LH and FSH concentration and follicular development in Nellore heifers submitted to fixed-time artificial insemination protocols with different progesterone concentrations

Cipriano, Rafael Silva; Carvalho, Brenna; Marangoni, Natalia; Nogueira, Guilherme de Paula

doi:10.1016/j.anireprosci.2011.06.002

Cited by 20 publications

(4 citation statements)

References 31 publications

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“…Em fêmeas da raça Holandesa, há relatos de valores entre 0,5 ng/mL a 1,5 ng/mL (GINTHER et al, 1999;KULICK et al, 1999;GINTHER, 2000;. Em fêmeas da raça Nelore há relatos entre 0,5 a 1,0 ng/mL após inserção de dispositivo de P4 (CIPRIANO et al, 2011).…”

Section: Divergência Folicularunclassified

Resposta ovariana, endócrina e molecular de novilhas taurinas e zebuínas submetidas a diferentes níveis nutricionais de ingestão de matéria seca

Batista¹

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Section: Divergência Folicularunclassified

Resposta ovariana, endócrina e molecular de novilhas taurinas e zebuínas submetidas a diferentes níveis nutricionais de ingestão de matéria seca

Batista¹

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“…Esta redução pode ser alcançada por meio da administração estratégica de PGF 2α antes da retirada do iP4, como previamente descrito para vacas leiteiras (PEREIRA et al, 2013a), e em fêmeas de corte (CARVALHO et al, 2008;DADARWAL et al, 2013;MANTOVANI et al, 2010;PERES et al, 2009). A luteólise precoce reduz as concentrações circulantes de P4 durante o protocolo de sincronização e favorece o aumento da freqüência de LH (ADAMS et al, 2008;CIPRIANO et al, 2011), permitindo maior crescimento do folículo pré-ovulatório (CARVALHO et al, 2008) e, conseqüentemente, o aumento na probabilidade de prenhez (DADARWAL et al, 2013;PEREIRA et al, 2013a;PERES et al, 2009). Esta estratégia certamente poderia ser avaliada em búfalas leiteiras cíclicas submetidas a protocolos de IATF à base de P4/E2 durante a ERF.…”

Section: Relação Entre a Resposta Ao Protocolo De Sincronização E A Eunclassified

Eficiência reprodutiva de búfalas leiteiras submetidas a protocolos de IATF à base de P4/E2 e eCG durante as estações reprodutivas favorável e desfavorável

Monteiro¹

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AGRADECIMENTOS À Deus, pelo dom da vida, pela saúde, pelas graças alcançadas, pelas pessoas boas que conheci, pelo que aprendi, pela segurança após tantos quilômetros rodados sem maiores problemas... À minha esposa, por tudo! Obrigado pelo amor, carinho, doçura e zelo... por todos os momentos certos de ouvir e falar... Sua sensibilidade e inteligência me fazem querer ser uma pessoa melhor a cada dia. Te amo! Aos meus pais, José Henrique Monteiro e Carmen Laura Moura Monteiro, pelo amor incondicional e por todo o esforço que fizeram pra que eu pudesse chegar até aqui. À minha família, em especial aos meus irmãos Henrique e Lucas, minha afilhada Ana Laura e minha sobrinha Ágatha, pelo carinho que ajuda a me manter firme, mesmo à distância. Ao amigo Celso Scatena, por ser meu grande incentivador e acreditar em mim, mais do que eu mesmo... Obrigado por acolher este estrangeiro, agora afilhado, como parte da sua família! Ao Prof e amigo Rinaldo Batista Viana, pela confiança, atenção e apoio, desde a graduação até hoje. Obrigado por todos os ensinamentos e lições! Ao Prof. Enrico Ortolani, pelas conversas, histórias e pelos sábios conselhos. Obrigado pelo exemplo de profissionalismo e entusiasmo! Ao Prof. Pietro Baruselli, pelo exemplo de profissionalismo e trabalho. Obrigado pela orientação do doutorado, pela confiança investida e pela oportunidade de aprender. Ao Dr. Nelcio Carvalho, pela disponibilidade de sempre e por ser um exemplo de profissionalismo e retidão. Obrigado pela paciência e pela ajuda durante toda a pós-graduação (mestrado e doutorado) e nos experimentos feitos no Vale do Ribeira. Ao amigo Dr. Manoel Sá Filho, pela "co-orientação". Obrigado pelas conversas, reflexões, risadas e por me ajudar e incentivar a ser um profissional melhor.

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“…Strategies were designed to reduce endogenous P 4 production or limit exogenous P 4 administration during treatment with a short-term progestin-based estrus synchronization protocol in an effort to improve pregnancy outcomes in Bos indicusinfluenced females exposed for AI (Carvalho et al, 2008;Peres et al, 2009;Mantovani et al, 2010;Cipriano et al, 2011;Williams et al, 2012). Carvalho et al (2008) noted that the addition of PG at treatment onset reduced serum P 4 concentrations and increased dominant follicle size and ovulation rate of Bos indicus and Bos indicus-influenced heifers.…”

Section: Indicus-influenced Beef Heifersmentioning

confidence: 99%

Considerations for reproductive management of bos indicus-influenced beef heifers

Locke¹

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The Bos indicus species of beef cattle presents a number of unique reproductive challenges, especially with regard to those that influence reproductive efficiency including timely attainment of puberty, response to certain pharmaceutical drugs used to control estrus and ovulation, and response to physiological stressors. Cattle of this biological type comprise a substantial percentage of the beef cattle population in southern regions of the United States because of their ability to withstand high ambient temperatures and relative humidity. Additionally, Bos indicus cattle are regarded to exhibit increased parasite and disease resistance, resulting in improved production in subtropical climates as compared to Bos taurus cattle in those same regions. Research utilizing composite breeds of Bos taurus and Bos indicus beef heifers has been limited in the United States, and adoption of reproductive technologies such as artificial insemination and estrus synchronization has been sluggish compared to Bos taurus cattle in other regions of the country. To help answer a number of questions about this biological type, an experiment was designed to evaluate reproductive performance of Bos indicus-influenced heifers (n = 1,456). Weights and reproductive tract scores (RTS; Scale 1-5) were obtained for heifers prior to assignment of one of five treatments: Non-synchronized + natural service (NS); melengestrol acetate + natural service (MGA + NS; 0.5 mg x animal-1 x d-1); 14-d controlled internal drug release + natural service (CIDR + NS; 1.38g progesterone); 14-d MGA-PG + fixed-time AI (FTAI); and 14-d CIDR-PG + FTAI. Heifers in the three NS treatments were exposed to fertile bulls for 65 d, beginning 10 d after progestin removal for CIDR + NS and MGA + NS groups. Heifers in FTAI treatments were administered PGF2[alpha] (PG; 25 mg, IM) 16 or 19 d following CIDR or MGA removal. Fixed-time AI was performed 66 and 72h after PG for CIDR-PG and MGA-PG treatments, respectively. Gonadotropin-releasing hormone (GnRH; 100[mu]g, i.m.) was administered at FTAI. Estrus detection aids were applied at PG for heifers in FTAI treatments and evaluated at AI. Heifers in FTAI treatments were exposed to fertile bulls 12 d following FTAI. Blood samples were collected and ovarian ultrasounds performed at PG administration and FTAI to compare serum concentrations of estradiol and progesterone and to evaluate follicular dynamics among a subset of heifers assigned to FTAI treatments. Pregnancy status was determined at the end of a 65-d breeding period. Data were analyzed using PROC FREQ and GLIMMIX procedures of SAS. Mean concentrations of estradiol at AI differed between MGA- versus CIDR-treated heifers (P = 0.04; 8.2 versus 6.6 pg/ml), however estrous response after PG (52% versus 53%) and pregnancy rates after FTAI (40%) did not differ between MGA- and CIDR-PG treatments, respectively. Across all treatments, pregnancy rates were compared on 21, 30 and 60 d of the breeding period based on pubertal status (prepubertal RTS = 1 and 2; peripubertal RTS = 3; pubertal RTS = 4 and 5). Pregnancy rates differed at each time point based on pretreatment pubertal status (P [less than or equal to] 0.02) and weight (P [less than or equal to] 0.05). No differences were apparent with regard to progestin type at any time point, although higher pregnancy rates (P [less than or equal to] 0.004) were observed among NS treatments than FTAI followed by NS exposure at Days 30 and 60. This experiment is the largest comprehensive field trial conducted in the United States and reported in the literature involving Bos indicus-influenced beef heifers utilizing estrus synchronization prior to natural service or FTAI. This study reinforced results from previous studies, however raises a number of questions yet to be answered for heifers of this biological type. These data should be used as a basis for improvements in reproductive management of Bos indicus-influenced beef heifers prior to their first breeding season, and creates a number of possibilities for future research trials that build upon results reported in this thesis. Selection, management, and post-weaning to pre-breeding development of Bos indicus-influenced replacement beef heifers should involve the cooperative efforts of beef producers, veterinarians, and research scientists to further investigate methods to improve reproductive efficiency and genetic merit of these herds.

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LH and FSH concentration and follicular development in Nellore heifers submitted to fixed-time artificial insemination protocols with different progesterone concentrations

Cited by 20 publications

References 31 publications

Resposta ovariana, endócrina e molecular de novilhas taurinas e zebuínas submetidas a diferentes níveis nutricionais de ingestão de matéria seca

Resposta ovariana, endócrina e molecular de novilhas taurinas e zebuínas submetidas a diferentes níveis nutricionais de ingestão de matéria seca

Eficiência reprodutiva de búfalas leiteiras submetidas a protocolos de IATF à base de P4/E2 e eCG durante as estações reprodutivas favorável e desfavorável

Considerations for reproductive management of bos indicus-influenced beef heifers

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