pregnant, for stimulated and non-stimulated heifers respectively). In conclusion, pregnancy rate was increased in high body weight heifers during late autumn-early winter natural service following pre-breeding exposure of the heifers to testosterone-treated steers.

Organic and conventional management in a Parda Alpina dairy goat production system in northeastern Brazil / Manejo orgânico e convencional do sistema de produção de cabras leiteiras Parda Alpina no Nordeste do Brasil

In this study, we compared organic and conventional management in a dairy goat production system in Angicos, Rio Grande do Norte, Northeastern Brazil. Twenty-six Parda Alpina dairy goats were used: 13 in organic management (OM) and 13 in conventional management (CM). The experimental design was completely randomized with two treatments and 13 repetitions. OM practices included estrus synchronization with the male effect, an herbal-based treatment against endoparasitoses (an extract of lemon [Citrus limonum] and garlic [Allium sativum]) and the control of mastitis using the Embrapa Kit for manual milking with a rosemary pepper (Lippia sidoides) tincture. CM animals received synthetic hormones (Promone®, Prolise®, and Novormon®) for synchronization of estrus, ivermectin for endoparasitoses, and iodized alcohol for mastitis prevention aided by the Embrapa Kit for manual milking. No significant differences were observed between the management types in the pregnancy rate, FEC, FAMACHA© (Faffa Malan Chart) scores, physico-chemical composition of the milk, or somatic cell count (SCC). Both OM and MC had pregnancy rates of 61.54%. The mean values of the egg counts observed in the OM and CM were 24 and 35 eggs g-1, respectively. The FAMACHA© scores were 1 or 2 and 2, 3, or 4 in OM and CM, respectively. The goats had average weights in OM of 48.53 kg and in CM of 55.92 kg. Milk production, fat, protein, lactose, total solids, and nonfat solids in OM (0.971 kg/day, 2,210, 2,322, 3,306, 7,866, 5,566, respectively) were slightly higher than those in CM (0.946 kg/day, 1,812, 1,812, 2.868, 6.74, 4.928). OM (904,860 cells/mL) and CM (1.02052 million cells/mL) SCC values were similar, with the OM within the acceptable range for milk goats.[...]

Objetivou-se neste trabalho comparar o manejo orgânico e convencional de um sistema de produção de caprinos leiteiros em Angicos, Rio Grande do Norte, Nordeste do Brasil. Foram utilizadas 26 cabras da Raça Parda Alpina em lactação, sendo 13 em manejo orgânico (MO) e 13 em manejo convencional (MC). O delineamento experimental foi o inteiramente casualizado, com dois tratamentos e 13 repetições. Os animais do MO foram submetidos à sincronização de estro com efeito macho, tratamento à base de fitoterápicos contra endoparasitoses (Extrato de limão (Citrus Limonium) e alho (Allium sativum), e no controle de mastite usando o Kit Embrapa de ordenha manual à base de alecrim pimenta (Lippia sidoides). No MC os animais receberam hormônios sintéticos (Promone-e®, Prólise® e Novormon®) para a sincronização do estro, Ivermectina para endoparasitoses e álcool iodado para prevenção de mastite auxiliado pelo Kit Embrapa de ordenha manual. Não houve diferença significativa para os resultados de porcentagem de prenhezes, OPG, escores do FAMACHA©, composição físico-química do leite e Contagem de Células Somáticas (CCS) nos dois tipos de manejo. No MO e MC as cabras apresentaram médias de percentagem de prenhezes positiva de 61,54% em ambos os sistemas. Os valores médios da contagem de ovos observados nos MO e MC foram de 24 e 35 de OPG, respectivamente. Pelo método FAMACHA© observou-se escores de 1 e 2; 2, 3 e 4 no MO e MC respectivamente. As cabras apresentaram pesos médios no MO (48,53 Kg) e MC (55,92 Kg). A produção de leite, gordura, proteína, lactose, extrato seco total e extrato seco desengordurado no MO (0,971kg/dia; 2,210; 2,322; 3,306; 7,866; 5,566) foram ligeiramente superiores aos valores do MC (0,946 kg/dia 1,812; 1,812; 2,868; 6,74; 4,928). Para a CCS o MO (904.860 cel/mL) e MC (1.020.520 cel/mL) apresentaram valores próximos, estando o MO dentro dos valores aceitáveis para leite de cabra.[...]