Navegando por Assunto "Ciclo estral"

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Acesso aberto (Open Access)
Influence of gender and estrous cycle in the forced swim test in rats
(2008-12) GOUVEIA JUNIOR, Amauri; AFONSECA, Taciana Lucas; OLIVEIRA, Caio Maximino de; DOMINGUEZ, Roberto; CARVALHO, Silvio Morato de
The present work aimed at studying the influence of the estrous cycle in the forced swim test, an animal model of depression. For this, 44 male and female Wistar rats were divided into five groups according to the hormonal state in the first day of the study: metaestrus (N = 12), diestrus (N = 8), proestrus (N = 7), estrous (N = 6) and males (N = 11). They were housed in groups of five, with water and food ad libitum under a 12/12 h light/dark cycle. Females were screened daily for the estrous cycle. The animals were subjected to two swimming sessions in a glass cylinder with water up to 15 cm at 28±2º C. The data of the first five minutes of a 15-min first session were compared to those of a 5-min second session 24 h later. The results indicate that the latency to the first immobility was substantially reduced in the second session and was longer for females in diestrus and proestrus in the first session. The results also indicate that females in diestrus and proestrus exhibited less immobility than males in the first session; females in diestrus also exhibited less immobility than females in metaestrus. Females in metaestrus and diestrus, as well as males, did not present the decrease in total immobility times in the second session. The present results are analyzed in terms of differential effects of progesterone and estrogen on a learning component and an affective component.
Acesso aberto (Open Access)
The stimulatory effect of male agouti (Dasyprocta prymnolopha) on the onset of female puberty
(Instituto Nacional de Pesquisas da Amazônia, 2009) GUIMARÃES, Diva Anelie de Araújo; RAMOS, Rosemar Silva Luz; GARCIA, Gary Wayne; OHASHI, Otávio Mitio
The objective of this research was to analyze female agouti puberty. We did not observe the onset of puberty when the females were raised without males. When an adult male was put together with other adults and no cycling females, the onset of estrous cycle was observed after 10 to 60 days. When the young females were raised with a male, the onset of puberty was reached at 9 months. We concluded that the male agouti influences the onset of puberty in females, and that the dominant female, apparently, inhibits or delays the puberty of the other agouti females of the group. We suggest further studies be made concerning the social control of the reproduction of these animal.
Acesso aberto (Open Access)
Utilização de derivado progesterônico na sincronização do ciclo estral em fêmeas bovinas e bubalinas utilizadas na inseminação artificial em tempo fixo (IATF)
(Universidade Federal do Pará, 2012-05-03) NOGUERA GUEVARA, Samuel Enrique; VALE, William Gomes; http://lattes.cnpq.br/7486151987920142
The use of intravaginal devices with progestin as protocol for synchronization of oestrus cycle for fixed time artificial insemination (FTAI) through “Pregna Heat - E'' protocol were used in 219 cows and 169 female buffaloes, belonging to six commercial farms located in the Tachira, Carabobo, and Portuguesa states, in the Bolivarian Republic of Venezuela with the aim to evaluate conception rates (CR) in beef cows and crossbred dairy cattle, milk buffalo and crossbred dairy cows, and crossbred beef and milk heifer as well as in milk buffalo heifers as well as, with the objective to evaluate several variables that can interfere with CR such as body condition score (BCS), number of births, birth interval treatment, degree of difficulty for AI in the farms in the Farm 1, whereas in other farms were evaluated only the CR. The farms adopted a semi-intensive management, with a diet based primarily on forage species introduced in a artificial pasture used in a rotational grazing system with supplementation on the field depending on the needs of each production system. On a Farm 1, located just south of Lake Maracaibo, Tachira State, were synchronized and subjected to FTAI, 22 crossbred dairy cattle heifers, 20 crossbred dairy cows in the postpartum period (PPP) and 18 crossbred buffalo dairy heifers inseminated when 27.2%, 30% and 0 (zero) CR were obtained; moreover in 24 buffalo cows in the PPP synchronized in the outbreeding season (February 2011), it was obtained a CR of 20.8%. For the Farm 2, located in the southern state Tachira, FTAI was performed in favorable season (November 2010) in 78 crossbred dairy buffalo cows in PPP it was obtaining a CR of 34.6%. In the case of Farm 3, located in Urama county in Carabobo State, 49 crossbred buffalo cows in the PPP, were subjected to FTAI when it was obtaining a CR of 42.8%; in Farm 4, located in Santa Ana county, Tachira state, 85 crossbred dairy cattle cows were used for FTAI with 40% CR obtained, whereas in Farm 5, located in Portuguesa state, 23 crossbred beef cows of dual purpose in PPP were subjected to FTAI and it was found47.8% CR; finally in the Farm 6 located in Portuguesa State 20 crossbred beef heifers and 49 crossbred beef cow, were subjected to FTAI were found a CR of 55 and 48.8%, respectively. Also on Farm 1 were compared variables such as CR and number of births, when it was clear demonstrated that CR in pluriparous beef cows with more than four parturitions the results obtained where quite higher when confronted with cows with 2-3 parturitions and primiparous (40.5 ≥ 4 births, 28.5% 2-3 births and 0% for primiparous), (P = 0.4130); when compared with CR and parturition interval and the use of FTAI protocol “Pregna Heat - E'', the CR is higher in cows between 60 and 200 days postpartum, than cows with the interval of more than 200 days, which showed a very low CR (9.0%) (P = 0.0241); regarding to ECC no significant statistical difference important were observed among females with BSC=3 submitted to FTAI when confronted to animals with higher BCS. In the case of Farm 3, located in Urama county in Carabobo State, 49 crossbred buffalo cows in the PPP, were subjected to FTAI obtaining a CR of 42.8%, whereas in Farm 4, located in Santa Ana county, Táchira state, 85 crossbred dairy cattle cows was used for FTAI, 40% CR obtained, and in Farm 5, located in Portuguesa state, where 23 crossbred beef cows of dual purpose in PPP subjected to FTAI, it was found 47.8% CR; finally in the Farm 6 located in Portuguesa State 20 crossbred beef heifers and 49 crossbred beef cow, were subjected to FTAI when was found a CR of 55 and 48.8%, respectively. Still in the Farm 1 were compared variables such as CR and number of births, when it was clear demonstrated that CR in pluriparous beef cows with more than four parturitions where quite higher when confronted with cows with 2-3 parturitions and primiparous (40.5 ≥ 4 births, 28.5% 2-3 births and 0% for primiparous), (P = 0.4130); when compared with CR and parturition interval and the use of FTAI protocol “Heat-pregna - E'' the CR is higher in cows between 60 and 200 days postpartum, than cows with the interval of more than 200 days, which showed a very low CR (9.0%) (P = 0.0241); regarding to ECC no significant statistical difference important were observed among females with BSC=3 submitted to FTAI when confronted to animals with higher BCS showing a very poor (P=0.1632). With reference to the degree of difficulty for AI, animals with 0 degree of difficulty for AI, presenting the highest conception rates compared to the animals of 1 degree (44.4 and 31.2%), respectively. The use of the protocol “Pregna Heat - E” for FTAI, can be recommended for both in cattle and buffaloes with satisfactory results, however the CR in the case of crossbred Bos taurus or crossed animals with more blood of this sub-species probably due the fact that are raised in hot and humid regions as in the case of Farm 1, it has been observed a decrease in CR, which can be attributed to environmental factors interfering negatively on this variable. Likewise it is important to note that female buffaloes must be synchronized at the favorable season, not in outbreeding season, since throughout this time there was a decrease in CR in buffaloes submitted to FTAI, 20.8 vs 34.6% and 42.8%, respectively. In the case of the use of synchronization protocols such as “Pregna Heat – E” for FTAI use in buffalo heifers in the present study showed to be inadequate, with zero of CR, probably due anatomical and physiological concerned to the reproductive tract (very small cervix), thus buffalo heifers should not be included in FTAI programs with conventional techniques. The protocol ''Pregna Heat - E” can be used as a viable tool for oestrus cycle synchronization and FTAI in both cattle and buffaloes, and in the present study with the bovine CR being higher than in buffaloes (40.1 vs 31, 9%) (Fisher = 0.9624, P = 0.0212, P <0.05). That being so the use of “Pregna Heat - E” protocol as was used in the present study needs to be further studied in buffalo to obtain higher conception rates.